Chainstays off centre?

[Thaumaturge]

Fool enough to leave a bike chained up in the west end one night and someone had tried to give the wheels the obligatory 'Dali-melting clocks' look. They must have been sensationally drunk or just weak as the wheels were fine and i only surmised what had taken place when i started having trouble shifting gears and saw the rear mech badly bent in. Since then the back wheel has been just enough out of centre to make using rim brakes (the only option) impossible, and i've relied on the disc front. Would be nice to have all the braking power though so is there a tried/tested method for correcting this misalignment? Is it something many bike shops would be able to sort easily?

 

[velomaniac]

Look up Sheldon Brown on the subject of cold forging/setting for steel frames. Basically its about bending everything back to correct alinement. A bike shop can do it if they have the correct tools and skills but in this throw away world many will claim its unfixable and try and sell you a new frame/bike. With patience you should be able to do it yourself.

 

[bren]

Strong cotton thread or fine string. Tie a loop to the end, hook it around one of the dropouts, run it up to and around the head tube, then back down to the other dropout. Tension it and tie it off.
You'll now have a piece of taught thread running past either side of the seat tube and this is your datum. Measure the distance from tube to string each side. Any discrepancy between the two measurements will show you how much and in which direction you need to bend the stays.

If at all?

Dish of the wheel could be out thinking about it.

 

[M-Power]

Give Chas Roberts or Condor a call and let an 'expert' sort it, especially if its a valuable or rare bike. If you know what you are doing then you can DIY but its easy to overdo things and make it worse or trash the frame. Used to see this all the time bitd in central London.

 

[jonthefish]

Strong cotton thread or fine string. Tie a loop to the end, hook it around one of the dropouts, run it up to and around the head tube, then back down to the other dropout. Tension it and tie it off.
You'll now have a piece of taught thread running past either side of the seat tube and this is your datum. Measure the distance from tube to string each side. Any discrepancy between the two measurements will show you how much and in which direction you need to bend the stays.

If at all?

Dish of the wheel could be out thinking about it.

Fit the wheel wrong way round. Is the off-centre to same side as before? If so it is probably a chain stay or dropout problem and not wheel dish. Confirm with another wheel.

It might be a bent dropout rather than chain stays (you say rear mech was mashed so bent dropout seems well possible). The string round the head tube will help here. Tie or tape string to chain stay as well as dropout and measure both. If chain stay measures same both sides and dropout doesn't then dropout is probably bent.

If the dropout or rear triangle is off then I'd be inclined to confirm diagnosis with local bike shop before doing anything drastic.

Bent dropout can be bent back with whopping monkey wrench. I dare say other options exist. Rear triangle on steel frame can be cold set with 2x4 and leverage.

I just went through same things. Rear triangle was indeed out on my old Explosif. Sheldon's cold set worked. Not for the faint hearted and if it a really valuable frame I'd be thinking twice. Or three times. But the 2x4 trick worked for me. See viewtopic.php?f=1&t=286271

 

[Thaumaturge]

Brilliant information and comments people! Love that idea with the string though I can see how limited you are in determining where the twist/misalignment might be coming from. It's only a cheap runaround bike so wouldn't be worth spending money on to rectify but i'm open to careful experiemnting with the 4x2" (as we call em, am actually a chippy myself ). AS for dropouts versus stays.. i have the bike upside down and looking down the line of the frame from behind the back wheel it's very clearly crabbing to the left from that POV.. the effect is noticeably more pronounced at the chainstays (abt 6mm) than the seatstays (4mm). As the tire/wheel is a clost thickness to the seat tube it's amazing how big those mm's off centre look! So does that crabbing point to any particular culprit in this scenario? Have yet to set the string up.. will report findings when i do..

Oh.. and flipping the wheel doesn't change things. Off centre the same side either way.

 

[Bryncrug72]

Would be interesting to see if the "Dali" look would work on the little scrotes legs that did the damage ? :evil:

 

[Thaumaturge]

Oh yes. Most assuredly yes... I staggers me going around central London how times you see it. I cannot get my head around the mentality. It would never occur to me to want to do such a thing. Off all possible vandalisms why do these morons have such a hard on for bike wheels? Maybe it's just one very busy obssessive nut! He's probably internationally active in these pursuits.