LightningRods mid drive kit

Lots of good info there eMTBHunter! I'm still not quite sure why 7-speed seems like a better option? Ok, yes, the cogs themselves are thicker, but commonly lower end components (materials and manufacture). The reason 10 and 11 speed chains are just as strong (if not stronger) is that they are made from better, stronger steel. The pros aren't going to use newer stuff if it's weaker or insufficient.

[youtube]fz2XpNzRAfQ[/youtube]

Here's a video I just shot, demonstrating various gears on a couple nearby hills. The long paved climb was done first in the 17t (straight chain line, tops out about 43mph on flat), and then again in the 11t (with a shout out to John Bozi). The grass hill climb doesn't look that steep in the video but I can guarantee it's remarkably steep, especially towards the top. I did go ahead and shift over 2 cogs to the 21t for this, and it barely pulled it off, from a standstill. Then to finish I ride some typically flat road in the 17t (stopped at red light, accelerates to 30mph just crossing the interestion, aka plenty of accel!) and then the 15t which pulls nicely from 40mph (at over 4,200W!). This is all with a 40t on the final drive. All 10 speed stuff, nothing goofy, everything works solid, no skipping, with >700 miles so far. Again, if your running less power you may need gears and can use them, if you run high power you hardly need the gears. Unless you want to pull tree stumps out of the ground and then ride off like a bat out of hell. :lol:
 
The unfortunate thing is that all of the "progress" is going in the wrong direction for our purposes. For ebikes it would be great to have a high quality index shifter 5 speed with a long cage arm. A 40T low should be low enough and we don't need a high gear with fewer than 16-18 teeth. Sadly most of the high end derailleurs and shifters are 10/11 speeds. That many speeds are not needed on an ebike with any kind of power. I loved the Rohloff that I had in the shop other than the fact that 14 closely spaced gears was way too many. You have to double or triple shift between gears. You find yourself wishing for fewer gears that are more widely spaced.

It makes no sense to make a blanket statement that an ebike with over 3,000 or even 5,000 watts doesn't need multiple speeds. If you're going to ride it around on the level on the street and don't want to go over 35 mph then that makes sense. What if you want to be able to climb steep, twisty trails with a 240 lb rider plus gear and you still want a 35 mph top speed on the level? What if you prefer to stay with a 48V battery pack? High voltage is a workaround for having only one speed. Multiple speeds are a solution if you don't want a huge (and potentially lethal) high voltage battery pack.

I am going to make my wide ratio seven speed. It will have a Shimano spline and 5mm spacing between gears. I'll let you know how it turns out.
 
LightningRods said:
The unfortunate thing is that all of the "progress" is going in the wrong direction for our purposes. For ebikes it would be great to have a high quality index shifter 5 speed with a long cage arm. A 40T low should be low enough and we don't need a high gear with fewer than 16-18 teeth. Sadly most of the high end derailleurs and shifters are 10/11 speeds. That many speeds are not needed on an ebike with any kind of power. I loved the Rohloff that I had in the shop other than the fact that 14 closely spaced gears was way too many. You have to double or triple shift between gears. You find yourself wishing for fewer gears that are more widely spaced.

It makes no sense to make a blanket statement that an ebike with over 3,000 or even 5,000 watts doesn't need multiple speeds. If you're going to ride it around on the level on the street and don't want to go over 35 mph then that makes sense. What if you want to be able to climb steep, twisty trails with a 240 lb rider plus gear and you still want a 35 mph top speed on the level? What if you prefer to stay with a 48V battery pack? High voltage is a workaround for having only one speed. Multiple speeds are a solution if you don't want a huge (and potentially lethal) high voltage battery pack.

I am going to make my wide ratio seven speed. It will have a Shimano spline and 5mm spacing between gears. I'll let you know how it turns out.
Click to expand...

I agree. As one with crazy wattage at my disposal, I would say a lower gear for tight tasks with steep hills is great. The closest thing I have found on my bikes is Delta/Wye switching. That is only usable on a few systems out there, though.

Matt
 
this yt api depreciation is bad for audio quality if people didnt notice....

Thanks for the shout out. Strangely though you were pulling lower watts at 11t about 2.6kw? were you holding back on the throttle? If not why would it do that...?
 
atarijedi said:
Has anyone here run the Big Block at 88V?
Click to expand...

