Chain Selection and Sizing for Mid Drive Applications

Discussions related to motors other than hub motors.
This includes R/C motors, botttom bracket, roller and geared drives.
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MitchJi   1 GW

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Chain Selection and Sizing for Mid Drive Applications

Post by MitchJi » Mar 08 2014 4:51pm

NOTE:

Posts from the Lightning Rod GNG thread have been relocated to this thread. Dedicated to the discussion of selecting the proper chain size for a given application.

Len*********************
spinningmagnets wrote:I believe that 72V X 30A = 2200W is very close to the max you can run through a derailleur with bicycle chain. Using more power is clearly possible, but wearing out the bicycle-grade chain and sprockets very fast, and sometimes breaking things is not a good system design. Nothing else on the market is close to what this kit will provide. The freewheeling bottom-bracket crankset is also another link in the power-limit. Since this motor can provide 2,200W all day without melting down, looking for a bigger motor is not needed for 2,200W.

Lukes Deathbike ran a single-speed left-side drive that used a #428 chain (and a large motor), that is the next step up. The GNG "Big Block" motor's stator has twice the width (and twice the copper mass) compared to the standard GNG motor, so I feel safe in suggesting that the Big Block should handle 60A well. That is not bicycle chain territory, and derailleurs are just not up to surviving that. The LightningRods jackshaft sprocket/pulley parts are reconfigurable for a variety of projects.
Maybe you mean multi-speed bicycle chain, rather single speed bicycle chain?

I rode two of Eric's (Green Machine) mid-hub ebikes. Both used the crossbreak configuration that avoided the BB. One used a crossbreak stlye modified Mac, driving an Alfine IGH, was set-up for 2.5kw:
Image

The other used an Astro 3215, driving an Rohloff IGH, was set-up for 5kw (the caption for the image states 3210 but I think he said the one I rode was a 3215):
Oh and here is one with an air cooled Astro 3210 running through a Rohloff 14 speed...47mph top speed.
Image

The weakest links were not the chain, but the Alfine, and possibly the Rohloff, although it hadn't caused any problems at that point.

The 2.5kw Mac, with the mid-drive reduction felt pretty powerful :D, but the 5kw Astro was a even more fun :mrgreen:.
Best Wishes!

Mitch


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Re: LightningRods mid drive kit

Post by Tench » Mar 14 2014 8:33am

I have put 3kw through a derailier system, I switched the 9 speed cassette for a 7 speed but with hind sight this was the wrong thing to do! it all worked fine except for the highest and lowest gear, the reason is the chain angle became too great with power trying to pull the chain onto the next inboard sprocket. If I did it again I would use a 10 speed cluster but remove the 2 top and 2 bottom sprockets. This would give me 6 very closely spaced sprockets and a massively reduced chain angle in the highest and lowest gears. The important factor is aligning the front chainwheel so that it is central to the sprockets you want to use, if it is dead inline with gear 3 remove 7,8,9 and 10 or change the bb to space the front chain ring where it needs to be to retain the gears you want to use.
Yes its a bit of faffing about but if you want to run a lot of power through a deralier system it will help with reliability and reduce wear.
I also retained the front changer although it was a single chain wheel as the changer acted as a guide to prevent the chain being pulled to the side by the power when using the extreme end gear ratios.
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Re: Chain Strength & Selection For Mid Drive Applications

Post by MitchJi » Apr 11 2014 2:59pm

Hi,
With the IGH the limit is only a mechanical rating of the internal gears, and is not "chain related" with a derailleur you have problems mostly while shifting, and for bad chainlines at the cluster's extremes...
derailleur chain chain is weaker (needs to be more flexible) and maybe the sprockets also.
MitchJi wrote:Need to consider that you need a lot more power to make up for not having use of the gears. Gary Goodrum ran at least 5000 watts through a Nexus three speed without any problems, he felt the three speed gave him the equivalent of twice the power. It may not have been that much, but you could see the bike jump each time he shifted gears on the video.
LightningRods wrote:Twice the power is what I have read in the literature of most EV conversion companies. I think this is more true when moving from a stop or negotiating hills. Once you are rolling fast enough to be in the range of high gear in a multiple gear setup, the more powerful direct drive rig will have an advantage. Just don't slow down. That's why you'll see a lot of direct drives in racing.
Same as a mid-drive vs a hub.
LightningRods wrote:It stands to reason that a three speed hub would be stronger than an 8 speed. Three gears is plenty for e-bike use. Was he using a hub that's still in production? I'm hesitant to recommend IGHs because I hear so many stories of them fragging.
3 speeds is enough for the motor, but if you want to assist with pedaling you need more speeds or you need to be able to maintain a cadence of 150-250.

