Bending an old steel frame
 

My 80's Raleigh road bike has 700c wheels on it now, and the rear wheel is wide for the width of the dropouts. They have to be flexed out in order to get the wheel to slide in. At home, it's a little bit of a pain, but doable. However, if I was to have a flat out somewhere and I needed to change the rear tube, I might be in trouble. Is there a way to permanently bend the frame so that it will fit the rear wheel smoothly?

Sheldon Shows you how. see links above.

What links above?

I'm guessing you meant the Sheldon shortcuts thread back in the mechanics forum? I looked through the rather long list, but I don't see the keyword "bend" anywhere. I'm not sure what to look for in that list.

Going from 126mm to 130mm is no big deal for a steel frame. Turn the bike upside down. It takes very little effort to spread each side 2mm so that you can drop in a 130mm hub. Noobs will probably do some damage the frame by applying too much force, or offsetting the frame's centerline.

Bending (cold setting for those that want it to sound technical) a steel frame, especially one of that era is about as easy as making a wish with a turkey wishbone. You'll need a 6" steel ruler, or an axle or threaded rod & 4 nuts to use as a gauge. (You can use a rear wheel also) Use the rod as a gauge by locking a pair of nuts a\against each other near one end then bolting the other end to one dropout with the nuts just touching the inner face of the dropout you're moving.

You want to bend each side separately so it's easier if you can stand the BB in a vice. If that isn't practical, lay the bike on the side, and with one foot on the lower chainstay up near the bridge, lift the upper dropout. At first it'll flex like a spring getting progressively "heavier" then you'll feel it move. Soon as it moves stop and check how far you've moved it using the ruler or threaded rod. When you've moved one side 2mm, switch and bend the other (don't forget to reset the gauge).

If you're a purist, and have the tool you can resquare the dropouts so they're perfectly parallel, but otherwise don't sweat it, 2mm per side doesn't change the angle enough to matter.

Sounds pretty straight forward. Thanks for the reply.

Note that the key to retaining the symetry is to bend only one side and measure. Then when it's just right to bend the other and measure again using the first bent side as your new reference.

FB mentioned this but I thought it worth stressing as if you don't do it with due care and consideration and planning you can end up with a non symetrical frame.

Oh, and Sheldon describes doing the job with a long 2x4 as a lever. It may well be worth using such a trick as it give you a more delicate feel of the yeild point and you're not popping a blood vessel trying to get enough force to do the bending.

I did a frame once without gauging. I reasoned that the two sides of the rear frame were pretty much the same, so if I simply pulled each dropout by hand in opposite directions, each side would bend the same amount. It did.

I believe it is important to hold the frame up only by the dropouts so that both sides bend evenly. I found it easiest to let the head tube dangle above my feet.

I got the front part of the dropouts to measure 130mm apart, then used a large crescent wrench to bend the dropouts inward so that they were once again parallel instead of splayed outward. This part was important because the hub would shift around when I pedaled until I did it. I eyeballed the parallelism. It is not safe to just tighten the QR until the dropouts bear squarely on the hub because if it's too tight, you'll ruin your bearings and cones.

I did it on my wife's old, steel road bike. I used Sheldon Brown's instructions (Google cold setting at SheldonBrown.com) As I recall, I needed a 2x4 or two, a metric ruler, and some string. It took about half an hour. It worked fine and my wife loves the bike.

OK, I've got a weird problem. I've been working with Sheldon's instructions and I've got the alignment pretty much near perfect, as far as I can tell, by using the string method. But for some reason, the rear wheel sits ever so slightly further back in the right dropout than it does in the left. This causes the rear wheel to sit at slight angle. Now, I can line up the rear wheel straight and tighten it on, but one side of it won't be pushed all the way down in the dropout. I can't figure out why one dropout seems to be further back than the other.

Odds are it was always that way, since nothing you did lengthened either chainstay. Make sure the wheel is centered between the chain and seat stays because that's what counts. If you have nutted wheels and tightening one side tends to move the wheel over in the other dropout, it's because the dropouts aren't parallel.

You can correct them with a special pair of costly tools, or with a big adjustable wrench (big enough to support most of the upper part of the dropout) using your wheel as a gauge.

Center the wheel, and note it's position in each dropout tighten one side and if the opposite end moves the dropout is off. Remove the wheel and tweak, and repeat. Keep doing this until you dial it in. Repeat the process with the other dropout. Doing it without the tools is much slower, but the tools aren't cheap.

BTW- If the wheel won't simultaneously center between the chain and seatstays (and the wheel is correctly dished) the alignment problem is more complex and you need to do a more complete analysis before tackling that, though you should still go ahead and square up the dropouts..

Yeah, I think it was always that way. I did square out the dropouts using my large adjustable wrench. I wasn't having any trouble with the nut tightening causing the wheel to be off center, thankfully. It was just simply that one drop out went further back than the other. Very weird. In any case, I "fixed" the problem with a dremel and a hammer. Everything is lined up now and works great.

On another note, I'm quite happy with my new multi-function apparatus that I acquired at The Home Depot.

http://bikeforums.net/attachment.php...hmentid=196763http://bikeforums.net/attachment.php...hmentid=196764

Are the chainstays each parallel to the centerline of the frame? Their angle as well as the amount that each splays out from the center line is important.

Edit: I guess I meant the dropouts not the chainstays.

huh???,

They can't both be parallel to the centerline since they aren't parallel to each other. They're wider at the back than at the BB shell. In any case you can't change where they start, and only care about where they end, ie 65mm out from the centerline for a 130mm bub. How they get from A to B doesn't matter, except that the right one has to clear the chainring.

Garage sale, I think you got darn lucky when you bent your frame open by just grabbing and givin'er. There is nothing at all in the metal that would encourage it to bend evenly. In fact the opposite is true. Tubing is this way since bending it at all involves it deforming to an oval which then tends to then bend more easily. So you got lucky that one time. The next one could just as easily bend all on one side or a little on one side and a lot on the other. In particular I would expect the drive side stays to bend out more easily due to the dimpling that is commonly done to give clearance for the chain rings where they pass the chain stays in order to keep the crankset in nice and close to the BB shell.

BR, you'll want to put a serial number on your custom frame adjuster and be sure it's included in with your household effects under "custom tools".... :D

Lulz

One chainstay is longer than the other. Assuming the frame has horizontal dropouts, as long as you can center the wheel in the frame (the axle doesn't need to be all the way back in the dropout) it will be fine.

I'm sure you meant to write "Are the dropout faces parallel to the centerline of the frame?"

I am not sure that was such a great idea. Now you are going to have to be careful how you are holding it. Nothing worse than a misaligned frame with no complaints.

Read of some peoples bridges across the stays popping the brazing.. when spread.
clamping at that point, so the spread takes place else where, in the tube,
would prevent that.

LBS has a fork tip alignment tool to make re setting the dropouts quick.

Older steel frames usually have a big crimp on the drive side chainstay, as a result it move easily than the non-drive side. Most frames I find already spread are offset. 4mm offset doesn't make much difference in handling (assuming it was square from the factory...) so most people never notice.

BCRider has it right, do one side at a time with the BB clamped in a bench vise.

It took me a few tries to get my alignment straight with Sheldon's method, but it's pretty solid now. I deepened one dropout slightly with the dremel to correct the other problem. I'm quite pleased with the result.

I wish I had a bench vise, though. Or a bench for that matter.