[lalittle]

I just re-packed my rear bearings (and replaced the ball bearings) on my Shimano freehub using Pedro's Syn Grease. After everything was back together, I no longer had the signature "clicking" you normally hear from this freehub system. It isn't just quieter, the clicking is completely GONE. It seems to function normally -- the wheel turns smoothly and it engages normally when pedalling -- but I'm wondering if something is wrong, or if perhaps I used too much grease when I packed the bearings, and the grease found it's way into the inner freehub assembly.

Is it even possible to use too much grease when packing these bearings? I basically just filled the cup/cone area so that as I was re-installing the axle, some grease squeezed out around the cone (i.e. the cup/cone space was filled.) I thought this was normal, but the end result clearly effected the freehub mechanism, so now I'm not so sure. I've ridden it a bit and spun the wheel quite a bit on the stand, but it's still essentially silent, which I've never experienced before with this wheel (although this is the first time that this particular wheel has been serviced/re-packed.)

Is it possible for grease to get into the freehub by putting too much around the bearings? I would have thought that any extra grease would either squeeze out around the cone, or squeeze into the hollow area inside the hub, but I didn't think it could squeeze into the freehub mechanism. Is this not correct? I did not remove or disassemble the freehub, and I thought that only a much thinner oil could get into it, but once again, the behavior suddenly changed after the bearings were greased.

On a possibly related note, as the wheel is spinning, I sometimes hear an odd noise coming from the hub area. It's hard to describe, but it sounds "sort of" like a grinding noise -- sort of a "deeper" grindy-clicking that does NOT sound like the normal freehub clicking. I should note that it does not sound like a "wheel bearing" grinding noise -- it sounds more like something in the freehub. It aligns with the frequency of the wheel turning, and it comes and goes -- I can't get it to happen on demand. I'm honestly not sure what to think. As I said, everything seems to work normally, but these two "sound" issues have me concerned.

Thanks for any feedback on this,

Larry

 

[SteveUK]

I wouldn't be concerned with pawls going quiet, at least not right now, but the grinding noise is obviously not right. For now, I'd treat the problem as over-tightened cones for now, so try backing them off a little and see if the noise persists. You may have just picked something up in the assembly which is moving around in either the seals or the grease, but start with the obvious. Are you 100% sure that you tightened the cone nuts fully? Did you check boths cups and cones for pitting? Does the same noise occur when you spin the wheel backwards?
Slightly over-filling the cups generally isn't an issue with Shimano hubs because, as you've said, excess grease will usually get pushed out into the axle space. However, some will work its way over the lip of the freehub cup and into the pawl mechanism. I used to deliberately slightly over-fill in order to reduce pawl noise. I no longer ride on any of the wheels that I serviced in this manner (here's how I did it), although my partner is still riding her hybrid around on the wheels that I serviced for that tutorial and they are still running perfectly. She averages around 30-40 miles a week commuting.

 

[lalittle]

Thanks for the response. My first guess was over tightening of the cones as well, but it seemed about right -- i.e. a tiny bit of play with the wheel off the bike such that the quick release takes this play out when tightened. That said, I'm going to try loosening it a bit more and see what happens.

Could you possibly clarify what you meant when you said "I no longer ride on any of the wheels that I serviced in this manner"? Do you mean you service them differently now, or do you use a different type of hub?

Thanks,

Larry

 

[SteveUK]

When I service my partner's wheels (Deore/Mavic 700c's) I have used and will continue to use the method in my tutorial. I use DMR Revolver hubs now and both have sealed cartridge bearings, as do the Specialized hubs on my spare wheelset. I would have mentioned it if I'd stopped because of catastrophic, excess grease related hub failure!!

If you're confident that you've set the cones correctly and there is no obvious external cause for the friction, you may just have to bite it and dismantle the assembly again. There is of course the possibility that the grinding noise and loss of pawl 'clicks' is indicative of some kind of failure in the freehub mechanism. How old is the hub? What kind of mileage?

 

[lalittle]

If you're confident that you've set the cones correctly and there is no obvious external cause for the friction, you may just have to bite it and dismantle the assembly again. There is of course the possibility that the grinding noise and loss of pawl 'clicks' is indicative of some kind of failure in the freehub mechanism. How old is the hub? What kind of mileage?

I re-tightened the axle again. I'm pretty confident that it's properly tightened -- just a bit of play with the wheel off the bike, and no play once the quick release is tightened. It spins real smooth and everything seems normal except when it's making that noise.

I listened to the noise again, and it really doesn't sound like "grinding" -- it sounds like several deep "clicks" in a row that take place for 1/3 of every turn. By "deep," I mean a distinctly different type of "click" than the normal high pitch click you normally hear from freehubs. The number of clicks per unit of turn, however, seems like it might be the same as the freehub clicks, so I'm wondering if it's somehow related to the freehub mechanism. The odd thing is that it just goes away and I can't get it to do it again for a while, at which point everything seems perfect. I lasts for a couple minutes, then just goes away again.

The hub is between 1 and 1.5 years old. It's had quite a few miles put on it (lots of uphill grinds), but I was under the impression that these should last a LOT longer. I'm not crazy about just replacing it, but I'd REALLY hate to have some sort of disaster out on the trail.

Thanks again,

Larry

 

[SteveUK]

You seem confident that it's not the bearings, which only leaves the freehub body. It would probably be worth you removing the freehub body and operate it independently. Tools are available (Morningstar Freehub Buddy) which will allow you to flush the freehub body through, although the cost about the same as a replacement freehub body.

 

[lalittle]

You seem confident that it's not the bearings, which only leaves the freehub body.

While I can't speak with 100% certainty, it just doesn't "sound" or "feel" like the bearings, and I wouldn't think it would be SO sporadic if it was the bearings.

It would probably be worth you removing the freehub body and operate it independently. Tools are available (Morningstar Freehub Buddy) which will allow you to flush the freehub body through, although the cost about the same as a replacement freehub body.

I've never been able to reproduce the sound with the wheel off the bike. My plan is to take it off the bike the next time it does it and listen to it that way. Unfortunately, it hasn't done it since I decided to try this.

I'll look into that Morningstar thing. On that note, can you buy just the freehub mechanism separately?

Thank again,

Larry

 

[SteveUK]

"While I can't speak with 100% certainty, it just doesn't "sound" or "feel" like the bearings, and I wouldn't think it would be SO sporadic if it was the bearings."

I would tend to agree with you, however...

"I've never been able to reproduce the sound with the wheel off the bike."

Man, this is perplexing! Without being able to hear/feel the problem, I don't think I can say with any degree of certainty what the problem could be. My hunch is the freehub body, which, yes, you can buy seperately (unusually expensive, though). If the problem persists, try removing the cassette and spinning the wheel whilst hold the freehub in a clenched hand. You should be able to feel any irregularities through your palm....

 

[Douglas Fir]

recommend flushing the unit

I recommend flushing theunit with the morningstar free hub BUDDY. You can buy a new FH every week and the last is no better than the first until you put good grease inside- which they also sell. morningstartools.com

good luck btw; the silence is not a problem.

df