How to ID bent forks or frame?

[20130814]

Hi,

I recently bought a 2nd hand frame which is pretty old (fits 27 inch wheels). When I bought it I thought that the forks looked a tiny bit out of line, but it was just a vague feeling rather than anything obvious.

Now I have built the bike up, I find I can't ride it with my hands off the bars (not a practical way to get around, but a good check that all is lined up properly).

Also, when I look down at the bars when I'm riding I feel like it's not quite right, or quite lined up right, but when e.g. I try to look down at the bars from above, with the front wheel completely straight, and the bars straight, it all looks fine, but I feel like something is wrong but can't find an accurate way to measure things to see if things really are bent somewhere.

I wondered if anyone might be able to advise how I could go about checking this out please?

Any advice much appreciated.

Thanks

Jim

[cycleruk]

Sheldon Brown "string method:-
http://sheldonbrown.com/frame-spacing.html
(scroll down the page)

Also check that the headset is good as a worn or misaligned one can effect the steering.

[Brucey]

Colin has posted some nice string/alignment pictures too;

http://forum.ctc.org.uk/viewtopic.php?f=1&t=59332

cheers

[20130814]

Thanks for the replies. Assuming the frame is a bit bent do I need to worry about it or isn't it all that important assuming that it is just a minor bit out of line? Could it have any lasting impact on me physically to ride a bike that is a bit out?

Thanks

[Brucey]

often you will sit lopsided on a bike that is out of line and this can alter your posture enough to cause problems. Other times you won't ever notice.

One thing to consider is that the frame may be damaged in such a way as it may later break; I would keep an eye out for cracks, whatever you do.

cheers

[RogerThat]

I've had the issue on a few bikes/ frames I've bought over the years and more often than not its been a very worn or pitted headset that's caused the steering problems. Take it to your lbs and ask them to check out the headset if it's not then you probably are looking at a damaged frame. I've seen people cold setting frames, and even forks but it's not a job for the faint hearted