Bit of a two-parter which is also on Reddit but spreading the net wide for help:
Components:
Miche race cl hubs (bolt thru)
GRX cranks
Ultegra BB
XT pedals
Issue:
While riding and putting a bit of load through the drive train (so silent on the stand) I will get a fairly regular clang/clunk that you also feel in the pedal. Initially, this was in the lowest gears where most torque is generated but it’s happening in a wider range now.
Work done:
I’ve:
swapped pedals
replaced the BB
new cassette (not much scoring on the freehub body)
different SPD shoes
at least 2 chains swapped out
Conclusion:
I think I’ve isolated it to a freehub pawl not quite locking into the recess so I think I need to clean and service them.
What sort of lube for freehub pawls? I’ve got various chain lubes (dries out?), grease (too thick?), GT85 (solvent?) but I can order whatever I need. Also, if anyone had instructions for getting a freehub off a thru-axle Miche that’d be awesome as guides look to be for QR hubs, I keep seeing questions online where the cassette and freehub have just come off which would be perfect right now but no such luck!
If not freehub does anyone have ideas what it is?
I know clunks/creeks can be very hard to identify as back in the day a creak on my Super V that sounded like the BB or pivot but actually, it was a creaking headset echoing down the massive downtube.
I had stuck pawls on a smart bike, and it was far more pronounced at higher loads and was more of a skipped/slipped gear feeling, sometimes appearing to skip ‘several’ gears. Sure a noise, but more of a snap, or crack. Clang/clunk makes me wonder if the chain is junk, or the chain or sprockets are stretched or bent, or tracking off angle.
However the one diagnostic, perhaps main diagnostic, would be to rip the freehub apart and check those pawls, and if there is any grease, and if it’s a solid monolithic useless mass. In my case, the ‘grease’ was solid, not mobile at all, and what they did put in it was so scant to be described as ‘greased in theory, not fact’. The pawls were actually coated with a thin layer of rust that kept them in a semi deployed state. Ripping it apart, digging the pawls and springs out of it, and cleaning the whole thing with alcohol and q-tips was a longer process than I thought should have been necessary, but every pawl I touched wanted to jam into the slot, so the whole thing was a disaster. It really was stunningly epic OMG/WTF, how in the heck did this happen.
I looked for the pictures, and can’t find them. I have a folder on a different computer.
Getting away from pawls like DT has done makes the most sense of anything I can think of.
Your other options: if it was bottom bracket, you should be able to grab the crank and squeeze it between the chain stays, popping it from one side to the other.
Did you try different cleats? Are they original brand/model cleats? Are they black or silver cleats? A remote reason: Are you sure everything is genuine? No counterfeit parts?
Different cleats and the same shoes are used on the MTB and gravel bike with only odd noises from the gravel.
I’m confident that the chain and cassette are genuine Shimano as it’s my local shop. BB is also from a reputable online shop (Merlin) so I’d hope they’re all good.
I think it’s going to be a work out how to get the freehub off the body job this weekend.
‘Bolt thru’ meaning ‘thru-axle’? They look like a DT copy possibly. Their website is annoying, and apparently they discontinued that model hub?
Their freewheel bodies look surprisingly like the one on the Neo Smart Bike. There are no manuals for any of their hubs, but it looks like they use a pressed in end cap, so pulling the thru axle, popping the end cap off, and slowly pulling the hub body off should free the pawls. They aren’t likely to pop out and fly away as the deep groove that holds the ring in is so deep, and the pawls have a similar groove to allow the ring to keep them deployed and engaged (provided they aren’t seized).
It looks like it shouldn’t take much to get to the pawls, but I can’t find a picture of that exact hub, so your mileage may vary. Perhaps someone else can help you better…
Here a pictures of a Miche Primato Syntesi hub with a CL in the middle and the Syntesi looks a bit more complicated to disassemble.
Sure, but it would seem more likely that there is something (or nothing) in there. I certainly was shocked to see the freehub body when I took mine apart. I’ve seen broken a broken pawl before, but it effectively gummed up with rust, in a NOS bike? I was dumbfounded… I don’t know what I expected, but TADA, that’s what I got.
