Cycling UK Forum

Having the bike up on the stand today I noticed the freewheel kind of wobbles side to side when the wheel rotates. The wheel itself is fine. There's very little gap between the brakes and the rim and I'm not getting any periodic rubbing.

Video attached.

Anyone any idea what's wrong here?

Tolerance stacking. The bane of all mechanical assemblies. Your video looks quite acceptable to me. They all do it mate...

Geoff_F wrote: ↑15 Sep 2024, 5:52pm Tolerance stacking. The bane of all mechanical assemblies. Your video looks quite acceptable to me. They all do it mate...

I'd never noticed before. Then again, the bike stand is a new addition , so I've probably not given such things nearly so close a look before since it was a literal pain in the neck.

mister_ed wrote: ↑15 Sep 2024, 5:55pm

Geoff_F wrote: ↑15 Sep 2024, 5:52pm Tolerance stacking. The bane of all mechanical assemblies. Your video looks quite acceptable to me. They all do it mate...

I'd never noticed before. Then again, the bike stand is a new addition , so I've probably not given such things nearly so close a look before since it was a literal pain in the neck.

Some co axial error and some out of square with the axis of rotation. Most of my cassettes have been similar to yours - some were better with only slightly discernible run out by eye. It looks horrible but does not have any meaningful effect in use

I suspect that it isn't a freewheel at all having counted the sprockets but I may be wrong. If it really is a cassette then maybe the locknut is loose. Seen that.

..yup.... mine currently does that too...

mattsccm wrote: ↑15 Sep 2024, 6:40pm I suspect that it isn't a freewheel at all having counted the sprockets but I may be wrong. If it really is a cassette then maybe the locknut is loose. Seen that.

Definitely a freewheel, specifically a sunrace megarange 7 speed 13-34, and the 4th one this bike has had over the years.

Slightly bent axle????

Agree it is a screw on freewheel.
The sideways movement is probably due to
1. The hub RH bearing cup is unevenly worn, so the hub runs a bit off centre on its RH bearing, or
2. It is a cheap 3 piece hub (central barrel plus a bit on each end), and the RH end bit no longer sits square on the end of the central barrel. You can check for this by spinnning the wheel and looking to see it the RH hub flange runs straight or not. Also the end of the barrel will run off centre as the wheel spins.
3. If the wheel is creaky as you ride it (ie under load), then the same effect can be had due to the bearing cup having come a bit loose in the hub shell. If this is the case, it is impossible to adjust the bearing correctly (ends up with play in the hub beaing while it is tight to turn).

If the RH bearing cup is worn, new wheel at some point. If you run a worn bearing cup for too long, the cup eventually collapses at the bearings wear right through the bearing cup.

All the freewheels I've had did this. It annoyed me but didn't give any problems. I'v swapped over to a free hub now.

All freewheels tend to do this 'cos it's difficult to get the hub and freewheel body threads very accurately co-axial and any small difference is visible as exactly the wobble the video shows. The laws of probability say that every now and again you'll get one that is bang on. I recall that BITD Bernard Hinault hated this wobble and insisted that his mechanics kept discarding them 'til a satisfactory one was found. Presumably the discarded ones got fitted to the bikes of the lesser mortals in the team

francovendee wrote: ↑16 Sep 2024, 8:17am All the freewheels I've had did this. It annoyed me but didn't give any problems. I'v swapped over to a free hub now.

If/when the back wheel conks out, I'll probably switch over to using a freehub.

KM2 wrote: ↑16 Sep 2024, 4:40am Slightly bent axle????

different symptoms entirely. It is best to check for a bent axle by turning it whilst the wheel is stationary. FWIW that doesn't seem too bad to me, they nearly always look worse than they really are; this is an optical illusion created by the chamfered tooth tops in modern cogs. This would probably have driven Bernard Hinault berserk.

Looks perfectly normal for a freewheel. If you do swop to a freehub it should eliminate this wobble and your shifting will be crisper. In fact its hard to beat the shifting of a 7 speed cassette as the tolerances are so wide compared to cassettes with more cogs. I sort of feel that freewheels now being entry level only have downgraded a bit in recent years as there are few premium freewheel options so its base level stuff only. I'd still go Shimano though for freewheels even though they probably don't make any themselves nowadays and just outsource them.

Bonzo Banana wrote: ↑21 Sep 2024, 10:39am..... I'd still go Shimano though for freewheels even though they probably don't make any themselves nowadays and just outsource them.

the current shimano design is potentially the lightest ever. However, I don't think HG sprockets are as hard wearing as UG ones and heavily overhanging sprockets seem to encourage the freewheel lockring to come unscrewed; in this design the lockring really needs a drop of threadlocking compound on it.

Nearly everybody has basically copied shimano's previous spline design for HG sprockets, to the extent that it is possible to freely interchange sprockets between some brands and many more swaps are made possible by a little filing or grinding. The closest thing we have to a 'universal donor' is the IRD freewheel; sprockets from this fit nearly everything else.

Many older shimano bodies are extremely hard wearing, so a good arrangement is to fit IRD or Sun Race sprockets to such a body. It is not difficult to tweak the sprocket spacing to better fit with some indexing systems, eg by altering the thickness of plastic spacers. The shift quality seems to be excellent with Sun Race sprockets, so not in any way second rate vs. shimano ones.