I seem to toast Freehubs

scrone · Post by **scrone** » Jan 12 2017 1:09pm

Does anyone have advice for me for freewheel hub and hub that won't go crunch after a few weeks of hard riding? My G N G is limited to about 1600 W but Is used mostly for extreme hillclimbing and difficult free ride. Three years, three different wheels. On the halo 24 inch wheel I have now, the hub has cartridge bearings which are fine, but the Shimano (Is this a Shimano?) loose balls in the free hub didn't last. I would love a screw in replacement for the free hub but I am open to suggestions. Has anyone tried a White Industries combination? If they are anything like their flanged freewheeI, I would try one. I can't possibly be the only one with this problem.

amberwolf · Post by **amberwolf** » Jan 12 2017 2:20pm

Are you shifting gears for the appropriate gearing for each climb? (lots of people don't, so they use motor power to overcome the too-high gear).

You might have to change the gearing at the cranks to get the right gearing for your low-speed/high-torque climbs. If you can't pedal it in that gear even for part of a crank rotation without motor power, the gear is probably not low enough.

I see a groove in the splines where your lowest or next-lowest gear probably is; is it actually spinning that sprocket on the splines, breaking the spline teeth? If so, maybe there's simply too much torque on them, or it is being applied too suddenly. Perhaps slower application of power would help, if that's the case. If it's not sudden application of power doing it, but just too much torque, you'd need a spline body (and/or sprocket) made of harder steel or hardened to a stronger level. (then you get to find out the next failure point, probably the pawls).

Regarding the bearings, if they can get contaminants in them (poor seals, maybe insufficient grease/oil of the right kind) that stick around, they can grind them up from the inside out, made worse by high-torque applications. You might just need to service the hub more often, so this doesnt' happen.

Chalo · Post by **Chalo** » Jan 12 2017 2:35pm

That's a Shimano pattern spline, but it's not a Shimano freehub. And that's probably one key to your problem.

Shimano freehub bodies were designed around a standard 10mm threaded axle, and they're just about as small in diameter as they can be while still being reliable. But when you put a larger hole through the middle (for a larger diameter axle), the ratchet clutch mechanism must get smaller to fit inside the same spline. It will necessarily be more fragile. That's why some manufacturers move the ratchet inside the hub shell to a point inboard of the spline, with a larger diameter.

The cheap and easy fix for your issue is probably to replace your wheel with a normal, nothing-fancy Shimano hub (e.g. Deore or SLX) laced to an appropriate rim. That will give you a more durable and proven freehub body that's relatively cheap and widely available when and if you need to replace it.

sather · Post by **sather** » Jan 12 2017 2:39pm

Karl seems to feel that cheaper steel freehubs are better suited than aluminum for ebike power levels.

Quote
"One of the big problems I’ve had with the Ludacris 50 Amp controller is the constant aluminum bodied freehub destruction. On cheap bikes like the $400 Deadeye the free hubs are generally made of steel which seems to be able to take high wattage power without issue. The more expensive fat bikes are almost exclusively made with aluminum freehub bodies which work fine for people power (350W or less) but can’t take real power (over 750W) for very long. I’ve burned through several freehubs on the Phat Phuk build, my last one lasting only a week."
https://electricbike-blog.com/2016/12/2 ... -doing-it/

scrone · Post by **scrone** » Jan 12 2017 2:58pm

I have a 14-36 cassette and a 32 on the cranks. I had a 24 on the cranks but it was way too slow, problems staying upright. The first wheel had a Deore, well lubricated but the balls failed. The one pictured is also steel. I don't know what the groove is for but the cassette does not spin. Is the key to have a free hub with a cartridge bearing?

Chalo · Post by **Chalo** » Jan 12 2017 3:21pm

Cup and cone bearings need some axial preload to be stable and to carry their intended load, while cartridge bearings need not to have axial preload to work correctly. So having a cartridge bearings on one side of a hub but a cup and cone bearing on the other side is a recipe for causing one or the other to fail.

scrone · Post by **scrone** » Jan 12 2017 6:12pm

As is visible in the photo, the free hub has its own adjustment for the balls, quite independent from the cartridge bearings

Chalo · Post by **Chalo** » Jan 13 2017 1:04am

scrone wrote:As is visible in the photo, the free hub has its own adjustment for the balls, quite independent from the cartridge bearings

I can't see that it has a cup on each side, opposed. That's what it takes to have independent bearing preload adjustment.

cheekybloke · Post by **cheekybloke** » Jan 13 2017 7:03am

Chris King hubs are the best available, i have put over 9500 miles on one at 2.5 to 3 kw.
My other bike has one and runs 6kw peak and i have done 1500 miles on it with no issues.
Darren.

