Classic & Vintage - How easy is it to bend the forks on a Raleigh Sports?

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Amesja
06-21-11, 07:39 AM
I had a bike that I restored a month or so back. It was all done and running fine and I had put a few miles on it to test it out before I started on the next project restoration.

The bike sat for few weeks in the line 'o bikes in my storage area (the living room) before I finally got it listed and even then it took a week or so before i finally got a bite.

When I went to take the bike out for a showing to a potential customer I noticed the bike pulled really hard to the right and there was a big black smudge mark on the sidewall of the gumwall tire. It had cleaned up the tire with a bit of alcohol on a paper towel but there wasn't anything I could do about the bike pulling. I had to call and tell the customer as they were on their way that I couldn't sell the bike that day in this condition but they were welcome to still come and see if it fit and check it out cosmetically. Since they were already on their way they decided to still come.

But I have to wonder WTH happened to the bike to bend the fork but not damage the wheel in any way (still true as an arrow without being off as much as a fraction of a mm.) Did I stumble through the mass of bikes in a drunken stupor one night and tip one over and step on the side of the fork and tire? I don't remember this but that is the thing with drunken stupors... I do remember a few bikes getting knocked over one day in a domino effect but since they are packed in there so tightly they can't fall very far and there isn't so much as a cracked or chipped cork grip in the whole line of bikes.

I have seen many bikes come into my shop with bent forks and always wondered what it takes to bend one as I've never done it while in my possession. Now that has changed and I still don't understand what happened. The big black mark on the side of the tire has to be a clue but I don't remember making it and my wife disavows all knowledge of any workshop bike-rack accident when getting her bike out of the mass on any caffeine-deprived morning pre-work ride.

Very strange. Maybe I have fork gnomes?


rhm
06-21-11, 08:49 AM
I have had a similar problem with my orange Norman. It always pulled to one side, I don't remember which. I finally got out the tools and measuring devices, figured out what was wrong, and proceeded to bend the frame using some 4x4 lumber and big carpenter clamps. And voila! The bike now rode straight. This was last Fall, or maybe the fall before that, I don't even remember now. I was very pleased that I could now ride no-hands.

Well, now it pulls again!

I haven't taken the time to figure out why. It could be something silly, like I put the front wheel in backwards if it's dished wrong, that'll do it; but I'm pretty sure the wheel is dished right). Or maybe the wheel isn't in the dropouts right.

Also on my Lambert. It used to have 26" wheels with a SRAM IGH hub (with which you are now familiar) and it rode perfectly. When I changed to 700c wheels I built up a 3 speed rear and used some random front wheel as a placeholder until I got around to building the front wheel with dynohub. Well, it pulled so bad I couldn't take my hands off the bar. But now that I've built my dynohub front wheel, and made sure it was dished right, the bike rides fine. Looky here Jim, no hands!

Amesja
06-21-11, 11:41 AM
Fork was really bent -about 1/2" both to one side as well as front/back. Straightening it helped run run no-handed again. Wish I knew what happened to this bike while it was sitting for the past few weeks since I last rode it.


realestvin7
06-21-11, 11:52 AM
Fork was really bent -about 1/2" both to one side as well as front/back. Straightening it helped run run no-handed again. Wish I knew what happened to this bike while it was sitting for the past few weeks since I last rode it.

Got any kids? Lol.

Amesja
06-21-11, 11:53 AM
Just the cat...

rhm
06-21-11, 11:54 AM
Got any kids? Lol.

Seriously. Or, what else happens in that garage? Someone parks a car in there? Garage door opener?

realestvin7
06-21-11, 12:01 PM
Unless you can prove you bend forks in your sleep or do other random destructive things in the garage whilst intoxicated, we may never know.

w1gfh
06-21-11, 12:43 PM
Maybe Uri Geller (http://en.wikipedia.org/wiki/Uri_Geller) got into your shop one night?

http://www.theness.com/images/blogimages/gellerspoon.jpg


there was a big black smudge mark on the sidewall of the gumwall tire.


they are packed in there so tightly they can't fall very far

Hm. The weight of a row of tightly packed bikes may be enough to bend a fork over time. Interrogate the neighboring bikes on either side of the victim. Get out your CSI kit and see if you can locate the source of the black smudgy material, e.g. another bike's chain.

robertob
06-21-11, 01:30 PM
Stupid question: What do you use for reference when straightening a fork? Surface plate and machinists blocks?? Plumb bob and careful measurement?

3speedslow
06-21-11, 06:49 PM
A friendly LBS that knows what they're doing. Hey, they have to eat too !

robertob
06-21-11, 06:51 PM
A friendly LBS that knows what they're doing. Hey, they have to eat too !

sadly those are very hard to find around here.

Amesja
06-21-11, 07:01 PM
I built a jig out of wood, some clamps, some straight-edges and a square to do the "measuring." It's just math.

Wood isn't up to the bending-back process. I slipped the steer tube into an 1-1/4" pipe that is embedded into the top of a concrete bollard out in the parking area of my building and just tweaked with my muscles in the direction(s) I thought it needed to go and then placed it back into the jig to re-measure and assess my work. Repeat as necessary until it is straight.

This isn't difficult if you have a good saw, some framing squares, straight-edges, and know basic finish carpentry to build something like that.

RobbieTunes
06-21-11, 07:08 PM
It's very easy to bend the forks. It's just hard to come out of the collision without injury.

Amesja
06-21-11, 07:58 PM
It's very easy to bend the forks. It's just hard to come out of the collision without injury.

Oh, how I know it!

I was test-riding the bike after straightening the fork and bopping around and some guy runs the stop sign at the end of my alley. Luckily the alloy rims on this build stop like a champ and he didn't run me over. I thought about the comedic value of having the bike just fixed when it gets crushed under a car after being ridden a whole 150 feet!

RobbieTunes
06-22-11, 06:53 AM
Comedic value if you break humerus.

Amesja
06-22-11, 06:53 AM
Comedic value if you break humerus.

That'll buff right out!