He was using the Nexus 3 speed, that is still in production AFAIK. Here is a post from a different build:
http://endless-sphere.com/forums/viewto ... 41&#p79741
GGoodrum wrote:I'm sure the Nexus hubs can handle the power. There's a guy with a bike shop down in San Diego (Rusty Spokes, in Pacific Beach...) who custom builds chopper-style motor bikes, using Etek and Mars motors. He uses these same Nexus 3-speed hubs with these beasts, and they have worked flawlessly, even pumping 15 hp through them. Instead of chain, hoever, his bikes are belt driven, using regular toothless v-belts. There's a little bit of "slippage" when starting out, which is like a clutch. Works great, he says, and these things can hit close to 60 in just 2nd gear. Anyway, he's never had a single problem with any of the Nexus hubs.

-- Gary
Eric (greenmachines) used an alfine 11 speed with a 2,500 watt mid-drive without problems, but he blew up an alfine 8 or 11 with a similar bike with a 5kw astro. He used a Rohloff for that system, and the last time I talked to him he hadn't had any problems with it.

That said, even though an IGH drive can be set to handle more power than a derailleur drive they are not indestructible.
Best Wishes!

Mitch


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Re: Chain Strength & Selection For Mid Drive Applications

Post by spinningmagnets » Apr 11 2014 5:06pm

I've had a soft heart for IGHs since I was a kid, so I notice when someone posts about them. AJ broke a Nexus 3-speed that was advertised as a "heavy duty" cargo trike unit. However, he was fond of dumping high power into his system to get snappy acceleration. second gear is a 1:1 and is reported to be the strongest of the three gears (first gear is 30% under-drive, and third is 30% over-drive). If you want to use a 3-speed IGH, you should add some type of throttle snubbing, but I don't yet know which kind would be best. (if you moderate the throttle power with some type of gradual ramping, no wheelies).

There was an interesting tidbit posted recently when I went back to read RWPs eCortina builds (three versions). He broke his IGH, and went then to a cassette sprocket cluster on the rear wheel. This allowed him to pick and choose each sprocket and also how they were spaced out. He chose three very thick sprockets in the best available ratios, and spaced them so that he could use a heavy-duty BMX chain. This also required him to add spacers to the derailleur, to allow space for the wider chain. He used a trigger-shifter, and had to pull the trigger two times for each shift.

He hasn't broken any more chains or sprockets, and I'd like to copy that custom set-up some day to test it.

http://www.electricbike.com/custom-buil ... -ecortina/
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Re: Chain Strength & Selection For Mid Drive Applications

Post by turbo1889 » Apr 13 2014 6:30pm

As to hubs for a mid-drive where your running the power through the bikes gear train. To my understanding the strongest hub out there that can take the most power through a modern cassette gearing on the rear is the Chris King hubs because they have two drive ring with inside faces of teeth where ALL the teeth engage each other every time and the more torque is applied to the driver the tighter those ring teeth are pressed into each other. Also noise as all heck when freewheeling from what I've heard. Everything else kind of gets less strong down the line along the general rule that you get what you pay for. I'm probably going to go with a White Industries Mi6 free-hub on the build I'm working on right now (DIY non-lighteningRod non-GNG RC motor based mid-drive at 1.2Kw peak) but just haven't totally decided and pulled the trigger yet. Seems to be strong enough for my needs without being too pricy and comes in the 48h drilling I want plus its "Made in U.S.A. by small family company" which is something I do not ignore.

Another build I've got on the drawing board I'm going to have to have a custom hub built for (weight issues not power issues needs to be able to take 500+ lb cargo loading over rough terrain with zero maintenance probably going to be motorcycle wheel parts) and then I've got a spare Staton-Inc hub right now that isn't being used anymore that I want to do a build on using one of LighteningRods motors in a left-drive hill-climbing-helper-only gearing the motor way down so I can pedal faster then the motor can go on the flat but on hills I've got a strong boost. I like to pedal and sometimes all I need is help on the hills and this motor properly geared should be able to give me "Hercules As My Stoker" type hill climbing help geared down so that the the motors free running no load speed translates to about 15-mph road speed so I'll always climb hills faster then 10-mph and I can pedal only at my normal 15-20 mph pace on the flat under human power only with no temptation to use the motor on the flat because geared down that much it don't do nothing anyway on the flat so I can use a small light weight Li-Poly RC pack for power that easily fits in a small bike bag because I only use the motor to help on the hills so I don't need very many Ah just some small light weight RC packs with high C rating for those short few minutes long bursts when hill climbing.

