mackgoo

If my freewheel axle is bent how might you expect it to affect the drive train?

FBinNY 

Explain please.

Freewheels don't have axles, so are you talking about a bent axle in the hub? Or did you simply note that the freewheel wobbles when you spin the wheel while holding the freewheel (which is normal)?

CliffordK

As FBinNY said, if you have a freewheel, it can wobble slightly when coasting which is perfectly normal. It has no effect on the drivetrain. I have wondered if a slight wobble was a benefit for shifting.

If you take a wheel off of a bike, then spin only the axle with your thumb and finger, you may notice that the axle wobbles with respect to the freewheel, or some other fixed point (another finger?). In that case you have a bent axle. I'm not sure how bad it is for the bike, but they are cheap to replace, or you can do a pretty good job straightening them. If the axle is very bent, then the bearings won't be loaded evenly, and you could experience greater wear, or something might rub causing more damage, or perhaps tearing you your grease seals which are harder to source.

A bent axle with a freehub/cassette is less common, but depending on how the hub is constructed, it might cause the freehub to bind.

John E

Bent or broken axles are fairly common on older bikes with 6- or 7-speed freewheels, because the drive side wheel bearings are so far inboard. As noted above, this was one of the big motivations (the other was easy removal) for replacing freewheels with freehub/cassette systems.

T-Mar

When an axle bends the freewheel cogs are no longer aligned vertically. Depending on the amountof bend, the effects can range from unnoticeable to all sorts of maladies including but not limited to, increased wear on cogs and chains, noisy running, increased shift effort, ghost shifts, missed shifts, chain skating, bent dropouts, etc.

steelbikeguy

in addition to what has already been said, my experience is that a bent axle will eventually become a broken axle. Interestingly, the QR skewer will hold the axle together, and the only sign of the damage can be that the wheel shifts a bit, depending on how forces are applied to the wheel.

A second effect of a bent axle is that the bearing load is spread over a smaller area of the hub's cup. I've had this happen, and it caused a crack in the cup. This means that either the cup has to be replaced or the hub shell (or complete hub) needs to be replaced.


Steve in Peoria

mackgoo

So I am seeing a slight wobble when the wheel coasts on the stand. That's normal? I question this, the wobble that is, because I've been working on getting a syncro setup, setup. I understand the syncro thing is a struggle. I finally have it working great with a Maillard 7 sp freewheel. It works great except when I torque 4th and 3rd, as in sprinting, it skips. I understand it's likely these cogs are simply worn but I figured I'd ensure the axle was squared away first. I guess I need to pull the axle first and check it's condition.
By the way, anyone have an MB 17 and MS 15?

FBinNY 

To be clear, I originally asked which, wobble or axle, because these are unrelated. A bent axle cannot cause freewheel wobble since the axle, straight or bent doesn't move.

Unless the freewheel wobble is extreme (very rare) it's not related to your problem, so you'll need to look elsewhere.

Also, if you're concerned about the axle, that's easy enough to diagnose. Remove the wheel, and QR skewer, then spin the axle in your fingers while watching the end, especially the right end. If it's bent, the end will wobble.

mackgoo

Thanks for the sanity check. If the axle were bent then things would be skewed? What would be an immediate tell tale of this condition? I'm looking for the two cogs, that makes the most sense. That freewheel wobbling as the rear wheel freewheels with the bike in a stand sure looks odd.

T-Mar

The major source of freewheel wobble issues is slightly misaligned cutting of the threads on the hub or frreewheel. First, you have determine if the issue is with your hub or freewheel. This is easily determined by trying your hub with a known wobble free freewheel and /or trying the freewheel on a known wobble free hub. Having said that, if all the cogs are wobbling and you're only having issues with 3 and 4, then freewheel wobble almost certainly isn't the issue, as the greatest lateral displacement will take place on the largest cog.

dabac

It'd take a SERIOUS bend or a good eye to see a bent axle with the wheel mounted.
Remove wheel from bike.
Spin axle with your fingers. Grip by one end at a time.
If the free end moves in a circle, the axle is bent.
Two sprockets moving about more than the others would be odd and rare. Can't really figure out what would allow that.
Chain slipping on two mid-stack sprockets, I'd suspect wear more than anything else.
Only until you've seen a few hundred of them doing the same while working just fine while riding.

wrk101

+100,000 freewheel wobble is pretty normal.