Chain Selection and Sizing for Mid Drive Applications

Good idea, thanks, Len.

I am open to learning something new, and also admitting I was wrong when I am presented with clear evidence. In the interests of full disclosure, much of what I write in my frequent posts has been gathered from reading other peoples experiences.

In the absence of any type of throttle ramping/snubbing (the rider snaps the throttle full on, but the power comes on in a gradual curve), I believe an IGH should remain an option for the BBS02, but for the 50V X 30A = 1500W that I feel this kit is suited to start at (Christerljung is running 100V), I would not recommend to anyone to use an IGH. The ability of the motor to use several gears is a huge benefit for off-road use, and any chain/sprocket system needs to have a chain that is flexible enough to be nudged sideways.

Roy's eCortina used a heavy-duty BMX chain (with 1/8-inch wide rollers between the link side-plates), and three cassette sprockets at the rear. I suspect he might have been able to squeeze-in 5 gears, and this would be my next most desired experiment.

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For a big block left-side-drive, there are several options. Of course Luke established that #428 works well. Also, #415H looks good on paper, but few people are trying it yet (difficulty adapting sprockets?). From the archives, here's a tip from farfle:

If you are willing to machine stuff, #40 industrial sprockets thinned to 3/16" run #415 chain great. Its what I run 24-HP through on my bike

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#219 chain and sprockets would be pricey, but would have no problems with high power.

Just want to come away with some good guidelines for which geared chain systems/speeds can work suitably at designated power ranges with the LR GNG kit.

Now that I am not polluting LR's thread, we can get into this.

1) Larger roller pins, both in diameter and width, will provide a greater surface area to purchase on the valleys of the teeth of a sprocket or chain ring. It would make sense that an 1/8" chain should be able to provide more purchase and handle more power without failing prematurely. However 1/8" chain does not have and ramps on the plates and are not suited for moving from cog to cog like a geared system.

2)The particular steel alloy used for the pins, rollers, and plates will play a role in the chains strength.

3) Finally, the design of the chain - the shape, joining methods of the pins to the plates, mass or thickness of chain parts, etc. will also have a bearing on the chain strength.

And turbo, for the record, rear derailleurs do not wear out under use. The only items that should need replaced, if ever, are the pulleys, and even these only require replacement if run in very muddy conditions.

Improper set up, including an improperly aligned derailleur hanger are the primary causes of poor shifting. Higher power levels only expose those issues much faster.

Len

Glad this stuff all got moved into its own thread.






With respect in my experience they do wear and do develop more "wiggle" in them.

I think you should seriously reconsider your "do not wear out" statement. Can you think of anything mechanical that is under constant dynamic use that it can be scientifically proven that it never wears out? Think about it for a while ~ Stuff that never wears out? Never? Does that make any sense about real world conditions that we observe every day. Even industrial diamond tooling made from freaking diamonds wears out in use over time.

Not trying to be an @$$ (but maybe I am) but in my experience rear derailers do wear over time and do develop more "wiggle" in their bushings/bearings over time and it isn't like I'm talking about walmart bike derailers. I'm including derailers that cost as much as a whole walmart bike. Pumping high motor power through them they do wear out (and in my experience for one example so far they also wear out with human power alone as well just takes a whole lot longer). For the record.

The 8-speed derailer I have previously mentioned that I need to replace on my pedal only woods bike currently has enough play in it so that I can wiggle it with my fingers far enough to each side for it to be pulled about 1/2 of the way onto the adjacent cogs on either side of the cog its currently indexed on just with the play in it before I'm pushing up against the main spring to one side or the sifter cable tension on the other. Needs replaced, its worn to the point where it has too much wiggle to hold proper index. Seen the same thing before on other bikes, this just the first time I've seen it on a pedal only bike where I owned the pedal bike personally from brand new off the bike shop show room floor until I wore out the original rear derailer to this point under human power alone. Granted that rear derailer has taken a bath in muck more times then I would even hazard to guess and I'm sure some of that grit helped wear the pivot points to the point where it has that much wiggle in it which if running an e-bike strictly on road should not be near an issue but still I've seen rear derailers wear out that were nice and tight to start with and developed more and more wiggle over time due to use.