I've been running it at 22s lipo for quite some time now. I usually start off at 90v and finish around 82v.... I use a EM3ev 12 fett 40a controller which overshoots quite a bit at times of need.

The CA is run at the WATT settings so open throttle is 3.5kw from start to end of ride if I am going off road steep... I also have a really really slow ramp up to get to 3.5kw, so it only can be used if it is really needed for continual stuff and it is practically impossible to just sit on the bike pull back and flip your ass onto the ground. No twatt can come along and grab it and do anything of consequence either.

On road 2kw is heaps even with the steep hills around my house. More gentle on the drive train.

Cheekbloke recommends the domino throttle which one day I think I will try if all else gets sorted.... as these cheaper ones are maybe creating tiny "random" spikes.


Higher voltage and lower amps are for the win for various reasons....
 
Alan B,

Torque does not require motion or acceleration. It is force times radius. It is a twisting force. Think of your torque wrench.
Click to expand...

You seem to have an incomplete view of these motion causing vectors. From physics for a mass-body we say: the sum of the forces on a mass-body = mass x acceleration and we also say the sum of the torques = moment of inertia x angular acceleration. Hence we know that if a body is not accelerating the vector sum of the forces on it is zero. Like wise if a body mass is not gaining spin speed the sum of torques on it is zero.

A single torque wrenches measures only one torque on a body at a time. If the angular velocity is not changing when adding more torque there must be other torques on the body ramping up [like friction] to keep it from having an angular acceleration.
 
There is a lot of chatter about weak drivetrains.

Has any tried the Sram ebike specific 11-48t, 8-speed cassette is machined from case-hardened tool steel. Its gear range is optimized for mid-drives, and has increased chain wrap on climbing cogs. Big steps between cassette cogs specifically engineered for electric mountain bikes. MSRP $390. if it is out yet?

Or the The Sram EX1 chain is wider and designed for the high-torque, heavy duty loads of eMTBs. It’s designed to run quietly and transmit more power to the rear wheel. MSRP is $25?
 
I haven't heard of anyone trying this yet. It has promise. IMO the 11t end is pretty worthless but the 48t end is not. It would work great if you blocked the top three gears and used it as a five speed. 48t to 18t is still a wide range. 48 to 11 seems like a lot for even a long cage derailleur to deal with.

Are there better quality 8 speed derailleurs than the 7 speeds? The main problem with 7 speeds is that you can't get good derailleurs.
 
LightningRods said:
I haven't heard of anyone trying this yet. It has promise. IMO the 11t end is pretty worthless but the 48t end is not. It would work great if you blocked the top three gears and used it as a five speed. 48t to 18t is still a wide range. 48 to 11 seems like a lot for even a long cage derailleur to deal with.

Are there better quality 8 speed derailleurs than the 7 speeds? The main problem with 7 speeds is that you can't get good derailleurs.
Click to expand...

9 speed rear mechs work with 8 and 7 speed.
I use Shimano xt stuff and it holds up very well.
Darren
 
cheekybloke said:
9 speed rear mechs work with 8 and 7 speed. I use Shimano xt stuff and it holds up very well.
Darren
Click to expand...

Really? The physical spacing between the sprockets is supposed to be different. I'm sure that you've actually tried this yourself instead of just talking out of your arse. The XT is the make and model of derailleur that I most often hear good things about. Thanks for checking in, Darren.
 
DingusMcGee said:
Alan B,

Torque does not require motion or acceleration. It is force times radius. It is a twisting force. Think of your torque wrench.
Click to expand...

You seem to have an incomplete view of these motion causing vectors. From physics for a mass-body we say: the sum of the forces on a mass-body = mass x acceleration and we also say the sum of the torques = moment of inertia x angular acceleration. Hence we know that if a body is not accelerating the vector sum of the forces on it is zero. Like wise if a body mass is not gaining spin speed the sum of torques on it is zero.

A single torque wrenches measures only one torque on a body at a time. If the angular velocity is not changing when adding more torque there must be other torques on the body ramping up [like friction] to keep it from having an angular acceleration.
Click to expand...

Switching from incorrect definitions to personal attacks and changing the subject/scope. Trolling.
 
