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Bent Frame- how dangerous?

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Bent Frame- how dangerous?

Old 07-31-10, 04:58 PM
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David325
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Bent Frame- how dangerous?

I picked up a '61 Raleigh Sports today with a bent fork. When I got it home, I realized the frame was slightly bent as well. There's a small rust spot on the top of the downtube near the head lug, and a small wrinkle on the bottom of the down tube near the head lug, which you can feel. I got the bike for free and have invested $0.00 into it, so should I go any further with it, or is it too sketchy? Is there a home-made way to straighten it out? Thanks
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Old 07-31-10, 05:31 PM
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I'd salvage everything off of it and look for a similar Raleigh frame or complete bike. Then you've got a warm and fuzzy parts inventory to go with it!
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Old 07-31-10, 06:07 PM
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Not particularly dangerous, just hurtful to a connoisseur's ego to ride one.

That said, if it isn't badly bent, a 20-30-tubed Sports can be cold set back into alignment with little issue; both frame and fork. You might still have a wrinkle mark left (and the top tube might bow somewhat in the process) but you can - most likely - get it back to its original geometry.

-Kurt
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Old 07-31-10, 06:37 PM
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I imagine I'd go about that by clamping the head tube in a vise between a couple pieces of wood and moving the frame? And the fork, I have no idea. Like I said, it was a free bike, so may as well go for it. If anything it turns into wall art.
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Old 07-31-10, 06:57 PM
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You would want to apply the load you describe then clamp some fitted blocks to the wrinkled tubes and press them back into shape with some twisting of the blocks.
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Old 07-31-10, 07:23 PM
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Got any pictures?
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Old 07-31-10, 08:03 PM
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Ftwelder's suggestion requires a repaint, and isn't worth doing to 95% of Raleigh Sports out there.

That said, if the wrinkle isn't that bad, it might not be that noticeable when you're done straightening the frame. This is the tool you need:

Park HTS-1:


Park HT-4 (with an FFS-1/2 leaning on it):


Both tools are long discontinued. An older bike shop may have them on hand. Excuse the mess in picture #2.

-Kurt
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Old 07-31-10, 08:52 PM
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The bend in the frame is hard to see by eye, I doubt I could capture it with my camera well. I may try to straighten it on a friend's vice or just leave it as the bike isn't too pretty to start with. The fork, though, I will definitely replace because I don't think I can straighten it. cudak- I guess they say you can never have enough tools!
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Old 07-31-10, 10:39 PM
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Originally Posted by David325 View Post
The bend in the frame is hard to see by eye, I doubt I could capture it with my camera well. I may try to straighten it on a friend's vice or just leave it as the bike isn't too pretty to start with. The fork, though, I will definitely replace because I don't think I can straighten it. cudak- I guess they say you can never have enough tools!
Rule #1 when examining frames for front-end collision damage: Put the bike against a neutral, single-color background. Preferably a wall with a contrasting color to the bike. Stand away 10 or 15 feet. Look at the top tube. Does it slope up? Look at the headtube, is it steeper than the seattube (generally only works with parallel angle frames, unless you have a really good eye). All this damage will be magnified when you look at the frame from afar.

Rule #1 when repairing a bent frame: You can't straighten the frame with a vise. Repeat with me: "You can't straighten the frame with a vise."

Your best bet will be to make a clone of that Park tool (not difficult, especially if you know someone who can weld up some U brackets), or find one locally.

-Kurt
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Old 07-31-10, 11:55 PM
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[
Your best bet will be to make a clone of that Park tool (not difficult, especially if you know someone who can weld up some U brackets), or find one locally.

-Kurt[/QUOTE]

I'm picturing a piece of round stock and a porta-power with some sort of v blocks to fit the BB and bar stock.
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Old 08-01-10, 07:40 PM
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I had a similar problem with my PX10 and this is how I fixed the bends.

Hope this is a help.
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Old 04-16-11, 01:58 PM
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Old 04-16-11, 02:04 PM
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Eddy Merckx used to just stare at frames long enough, and they'd straighten up. But this only works with bikes circa 1965-78. Works with errant teammates, too.
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Old 04-16-11, 03:13 PM
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This is what little I know about vintage road bicycle frame sets and repair...
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Old 04-16-11, 03:29 PM
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Originally Posted by randyjawa View Post
This is what little I know about vintage road bicycle frame sets and repair...
I'd take those backdrops off, if I were you. The site looks good with a simple tan background. The pictures only render the text hard to read.