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Re: Chain Strength & Selection For Mid Drive Applications

Post by spinningmagnets » Apr 14 2014 5:38pm

There are a lot of riders right now that are having a lot of fun off-road with a rear direct-drive hubmotor. A mid drive gives the motor the use of some gears, so the efficiency is much better than a hubbie.

The good news about a mid drive is that if you truly want to improve your systems efficiency at a specific 5-MPH in first gear, you can change out the sprockets, which would also have the negative effect of taking away some of your top-speed, but...at least you have the option (no cheap and easy range/speed/efficiency changes possible with a DD hub). A corollary effect is that when you lower the overall ratio of all the bikes gears, the entire system will run cooler.

It's possible to use a cassette rear wheel that has 9-speeds, but a 7-speed chain will be stronger, so...just limiting ourselves to 7-speeds, and then choosing a lower top gear of 25-MPH in 7th gear using 50V X 30A = 1500W...first gear will have some incredible climbing ability. Actual data to be posted as soon as possible...

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Re: Chain Strength & Selection For Mid Drive Applications

Post by Wishes » Apr 14 2014 7:37pm

As spinningmagnets said, with a mid drive motor, you can make any speed efficient, it is all about the gearing ratio you use. With the right ratio, you can have incredible torque even at the stock power level of 1200 watts. You just won't have much top speed.

And I highly suggest using a 7 speed cassette and chain instead of the 9 if you run with anything but stock power levels. They will last much longer.

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Re: Chain Strength & Selection For Mid Drive Applications

Post by turbo1889 » Apr 14 2014 8:43pm

Considering how critical I am of my own work it ain't like I'm going to get offended or anything if someone else is as well !!!

Actual real world data is always better then computer theoretical modeling.

I totally agree as well about almost anything being possible with enough gearing range. Problem is the guys that both want to go crazy motorcycle fast on the flat, climb any hill, not have to use too big of a motor or battery, and want a simple set-up with minimal gearing if any. Both fast and good hill climbing is possible with a not ridiculous size motor and battery if your willing to put the time and effort into a wide range multiple gearing system. It is also perfectly possible to keep it dirt simple with just a single speed for the motor left side drive single or double stage reduction and have either good hill climbing gearing low or good top speed gearing high with this motor. But you can't have both in this motor size if you want to run a simple no gear changing left drive.

I found a combination for another member who was asking that would both allow him to climb a 10% grade hill with this motor only running 30-Amps with a GVW of up to 350 pounds and also have a top speed of about 25-mph on the flat and not have to do any gear changing simple one ratio left side drive. BUT in order to accomplish that he had to run the motor at very high voltages off a 30s Li-Poly pack with a controller that could take that level of voltage and do a double stage reduction. Not fast enough for him on the flat and he didn't want to run more then 20s Li-Poly.

Everything is a balancing act and you never get to have it all.



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As to derailer chain systems I've had good luck running 8-speed spools in the rear on a decent free-hub at up to about 1.5-Kw (mechanical output) power. I wouldn't even consider to run 9 or 10 speed chain spools and derailers unless it was a 500-watt (mechanical output) or less system.

7 & 8 speed use the same full 3/32 traditional derailer chain its just the spool width is just a tiny bit wider for the 8-speed with just a tiny bit tighter spacing between the cogs so to squeeze in that one extra cog they both made the spool just a little bit wider and also squeezed the spacing between cogs just a tiny bit as well.

If your using old style 1.37"x24tpi screw on freewheel spool on your drive hub then absolutely 7 speed is the way to go. But if your running a cassette freehub then 8 speed is an option as well where the only real down side is that you have to replace the rear derailer a little sooner because once it gets worn and has some play in it it takes less play to make the chain skip between cogs then a 7-speed which has a tiny bit more spacing between the cogs but the difference is not all that much by any means.

Long story short, 8-speed cassette on a free-hub is a very good option as well as the 7-speed especially since you can hardly get 7-speed cassettes or spacers for free-hubs anymore.

For old screw on freewheels though, absolutely 7-speed is currently the name of the game because 8-speed freewheels are unreliable junky brand only where as you can still get decent quality Shimano 7-speed screw on freewheels and also decent Shimano shifters for 7-speed as well. Yah you could go all the way down to 6-speed and you can still find the occasional decent one that isn't a junk freewheel but hard to find good shifters for 6-speed.

Long story short, IMHO: If you are using screw on freewheels then go for a 7-speed Shimano. If you have a free-hub then 8-speed cassette is probably the best bet.

