Classic & Vintage - slightly bent rear axle.. normal?
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yes sounds like a stupid question :D but here goes..
on one of my mountain bikes with a solid axle, while repacking the rear hub i rolled the rear axle on a flat surface to see if it was straight.. seemed to be slightly bent.
i went to a local shop, the guy brought out the one solid axle they had left.. i checked it.. slightly bent as well.
went to a 2nd bike shop.. looked at another rear axle.. also had a slight bend. what's going on here?
is this slight bend acceptable? is quality control that bad? or is it this a normal/acceptable deviation from 100% straight? do i need to find some better shops LOL.
i'm concerned since i don't want to wear out the hub running on a bent axle.. but hey.. if a small bend is okay.. then its just less for me to worry about.
thanks for reading
No, Change/repair it ASAP!.....
11-15-11, 07:08 PM
is it normal/correct? no.
is it acceptable? yes. you probably would have never noticed.
you can also tell without removing the axle, if you look closely. just keep riding it and checking it periodically.
11-15-11, 07:10 PM
You can get by with a slight bend. Were these used parts these LBSs were trotting out? They should be straight when new. Unfortunately most new solid axles are pretty cheap and they'll be pretty easy to bend, especially if you're running a 7-speed freewheel.
11-15-11, 07:13 PM
You'll wear out the bearing races more quickly if you leave it.
the first shop said it was a new takeoff from a bike.
at the 2nd shop the employee said he didn't know the history behind the axle.. he dug it out of a bin full of axles, of course the others were all QR.. i didn't think it would be so difficult to find (good) solid axles in stock locally.
its good to know they should be straight though.. but yes i am running a 7 speed freewheel..
what is reassuring is that the bearing surfaces all look good. i will be replacing the bearings though, i found 3 that are starting to pit.
thanks for all the responses!
but looks like we have a mixed crowd again, 2 voting for "change it!" and 2 with the opinion that it is either futile to change the axle due to inevitability it it will bend again/or that the slight bend may be okay and that monitoring the wear to the hub may be the best way to approach it.
11-15-11, 07:30 PM
If it's bent it's gonna bend more... that's my thought anyhow.
11-15-11, 07:30 PM
I can never keep axles straight for very long on 7-speed freewheels. They just don't hold up to even small bunnyhops, curbhops, etc. That's why I think it's a waste of time to change axles, unless you find someone who'll sell you say a box of 20 for $1 apiece.
Long term, I think I'd look into getting a wheel or wheelset with a freehub and 7-speed cassette, they hold up to my riding style much better. Perhaps they would yours also.
Not normal, just find a more reliable source or order a new one online. Wheels Manufacturing has good products.
One of my mtb's came with a solid axle Shimano freehub. It rolls flat. Of course, conventional hubs put more stress on an axle.
A lot of LBSs will actually strip and sell used stuff that isn't being made anymore. Not uncommon.
Go with a vintage Mavic freewheel hub. Legendary spin forever hubs. I prefer the 501 series better than the 500RD. Cartridge bearings. Won a Paris-Roubaix (Sean Kelly) and a Gran-Tour (Lemond). Bombproof, absolutely bombproof. Same exact hub just widened to 135mm and rebadged for the Mavic mountain group (577 series). That's how strong it is. It's a half step down from a Phil Wood touring hub, seriously. Both a Mavic and Phil Wood use 15mm axles. The only difference is that the Mavic necks down from 15mm to 12mm at the bearing. People don't even know what these things are and how fantastic they are. I've seen 'em sold at swaps for $5. They came in all kinds of drills as I've seen 28h, 32h, 36h, and even 40h and 48h which weren't really supposed to actually exist.
You'll never bend a Mavic axle, and if you do, you were actually trying to by doing drops off flights of stairs or something.
Given that the axle is bent, the dropouts have probably bent too. Consequently, a new axle has a very high probability of bending, unless the dropouts are realigned.
Most solid axles are relatively soft, carbon steel. If you want a stronger, solid axle, ask for a CrMo BMX axle. Just make sure the diameter and threads are the same, as some come in oversize diameters and different thread standards.
As previously suggested, the best solution is to convert to a freehub with cassette.
11-16-11, 08:55 AM
From a Machinist standpoint...it's really a matter of WHERE it is bent. If the area of concern is outboard of the cones / bearing area, no biggie. Additionally, it is very possible that in a "relaxed" state, the bend is apparent but once torqued, all is ducky and true! :)
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