One image of that NEO hub. The pawls were able to move, but when I pulled them out for what would be to engage the outside of the hub cavity, but they wanted to stay there, and when pushed back in as if passing over the teeth in the hub body, would stay in likely just enough to engage the corresponding teeth but not enough to avoid them popping to the next row, and the next, but would occasionally be deployed far enough that one or possible two would get wedged in the teeth like they are supposed to be if they could move. (This was from a ‘new’ bike, not a refurbished one)
How do you know it’s the pawls? Could it just be the freehub bearings?
I’d think that stuck pawls result more in a skipped gear / non-engagement feeling. A loud clunk sound doesn’t seem that likely - but as you say, sounds are really hard to trace!
My experience with the above stuck pawls was very much a snap sound, and a jumping of the cranks as they pawls caught on another ridge tooth. It got worse as it went along and would skip several teeth before it caught. It was like a car transmission that is dying, you hit the pedal, the engine revs, then catches and SQUAWK and you’re moving again. But instead of a squawk, it’s a loud snap and instant resistance. (It would also have a kinda crunching kind of sound as it skipped over teeth under pressure)
You can use a threaded rod with bolts and washers as a press, and use a socket set for drifts to press the bearings into the hub (Just when installing, press from the OUTER race of the bearing, not the inner race) Yeah, I’ve got the Park Tool press and it makes it easier, and with the drifts it’s easier to press from the outside race, but it’s not mandatory by any means. (A drift kit would be nice, don’t get me wrong, but if you have a socket that fits the outer race diameter, you can do that all day and be fine) Not using a hammer to seat the bearings insures that they are driven straight. If the existing bearings are shot, you can use what you need to get them out, just make sure they come out straight. The bearing race is far stronger than the aluminum hub shell it’s pressed into.
Overhauling the freehub sounds like the right move here.
Typically you just need a few hexkeys or cone wrenches.
After cleaning everything I’d recommend using some freehub-specific grease such as Dumond Tech. Anything else will be far too thick and this stuff is recommended by most hub companies that I know.
I’ve used Phil’s Tenacious Oil too. It’s possibly more available. I used Phil’s grease on the replacement hub pawls as it didn’t have enough grease IMO. Works fine. I got new ratchet discs for a DT hub set, and it cam with their ‘special grease’, and it wasn’t much different IMO than Phil’s grease. But don’t mix greases as some have additives and may not play with other greases.
Also some hubs should only use an oil like Tenacious Oil. Thinking race hubs for bike racers. They need the lubrication, but not the drag of thicker grease(s).
I have a stock Giant-branded carbon rear wheel on my gravel bike with a 3-pawl hub that occasionally develops a sticky pawl, with the sound/feeling you described above. I’ve serviced it successfully a few times, and I believe I’ve used a very thin coating of DT special grease. Now that you mention it, it’s been quite a while since I last needed to do this, so it must be working
One thing I’ve discovered over the years was my belief that there was no such thing as too much grease doesn’t apply to hubs. I over filled a DT rear hub. I didn’t think I had put too much in it…
Well, that was annoying, the axel end not shown is a 12mm allen socket and my set went up 10mm. LBS didn’t have any for sale so the postie has just delivered the tool. I had the freehub off and the grease in there was black! I cleaned it and got it back together so I will have to see what it’s like.
Plus point, I now have more tools (and should get some spanners instead of a mole grip) and have a better understanding of hub maintenance.
So win-win! Good for you!! I love taking things apart and learning how they work. That I can usually get it back together and it still works is a plus.
On tools: what I hate are the SST (Special Service Tools) that I’ll likely never ever use again, but you have to have it to get the job done. Sometimes you can work around them, sometimes you can’t. (Mole grip = locking pliers? They can get you out of trouble, and sometimes put you in deeper too)
I didn’t think I had put too much in it…
Sometimes you can work around them, sometimes you can’t. (Mole grip = locking pliers? They can get you out of trouble, and sometimes put you in deeper too)