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Re: Chain Strength & Selection For Mid Drive Applications

Post by Lenk42602 » Apr 15 2014 10:59am

spinningmagnets wrote:It's possible to use a cassette rear wheel that has 9-speeds, but a 7-speed chain will be stronger, so......
Wishes wrote:And I highly suggest using a 7 speed cassette and chain instead of the 9 if you run with anything but stock power levels. They will last much longer.
turbo1889 wrote:
As to derailer chain systems I've had good luck running 8-speed spools in the rear on a decent free-hub at up to about 1.5-Kw (mechanical output) power. I wouldn't even consider to run 9 or 10 speed chain spools and derailers unless it was a 500-watt (mechanical output) or less system.

7 & 8 speed use the same full 3/32 traditional derailer chain its just the spool width is just a tiny bit wider for the 8-speed with just a tiny bit tighter spacing between the cogs so to squeeze in that one extra cog they both made the spool just a little bit wider and also squeezed the spacing between cogs just a tiny bit as well.

If your using old style 1.37"x24tpi screw on freewheel spool on your drive hub then absolutely 7 speed is the way to go. But if your running a cassette freehub then 8 speed is an option as well where the only real down side is that you have to replace the rear derailer a little sooner because once it gets worn and has some play in it it takes less play to make the chain skip between cogs then a 7-speed which has a tiny bit more spacing between the cogs but the difference is not all that much by any means.

Long story short, 8-speed cassette on a free-hub is a very good option as well as the 7-speed especially since you can hardly get 7-speed cassettes or spacers for free-hubs anymore.

Fellas, I am planning on installing one of these kits on a bike. The consensus in this thread (above) is that 7 speed cassettes and chains are somehow "stronger" than 8 or 9 speed systems? Can anyone that has actually run all 7, 8, and 9/10 speed cassettes over 1200 watts actually confirm that any of these configurations are actually "stronger"? Since chain wear is strongly aggravated by dirt getting into the links, the lifetime of a chain depends mostly on how well it is cleaned (and lubricated) and does not depend on the mechanical load.

- Chains and cassettes often wear out due to excessive mileage. Although chains are referred to having "stretched" when they wear out, this is not the case. What actually occurs is that the rollers (bushings and pins) between the plates wear to a point that the inner distance between rollers increases per given link, measured in tenths of 1% of the standard 1/2" distance o a new chain . This increased distance actually re-profiles the teeth on the cassette if the chain is left on beyond the recommended range that the chain should be replaced.

- When you all are speaking of chain "strength", if it is not wear, who is snapping chains? Please indicate power levels if you are and set up.
- If anyone has "snapped" a chain, what chain was it? Where did the chain fail? More directly did the chain fail at the master pin or link? Was the chain closed with a pin re-inserted or a master link? I have seen many chains that are closed with a master pin (instead of master link) fail due to improper installation.

- Chain "skip" and poor shifting is a chain/cassette wear issue.
- Low quality or improperly set up derailleurs (B-screw, cable tension, high & low limit screws) also have nothing to do with chain "strength"

All geared chains for bicycles - 7/8/9/10 are 3/32"

Len

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Re: Chain Strength & Selection For Mid Drive Applications

Post by notger » Apr 15 2014 12:47pm

how do you actually calculate or measure the "mechanical output"?

At least my electric wattage is 2100Watt peak and 1000 Watt "constant" at 30Volts (8s) and 35/70Amps

an to the chain question i use the standard quality XT HG95 10 speed shimano chain in extreme dirty sandy conditions and it lasts about 500km after that distance it's streched (to a length of about 120,6mm)or actually like you explained the rollers are completetly worn out.

i also do not take care about my chains too much i clean an lubricate them about every 100km

it snaped once not at the master link, but that can be caused by several chainsucks i had in the past.

i do not see alot of wear on the cassette, but on the biggest 44t chainring in the front (shimano xt) wich i use most

I do not see a need to change to 8speed or singlespeed right now, i read about tests made with 10speed chains and the XT HG95 was the best in weardown and strength so i use this one for about 2000km gng now and changed it 3 times

does anyone know a stronger 10 speed chain than the xt HG95 ? I'm up for testing it

I also used pieces of the hg95 10 speed chain for the primary and secondary drive without measureable stretch or any broken chain for 1000km, but i changed the sprocket and it just fits 8 or singlespeed chains now,
but that was a nice recycling for chain leftover pieces and showed me that it's just about dirt and not about the force you put on a chain, cause nearly no dirt reaches the primary and secondary chain.