Chalo · Post by **Chalo** » Jan 14 2017 3:54am

cheekybloke wrote:Chris King hubs are the best available,

They're very noisy, very draggy, and very, very expensive. Together I think that neatly exempts them from "best available".

For what it's worth, that's one of the designs that moves the ratchet outside the freehub spline to a place where it can engage at a larger radius. It also uses a face ratchet with many teeth engaging simultaneously. Those features both add strength but also drag when coasting.

For better or worse, I think one of the Shimano hubs with a normal 10mm axle is likely to offer the best combination of robust freehub body, durable bearings, indefinite maintainability, and reasonable cost.

recumpence · Post by **recumpence** » Jan 14 2017 11:17am

Ok, is it just me or is anyone else on this forum tired of hearing people complain that their crappy low quality bicycle parts aren't able to handle the power of electric drive?

Geeze, the solution is so simple...... But decent parts and you won't suffer constant failures.

Matt

WoodlandHills · Post by **WoodlandHills** » Jan 14 2017 12:38pm

With 3000w who cares about hub drag? And could you even hear a noisy freewheel over the whine of the motor and drivetrain? With 3 replacements in three years perhaps the higher initial cost of Chris King setup would be cheaper in the long run, if it holds up? This is getting up into small motorcycle territory and the compromise between efficiency and longevity/reliability is different from a more bicycle-like ebike.

What makes this thread interesting is that the cheap parts are purported to be stronger than the expensive ones.......

recumpence · Post by **recumpence** » Jan 14 2017 2:13pm

WoodlandHills wrote:With 3000w who cares about hub drag? And could you even hear a noisy freewheel over the whine of the motor and drivetrain? With 3 replacements in three years perhaps the higher initial cost of Chris King setup would be cheaper in the long run, if it holds up? This is getting up into small motorcycle territory and the compromise between efficiency and longevity/reliability is different from a more bicycle-like ebike.

What makes this thread interesting is that the cheap parts are purported to be stronger than the expensive ones.......

You don't need a stupidly overpriced Chris King hub to have reliability. Then again, a cheap crap hub is not the solution either.

scrone · Post by **scrone** » Jan 14 2017 3:58pm

The wheels I’ve had so far are Mavic, AlexRims BHPro and Halo Combat. A 36 spoke Halo is like a brick outhouse. Unfortunately, they all were built (not by me) with cheap freewheel hubs. Gravity riders don’t care about this because they are not putting much torque on the rear wheel. Some cheap parts (steel=heavy) are more suited because they are stronger than expencive (aluminium=light) parts. Extra grams on an Ebike are unimportant compared to muscle power rides. To ask again my original question, what do people suggest for a rear hub? I am thinking of starting fresh because I can’t find a screw in replacement. Thanks Cheeky, I have heard elsewhere as well that the Chris King is great but loud. My bike is pretty quiet and whenI coast the only noise is the free hub so it is a major consideration. True Precision Stealth is interesting but reports are they don’t handle high torque. Is this true? I did not intend to upset our friend Matt so much but I would like to hear from people like him (or even him) who are very knowledgeable.

briangv99 · Post by **briangv99** » Jan 15 2017 1:17am

scrone wrote: True Precision Stealth is interesting but reports are they don’t handle high torque. Is this true? I did not intend to upset our friend Matt so much but I would like to hear from people like him (or even him) who are very knowledgeable.

True Precision Stealth run a roller clutch bearing, which are very prone to failure.

I'm running a Onyx Racing Products http://www.onyxrp.com sprag clutch hub offroad/single track, these hubs are tough as nails, silent, have virtually no drag, and very pricey (but well worth the cost). I run my hub with a 6kW Tangent Astro 3220, with not a hint of a problem, love the silence and how well it coasts.

Endless Sphere

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