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Old 10-10-06, 03:02 PM   #1
Grand Bois
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Coldsetting a frame with a threaded rod

I've always used the 2X4 method described on Sheldon Brown's site to spread the rear triangle, but I thought I'd try using a threaded rod, nuts and washers this time because I had the hardware on hand. I needed to spread a mixte frame from 126 to 130. Mixtes are a little harder because they have three stays per side.

I had the frame and fork in the workstand hanging by the seatpost. The first problem I had was that the threaded rod tended to turn and slide out of the dropout when I turned the nut, so I had to hold it in place with my left hand. The second problem was that, in order to check progress, I had to back off the nut and that's a lot of work when you're turning the nut 1/3 turn at a time with an open-end wrench with one hand and gripping the threaded rod with the other. I ended up taking it all the way out to 165mm, but it sprung back to 127mm when I backed off the nut.

It always bothered me that using this method assumes that the stays will bend equally when equal pressure is applied to them. There's no reason to believe that, especially when the drive side stay is crimped for chainwheel clearance.

I had just decided to give up this lame method and do it the right way when the seatpost pulled out of the frame. I had a firm grip on the threaded rod and I instictively raised my arm to keep the frame from hitting the concrete. The frame swung down and a fork end caught me on the shin bone. After I got through screaming and swearing, I got out the 2X4, string and ruler, laid the frame on a piece of carpet and spent about five minuts spreading a realigning the frame the right way.

The reason I have time to write all of this is my lower leg and foot swelled up and turned purple and I'm under doctor's orders to stay home from work and off my feet. I'm waiting for UPS to deliver a bunch of parts for the mixte, so I won't be staying off my feet.
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Old 10-10-06, 03:24 PM   #2
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ouch!
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Old 10-10-06, 03:26 PM   #3
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Quote:
Originally Posted by Dirtdrop
I had just decided to give up this lame method and do it the right way when the seatpost pulled out of the frame. I had a firm grip on the threaded rod and I instictively raised my arm to keep the frame from hitting the concrete. The frame swung down and a fork end caught me on the shin bone. After I got through screaming and swearing, I got out the 2X4, string and ruler, laid the frame on a piece of carpet and spent about five minuts spreading a realigning the frame the right way.
I'm sorry, but when you picked up the 2 x 4, I started laughing. I thought the next bit was going to read: "And I beat the crap out of it. Within five minutes I had a ball of twisted up tubing sitting on the floor in front of me waiting to go to the dump. The 2 x 4 method works a treat when all else fails!"

I admire your fortitute in the face of unyielding pain and I hope the wounds heal with suitable trophy scarring.
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Old 10-10-06, 03:40 PM   #4
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First, sorry to hear about your injury, Dirtdrop. And I agree, it makes more sense to use the "2 x 4 method" than the "all-thread method" for coldsetting, since it takes into account the issue of alignment. I've never used a 2 x 4 for coldsetting, but when I find the need to coldset another frame, I'm going to go that route. But I can't completely condemn the all-thread method, that's what I used on my '83 Schwinn le tour luxe (126mm to 130mm). I checked the alignment with a string recently, and if it's out of alignment it's not enough for me to detect with the string. I think I got lucky, though, and I'd rather not depend on luck for proper alignment next time..........I've put over 3000 miles on the Schwinn since I rebuilt it (and coldset the frame), and Saturday before last I did a century on it (105 miles to be exact). It may be my favorite bike ever, "all-thread" coldsetting and all-

Last edited by well biked; 10-10-06 at 06:20 PM.
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Old 10-10-06, 08:17 PM   #5
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Quote:
Originally Posted by Dirtdrop
It always bothered me that using this method assumes that the stays will bend equally when equal pressure is applied to them. There's no reason to believe that, especially when the drive side stay is crimped for chainwheel clearance.
I recently spread a frame from 126 to 130 and thought about that same problem. Instead of cold-setting the frame I just spread it the 4mm to get the rear hub in there. It wasn't too hard and everything seems to be aligned correctly.

I'm going to need to do the same thing with some forks. Modern hubs seem to be about 4 to 6 mm wider. Do we think the same thing will work?
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Old 10-10-06, 09:00 PM   #6
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The 2X4 method bends one side at a time so you just have to bend them equally, or not, if you're starting with a frame that's out of alignment. The seat tube acts as the fulcrum for the 2X4 lever. Offhand, I can't think of a way to do that with a fork. I'll bet someone on the framebuilder forum could help with that one.
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Old 10-11-06, 04:00 AM   #7
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Originally Posted by reverborama
I recently spread a frame from 126 to 130 and thought about that same problem. Instead of cold-setting the frame I just spread it the 4mm to get the rear hub in there. It wasn't too hard and everything seems to be aligned correctly.

