Twisted Rear

[terry26rims]

I have a Saracen Flea 4 that has vertical drop outs and my tyre is NOW rubbing the non-drive side chain stay 97% of the time, more so when pedalling. Is it possible to twist the frame before first destroying the wheel? It's lasted over 2 years non serious riding, do i really have to give up on Saracen for Trials?

[TROYston]

Sounds like its flexing as you pedal, might be an idea to check your spoke tension.

And true your wheel back into the middle.

[craigjames]

Might be the wheel, but then i managed to twist two of the rear ends of these frames, so yes it is possible.

[terry26rims]

it's not the wheel. I'm going to have my step dad look at it and see if the frame is fixable or not. Probably not. (

[Mark W]

If you measure from the dropout to the BB on each side, if it's twisted it should be shorter on the side that it's twisted towards, theoretically?

[manuel]

If you measure from the dropout to the BB on each side, if it's twisted it should be shorter on the side that it's twisted towards, theoretically?

that wont work unless its actually bent the stay (the difference wont be that huge ?)? better to put the bike straight and measure distance between front and rear axles on both sides ?

[terry26rims]

If you measure from the dropout to the BB on each side, if it's twisted it should be shorter on the side that it's twisted towards, theoretically?

Ok will do. If it is, is it new frame time?

[Mark W]

that wont work unless its actually bent the stay (the difference wont be that huge ?)? better to put the bike straight and measure distance between front and rear axles on both sides ?

I thought it would've had to alter that measurement though, 'cos if the frame's been twisted if you measure directly from the axle to the BB axle, then it'd have to be different? The 'outside' of the bend would have to be longer?

[psycholist]

To check frame straightness get a piece of string and run it from the drive side dropout across the front of the headtube to the non drive side dropout. Measure the distance from the string to the seat tube on both sides and if there's a significant difference the frame is not straight. If it's just a wheel rubbing though, chances are you just need to dish the wheel back to the centre. Start at the valve hole and tighten each spoke pointed towards the flange you want to move the wheel towards a half turn until you get to the valve hole again. This will move the rim uniformly towards the hub side you've tightened the spokes to.

If the frame is slightly bent, but there's no sign of cracking and you can't feel it pulling sideways on you while riding it, then dishing the wheel will sort this problem too.

Edited May 14, 2010 by psycholist

[forteh]

Have you tried slackening and reseating the rear wheel? Could be its pulled out the dropouts on one side, this could cant the wheel over enough to rub the stays.

[terry26rims]

I have measured the frame and there doesn't seem to be any significant difference aprox 957mm from rear axle to headtube both sides, 383mm drive side bb to rear axle and 385 the non drive side. I'm going to try an old alexrims x2100 wheel in a bit as my trials rear wheel is an echo tr with tr freewheel using a tr tensioner and this maybe acting too much as a spacer. May need to alter the tensioner some how.

[terry26rims]

measured drop out height from floor and there is a 9mm difference. non drive side is higher and if i put the wheel in that side not all the way it works! I'll try and give it some brute force later to maybe succeed in bending it back. Wish me luck.