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Old 09-17-12, 12:07 AM   #1
chalol
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re bending fork / compromised frame

Hello all,

I have an '84 Trek 760, with reynolds 531c tubing. I built the bike up a little while ago and noticed the front wheel was very close to the down tube. I was so excited about the build I basically ignored it. After visiting a frame builder, I now know that the bike was in some sort of accident. The fork is obviously bent back some and the frame builder pointed out some slight bulges in the top tube and down tube right at the lugs and head tube. I was told that I could just have the fork straightened and be able to ride it.

Is the bike compromised and less safe?

Thanks, once agian in advance for all the great advice,

Chalol
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Old 09-17-12, 06:28 AM   #2
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If it's a small bend in the fork, then maybe it can be bent back, but the bent frame will affect how the bike handles. I guess you can try it and see if it rides "well enough". Depends how picky you are, how much you ride this bike. It may be better off as wall art. Did you buy it damaged ?
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Old 09-17-12, 07:39 AM   #3
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Strength of frame is not likely compromised that much. No way to tell how much handling will be affected without knowing what the head tube angle is now vs. stock. No wayu to tell remotely how bad fork is and how many ways it might be bent. You would have to remove the fork to have it evaluated by inspection and putting it into a fork alignment guage.
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Old 09-17-12, 07:52 AM   #4
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Can the builder straighten the frame? How bent and where is the fork bent? Forks are cheap you can used replacements for peanuts and carbon for less than $100 in fact I saw a Alloy/Carbon blend frame in a nashbar catalog for a few hubdred. Anyway better safe than sorry get a new fork.
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Old 09-17-12, 01:06 PM   #5
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Steel is quite forgiving of such insults. If the frame builder thought he could straighten it into rideable condition for a reasonable price, go for it.
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Old 09-17-12, 01:35 PM   #6
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Pictures would be helpful. But that said, any bike that has bulges at the top and down tube is suspect. It may give you years of service or it may fail tomorrow. Whether or not you want to risk it is up to you. However, the world is full of bikes that haven't been crashed and don't have suspect frames. This one isn't special enough to fix or continue riding. Find another one.
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Old 09-18-12, 10:50 PM   #7
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I agree with John D and would go with what an experienced framebuilder tells you.

The frame builder will be able to see the frame and see the rider's size (weight) to judge the suitability of a low-cost repair.

My haphazard guess at this point is that the frame has years of use left in it, although creases in the tubing might reasonably be expected to have at least some effect on the ultimate service-life of the frame. Aligning a fork is no big deal when it's steel.
The builder can measure your head tube angle and will know what amount of rake to put into the fork to balance out the front end geometry.
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Old 09-18-12, 11:30 PM   #8
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I'd try riding it as is first. I had a bike with slight frame damage like that, fork didn't look bent, but the front wheel did seem a little pushed in, and I really liked the way it rode and steered. If the fork is slightly bent back, and you straighten it without straightening the frame as well, it might just make things worse.
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Old 09-19-12, 02:57 AM   #9
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Thanks everyone.

Actually, this frame is special enough to fix. I'm going to have the fork bent. I've been told that it might be too bent, we shall see.

Chalol

Last edited by chalol; 09-19-12 at 03:04 AM.
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Old 09-19-12, 08:28 AM   #10
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Originally Posted by chalol View Post
Thanks everyone.

Actually, this frame is special enough to fix. I'm going to have the fork bent. I've been told that it might be too bent, we shall see.

Chalol
Are you going to replace the bent tubes, paint the bike and restore it to showroom freshness? Or are you just going to ride it and hope that you never have to use your face for a brake pad? Trust me, using your face as a brake pad isn't as sexy as it sounds. Either way, when I say that the bike isn't special enough to fix, I mean that a true repair...i.e. replacing the bent tubes and painting...would cost more than the bike is worth. You can find Trek 760s for around $300, which is over priced. A frame builder won't fire up the torch for that much nor would a painter mix paint for that price. And you couldn't even get close to facial reconstruction for that price.

It's your face but a bent production frame is a dead frame.
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Old 09-19-12, 08:38 AM   #11
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If we're talking a light rider on a smallish frame, I have a hard time imagining any dramas.
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Old 09-19-12, 09:13 AM   #12
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Longterm, suggest the best course is to salvage any parts of value and then use a saws-all to cut the frame into at least two parts so it will better fit into a recycle bin. Only exception I can see is if the bike is the only ride available and a tiger is about to start chasing you; Well then jump on and peddle like a crazy man being sure to steer near anyone you pass who is ugly/fat so the tiger might stop for a snack there instead of muching your hide. Basically there are too many undamaged bikes available to risk it failing on you..such as having a folk snap off as you are pulling up to a busy intersection spilling you head first into the wheels of big uglies.
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Old 09-19-12, 10:26 AM   #13
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If an experienced framebuilder says he can make it good, in the absence of pics, who am I to argue?

Odds are the guy isn't a raving loony.
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Old 09-19-12, 12:05 PM   #14
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I guess you can judge people by their avatars...
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Old 09-19-12, 01:24 PM   #15
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I might be gonzo, but I've never so much as broken a bone.
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Old 09-20-12, 12:39 AM   #16
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Wasn't thinking of you Kimmo...

Thanks again everyone for the varied responses, really helped me make my decision.

Chalol
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Old 09-21-12, 09:01 AM   #17
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Wasn't thinking of you Kimmo...
We know who you were thinking of.

You asked the question. If you don't get the answer that you want, don't blame the messenger. I know you have lots of time and energy invested in this bike but sometimes your investments just don't pan out.

Here's something more to consider...if you haven't disappeared into the ether...on your decision. Your frame/fork is bent so that the wheel is closer to the down tube than it should be. Not only is your fork bent...although the wheel being closer could be due to the bends in the frame...but because of the buckled tubes, your head angle is steeper. This will have an effect on handling. Your head tube may not be perpendicular anymore which will also have and effect on handling. A 'compromised' frame isn't just a frame that is bent but a frame that doesn't work the way that it should.
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Old 09-21-12, 09:45 AM   #18
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Haha, no just you know. You assume my frame is more bent or compromised than it is. Remember that you don't have pictures which would be nice. The damage to the frame itself is very, very slight. almost not perceptible. The fork is another question. I have had it looked at by very reputable frame builders, and one actually has the time to straiten the fork for me. Like others have said, he would not do, or very readily tell me not to, if he thought the bike was a total loss. For what I am using this bike for, it will be fine.

And yes, I am here to stay. A good part of the advice here is cogent, professional, and cordial. One has only to recognize it.
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