Maybe you haven't seen it happen and have never yet encountered a rear derailer that wasn't junk from the get-go truely worn out to the point where it had too much wiggle in it to hold proper index. You probably won't be convinced until you do, and that's cool. Sometimes I have to see stuff for myself before I'll believe it as well. My purpose in what I have posted, however, is not to convince you. I'm trying to share my experience so that newbies know what is happening when they run a high sprocket count rear end with tight spacing and it works fine at first but then when they really start putting some miles on the bike then all of a sudden they start having trouble with the chain staying where it is supposed to on the rear end and not trying to jump around on its own occasionally at the most inconvenient times and no amount of re-adjusting and truing up the rear derailer seems to fix the problem.

At this point they should take the rear derailer and gently wiggle it with their fingers from side to side up against the shifter cable tension on one side and until they encounter pressure from the derailers main spring on the other and see how much "wiggle wear" has developed in their rear derailers pivot joints. It's especially nice if you have another new tight non-worn rear derailer to compare with side by side. If sure enough they have enough wiggle wear to be what is causing the problem then they need a new derailer and if this is happening way too often for their liking to be replacing the rear derailer that often and/or have to be really sure to buy a really good one. Then their other option to cure the problem is go to a lower number of cogs that are spaced further apart so it takes a lot more wiggle to cause the same problem.

If that never happens to you ~ well good for you, but I've had to deal with that issue way too often for my own liking so at this point anything more then a low power system of 500-watts or less I'm not running more then an 8-speed rear end personally.

YMMV

Oh, yah, when checking for this "wiggle wear" issue in a rear derailer don't just gently push side to side also put in a gentle (just finger pressure) twisting motion. A good quality derailer when new has almost absolutely no wiggle at all in it with a twisting motion so if there is noticable wiggle room to allow some twisting that really shows if there is pivot wear that is introducing too much "wiggle wear" such that the rear derailer can no longer hold as tight of an index on the rear sprockets regardless of how well it is adjusted and trued up.

You all may think I'm nuts and off my rocker, but I've seen rear derailers wear out like this. Everything wears out eventually just a matter of how long it takes and I'm pretty sure that running more power through them wears them out faster, non scientific personal observation.

http://www.parktool.com/blog/repair-help/rear-derailleur-overhaul

Park Tool Website (link above) said:

. . .

Derailleur Wear

The rear derailleur will become worn with use and abuse. As the derailleur wears, it will develop play at all pivot points. Grab the cage at the lower pulley of a new derailleur while mounted to a bike and wiggle it side to side. Do the same test on an old model to compare. Replace derailleur when this play becomes significant.

. . .


(Emphasis Added)

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Does or does not running Kw+ levels of power through a derailer that was never designed to handle that much power and was only designed around human power output capabilites qualify in the "abuse" category referred to above that goes beyond normal "use" wear category?

What about this for a strong chain:
Connex by Wipperman 1E8



1E8
(nickel, reinforced)
extremly long lasting
for all E-Bikes with hub gears on the market
1/2" x 1/8“, pin length: 10.5 mm
weight: 508g/110 links
124 links incl. inkl. Spring Clip connector

I think this thread would be a great resource for us to find the best of the best when it comes to high powered mid drive parts.

turbo1889 said:

With respect ........in my experience they do wear and do develop more "wiggle" in them..... on my pedal only woods bike currently has enough play in it so that I can wiggle it with my fingers far enough to each side for it to be pulled about 1/2 of the way onto the adjacent cogs on either side of the cog its currently indexed on just with the play in it before I'm pushing up against the main spring to one side or the sifter cable tension on the other. Needs replaced, its worn to the point where it has too much wiggle to hold proper index. Seen the same thing before ...... much wiggle.... .......more and more wiggle over time due to use....Maybe you haven't seen it..... At this point they should.......number of cogs that are spaced further apart so it takes a lot more wiggle to cause the same problem....
YMMV

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Listen Dude. You are posting about a subject completely unrelated to the thread topic, which is chain selection and sizing a thread of which is placed in a area of the forum board that is designated to discuss non hub motor drives. You have posted three successive posts that have less to do with the thread topic and more to do with trying to prove your point in front of an audience. I spent enough time yesterday trying to be accommodating and spent time moving off topic stuff into this created thread.

Get it?

You don't need to quiz me about bike mechanics. Get it?

You don't seem to realize that YOU are a newbie. Please respect the posting guidelines and cease polluting threads with off topic discussion. I'm not planning on relocating another batch of discussions that you are driving. You may not be aware, but in your quest to enlighten everyone, there are other individuals trying to obtain quick and specific information for certain issues or references purposes. I know you think you are helping the forum, but you really are not. There are highly capable individuals here that have posted much more valuable content in a single post, and have done so with much less verbiage than you and I combined in the last several days

Consider this your first moderator warning. Slow your roll. Warnings lead to banning.

