Suggestions for a "robust" ebike cassette

greendream

Likes Bikes
I have a mate whom enjoys his Spec. Evo Levo ebike and has managed to bend the shit out of his SRAM GX 11speed cassette. As he now needs to replace it he has asked what would be suitable for his type of riding? (I suggested he try to refrain from crunching his shifts, especially the upshifts, but I'm not sure if this may be an ebike thing).
What would be the burners suggestion for a replacement cassette? Are there any models that are more difficult to bend than others?
 
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Minlak

Loves the template
I have a mate whom enjoys his Spec. Evo ebike and has managed to bend the shit out of his SRAM GX 11speed cassette. As he now needs to replace it he has asked what would be suitable for his type of riding? (I suggested he try to refrain from crunching his shifts, especially the upshifts, but I'm not sure if this may be an ebike thing).
What would be the burners suggestion for a replacement cassette? Are there any models that are more difficult to bend than others?
Even more so with e-bikes due to the increased load you have to learn to back off on the shifts then re engage - I like the shimano slx level ones but others may have more ideas
 

Isaakk

Likes Dirt
Even more so with e-bikes due to the increased load you have to learn to back off on the shifts then re engage - I like the shimano slx level ones but others may have more ideas
I'd be suggesting 12sp Deore or SLX if he tends to hammer gears too.
 

Calvin27

Eats Squid
I'd be suggesting 12sp Deore or SLX if he tends to hammer gears too.
I'd be suggesting 8 speed.

I have no idea why bike folks thing it's necessary to stick ultra-lightweight bicycle parts on an ebike and then have things like double cranks - you have an ebike! I run 42f 32 rear on my ebike in 1x8 speed configuration. I wouldn't be able to afford the maintenance if it was anything 10 speed or more - they burn through groupset so a thick cheap gruppo is preferred imo.
 

Isaakk

Likes Dirt
I'd be suggesting 8 speed.

I have no idea why bike folks thing it's necessary to stick ultra-lightweight bicycle parts on an ebike and then have things like double cranks - you have an ebike! I run 42f 32 rear on my ebike in 1x8 speed configuration. I wouldn't be able to afford the maintenance if it was anything 10 speed or more - they burn through groupset so a thick cheap gruppo is preferred imo.
I was thinking more for the ultra-glide HyperGlide under power than the weight. The new Shimano 12sp stuff shifts extremely well under power.
 
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greendream

Likes Bikes
Thank you all. Looking at the cost of replacement cassettes he certainly needs to learn to moderate his power during shifting. I myself will be taking a particular interest in chain maintenance.
 

Calvin27

Eats Squid
I myself will be taking a particular interest in chain maintenance.
In my experience, the chain is going to cop it no matter what. Chain wear on ebikes is all about power. Some of the big strong riders putting out massive power/torque burn through chains compared to lightweight spinners. An ebike is like having olympic sprinter legs all the time without a natural progression like a normal human would. The chain stretch is rarely about abrasive wear or lubrication but cold hard forces acting and stretching it. Hence my recommendation about going to lower speed and ultimately thicker chains.
 

hellmansam

Likes Dirt
On the couple of rides I've had on a Turbo Levo, I found my normal amount of backing off to shift wasn't enough, as the motor took longer to back off than me, had to work on backing off a bit sooner, and more.
As for chain wear I've always believed the wear happens in the rollers rather than stretching of the side plates. Could be wrong but I CBF doing the kind of measuring that would differentiate. Yes they wear, eBikes more so, 11 and 12 spd cassettes aren't cheap so don't wait too long to replace the chain.
 

The Duckmeister

Wheel size expert
As for chain wear I've always believed the wear happens in the rollers rather than stretching of the side plates. Could be wrong....
No you're on the right track. Not just rollers though, the pins and the holes of the inner plates wear as well, causing the chain to appear stretched. The plates stay the same length.

Now, the original problem. I've seen plenty of bent & broken teeth on 11 & 12-sp. cassettes, particularly the aluminium sprockets (the biggest one, but depending on model can be the second one too) on naturally-powered bikes, so there's a considerable element of technique at play, not just e-power delivery. Additionally, SRAM 11 & 12-sp. drivetrains are very sensitive to proper B-tension gap; if it's not spot on the chain sometimes doesn't mesh properly on the sprockets, and that could be a cause of damaged teeth.

Now, the OP specifically mentions GX 11-sp, so that rules out some of the alternatives mentioned previously without additional changes. SRAM's lower level, all-steel NX cassette needs the hub driver changed from XD to standard Shimano HG-type, as do all Shimano 11-sp. cassettes. Anything 12-sp. needs both shifter & derailleur, as well as a driver for SRAM SX or NX (HG-type) or Shimano Microspline, which may not be available for the hub in question.
 

Minlak

Loves the template
No you're on the right track. Not just rollers though, the pins and the holes of the inner plates wear as well, causing the chain to appear stretched. The plates stay the same length.

Now, the original problem. I've seen plenty of bent & broken teeth on 11 & 12-sp. cassettes, particularly the aluminium sprockets (the biggest one, but depending on model can be the second one too) on naturally-powered bikes, so there's a considerable element of technique at play, not just e-power delivery. Additionally, SRAM 11 & 12-sp. drivetrains are very sensitive to proper B-tension gap; if it's not spot on the chain sometimes doesn't mesh properly on the sprockets, and that could be a cause of damaged teeth.

Now, the OP specifically mentions GX 11-sp, so that rules out some of the alternatives mentioned previously without additional changes. SRAM's lower level, all-steel NX cassette needs the hub driver changed from XD to standard Shimano HG-type, as do all Shimano 11-sp. cassettes. Anything 12-sp. needs both shifter & derailleur, as well as a driver for SRAM SX or NX (HG-type) or Shimano Microspline, which may not be available for the hub in question.
I didnt think of that - in hurry to be first and gain internet cred I just typed away
 

greendream

Likes Bikes
So my mate went out & purchased the same OEM cassette, fitted & went out for a spin..... oh, oh. motor has died. In for warranty repair to replace motor/clutchpack. One week turn around & appears to be a not so unusual failure.
 

Minlak

Loves the template
So my mate went out & purchased the same OEM cassette, fitted & went out for a spin..... oh, oh. motor has died. In for warranty repair to replace motor/clutchpack. One week turn around & appears to be a not so unusual failure.
Well there is a reason they have extended the warranty on all the Specialized motors to try and win back consumer confidence- Rider up here in 12 mths on their 4th motor
 

rowdyflat

chez le médecin
Companies have not thought enough about the problem of excess forces, easily 3 times what the stuff was designed for .
They have just tacked a motor on a 11 or 12 speed duallie.
Locally there have been lots of broken derailleurs fall into the spokes,break spokes, then flatten tyre even , twist the chain, hanger , $450 later.
Stupid really you dont need a 12 speed pizza tray cassette ebike .
7 , 8 , 9 speeds with a sturdier chain and shorter derailleur would be fine .
Mine has 9 its plenty.
 

mtb101

Likes Bikes and Dirt
remove chain turn into balance bike and lock motor on. changing gears pretty complicated for ebike owners.
 

The Duckmeister

Wheel size expert
.....there have been lots of broken derailleurs fall into the spokes,break spokes, then flatten tyre even , twist the chain, hanger , $450 later.
That happens a lot without e-ssistance. The hugely long derailleurs necessitated by massive cassettes are very exposed to damage from trail debris or just shit technique.
 
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