What to do about a bent fork
#1
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From: Akron, OH
Bikes: 2008 Seven Axiom Steel, 1984 Colnago Nuovo Mexico, 2008 Cervelo P2C, 2000 Trek Multitrack 7200
What to do about a bent fork
I posted this question under a different title without much response (1). I have a newly purchased 1959? Raleigh Dawn Tourist that pulls to the left. When I attached the front wheel, I noticed that one of the legs of the fork was slightly ahead of the other by a few degrees. Seems like that explains the pulling left problem. My local bike shop is reluctant to try to reallign the two forks for liability reasons due to the age of the steel. I guess that's good advice considering metal fatigue, etc. What's the fix? Look for a new fork on ebay?
TSapp
TSapp
#2
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From: Thunder Bay, Ontario, Canada - burrrrr!
Bikes: 1958 Rabeneick 120D, 1968 Legnano Gran Premio, 196? Torpado Professional, 2000 Marinoni Piuma
I have repaired slightly bent forks and frame sets. If you have the tools and the knowledge, you can effect simple repair. But you should, at least, know what you are doing or the liability thing might turn into a hospital thing.
Your fork will be hard to find. You might get lucky but I would suggest that you simply advertise your need on the forum. To do so, you will need to join and pay a very small sum to do so. Once done, you are free to advertise what you want to sell or buy. I think it is a very worthwhile way to spend a few dollars and other forum members can prove to be very helpful.
Your best bet would be to have a shop repair the forks. You might have to send the fork set away but the result would be worth the cost, in my opinion.
Hope this is a help.
Your fork will be hard to find. You might get lucky but I would suggest that you simply advertise your need on the forum. To do so, you will need to join and pay a very small sum to do so. Once done, you are free to advertise what you want to sell or buy. I think it is a very worthwhile way to spend a few dollars and other forum members can prove to be very helpful.
Your best bet would be to have a shop repair the forks. You might have to send the fork set away but the result would be worth the cost, in my opinion.
Hope this is a help.
#3
It really depends on how severely the fork is bent: Age has nothing to do with it - and if your LBS has ever sold a bike with a carbon fork, liability has nothing to do with it either. (See what the Trek website has to say about metal and carbon below.)
A mildly bent steel fork can be pretty easily repaired - (I've done it myself a few times) but it does require some level of skill and if the fork is going to be hard to replace, then Randy Jawa has given sound advice: Send it to someone else who knows what they are doing.
...Unlike metal parts, carbon fiber parts that have been damaged usually do not bend, bulge or deform; they break. A damaged carbon part may appear normal at a quick glance, but could suddenly fail without warning.... - Trek website
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#4
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Bikes: 1940s Fothergill, 1959 Allegro Special, 1963? Claud Butler Olympic Sprint, Lambert 'Clubman', 1974 Fuji "the Ace", 1976 Holdsworth 650b conversion rando bike, 1983 Trek 720 tourer, 1984 Counterpoint Opus II, 1993 Basso Gap, 2010 Downtube 8h, and...
The advice, "give it to someone who knows what they are doing" is always good, and always worth repeating. That said, there are some among us who like to do things ourselves, even if we don't know what we're doing. After all... what could possibly go wrong?
You probably only need to bend one blade a tiny bit. It's okay to bend it a little, then a little more, then a little more, until you get it right. It's a bad idea to bend it too much, because then you have to bend it back the other way again, and each successive bending fatigues the metal; sooner or later it will break.
I'd look around at the caveman tools at my disposal and come up with some kind of cheater bar I can attach to the bent fork blade to dramatically increase my leverage. Very likely I'd make the correct tool out of a couple pieces of wood held together with carpenter's clamps, etc. Ideally the fulcrum point should be as close as possible to the point where the fork is bent. Then with the bike upside down, and braced as necessary, I'd use that long lever to bend the fork blade straight. I'd probably remove fender, brakes, etc. and turn the fork around backwards so I could stand over the bike, feet on the ends of the handlebars, pulling the lever towards me, or something like that. This kind of thing is hard to figure out in the abstract; you'll figure it out if you try it.
When it comes to the actual bend, you have to feel the way the metal behaves; when you first lean into it, you'll feel it resist, then give; as soon as it gives the tiniest bit, stop and check your work. Repeat as necessary. If you put all your strength into it and nothing bends, you need a longer lever.
Okay, that's approximately what I'd do. Now take your fork to someone who knows what they're doing. That's always a good idea.

You probably only need to bend one blade a tiny bit. It's okay to bend it a little, then a little more, then a little more, until you get it right. It's a bad idea to bend it too much, because then you have to bend it back the other way again, and each successive bending fatigues the metal; sooner or later it will break.