Originally Posted by Picchio Special View Post
Eddy Merckx used to just stare at frames long enough, and they'd straighten up. But this only works with bikes circa 1965-78. Works with errant teammates, too.
What's Peugeot's excuse?

-Kurt
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Old 04-16-11, 04:43 PM
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Originally Posted by cudak888 View Post
Ftwelder's suggestion requires a repaint, and isn't worth doing to 95% of Raleigh Sports out there.

That said, if the wrinkle isn't that bad, it might not be that noticeable when you're done straightening the frame. This is the tool you need:

Park HTS-1:





Park HT-4 (with an FFS-1/2 leaning on it):


Both tools are long discontinued. An older bike shop may have them on hand. Excuse the mess in picture #2.

-Kurt
You missed a spot, I can actually see a clean spot on that bench....
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Old 04-16-11, 05:08 PM
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Originally Posted by cudak888 View Post
Park HTS-1:
You can basically do the same thing as this Park tool does, without the tool. You need two stout steel bars, like the one that goes through the head tube in this photo. Put one through the head just like in the photo (let's call it bar A); the other goes through the BB (let's call that bar B). Sit on the floor in front of the frame, with your feet on bar B, with bar A right in front of your body. Pull on bar A while straightening out your legs to force the two bars apart. You'll see the head tube and the down tube bending into a gentle bow shape, and if anything bends back to original shape, you'll feel that too. Relax and take a look. You may have to try a few times.
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Old 04-16-11, 06:07 PM
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back in the 80's I had a raleigh and I bent the frame like that - I rode it like without problems for thousands of miles
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Old 04-16-11, 06:23 PM
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Originally Posted by rhm View Post
You can basically do the same thing as this Park tool does, without the tool. You need two stout steel bars, like the one that goes through the head tube in this photo. Put one through the head just like in the photo (let's call it bar A); the other goes through the BB (let's call that bar B). Sit on the floor in front of the frame, with your feet on bar B, with bar A right in front of your body. Pull on bar A while straightening out your legs to force the two bars apart. You'll see the head tube and the down tube bending into a gentle bow shape, and if anything bends back to original shape, you'll feel that too. Relax and take a look. You may have to try a few times.
Can be done, but it is far easier and more accurate with the HTS-1 (and you don't risk twisting the headtube off alignment with the seattube), and some tubing won't react to run-of-the-mill brute force.

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Old 04-17-11, 10:44 AM
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Originally Posted by cudak888 View Post
Can be done, but it is far easier and more accurate with the HTS-1 (and you don't risk twisting the headtube off alignment with the seattube), and some tubing won't react to run-of-the-mill brute force.
+1. I tried that trick on a 531 frame, and nothing happened; I'm just glad I stopped before I hurt myself.

For some jobs, you absolutely need the right tool; for others, it's good to have the right tool but you can do without if you really need to. Cotterless cranks, for example; without the right tool you will certainly hurt the crank. Cottered crank, well, I don't recommend it but you can do okay without the right tool. I'd love to have a HTS-1, but am willing to do without. Sometimes.
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Old 04-17-11, 10:58 AM
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I posted my picture above by mistake as I thought I was postihg to my thread "Bent Zullo" I am not recomending to do it this way. Once a compact jack is found a tool like the Park one can be made. I am looking for one and will post a pictore when I get the tool made. A post jack may work.
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Old 04-17-11, 11:02 AM
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Originally Posted by 009jim View Post
back in the 80's I had a raleigh and I bent the frame like that - I rode it like without problems for thousands of miles
+1 -- I've been riding my DL-1 like that for years.
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Old 04-17-11, 12:21 PM
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Originally Posted by EddyR View Post
I posted my picture above by mistake as I thought I was postihg to my thread "Bent Zullo" I am not recomending to do it this way. Once a compact jack is found a tool like the Park one can be made. I am looking for one and will post a pictore when I get the tool made. A post jack may work.
Ed
I don't remember what they're called, but those turnbuckles which are used for adjusting tractor implements might just work well. I imagine they can still be bought new.
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