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Old 11-29-05, 10:29 PM   #1
TallRider
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traditional rear hub with bent axle - try to fix or just build new wheel?

I recently bought a used Centurion road bike on eBay, from the late 80's with Shimano 105 6-speed drivetrain. The rear hub is a traditional sort, with a freewheel. Problem is, the axle is rather bent. However, the bearings seem perfect, which means that the axle is bent only on the exposed portion. I might be able to straighten it, but I'm 6'5" and 185# and would probably bend it again anyway. Should I try to straighten it out and use it, or is this a futile endeavor?
My alternate option is to use a mid-90's 105 freehub (which will accept 8/9/10 speed, 130mm spacing) and build a new wheel, perhaps with the rim from the current hub. (The rim is a Wolber anodized, box-section rim, seems to be in very good shape.)

Apart from concerns about 6-speed vs. 8-speed, is it worth bending the axle back to straight on this freewheel rear hub, or will it likely just bend back in short order? Thanks.
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Old 11-29-05, 10:35 PM   #2
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If you can do the work yourself, put a new axle in. You can get one for $12 and overhaul the bearings while you are there.
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Old 11-30-05, 12:07 AM   #3
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Originally Posted by Rev.Chuck
If you can do the work yourself, put a new axle in. You can get one for $12 and overhaul the bearings while you are there.
I could get a new axle easy enough, I guess. My worry is that, at 185#, I'm likely to just bend it again in short order. Should I be less worried about this? I've bent cheap axles on my commuter (27" wheels, 7spd freewheel, solid axles no QR) over and over again, and have decided to just ride the hub into the ground on that machine.

Btw: where are you at in Raleigh?
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Old 11-30-05, 12:44 AM   #4
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Not a problem with being 185#, it really has to do more with the peak G-forces you apply to the bike during the ride. Just sitting on it won't do anything. Hitting speed-bumps with your full-weight on the saddle will increase the load in relation to speed. So watch the bumps, get up on the pedals to let your knees absorb bumps and you'll be fine.

When I was 245#, I'd bend/break one axle a year. But I'd also be bunny-hopping up and down kerbs, over speed-bumps & potholes at full-speed as well as and bombing the downhills too.

Get a chromoly axle... it'll be fine.
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Old 11-30-05, 12:45 AM   #5
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I weigh 211, 5',11" and in 35 years have never bent an axle.
Remember that with quick release the axle is hollow, so if your really worried about it, replace with a solid axle, even something beefy like a 14mm axle. How do you manage to bend so many? Bikes are precision machines, and i have 2 centurions, one a 1977 super lemans and one a 1984 elite. both great frames and great bikes. The super lemans I built up with vintage campy nuevo record through out. i even kept the ranndour handle bars and but went from a touring set-up to a sport touring /racing. changed the cluster from 14-32 to 14,15,17,19,21. and went to sew-ups
sorry for the digression,if it was me, i would tap the axle on a flat anvil with a light hammer, and gently tap out the high points of the axle, looking at when the light shines through were the axle contacts the flat anvil. If done right this is a flawless way to make anything perfectly true.(It's the same way they straighten out Saxophone key rods). while you're at it, it's not a bad idea to replace the bearings.
If you don't feel like going to all this trouble, just replace the entire axle.Good as new, problem solved.
Have fun with your Centurion, a blast from the past, !
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Old 11-30-05, 01:07 AM   #6
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The solid axles that I've bent on my commuter are probably all cheap steel.
However, freewheel-hub rear axles getting bent was a pretty common problem in my understanding, at least with a lot of hubs out there. This was the main reason for the switch from freewheels to cassette hubs (well, this combined with increasing # of cogs, which meant wider cogs, which meant more axle hanging out there to be bent easier).

I'll pick up a cromoly axle and put it in, and tap the old one straight when I'm at my parents' place over Christmas. (Grad students don't have nice workbenches, even if they have a full stock of bike tools.)
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Old 11-30-05, 02:05 AM   #7
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Tim,
good luck, by the way i cant believe what happened to Sydney? i just found out he had been killed by a stupid teen ,text messenging on his cell phone while driving a big truck. Sydneys real name was Jim Price, 63 years old, and he probabaly never knew what hit him.He was like sheldon brown, in terms of his total knowledge of all aspects of cycling.
He will be missed! that's for sure.
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Old 11-30-05, 04:20 AM   #8
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Quote:
Originally Posted by timcupery
The solid axles that I've bent on my commuter are probably all cheap steel.
However, freewheel-hub rear axles getting bent was a pretty common problem in my understanding, at least with a lot of hubs out there. This was the main reason for the switch from freewheels to cassette hubs (well, this combined with increasing # of cogs, which meant wider cogs, which meant more axle hanging out there to be bent easier).
Yeah, going to the 130mm spacing for 8-speeds really added a long section of axle with the bearings way on the inside. I don't think I ever broke an axle with the old 126mm 6-speed set-up (of course I only weighed 160# at that time too).


Quote:
Originally Posted by timcupery
I'll pick up a cromoly axle and put it in, and tap the old one straight when I'm at my parents' place over Christmas. (Grad students don't have nice workbenches, even if they have a full stock of bike tools.)
Here's a trick if you really want to straighten out and re-use a bent-axle. Roll it on some V-blocks to find the bent spot, mark the high-side. Lay it on a piece of wood with the high-spot aimed up. Smash that spot with a hammer. Then re-check on the V-blocks, repeat as necessary. The wood's so you don't mess up the threads and it gives to let you bend the axle beyond flat to the other side a tiny bit and it springs back flat.

When you re-install, reverse the axle so that the bent-spot ends up between the bearings. This places the bending load on a stronger, unbent portion of the axle.

Last edited by DannoXYZ; 11-30-05 at 02:27 PM.
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