KT Hubs - Any Good?

[Elliot]

Whoa! I have exactly this noise problem with my fleet of Huffy Cranbrooks! (Yes, 16 of them. Burning Man bikes.) They make a buzzing grinding sort of noise when coasting. It goes away when I pedal backward a little bit, but people cannot be expected to do that.

I also do bike repair at Burning Man, and I'm at my wits end for how to deal with this problem. We must have had 500 bikes come in with this complaint last year.

A mechanic told me these are KT hubs. And they are the same as HiStop and one Shimano model.

He also said something about the spring catching or hanging up, causing this noise, but I have not yet gotten this clarified.

The noise does sound a bit like something is rubbing on a steel spring.

There is an online article that shows this exact hub being overhauled. Here is the link:

http://www.troubleshooters.com/bicycles/1speed/1speed_overhaul.htm

Can anybody see a likely suspect for this noise?

 

[Elliot]

I found the noise!

The drive clutch has serrations. The "race" in the hub shell does not -- from the factory.

But in the noisy hubs, there are serrations in the hub shell "race".
The drive clutch has "tooled" serrations into the hub shell.

I might call this brinelling, even though brinelling is usually associated with roller bearings. The drive race in the hub shell is very much like the outer race of a roller bearing.

For starters, I want to blame faulty tempering (hardening). But so many of these came in with the bearings wildly loose, that this seems a likely cause, or at least contributing cause.

Over-tight bearings, and over-tight chain -- common on these bikes -- probably also deserve a mention.

 

[Bicycle808]

I found the noise!

The drive clutch has serrations. The "race" in the hub shell does not -- from the factory.

But in the noisy hubs, there are serrations in the hub shell "race".
The drive clutch has "tooled" serrations into the hub shell.

I might call this brinelling, even though brinelling is usually associated with roller bearings. The drive race in the hub shell is very much like the outer race of a roller bearing.

For starters, I want to blame faulty tempering (hardening). But so many of these came in with the bearings wildly loose, that this seems a likely cause, or at least contributing cause.

Over-tight bearings, and over-tight chain -- common on these bikes -- probably also deserve a mention.

Yeah, and under-lubrication.....