6-speed freewheel shim?

[Alan O]

On an old-style 6-speed bike I've just replaced wheels, chainset, chain and block/freewheel. The problem I have now is that the rear derailleur won't engage the bottom gear - I've adjusted it as far as I can, but it's just outside of its range now.

Comparing the old and new wheels, I can see that the geometry is slightly different and the freewheel on the new one is closer in to the centre line of the bike.

A different derailleur with a greater adjustment range might do the trick, and the old one is getting a bit worn now and doesn't always engage as smoothly as it should. So I have been thinking about replacing it - I put a SunTour Vx on another bike and I really like that.

But my question is, can you get any kind of shims for old screw-on freewheels to adjust the positioning of the gear block?

Thanks in advance,
Alan

 

[si_c]

You don't need a shim, it wouldn't work like that, you can get different axle spacers which would allow you to change the position of the wheel in the dropouts and move it over a touch.

 

[Alan O]

You don't need a shim, it wouldn't work like that, you can get different axle spacers which would allow you to change the position of the wheel in the dropouts and move it over a touch.

Thanks, but I'm not sure I understand that - wouldn't the axle no longer fit between the dropouts if I add a spacer?

Alan

 

[raleighnut]

Thanks, but I'm not sure I understand that - wouldn't the axle no longer fit between the dropouts if I add a spacer?

Alan

You'd need to swap the distance 'left-right' to maintain axle length but then the wheel would need 're-dishing' for the rim to be central.

 

[davidphilips]

dont know if a shim is available but perhaps a different derailleur may be best way just my thoughts as if you moved wheel over then bike would be out of line? may work but a look at old derailleur just in case it is sticking and a bit of tlc could have it or a replacement working well, good luck

 

[Alan O]

You'd need to swap the distance 'left-right' to maintain axle length but then the wheel would need 're-dishing' for the rim to be central.

Hmm, yes, I'm beginning to see what you mean, thanks. It's sounding like a big job - redishing would be beyond me, and paying a shop to do it would cost more than the wheel. I have been looking closely at the wheel axle, but I can't even get the locking nuts to shift!

If only there was some sort of shim I could use to back off the freewheel a little (ie so it was screwed on a couple of millimetres less).

Alan

 

[Alan O]

dont know if a shim is available but perhaps a different derailleur may be best way just my thoughts as if you moved wheel over then bike would be out of line? may work but a look at old derailleur just in case it is sticking and a bit of tlc could have it or a replacement working well, good luck

Yes, thanks, I think a replacement derailleur might be the way to go. I've closely inspected the old one and I can see where it's hitting on its movement limit, so unfortunately it's not just stuck - it just doesn't seem to have a lot of left-right movement. (It's an Exage 300EX, about 30 years old).

 

[si_c]

Yes, thanks, I think a replacement derailleur might be the way to go. I've closely inspected the old one and I can see where it's hitting on its movement limit, so unfortunately it's not just stuck - it just doesn't seem to have a lot of left-right movement. (It's an Exage 300EX, about 30 years old).

I have the same dérailleur on one of my bikes, if it's the long cage version then you should have plenty of range. It's a pity you're having trouble getting the axle locknuts off as you could in theory move the spacers from the old wheel to the new. Meaning the old dérailleur would be fine.

 

[Alan O]

I have the same dérailleur on one of my bikes, if it's the long cage version then you should have plenty of range. It's a pity you're having trouble getting the axle locknuts off as you could in theory move the spacers from the old wheel to the new. Meaning the old dérailleur would be fine.

I think it is a long-cage one - it looks like it's got a good wide tooth range. It is pretty old and worn though (like me, I guess ), so I might replace it anyway.

And yes, the locknuts are a pain. The ones on the old wheels are fine, even after years, and I had no trouble getting them off last year to re-lube. Looking and pondering some more, I see the right-hand (chain side) lock nut on the new wheel is thicker than the one on the old wheel, and the new wheel does look like it needs to be shifted right a couple of mm. Using the spacing from the old wheel would probably be perfect.

I think tomorrow I'll see if my bench vice is any good for helping shift the nuts

 

[User32269]

Soak in wd40 overnight and get yer old nuts in the vice!

 

[Poacher]

I dimly recall using a shim on a freewheel block - as much to facilitate later removal as to move the block out a fraction. Would this do the job?

 

[Alan O]

I dimly recall using a shim on a freewheel block - as much to facilitate later removal as to move the block out a fraction. Would this do the job?

Ah, that might do it - I'll see if I can adjust the spacing first, and then might try one of those if needed. Thanks.

 

[si_c]

I'd be concerned about using one of those as you are reducing the number of threads being used on the freewheel. Unlike a freehub, this has the potential to cause problems.

 

[Alan O]

Didn't get round to it yesterday, with other jobs to do in the morning. Then the weather in the afternoon was perfect for a ride on my MTB instead - and by perfect I mean it was wet and I know a great mudbath to play in!

Then home, clean down the bike, nice hot bath, wash my muddy clothes... and all I was fit for then was to veg out in front of the telly.

Hopefully I'll fix it this week some time - and yes, I'll make sure the spacing is right before I consider using a shim.

Thanks everyone,
Alan