LightningRods said:
Interesting insight about torque. If the resistance exceeds the the torque no motion happens. If the combination of resistance and torque exceeds the strength of the part caught in the middle of this conflict, the part will bend, twist or break. I'm trying to decrease torque and resistance at the problem points in addition to making the parts stronger.
Click to expand...

14188438_10154301478804845_2567089555226682469_o.jpg
 
8 speed and 9 speed chain and derailleur compatibility?

Bike chain dimensions
https://en.wikipedia.org/wiki/Bicycle_chain

Sheldon Brown cassette spacing (scroll down)
http://www.sheldonbrown.com/cribsheet-spacing.html
 
They're definitely headed in the right direction. It will be interesting to see how much they prioritized light weight over strength. The bike industry still has a tendency to think of "ebike" as 350-500 watts. If SRAM designed in a huge durability margin this set might be strong enough for what we think of as ebike power.

At nearly $400 or $50 per cog, they're leaving plenty of room in the game.
 
LightningRods said:
They're definitely headed in the right direction. It will be interesting to see how much they prioritized light weight over strength. The bike industry still has a tendency to think of "ebike" as 350-500 watts. If SRAM designed in a huge durability margin this set might be strong enough for what we think of as ebike power.

At nearly $400 or $50 per cog, they're leaving plenty of room in the game.
Click to expand...

That kind of wattage is pedal assist...not motorcycle assist. :p
 
Noticed that KMC has an ebike chain. Anyone used it? As noted above, seems they were thinking in the 300-500w range, but maybe it's at least directionally correct.

http://www.chainreactioncycles.com/mobile/us/en/kmc-x10e-hp-ebike-10-speed-chain/rp-prod120636
 
Hi all,

I'm currently searching for a bike to re boot my e mtb hobby.

Something I had a lot of trouble with my last build was shifting the rear gear with standard trigger shifter's mounted on the right side, which I had to move inboard to make room for the full throttle.
The main problem is that I have small hands, I had to take my hand off the hand grip and slide it over the controls to reach the gears. Which is a bit dangerous on rough tracks.)

I'm considering mounting a grip shifter to the left side to change rear gears, and hope for the best.

Another idea I had was to try a pedal assist throttle which I believe is linked to the cranks right ? Does anyone have any experience with solutions to this problem ?
 
Remus if your off road is rough enough to be dangerous when moving your hand over, I personally would advise against pedal throttle. Turning your crank to get the right foot position means it would kick forward even when you don't want... each to there own, but it felt dangerous to me even more so waiting at traffic lights.

Not sure how many speeds but I have happily used those cheap old twist shifter in the past, but they don't work as nicely obviously as the modern stuff.....
 
Remus if your off road is rough enough to be dangerous when moving your hand over, I personally would advise against pedal throttle. Turning your crank to get the right foot position means it would kick forward even when you don't want... each to there own, but it felt dangerous to me even more so waiting at traffic lights.

Not sure how many speeds but I have happily used those cheap old twist shifter in the past, but they don't work as nicely obviously as the modern stuff.....
Click to expand...

Trigger shifter's are great in rough tracks. But I simply can't reach over the part of the electric throttle that houses's the moving parts and cable connection, no matter which way I position the throttle. The problem is I have very small hands.

I AM right handed, and considering this is a dangerous activity, I thought it best to have a right hand throttle.

At the moment, I can't think of a better way of doing things than to mount a grip shifter for my rear gears on the left side, and at least try it out.

I'm still searching for a bike....

I went into the LBS yesterday, and all they had in stock was stuff with trigger shifter's. I'd have to buy a NEW bike, then pay for new rear deraiuler, and grip shifter. front derauiler that will work with a friction lever shifter. new brake lever's, as everything in the shop was integrated (brake/shifter). I think doing that way would get very expensive, even if they gave me a discount on selling the parts on the bike I don't need back to them.

So I'm looking at the second hand market on gumtree.com.au around the Brisbane City +50km for older bikes that came as standard with grip shifter's. At least then I have a chance to save some bucks.

I was thinking of upgrading my 1983 Giant mtb of unknown model but its got a 1" threaded fork... And christ knows if I can even get front suspension forks to replace the ridged ones on there now.
 
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