|Mechanical minds - HELP!||Matno|
Mar 7, 2003 8:37 AM
|I'm going to start this post with a disclaimer: I KNOW that what I want to do is not advisable or safe. That doesn't bother me. At this point, I just want to see if it can be done because it's been bugging me. Now, on to the issue:
I recently acquired a Cannondale Slice fork with 1" alloy steerer on which the steerer is bent. It's not dramatically bent, just enough to tighten up the headset after about 80 degrees of rotation in either direction. Does anybody have any bright ideas as to how this might be straightened? I already tried one not-so-bright idea that put a lot of pressure on the steerer with no effect whatsoever. (Dang those things are strong! I'd sure like to know how this one got bent!) Help please!
I'm already looking into replacements since the guy I bought it from gave me a big refund for the fork, but this fork has a beautiful custom paint job, and I just don't like the look of black forks - unless they're on a black bike! While we're on that subject, what aftermarket carbon forks compare favorably to Cannondale's (Time) Slice? I am mostly interested in a smooth ride. Stiffness is nice, but I'm only 140, so as long as it's not super flexy laterally, I'd like the most vertically compliant fork I can find.
|Just say no.||brider|
Mar 7, 2003 8:49 AM
|Okay, I realize you already know it's not advisable, but do you know why? |
First, even if the bend is slight, any had-working of the steerer would likely make it worse not better.
And any fork can be painted.
|Gee thanks.||Jomo Kenyatta|
Mar 7, 2003 9:35 AM
|I'm not familiar with "had-working" but I've had good success with straightening things by hand in the past. I've straightened, among other things, cranks, chainrings, and a fly reel that was crushed by a Mitsubishi Montero. (If I can get a completely smashed fishing reel back to perfect working condition, a steerer seems like small potatoes). Everything I've straightened now functions well within the original tolerances so the only real issue is how to exert enough pressure to handle this. I am familiar with aluminum's properties that will likely make this steerer weaker than it originally was. Now it's just become a personal quest to see if I can do it! (Even if I straighten it, I'll likely replace it anyway, just to be safe).
As for painting, any recommendations on how to paint a carbon fork (with a two color fade)? How much would that likely cost me?
|Bad proof reading...||brider|
Mar 7, 2003 10:35 AM
|Actually, that was "hand-working." As in straightening by hand (of course you'd use some tools). |
But there's also the work-hardening aspect, and with something that's as intollerant of misalignment as a steerer, I would think that it would just get worse.
As for "how":
Would depend on how sharp the bend is. If there's a distinct point of bend, then things get real sticky -- how to band it back without bulging/crumpling the tube. You may want to consider sacrificing the crown race for this project, since it's likely that you wouldn't be able to re-install it after bending (in the case of crush or bulge). If the bend is very gradual, then it should be easier. You can use a semi-soft surface to gently bring it back. A cut car tire might help. Cheater bar is a must, hopefully with a very close fit, and a reinforcing tube/plug it the end.
And I'd too be curious as to how it got bent.
Mar 7, 2003 11:49 AM
|Speaking of bad proof reading... Weird how that last message got posted under a different name. I was at school and didn't notice that the computer was already logged in under another name. Here I am complaining about never having anyone to ride, and there's someone right around here!
I like the car tire idea. I'm looking for a cheater bar today. Hopefully I can find something that fits.
The bend is not sharp at all. Very gradual so I think this MAY be doable. (And darn it, if it is possible, I'm going to do it!) :^)
Thanks for your help.
|What do you know? It's steel!||Matno|
Mar 7, 2003 12:07 PM
|Turns out, this steerer is steel after all! The seller said it was aluminum, but obviously there was more than one thing he didn't know about this fork (at least he seemed like a trustworthy guy). I just checked it with a magnet, and lo and behold, it stuck! That should make things a little easier (and possibly make the fork more likely to be "recoverable").|
|Try an auto exhaust specialist.||DERICK|
Mar 7, 2003 9:27 PM
|These guys bend tubing for a living and have the machines to manipulate tubing without damaging it. My guess is that if they charged you at all it would be minimal. I think even with a cheater bar you will still create a bulge in the tube where the end of the bar hits it. If that happens no one will be able to fix it.|
|try a machine shop....||ukiahb|
Mar 7, 2003 9:19 PM
|It will take precision equipment and a press to straighten that fork accurately enough so that the bearings don't bind, but a good machine shop can probably do it.|
Mar 8, 2003 10:07 PM
|I got a 6 foot cheater bar at Home Depot and with the help of a phone book, an inner tube, and a hole in the wall at the local playground, my steerer is now PERFECTLY straight. You would need a pretty sensitive gauge to find any imperfection at all (my straight edge lined up with no gaps on all sides), and it rotates smoothly in the headset. Of course, if I were the worrying kind, I might have nagging doubts about its reliability, but seeing as how I'm a skinny little guy who doesn't worry much about anything when it comes to safety... :^) I think I'll be okay. I'm actually much less worried since I found out my steerer is steel rather than aluminum. Of course, now I'm worried that it's too heavy!|| |