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Technical & Reference Section => Tech and Restoration => Topic started by: S1 on July 23, 2008, 12:19 PM

Title: Straightening forks
Post by: S1 on July 23, 2008, 12:19 PM
Ive got a Mongoose Californian F&F i recently bought on ebay. Checking it over last night I discovered the forks are bent, one leg is about 10-15mm further forward than the other. I think the left/right aspect is ok. Has anyone sucessfully straightened a pair of forks? and can they recommend a method of doing so?
Title: Re: Straightening forks
Post by: toys19 on July 23, 2008, 12:25 PM
Well the proper engineering method would be with a press loads of motorcycle and car places do straightening, depends on how much you want to spend..
A few years ago I had some warped motorcycle disc brakes straightened for about 30 quid. 
Lots garages have presses. You can use a bottle jack as a press if you can find some way to secure everything.

Or you could get a couple of scaffold bars and try and bend the forks back towards each other. Cover the forks with inner tubes to stop the bar from marking them.
Title: Re: Straightening forks
Post by: Bob_Acid on July 23, 2008, 01:44 PM
Stick them in a vice and, like toys says, get a scaffold pole on them.

You could just stick it together and see how bad it is when you ride it though. I've got a bike with twisted forks and you can only really notice it when you sit on it looking down.

I wouldn't ride the bike hard though but it's fine for crusing about.  :daumenhoch:
Title: Re: Straightening forks
Post by: toys19 on July 23, 2008, 01:50 PM
The main things to worry about with doing this is ensuring that the vice and scaffold pole dont mark or dent anything, and remembering that to get the forks where you want them you will have to bend them a bit further than your target bend, because you will always have a bit of springback from the bending. My geek gland is pulsating now so be warned that, if asked to explain springback, I might go on a bit...   
Title: Re: Straightening forks
Post by: S1 on July 23, 2008, 02:33 PM
Thanks guys, now all I gotta do is work out which leg is bent, do I bend the left leg forward, or the right leg backward. or something...

If it fails, whats the going-rate for a set of californian forks? 'Tis a shame, the frame is straight as a die and the chrome is a lot better than I thought it was gonna be!
Title: Re: Straightening forks
Post by: pickle on July 23, 2008, 02:37 PM
if it's for a rider, just get a set of Tange forks from Alans for about £30  :daumenhoch:
Title: Re: Straightening forks
Post by: MartyC on July 23, 2008, 03:16 PM
Just ride fast into a wall - job done  :daumenhoch:
Title: Re: Straightening forks
Post by: S1 on July 23, 2008, 03:30 PM
Just ride fast into a wall - job done  :daumenhoch:

That would have been the answer had they both been bent the same amount. Got nothing to loose tbh, will try n strighten em. otherwise its a set of Tange's
Title: Re: Straightening forks
Post by: PHIPPSIO on July 25, 2008, 01:00 PM
I straightened a seat post recently for a show bike and i used a little heat from a hair dryer. Sounds stupid i know but it gave it that little bit more flex when i applied the pressure. Dont use a naked flame though
Title: Re: Straightening forks
Post by: jT Racing on July 26, 2008, 06:00 PM
I straightened a seat post recently for a show bike and i used a little heat from a hair dryer. Sounds stupid i know but it gave it that little bit more flex when i applied the pressure. Dont use a naked flame though

never put heat in tempered metal if you can help it. golden rule!
Title: Re: Straightening forks
Post by: MartyC on July 26, 2008, 06:04 PM
I straightened a seat post recently for a show bike and i used a little heat from a hair dryer. Sounds stupid i know but it gave it that little bit more flex when i applied the pressure. Dont use a naked flame though

never put heat in tempered metal if you can help it. golden rule!

Yep, as it has a negative effect and weakens the metal  ;)
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