If you want to talk at length about anything - derailleurs wiggling, cargo bikes, want to post pictures of what bikes you've built or currently ride, create a spread sheet with graphs, cut and paste information you have found on the internet, feel free to do so, just start your own thread and discuss away!


Len

jdevo2004 said:

What about this for a strong chain:
Connex by Wipperman 1E8

1E8
(nickel, reinforced)
extremly long lasting
for all E-Bikes with hub gears on the market
1/2" x 1/8“, pin length: 10.5 mm
weight: 508g/110 links
124 links incl. inkl. Spring Clip connector

I think this thread would be a great resource for us to find the best of the best when it comes to high powered mid drive parts.

Click to expand...

That is definitely a stronger chain, but I do not think you can get that to work with a derailleur. The 1/2 and 1/8 inch chains are using strictly for single speed applications. I could be wrong and i'm sure one of our local experts will correct me if I am.

Wishes

jdevo & wishes,


Correct- that chain is not designed to be shifted across cogs on a cassette.

Len

was never designed to handle that much power

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Raising the power that we run through various bicycle components to see when they start wearing out faster, and when they break...it is a frequent exercise around here. I think it's fun to do, and I like reading about when other people try that too...

How about this chain:

Wippermann conneX 8sE (nickel plated, stainless steel) 6/7/8-speed / E-Bike Chain



This chain can be used on all 8-, 7- and 6-speed drive systems and E-Bike drive trains. With an outer plate made of innovative and particularly hard material that withstands the high load changes of E-Bike drivers. The stainless steel inner link also guarantees long service life. The chain is equipped with a reusable conneX link that allows assembly and disassembly of the chain in seconds, by hand! Chain with 124 links, 1/2 inch x 3/32 inch, pin length: 7,2mm.
8sE (nickel plated, stainless steel)
extremly long lasting
for all 8-speed drive systems on the market
1/2" x 3/32“, pin length: 7.2 mm
weight: 308g/110 links
124 links incl. Connex Link

I am just compiling some info from 2 different sites on this chain. It seems to be pretty strong...but it is 4000 watts strong is the real question.


.

.but it is 4000 watts strong is the real question.

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This is very easy for such a chain. The max power you can push through a chain can be calculated: The max force till it breaks is normally about 10 kN for common 6-8 speed bike chains. You can use 2.2 kN without having any issues. Max chain speed for such a chain is around 15-18 m/s. So max power you can push through it is P = F * v, here P is Power (in kW), F is Force (in kN) and v is velocity (in m/s) .

So max power you can run through any normal bike chain is: 2.2 kN * 15 m/s = 33 kW

so the 4 kW you ask for is really no issue. You just have to keep the 15 m/s

Also have a llok into the Drive systems: Chain section of our wiki: http://endless-sphere.com/w/index.php/EBike_DriveSystems_Chain

Question is, do you really need 33kW? Or is it better to be able to use smaller front sprockets? smaller front sprockets are nice, since you can gain more reduction with the same dia rear sprocket. For example 110T #25 chain (which does about half force of a derailleur chain) sprocket on the rear and 13T in front still runs fine, where 110T does not look too odd (~22cm in dia or 0.22 m), and a 13T still has acceptable polygon effect. You get a chain reduction of almost 8.5 : 1 with a max power of 15 kW.. but that 15kW are at 18m/s chain speed (remember.. chain speed is important).

You gain these 18 m/s at a wheel speed of 18 [m/s] / (0.22[m] * Pi) = 26 revolutions per second or 1520 rpm.. in a 26" wheel that would be 190 kph or ~118mph :lol:

so at 85kph you have to be fine with half of that (half of the chain speed) so 7.5kW, at 47.5kph with 3.75kW and so on...

At the end of the day you get a torque of around 192Nm at the wheel in AVARAGE, which means you should not get any issues with double of that in peak. I think that is more than one can ask for in a "bicycle".

I hope i did not miss the point here. you can forget about IGH at normal ~26" wheel with your aprroached power level. even with derailleur you will have a hard time. You simply need a very large cassette like 13-34 shimano HG50 and use only gear with 17T+, so just gears: 17 - 20 - 24 - 29 - 34 only 5 speeds that should be plenty. I ride 36-14T which also does fine (HG61 9 speed with only 7 gear in use).. i do only 3kW electric or about 2.2kW at the chain but i will try 5kW electric soon and post my results

I've been running SRAM 9spd chain (PC-991) on my pedal power roadbike. I've broken it perhaps 5 times, typically while clipped-in sprinting very steep hillclimbs, and almost always resulting in smashing my balls or wrecking when it snaps. lol

I abandoned the whole concept of bicycle chain for motor power transfer after experiencing repeated catastrophic chain failures, even while only in the few kW power range.