I'd look around at the caveman tools at my disposal and come up with some kind of cheater bar I can attach to the bent fork blade to dramatically increase my leverage. Very likely I'd make the correct tool out of a couple pieces of wood held together with carpenter's clamps, etc. Ideally the fulcrum point should be as close as possible to the point where the fork is bent. Then with the bike upside down, and braced as necessary, I'd use that long lever to bend the fork blade straight. I'd probably remove fender, brakes, etc. and turn the fork around backwards so I could stand over the bike, feet on the ends of the handlebars, pulling the lever towards me, or something like that. This kind of thing is hard to figure out in the abstract; you'll figure it out if you try it.
When it comes to the actual bend, you have to feel the way the metal behaves; when you first lean into it, you'll feel it resist, then give; as soon as it gives the tiniest bit, stop and check your work. Repeat as necessary. If you put all your strength into it and nothing bends, you need a longer lever.
Okay, that's approximately what I'd do. Now take your fork to someone who knows what they're doing. That's always a good idea.
#6
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I think what's most important is to try not to damage the brazed joint at the fork crown and hopefully most of the bend is enough distance away from from the crown that there's a way to isolate the the brazed joint from the bending forces you will need to exert to work out the bend on the fork leg. I would think that if the bend is very close/right below the fork crown joint it will be less feasible to fix the fork yourself. In such cases, A frame builder can maybe just dettach the fork leg from the crown by heating it up, bend the fork leg back to spec while it's off and then re-braze it back on the fork. Worse comes to worse maybe both legs can also just be replaced.
Chombi
Chombi
#7
Randomhead
Joined: Aug 2008
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From: Happy Valley, Pennsylvania
you should be able to straighten that fork with no problem. Steel doesn't really age. I suppose you could worry about rust, is it heavily rusted?
Don't bother cross-posting in the framebuilding forum, half of the framebuilding forum regulars post here. I don't see the upside for me in replacing fork blades or steerers. I would be far more reluctant to start cutting on that fork than to just bend it back.
Don't bother cross-posting in the framebuilding forum, half of the framebuilding forum regulars post here. I don't see the upside for me in replacing fork blades or steerers. I would be far more reluctant to start cutting on that fork than to just bend it back.
#8
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From: Akron, OH
Bikes: 2008 Seven Axiom Steel, 1984 Colnago Nuovo Mexico, 2008 Cervelo P2C, 2000 Trek Multitrack 7200
Well, since I definitely do not know what I'm doing most of the time anyhow, taking the bike to a shop that can do the job seems like the best advice to me. In my earlier post, a member suggested a shop in Wooster, Ohio that might do the job. I sent them an email as to the problem, but no response back yet. Any of you happen to be Buckeyes out there and know of a shop within an hours drive of Akron? Great info all! Thanks for the input.
Terry
Terry
#12
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From: Akron, OH
Bikes: 2008 Seven Axiom Steel, 1984 Colnago Nuovo Mexico, 2008 Cervelo P2C, 2000 Trek Multitrack 7200
Here's a good one! An Ohio shop I contacted would do the job for a mere $60/hour, two hours minimum provided I remove all components before bringing the bike in. Maybe I'm a little ignorant as to what this should cost, but seems a bit too pricey to me. Is this a "Thanks, but no thanks!" situation?
TSapp
TSapp
#13
Here's a good one! An Ohio shop I contacted would do the job for a mere $60/hour, two hours minimum provided I remove all components before bringing the bike in. Maybe I'm a little ignorant as to what this should cost, but seems a bit too pricey to me. Is this a "Thanks, but no thanks!" situation?
TSapp
TSapp
#14
Here's a good one! An Ohio shop I contacted would do the job for a mere $60/hour, two hours minimum provided I remove all components before bringing the bike in. Maybe I'm a little ignorant as to what this should cost, but seems a bit too pricey to me. Is this a "Thanks, but no thanks!" situation?
TSapp
TSapp
On the other hand, if THEY remove/reinstall the fork, headset, stem, brakes, and bar tape, two hours would be reasonable.
PS - personally, I'd have more confidence in ftwelder for this kind of work anyway, because he's a framebuilder.
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Last edited by auchencrow; 10-22-10 at 06:19 AM.
#15
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From: Akron, OH
Bikes: 2008 Seven Axiom Steel, 1984 Colnago Nuovo Mexico, 2008 Cervelo P2C, 2000 Trek Multitrack 7200
I thnk they want to put it on this "magic machine" to check if there is some other problem causing the "pull to the left" other than the bent fork. The machine must look at the entire allignment of the frame, fork, and whatever else could be out of line. I guess I'm making a payment on the "magic machine" (or someone's boat). It's not like this bike is about to be used in the "Tour"!
TSapp
TSapp
#17
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From: Maidstone, Kent, England
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I thnk they want to put it on this "magic machine" to check if there is some other problem causing the "pull to the left" other than the bent fork. The machine must look at the entire allignment of the frame, fork, and whatever else could be out of line. I guess I'm making a payment on the "magic machine" (or someone's boat). It's not like this bike is about to be used in the "Tour"!
TSapp
TSapp
"Magic machine - a tape measure! You won't do better than FTwelder's offer IMHO
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