I'm also curious about other "chain-stories"

greets from austria

gernot

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Re: Chain Strength & Selection For Mid Drive Applications

Post by panurge » Apr 15 2014 2:40pm

Lenk42602 wrote:- When you all are speaking of chain "strength", if it is not wear, who is snapping chains? Please indicate power levels if you are and set up.
- If anyone has "snapped" a chain, what chain was it? Where did the chain fail? More directly did the chain fail at the master pin or link? Was the chain closed with a pin re-inserted or a master link? I have seen many chains that are closed with a master pin (instead of master link) fail due to improper installation.

- Chain "skip" and poor shifting is a chain/cassette wear issue.
- Low quality or improperly set up derailleurs (B-screw, cable tension, high & low limit screws) also have nothing to do with chain "strength"

All geared chains for bicycles - 7/8/9/10 are 3/32"
My System:

Astro 3220 4t + HV160 + CA-LRC at 12s x 19:1 reduction in a separate, LH, 24"x2.5" wheel drive.

LH 1/8 chains are the most consumable part in my bike (stretched). Some snap happened for fails on other parts of the drivetrain. One time I had a snap landing from a serious jump and applying throttle while the suspension was still compressed (and the chain tensioned too much) this was the only straight snapping that occurred me, I think that the sum of the suspension stretch and the motor torque together, have snapped that gusset 1/8 chain.
After this, I've only used 1O8 or 1G8 whippermans and for the cost of an half pound, I'm in peace with chains right now, they still stretch, though... I had a chainsuck with an 1G8 that snapped all the left spokes... but the chain has not snapped and I have it as spare, I'm sure it is still safer than a cheap chain... :)

Note that roller width is not the only significant characteristic of a chain, pin length and shape, materials, plating technologies, plate thickness.....are really important things too, also, 8-9 v chains are usually 11/128" (2.18mm), 3/32" are used until 7 speed, and 1/2 have been used until 3 speed....
10speed are 2.1mm while some road 11 speed is 1.98mm x 5.5mm total width.... :shock:
I'll bet that a top 11/128" chain is stronger than a cheap 1/8 one....
JulesL.


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Re: Chain Strength & Selection For Mid Drive Applications

Post by Wishes » Apr 15 2014 2:45pm

Here is a copy paste from wiki on chains. They come in different sizes and when it comes to derailleur chains, they come in different widths. All these differences will have an impact on the durability and how much punishment it will handle before wearing out, stretching or snapping altogether. The wider the chain, the more surface it provides, the stronger it will be.

Chains come in either 11/128", 3/32", 1/8", 5/32", or 3/16" roller widths, the internal width between the inner plates. 1/8" chains are used on bikes with a single rear sprocket: those with coaster brakes, hub gears, fixed gears such as track bicycles, or BMX bikes. Chains with 3/32" wide rollers are used on bikes with derailleurs such as racing, touring, and mountain bikes.[9] Fixed sprockets and freewheels are also available in 3/32" widths so fixed-gear and single-speed bikes can be set up to use narrow and lighter 3/32" chains. Finally, chains with 5/32" wide rollers are used on freight bicycles and tricycles.

With derailleur equipped bicycles, the external width of the chain also matters, because chains must not be too wide for the cogset or they will rub on the next larger sprocket or too narrow that they might fall between two sprockets. Chains can also be identified by the number of rear sprockets they can support, anywhere from 3 to 11, and the list below enables measuring a chain of unknown origin to determine its suitability.

6 speed - 7.8mm (all brands)
7 speed - 7.3mm (all brands)
8 speed - 7.1mm (all brands)
9 speed - 6.6 to 6.8mm (all brands)
10 speed - 6.2mm (Shimano, Campagnolo)
10 speed(Narrow) - 5.88mm (Campagnolo, KMC)
10 speed(Narrow, Direction) - 5.88mm (Shimano CN-5700,CN-6700,CN-7900)
11 speed - 5.5mm (Campagnolo, KMC, Shimano CN-9000)
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Re: Chain Strength & Selection For Mid Drive Applications

Post by windtrader » Apr 15 2014 3:10pm

FYI - I have been using Worksman as the benchmark for bicycle tuff duty specs. They use 3/16" chain.

Note regarding chains- Worksman Business Cycles utilize 1/2x3/16" wide chain
which is 50% wide than standard chain please order accordingly.

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Re: Chain Strength & Selection For Mid Drive Applications

Post by turbo1889 » Apr 15 2014 4:13pm

"Mechanical output power calculated by known physical load that was pulled." ~ That is my answer as to how I know the mechanical power output.

