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Car accident: re-aligning rear drop-outs

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Car accident: re-aligning rear drop-outs

Old 08-10-20, 10:21 AM
  #1  
Laingod
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Car accident: re-aligning rear drop-outs

Good day bikeforums community!

I am currently finishing up some of the numerous projects lying around my appartment and am facing a new challenge. A couple months ago I picked up a decent bike and tuned it up for a friend who really needed to get some fresh air after being enclosed for months. He was so happy riding his bicycle around town I hadn't seen him smiling like that in ages. The bike is nothing fancy but really suited him so I spent quite a bit getting decent parts.



Unfortunately, a month later he got hit by a car on the way to my place: he was caught from behind sideways and fell badly. I picked up the frame as the ambulance took him to the hospital.
Luckily hes recovering nicely and I plan on fixing or providing him with another bike in the upcoming weeks. I plucked out whatever was finished and am now left with this:










From what I can see the geometry is still good somehow, no cracks or dents anywhere. The rear wheel was wrecked and its axle too.
My question is this: I tried bending it back with vise-grip pliers but I won't get it back to its original state - would it affect the riding a lot if I were to put back a wheel and secure it tightly, ensuring it's aligned with the frame?
I also plan on taking it to my lbs this week to get their advice as well and maybe give 'em the job if not too expensive as I am no expert. Just curious to know if anyone's ever tried that before.
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Old 08-10-20, 10:37 AM
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fietsbob
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camera wont measure

Bike shop tool is made for that ... https://www.parktool.com/product/fra...e%20%26%20Fork

or take a length of All Thread* & 4 nuts..
Cut the all thread in what will be halves clamp the halves with the nuts to the dropouts..

when dropouts are parallel the 2 halves will be as if a straight line,

then you figure out if the dropouts are back to being equidistant to the center-line..

* long 10mm or 3/8" bolts maybe , but will offer no leverage to bend the dropouts back..







...
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Old 08-10-20, 11:15 AM
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Very interesting!
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Old 08-10-20, 11:35 AM
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This is more or less how I do it here...











...you can improvise a lot, but you do need string, some sort of measuring device (a caliper works best, but you can get by with a ruler), some way to hold the frame while you tweak the stays (which you can often do with hand and arm strength alone on a frame like that), and some sort of homemade tool to do the final dropout alignment. You can pound them flat with a hammer on some flat steel surface, or wood blocks if that's all you have. the best way by far to flatten the dropouts is with a vise, squeezing them flat in the jaws one at a time.

My photos never seem to load in order here, but the last one is the initial setup.
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Old 08-10-20, 02:01 PM
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That's smart, I have a good ol' workmate bench that acts as a vise but not as strong as a steel one. Should be able to maintain it in place with it with the bottom bracket.
Had trouble figuring out a couple of the shots though, is the string here so you can check the distance between it and the seat tube?
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Old 08-10-20, 04:43 PM
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Any chance of finding a frame and moving the parts over? Local Co-op or craigslist. ?
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Old 08-10-20, 04:57 PM
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Did the guy that hit your friend stop and does he have insurance? Along with paying for medical costs it should cover the cost of repairing or replacing the bike.
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Old 08-10-20, 06:59 PM
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Yield to the master

https://www.sheldonbrown.com/forkend-alignment.html

Vice grips were probably not the best choice.
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Old 08-10-20, 08:30 PM
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There are some people that are gifted when it comes to making something totally trashed into something that is a treasure.

Ok think this through. Imagine that the only thing damaged was the frame, that the wheels and hang-on components were fine. You are going to spend hours bending the frame back into something that will function but what do you now have? What you have is a not so pretty bike that has big dents and a bad paint job. What is the goal here, to have a bike that "works" or something that is safe and fun to ride?

For some reason some bicycle people hate to state the obvious. Given everything as I see based on the OP details and the pictures there is very little there to work with. The bike fails the Thomas15 "cost/effort vs. potential rewards" test.

Last edited by Thomas15; 08-10-20 at 08:34 PM.
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Old 08-10-20, 09:30 PM
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Originally Posted by Laingod View Post
That's smart, I have a good ol' workmate bench that acts as a vise but not as strong as a steel one. Should be able to maintain it in place with it with the bottom bracket.
Had trouble figuring out a couple of the shots though, is the string here so you can check the distance between it and the seat tube?
...I used to use a workmate before I had the cash to mount a decent new Bench vise. If you use some short pieces of aluminum angle as jaw covers, you can avoid marring up the workmate surfaces, if that's important to you. Yes, the sole purpose of the string is so you can measure the distand at the seat tube, to determine whether one or the other (or both) of the rear triangles might have gotten pushed off to one side or the other. When a bike gets hit by a car like that, with a wheel installed in the dropouts, it's not unusual for both of the rear triangles of seat and chain stays to move to one side or the other.

When you string it up, make sure the string comes off each dropout at the same point, or it can introduce some error.

In essence, you are at one and the same time trying to get the dropout spacing right for your new wheel OLD (120mm, 126mm. 130mm), and do it in such a way that each dropout surface is equidistant from the frame's centerline plane. Which is where you want the rear wheel to run.
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Old 08-12-20, 07:34 AM
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Thanks for all the answers. I would move the parts to another frame if I had one but got nothing around at the moment. Besides I think of this as a good challenge as I've never dealt with geometry on a frame before, so the time and effort I'll spend on this will be rewarded with trial and error (and who knows, I might somehow succeed.) and more valuable knowledge. Indeed the point is to turn it back into something safe to ride so I won't take chances if my work isn't sufficient.

As for the insurance, turns out my friend only has basic healthcare but no proper insurance, so the driver who ran into him is asking for 5000$ in repairs because he smashed the door real hard with his head... he's ready to pay up to get this over with but I believe some negotiation can be done here since the police report is rather incomplete. Bikers getting hit is unfortunately pretty common here in Montréal and there's only so much they will do.

Anyhow cheers for the tips!
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