atrp2biz

I recently purchase a commuter bike from the LBS. With the purchase comes a one-year maintenance package (parts not included).

On my ride in to work yesterday, my freehub stopped engaging--I could pedal, but obviously went nowhere. Leading up to yesterday, periodically the freehub would delay engagement for 1-2 pedal revolutions if I cruised for a little bit. Annoying, but manageable. Yesterday was the first time I simply couldn't ride.

I brought the wheel into the LBS today and the service guy immediately went to order the hub body. I was appalled by this. As part of the maintenance package, I would have thought he would have disassembled the hub to investigate the issue with the hub. I asked him about this and whether he should first disassemble the hub to see if cleaning it would work, but he said no and that they just order the part.

Should I be looking for another LBS or should I just replace the thing?

Jed19

The mechanic is probably right in ordering a new freehub body. In my experience, what you described sounds like broken pawls. Taking the freehub apart, cleaning and lubing same ain't gonna fix that.

What hub is it?

joeyduck

Yeah I've had a few free hub bodies replaced. I've place tried to clean it but they it never worked quite right.

Maybe manufacturer warranty should be considered fora new likely defective part, which is what it sounds like to me.

atrp2biz

Sram mth-306

Jed19

Yeah, if less than a year, you should be looking towards warranty.

jimc101

So you have more knowledge than the mechanic? The mechanic will have more knowledge/experience of this type of issue, and will know if it's worth attempting to repair, or more likely, easier and cheaper to replace the whole assembly.

atrp2biz

1. I asked the likelihood of requiring a new part. The response was 90%.
2. Given a 10% chance of success, I would have appreciated the 5-min attempt to disassemble the body since he said the part is not with the distributor and would would be approximately a one-month lead time.

ljsense

At least you could solve it with a free hub body. Some entry level hubs don't even allow that, and you're looking at a new wheel.

SRAM doesn't list parts for that hub, so I'm surprised your mechanic was able to service it at all.

https://www.sram.com/sram/mountain/p...s/sram-306-hub

https://sram-cdn-pull-zone-gsdesign....spc_reva_0.pdf

atrp2biz

Another point of clarification:

At ambient temperatures, the hub periodically engages, but not reliable enough to ride.

atrp2biz

They're actually getting back to me on the service, but if they can get it, it would be at least a month away. It is true I might just have to get a new wheel.

FBinNY 

You're in Calgary Alberta. It's January, The mechanic wasn't thinking. There was a very good chance that if he simply waited for the bike to come to room temperature the problem would have fixed itself.

Freehubs have fairly heavy oil or grease in the ratchet unit. When cold enough, the oil can thicker to where it's too much for the light pawl springs, and the pawls "freeze" in the retracted position. When warmed back up, the hub performs normally. This viscosity change is why cars have climate or temperature rated oils. The fix for cold weather riders is similar, --- use lubricants that won't overly thicken at low temps.

Of course, you might have a truly broken freehub, and these are generally not rebuilt, but there's no way to know until the bike is warmed.

dabac

At home, I'll gladly disassemble, clean and relube (Shimano) freehubs. By it does take a little while, and not all can be saved. I wouldn't spend much effort on second-guessing a payed mechanic who'd order a replacement part w/o further ado.

With one exception - (severe) cold.
With Shimano, every now and then they seem to release a bunch of freehubs with too much grease inside. They work OK at moderate temperatures, but if it gets too cold the pawls begin to stick.
And if you simply replace, the next part might just as likely do the same.
This situation, disassembly and relube offers better control of the result.

Jiggle

I would also be appalled by that. Rule #1 of fixing a problem: Find out what the problem is. It is certainly possible to easily do so in this situation.

FBinNY 

Beat you - Iguess I'm a faster typist.

But now to answer the last part of the OP's question.

If it does turn out to be the cold, then I'd find a new mechanic. Any mechanic working in that climate who is not familiar with it's effects isn't worth a dime.

Little Darwin

I am just curious why under warranty, you are offended by the mechanic not tinkering with it, and replacing it with a new part... If he spent the time, and could get it to work, and it failed again 30 days after the warranty expired, I suspect you would be here complaining that he didn't order you a new part.

A lot of things are simpler to replace than fix, and I tend to trust the professionals to do what is cost effective, especially under warranty... Whether it is my bike, my car or my appliances.

atrp2biz

If under warranty, cost is not an issue. The mech never mentioned anything about a warranty so it was not part of my thought process. But the part is nowhere to be found and would take a while to get in (I make reference again to the month+ potential lead time).

Hypno Toad

I've had this issue with winter riding. It's the grease in the hub. Most bikes aren't built for cold weather. My LBS in Minneapolis is good with winter commuters and knows to flush the hub and use a lube for cold temps. Today was -13F in Minneapolis, no problems with the freehub. Make sure your LBS supports winter riders and has the knowledge to keep your bike happy in the cold.

FBinNY 

It would be truly sad if you waited a month, or paid for a replacement, then went out into the cold and the same thing happened.

Freehubs having this problem in the cold isn't rare, and it should have been as obvious as a snowball in the face for any mechanic in your area. It would be like going to a doctor with head pain and being prescribed aspirin because the doctor didn't notice the arrow in your temple.

atrp2biz

I just tried the following which might be of interest:

If I try rotate my cassette clockwise from a stationary position, the hub engages and I cannot turn it. If I turn the cassette only slightly counter-clockwise and then flip it to clockwise, it does not engage.

Jed19

Your clarification makes all the difference in the World. Yeah, I'll think heavy grease is clogging the pawls. A flush and lube job should fix that.

FBinNY 

A classic sign of sticky lube. Just about confirms the blind diagnosis of the northerners here.

Odds are that as you turn the cassette backward you hear only very light or muffled ticking from the ratchet vs the clean and sharp tick! that you should.

atrp2biz

Thanks. I'm going to try to take care of this myself. Would Phil Wood grease work for this (given temps as low as -15°F) or something lighter like Tri Flow?

FBinNY 

Start with the understanding that the ratchet mechanism has the most minimal lubrication needs because there are no parts moving under load. When you're pedaling the mechanism is locked and moves as a unit, and when you're coasting, the only load is the light pawl springs. So all you want is a thin coat of something that won't resist movement, but will coat the metal and prevent rust. IMO Phil grease is overkill especially at low temps. You want something like a very low viscosity grease formulated for cold conditions, or an all weather oil.

I'd look to something like a 5w-xx motor oil, or Mobil 1, or a light coat of very light grease. Whatever you're considering, you can test it by putting a sample into your freezer (or leave it out overnight) and see how much it thickens.

If you can get it on the ratchet, without flushing the grease out of the bearings, tri-flow is probably OK, though it might make your freehub noisier when the weather warms.

Dfrost 

I once tried Phil grease in a freehub and noticed that engagement was spotty (sure was quiet!) and my winter temps are nowhere near as cold as Calgary's. Rinsed it out with a solvent, then used Phil's Tenacious Oil, similar to FBinNY's suggestion. Works great.

.

atrp2biz

Problem solved...for now.

Went back to the LBS and this time they just gave me a new wheel. If this happens again, I'll degrease and relube with a heavy oil.