I have actually stretched and broken both bicycle chain (1/8" BMX and 3/32" 6-7-8-speed) and #25,#35, & #41 industrial chain for real as in actual side plate stretching not just roller joint wear and actual breakage that is not due to excessive wear but actual full on overload and break the chain. Actual side plate stretching determined by measuring single inner links with micro-meter and also some half link chains where you could physically see where the step in the half link plates had been pulled out of step and into a straight taper. I do agree that normally any "chain stretch" is not actual stretch at all but just pin and bushing wear as you correctly point out. But with enough tension applied to the chain with enough geared down motor torque and enough cargo load (I run cargo loads on cargo bikes up to 600-lbs on the bike itself or up to 1.5 tons on a trailer, at least those are my personal records so far with half of those record loads being fairly normal to haul or tow) it is possible to stretch and break roller chains for real.

As to what specific bicycle chains I run for 3/32" 6-7-8-speed bicycle chain usually the more expensive Shimano name brand chains (HG-91 is the model of the couple of spare I've got in the box on my shelf right now). But for two bikes where I really wanted stainless steel chain I used Connex 8-speed stainless steel chain on them. Can't tell you what specific 1/8" BMX chains I've run but I try to get good stuff not just the cheap junk. Industrial chain sizes I try to buy the good stuff that's either U.S. or Japanese made not the cheap China junk.

As to the claim that all derailer bicycle chain is 3/32". Granted I could be wrong especially since I'm not a fan of the 10 and 11 speeds and haven't dealt with them personally but I've heard that those two are 11/128" chain. 9-speed still being 3/32" but with thinner side plates then normal 6-7-8-speed chain. Are you saying that 10 & 11 speed chain are still 3/32" just will still thinner side plates then 9-speed? I've heard that they are 11/128" not 3/32" (in combination with still thinner side plates).

Personally the main problem I've had with all "normal" non-heavy-cargo-hauling/towing mid-drives with derailer chain has not been with the strength of the chain itself but rather with the power and extra wear involved meaning the rear derailer has a harder time holding good indexing over time. The tighter you stack those sprockets in together the less and less little bit of wiggle due to wear and/or the twist torquing effect of power spikes and chain whip that it takes to make the chain want to spontaneously jump for an instant in a false aborted shift up or down to the adjacent cog.

Taking this all with a grain of salt realizing that so far 9-speeds is as high as I have personally gone. But I did have trouble with that 9-speed exactly as described due to rear derailer wear trying to run a Kw or so through it and I was using a good quality Shimano non-cheap rear derailer. Changed it out for an 8-speed cassette and shifter and the problem went away and has not come back at least so far but I don't have a huge number of miles on it either since I swapped over. The problem crops up with 8-speeds as well (and even 7 speeds if the rear derailer is really, really worn out) just not near as soon !!!

Not trying to be argumentative - just sharing my experience so far as I think it could be helpful to those doing there first builds. Unless your a cargo nut like I am stretching (for real) or breaking chains is probably not a huge worry.

But being able to hold good index on the rear sprocket spool when the rear derailer starts to get some wear on it is the thing that probably should be the biggest question. Heck, I've got an 8-speed with good quality non-cheap non-junk rear derailer on it that has never had anything but human pedal power go through it with about 5-years of use on it that is due for replacement of the rear derailer because it is worn to the point where no amount of fiddling or adjusting makes it constantly hold true solid index. And has enough wiggle in its mounting and pivot bearings and bushings to allow the occasional spontaneous aborted attempt at a false shift to an adjacent cog especially when hitting a big bump that bounces the bike hard enough to make the rear derailer wiggle around where it is worn. Granted I pedal hard and pound on that bikes drive train but still human power alone over 5-years with good consistent chain replacement soon enough to prevent sprocket damage do to running a worn chain and I don't even ride it every day especially with all the powered bikes I've got now. Where as I've got an old 6-speed from the early 90's that still has the original rear cheap junk walmart quality rear derailer on it that I have been running about 800-watts or so mid-drive on for a couple of years and it still holds true solid index on the rear sprocket spool and there is certainly plenty of wiggle in it as well its just that the spacing isn't as tight so it can take a lot more wiggle without trying to spontaneously do an aborted false shift to an adjacent cog on the rear spool due to how much wiggle wear is in the rear derailer. Yah, it would be nice if rear derailers never got any wiggle in them due to wear but unless you make them out of "notreelzrowairtanium" that ain't happening.

Bottom Line= How good of a rear derailer do you want to have to buy and how often do you want to have to replace it?

