Sram XD freehub failure luna ludacris

[Larrysog]

Hey everyone new to the forum, got steered here from luna sales. I Have KHS 680+ WITH the luna ludacris controller. My problem is that I keep blowing out the bearings in the sram XD freehub. I've tried chrome and stainless steel bearing and both failed. Any help or tip would be appreciated.

[calfee20]

Oops......That is not good to see. That is an expensive piece to.

[Larrysog]

Oops......That is not good to see. That is an expensive piece to.

Yeah tell me about it.

What are the guys with the fat tire bikes doing for drives? Are the Shimano drives stronger?

[calfee20]

There was a small thread on cassette failures. It took me a while to find it so here it is. http://electricbike.com/forum/forum/...eared-from-50a 50 volts and 50 amps seems to be a failure point. I don't know how much help it will be. There were a lot of opinions there.

[Rider]

That makes me want to inspect the bearings on my SA 3spd IGH that I just found a cranked knurled locking nut on and slop in the bearings. Bicycle parts simply aren't designed for the kind of TORQUE the electric motors are putting through them. Only running a BBS02B 750W/48V here.

https://www.sheldonbrown.com/twist-internal.html

[Sneakers915]

I'm surprised it's the bearings and not the pawls, I'm guessing that there's enough torque to side load the cassette past the point the bearings can handle it.

[commuter ebikes]

I know that you are not set up for a White Industries freewheel and you probably wouldn't want to change your hub, but the White Industries freewheels might be the most bombproof units made. Most are single speed, and a few are two speed, but you have to manually move the chain to switch gears. I switched to White Industries freewheels even though it meant reducing my number of gears. They are very well made!

[Larrysog]

I would got single speed is there a easy way to set that up with what I have?

[Larrysog]

I'm surprised it's the bearings and not the pawls, I'm guessing that there's enough torque to side load the cassette past the point the bearings can handle it.

Yeah I even put 3 bearings in the free hub (usally has 2 with a spacer)and it still failed.

[JPLabs]

Honestly, I don't understand the loading of your particular failed bearing in detail, but I recently witnessed a freewheel bearing failure which was caused by side loading the bearings, it fractured the races. He tried a few times, it lasted days or weeks each time. The axial clamp force from his axle nuts was completely side loading the bearings, due to improper setup.

You broke parts, you didn't just wear them out, from the looks of the pictures, is that right? I mean, did they get noisy and grindy, slowly, then fail over many more miles, or were they quiet and fine, then bang, exploded after zero, or brief, noisy operation. If the latter:

I really wouldn't expect bearings to fail like that, merely from higher chainline tension of the Ludicrous system. That might be it, but I'd be looking for something else, at the same time.

Perhaps the setup is not right and the bearings are being loaded axially? I mean side loading, perpendicular to the bearing's flat plane. Are they being axially loaded from the tension on the axle bolts (or QR axle) due to a missing spacer, or something like that? Are the inner and outer races of each bearing fully supported with zero free play? True? Things like that.

Loading bearings in the wrong way can break them fairly easily. Just loading them 66% harder in the intended direction, as with moving from 30A to 50A, not so much. I'd expect them to slowly get noisy and wear out, not fracture and come apart, in that case. So, check the setup carefully. You can feel the bearing's drag and free play as you tighten your axle - does the bearing seem to get tighter as you tighten the axle? It should not.

Side loading could also accelerate wear and be noisy first, that might be a 'red herring' but I think it would happen a lot faster. A few dozen miles, not a few hundred, I suppose.

[calfee20]

This maybe a badly engineered part. Here is a link to a similar failure. http://forums.mtbr.com/wheels-tires/...f-1018539.html

[commuter ebikes]

Yeah tell me about it.

What are the guys with the fat tire bikes doing for drives? Are the Shimano drives stronger?

I use multiple speed freewheels such as this: http://www.interlocracing.com/casset...eels-567-speed and single speed like this http://www.whiteind.com/new-page.

These freewheels have a wide range of gearing (11 to 34T), but an English female thread, so you would have to use a hub with an English male thread https://www.sheldonbrown.com/freewheels.html. It is known as 1.375" x 24 tpi ISO (or English) freewheel thread. It is very common and has been around for decades.

The most bombproof one made is by White Industries. That freewheel is never the weak link in anybody's drivetrain.

If you were willing to change to this hub, it would look like this:

[Larrysog]

Thanks for all the info guys. I think I'm going to change my hub out. I think the whole design of the setup that I'm currently using is not a good design for a high-powered ebike set up I think changing the Hub out to say a hope Hub with a Shimano gear set should help my problem what do you guys think I still want to be able to change gears.

[Larrysog]

Oh and also I have a 12 mm axle.

650B Alloy 6061 Double Butted Custom Formed TT&DT with Replaceable Derailuer Hanger, 1.5 Taper 12x148 Boost

[Larrysog]

I use multiple speed freewheels such as this: http://www.interlocracing.com/casset...eels-567-speed and single speed like this http://www.whiteind.com/new-page.

These freewheels have a wide range of gearing (11 to 34T), but an English female thread, so you would have to use a hub with an English male thread https://www.sheldonbrown.com/freewheels.html. It is known as 1.375" x 24 tpi ISO (or English) freewheel thread. It is very common and has been around for decades.

The most bombproof one made is by White Industries. That freewheel is never the weak link in anybody's drivetrain.

If you were willing to change to this hub, it would look like this:

I looked for a hub/cassest that will work on the links you provided. Would you know if any would work for my khs 680+? Thanks again