I'm going to need to do the same thing with some forks. Modern hubs seem to be about 4 to 6 mm wider. Do we think the same thing will work?
Does this mean that you didn't check the alignment after cold-setting?
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Old 10-11-06, 05:15 AM   #8
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I did some cold setting last night and used a threaded bar + washers + some old rubor car floor matting to stop the the bar slipping and to stop scratchs. Worked fine for me checked my alingment was slightly out but by possitioning the bar appropeatly I was able to tweak each side correctly. Checked my alignement again and it was fine. It did take some time tweaking bolting and unbolting e.t.c. I think I would use the 2x4 method in future but living in a small flat I don't have any 2x4 around but I do have threaded bar in my tool box (it's my head set press!). It is alot easier to be a mechnic when you have every tool under the sun but some times you need to improvise and make do.
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Old 10-11-06, 05:17 AM   #9
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Quote:
Originally Posted by onbike 1939
Does this mean that you didn't check the alignment after cold-setting?
This question was not asked of me, but I would like to make a general comment.

Thousands of people for decades didn't worry about alignment nearly as much as they do today. Nor did they worry about dishing to the precision that people do today, and a little wobble in a rim was just fine as long as the brakes didn't rub. This doesn't apply to everyone from years past, ut there are some of us hacks that didn't check such things.

And we still had fun riding the bikes even though I guess we should have been surprised that they could ride at all.

A properly aligned frame is nice, and now with the internet we know how to ensure alignment and dish and everything else that needs verification... but the extra steps aren't essential to a ridable bike. If people can ride swing bikes, surely they can ride a bike with the rear dropouts off center by a millimeter or two.

Just to clarify... I am not saying that people shouldn't check things like alignment and dish, I am just saying that you shouldn't be surprised if someone has a perfectly ridable bike without checking things with the precision that they could use.
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Old 10-11-06, 07:05 PM   #10
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Quote:
Originally Posted by onbike 1939
Does this mean that you didn't check the alignment after cold-setting?
I didn't cold set it. I just put the hub in there. When I remove the hub, the frame goes back to where it was. I'm able to ride the bike no-hands without any trouble at all so I'm assuming it is aligned correctly.
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Old 10-11-06, 07:47 PM   #11
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I could see a park tool that could make the threaded process a whole lot easier like a ruler built into it that measures as you adjust the frame
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Old 10-11-06, 09:17 PM   #12
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Originally Posted by ryanparrish
I could see a park tool that could make the threaded process a whole lot easier like a ruler built into it that measures as you adjust the frame
That won't help. As I said in my original post, I spread the frame all the way out to 165 and it sprang back to 127 when I released the tension. Steel is springy. That's why steel frames ride so well.

The job can be done much more quickly and accurately using the 2X4 method described by Sheldon Brown.
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Old 10-12-06, 04:10 AM   #13
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Quote:
Originally Posted by Little Darwin
This question was not asked of me, but I would like to make a general comment.

Thousands of people for decades didn't worry about alignment nearly as much as they do today. Nor did they worry about dishing to the precision that people do today, and a little wobble in a rim was just fine as long as the brakes didn't rub. This doesn't apply to everyone from years past, ut there are some of us hacks that didn't check such things.

And we still had fun riding the bikes even though I guess we should have been surprised that they could ride at all.

A properly aligned frame is nice, and now with the internet we know how to ensure alignment and dish and everything else that needs verification... but the extra steps aren't essential to a ridable bike. If people can ride swing bikes, surely they can ride a bike with the rear dropouts off center by a millimeter or two.

Just to clarify... I am not saying that people shouldn't check things like alignment and dish, I am just saying that you shouldn't be surprised if someone has a perfectly ridable bike without checking things with the precision that they could use.

I've ridden a bike for a few decades now (30 odd years) and would regard a well aligned bike as more than "nice".
I don't admire the philosophy of the "anything will do" school of thought and still cling to the idea that a job is worth doing well. After all a frame that is aligned is a pretty basic requirement I believe.
Then again I see these things a a matter of giving respect in that a bike can provide thousands of miles of enjoyment and it seems little to ask that one keeps it well-maintained.
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