Not saying I'm anywhere close to an expert just a guy who has broken and worn out a lot of stuff and am sick of dealing with the hassle. If in doubt over-build and over-engineer and plan for it to still work even when it gets worn out and gets all wiggly and sloppy. User thicker sprockets spaced farther apart with wider chain. Sacrificing an extra cog or two being more then worth it in the end.

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Re: Chain Strength & Selection For Mid Drive Applications

Post by turbo1889 » Apr 15 2014 4:35pm

Also, I keep hearing some people say "A good 9+ speed chain is better and stronger then a cheap 7 or 8 speed chain."

I do not doubt that there is certainly truth in that statement.

BUT, is a good high quality 7 or 8 speed chain better and stronger then a good 9+ speed chain and the same question for the cassette sprockets it runs on?

That is the real question when we are considering mid-drive set-ups and since there are those who have modified derailers and shifters to accommodate a smaller number of wider spaced thicker 1/8" BMX sprockets and chain you can throw good high quality 1/8" BMX chain into the mix as well or if you want to get into some really serious stuff how about the heavy wall side plate super duty version of #40 industrial chain ??? (Good stuff by the way only thing that held up on the final reduction stage of one of my heavy hauler cargo bikes.)

And then there is the #219 Kart chain used in the LighteningRod mid-drive. For those planning on doing left drive builds using the motor he supplies instead of mid-drives there is certainly the option for them using his adapter for the big high tooth count #219 sprockets to use that chain for their left side chain drives. I don't think you could run it in a multi-speed derailer system but for left drives it looks like a very good option.

Ultimately everyone has to make there own choice, but I can't imagine running this LighteningRod improved more powerful mid-drive kit at 1-to-2.5 Kw power level through a 10-speed chain derailer system would hold up for long. May just be ignorance or lack of imagination on my part but I just don't see it.
Last edited by turbo1889 on Apr 15 2014 6:05pm, edited 1 time in total.

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notger   100 W

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Re: Chain Strength & Selection For Mid Drive Applications

Post by notger » Apr 15 2014 5:15pm

I'm also missing my good old 7speed it took more than 8000km offroad and was still quite ok.
Why i swapped to 10speed is that it seems to have a technical possible end there or at least at 11 speed and so getting spare parts is not that hard.

Does anyone of you know a source for some good quality 7 or 8speed derailers an shifters ?

Shimano and sram even stopped producing 9speed spare parts.

is there an manufacturer that still produces 6,7 or 8 speed systems?

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Re: Chain Strength & Selection For Mid Drive Applications

Post by windtrader » Apr 15 2014 5:36pm

This topic is wading right into my pile of swamp mud. What is going to hold up under various loads? It seems to me that there are at least three power profiles. 750 watts and less seem able use just about any off the shelf drive line: derailleur, freewheel IGH, or coaster IGH (2-3 sp). Between 750 and 1500, is another range. Maybe these reduced and upgraded cluster sprockets will do. 1500-3000 not clear and over 3000 watts and it seems you have to left direct drive it.

Sure would be great to get a simple guide on this topic as it would reduce a lot of thinking to nearly a checkbox when planning to do a kit like this.

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Re: Chain Strength & Selection For Mid Drive Applications

Post by turbo1889 » Apr 15 2014 6:24pm

Well, I for one apologize for being one of the swamp mud thread drifters.

That said as far as quality rear derailers I watch closely on salvage bikes to pick off all the goodies, that is the "cheap @$$scrounger" part of my nature. You would be surprised what you can find other people throwing away just because it ain't the new fangled thing even though it is good high quality stuff just a few years out of date.

And then otherwise I pretty much try to get the best quality Shimano/Sram (the two "S"es) that is still available new for rear derailers, shifters, cassettes, and Shimano still makes some decent 7-speed screw on freewheels for those running hubs that need the old screw on freewheels with more then just one speed.

I don't know about you guys but I don't seem to have a hard time still finding Shimano/Sram 8-speed stuff on the shelf or online and often you can make 8-speed stuff work for 7-speed so long as you still have a 7-speed shifter and cog spacers. Same sprocket thickness and same derailers just a difference in spacing for the cogs and the clicks in the shifter.

And of course watch online for high end quality "new, old stock" items. That's how I finally scored a high-end quality vintage corn-cob screw on freewheel that I had been looking for a long time for.