I'm personally looking at a gates carbon belt drive setup with an internally geared hub for my pedal-only roadbike, just to hopefully find something that can consistently endure a pair of strong legs sprinting as hard as they can up extremely steep pitch hills.

I experienced the same failure before analyzing and solving the problem. The bicycle "mafia" dictates chain rings with 22T and sprockets with 11T. I dont ever use both of them since they are producted only to break chains LOL

crossbreak said:

I experienced the same failure before analyzing and solving the problem. The bicycle "mafia" dictates chain rings with 22T and sprockets with 11T. I dont ever use both of them since they are producted only to break chains LOL

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Cross, I am trying to get my head around what is actually occurring when a low tooth count sprocket or pulley engages a chain regarding the degree of wear. I get that there is less chain wrap, and less purchase between the chain/teeth, but there has to be more going on wrt tangential force as well?


len

After rereading the thread title and YES I am a new noobie but I don't hear see many posts about the 3/16" chains. Can I assume that those running them are happy campers, no matter how much torque running through the drivechain? My next step up is to go with the light atv size chains.
Thanks

sorry i dont know a 3/16" chain... i'm from europe so i dónt get your imperial stuff at all times. I think you may mean a 415 chain? I think this one is just not very common? or is it 420? which i use as well and..what shall i say.. it does just fine as millions use it :?

Cross, I am trying to get my head around what is actually occurring when a low tooth count sprocket or pulley engages a chain regarding the degree of wear.

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it's called a "roller chain". if chain wrap is too small or the sprocket is worn, then the last (not the first) roller that engaged rolls up it's sprocket tooth and disengages... then the next.. and the next.. till the last.. and it jumps...there really isnt so much science in this:



..till you take a closer look at the angles and forces at which this effect appears. A very bad lubricated chain will actually feel "unworn" since it can't roll up and jump over.. instead it is stuck due insufficient lubrication and will work as usual. still, the sprocket is is worn.. it may still work but efficiency and chain growth will suffer.. it will even grow/wear even faster


this is why i propose to change the chain as soon as the growth has become 1%. Then you can be sure that your sprockets where not damaged too much yet and you can simply change the cheap chain ($3) before you change your expensive sprockets ($15)

i drive my sprockets with 2-3 chains usually till i change them. My chains usually last more than 3000km even in my ebike... but it does not see the calced 1.75kN very often i must say. Mostly during acceleration as my drive sees only half of that on a hill ( i have a fast chain drive with low force)

if you wanna know more science: the derailleur sprockets have very low teeth to make it possible that the chain can change sprocket without "sitting" on one tooth with a roller. This is called uniglide. additionally there are pockets in the teeth to help the next link to flip over, this is called hyperglide (by shimano). This accelerates shifting a lot and makes it less rough, since the actual dia the chain "sees" does not vary a lot. BUT: it makes it also easier for the chain to roll up a tooth and jump over. So sprockets are worn faster. They are "worn" from the beginning when compared to single speed ones.

If you now use a new chain on a worn sprocket than it should be crystal clear now : It jumps over only since it is well lubricated and "climbs" the worn teeth easily... your old one simply didnt

btw i have to admit turbo that derailleurs get worn. Maybe no a lot more if you push through more power but if you shift more often, as mechanical links wear as they are moved.

Thanks.

I have worked in the bike industry for a long time and know about chain and wear, was just looking for a mechanical explanation of why a smaller tooth count chainring or sprocket tends to wear faster than a larger one. I assume based on your explanation of the science, that due to less chain wrap the opportunity for the chain to ride up and roll over to the next rear cog increase to a greater degree proportionately with the cog size and amount of chain wrap . As the chain growth continues of course.

Folks commonly come into the shop to determine both chain and cassette wear, and we have the tools to determine both.

Your explanation below speaks to how pulley teeth become shark finned, but not why smaller ones wear faster than larger ones, which they do.

I'd love to talk about derailleurs in a different thread - proper set up, adjustment, the context in which the original discussion began, maybe some pictures about turbos set up.

Someone create one. To do so here would be hypocritical.

Len

beside from higher forces for smaller cogs there is one very clear reason: if you have twice or three times the teeth per cog every teeth is involved only half or a third of the time therfore wear is reduced by that amount.