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Re: Chain Strength & Selection For Mid Drive Applications

Post by windtrader » Apr 15 2014 6:43pm

Well, I for one apologize for being one of the swamp mud thread drifters.
Well, I apologize if I slung any mud on you. :roll:
You see your reply is as vague as all the rest. Nobody seems able classify these options into power categories. I am as much as a scrounger as anyone but that does not bring the answer any closer. Is there any agreement that a stock 8 speed cluster holds up at 750 watts?

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Re: Chain Strength & Selection For Mid Drive Applications

Post by turbo1889 » Apr 15 2014 8:34pm

Part of the reason it is so vague is because there is more then one way to run 750-watts (or any other number) through the system. Higher chain speed with lower tension or higher tension with lower chain speed, different drive wheel sizes, different gearing ratios, people that overspin on the crank with the motor that you could never pedal along with and others that gear the motor to pedal speed. Can you use wood to cut a diamond - normally no, but yes if its a wood mallet you hit the splitting chisel with.

Or a more humorous question for this thread at this point: Is mud stronger than steel? Normally no but there are ceramics that are stronger then steel that start out as mud!

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Re: Chain Strength & Selection For Mid Drive Applications

Post by Lenk42602 » Apr 15 2014 9:19pm

who ever wants to do the work to get the easy answer, here is the start:

http://chain-guide.com/basics/index.html

http://chain-guide.com/basics/4-1-3-dri ... ction.html
windtrader wrote:You see your reply is as vague as all the rest. Nobody seems able classify these options into power categories. I am as much as a scrounger as anyone but that does not bring the answer any closer. Is there any agreement that a stock 8 speed cluster holds up at 750 watts?
Have to agree with windtrader above. I will be running a 9 speed 11-36 rear cassette, probably a 44-48t chainring on Rod's kit. 48v/12.5 ah 5c LiMnC pack, probably right around 800-1000 watts continuous, 1500 peak.

Once I get the kit, install it, run it and have tangible results to share, I will post it. Perhaps a separate "Chain sizing and selection guide for mid drive motors" thread should be started so the Lightning Rods mid drive thread stays as packed with direct, pertinent information as possible. Until there is another thread or I have actual data to share I will not post about speculation.


Len

Len

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Re: Chain Strength & Selection For Mid Drive Applications

Post by windtrader » Apr 15 2014 10:21pm

who ever wants to do the work to get the easy answer, here is the start:
Hey, that is pretty good. That will glaze over all but the most talented mechanical engineer who HAS to do some chain calc. For 99.9% of those wanting a kit, it may as well be calculating fuel load for a rocket to Mars.

If someone wants to run this kit at 1000-1500, my feeling is you can do this on just about any running gear. Over that i think you start stretching chains and breaking gears and such so going LD eliminates all the drive train worries.
Last edited by Lenk42602 on Apr 16 2014 2:31pm, edited 1 time in total.
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notger   100 W

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Re: Chain Strength & Selection For Mid Drive Applications

Post by notger » Apr 16 2014 3:54am

Hey i just found it

it's a article from a german bike magazine, they tested 10 and 9speed chains under same and pretty realistic mtb situations, but in labratory style with sand,water mud, in a machine under 48 hours constant running.

the article is in german but the tables are selfexplaining.

this tells me neither price, brand , or series(dura ace,xtr,xt) tells anything about chain strength, but there is a winner of this competition

greets

gernot
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crossbreak   100 MW

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Re: Chain Strength & Selection For Mid Drive Applications

Post by crossbreak » Apr 16 2014 5:00am

thanks for that file. I can confirm that HG53 lasts longer than Connex.. but the connex link is really an innovative master link... good to have one in spare for longer trips.

I broke a connex on my converted Hubdrive on the first longer ride. Shimano now still lasts... the connex tend to brake during shifting (broke 2 so for but never a shimano)
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Re: Chain Strength & Selection For Mid Drive Applications

Post by MitchJi » Apr 16 2014 9:49am

:x Hi,
Fellas, I am planning on installing one of these kits on a bike. The consensus in this thread (above) is that 7 speed cassettes and chains are somehow "stronger" than 8 or 9 speed systems? Can anyone that has actually run all 7, 8, and 9/10 speed cassettes over 1200 watts actually confirm that any of these configurations are actually "stronger"? Since chain wear is strongly aggravated by dirt getting into the links, the lifetime of a chain depends mostly on how well it is cleaned (and lubricated) and does not depend on the mechanical load.
In my opinion, this whole discussion should be moved, by a moderator, to a new thread. Both to keep this thread on topic, and so that all of the information can be easily found. Also in a dedicated thread more people will probably contribute useful information.


******************DONE SIR! **************************************************************


Len
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Best Wishes!

Mitch


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