Three-speed question
 

I use it for commuting, so I'm starting on this forum. I have an old Schwinn 3-speed that I love. Only problem is I have to keep loosening the rear wheel and pulling the chain tight again because the wheel slips forward, I'm guessing from trying to power up the smallish hills here in B'more. I imagine there's a simple fix to this, or at least hope, because I'm getting tired of the whole slip, no movement thing that keeps happening to me. Thanks.

joel

Sounds like maybe a new set of axle nuts might help. The knurling on the old ones might be worn down, making them prone to slipping. Also, check to see that the fork ends aren't rusting. Even shiny new axle nuts will slip if they don't have a good surface to grip.

The original washers that were between the axle nuts and the dropouts on most old 3-speeds were serrated on at least one side as I recall. Maybe yours are the wrong ones or have lost their bite. I was always amazed that my axle didn't slip considering how high geared it was and the pressure it took on the pedals to climb some of the hills around here. You also might check the threads on the axle and the nuts to make sure they aren't stripped.

My three speed IGH chain loosens without the axle slipping. I just keep tightening it (not too tight) by periodically and incrementally, moving the axle further back until there's no more room in the dropouts. I then take a link out of the chain. At this point I start thinking about replacing it.

The only thing I can think of that might be causing this is towing a trailer on these sand roads, but the thing I can't figure out is how it's happening. The axle isn't slipping. In fact, I have to move it further back every time I tighten the chain. The chains don't show any signs of undue wear on the pins. Nothing is loose or broken. I've pretty much given up on trying to figure it out.

When I'm riding that bike regularly it takes a new chain about every three months.

Your drive train is severly worn out if you are replacing the chain every three months. Taking links out to compensate for "stretch" will only make things worse.

I thought of that, but that bike doesn't have that many miles on it, even taking the wear of the sand roads into consideration, and there's no visible signs of undue wear. Taking out a link only changes the total length of the chain, it doesn't change the length of the individual links nor their relationship to the chainring and gear.

One thing I have thought of that may be exacerbating the problem is my using cheap chains.

It's only happening on this one bike. I haven't run into this with the derailleur bikes. Although the road bike almost never gets ridden on sand, but the others do.

" and there's no visible signs of undue wear"
Did you actually measure it with a device called a "ruler"?
In 12", >1/16" is max.
When you put your new chain on the old sprockets, only a couple links are supporting the drive force, instead of the links all around that 1/2 of the sprocket.
http://www.sheldonbrown.com/chains.html

I actually, at different times, took a couple of old ones apart with a device called a "chain tool," and inspected the pins for wear with a device called the "naked eye." If there were any wear it would be visible on the pins.

Thanks for the link, Bill, but I've been using Sheldon's site for a few years. That particular info doesn't seem to fit the scenario for this problem. The rear cog on this bike looks very much like the new cog in Sheldon's photo, in terms of wear. It's just that this bike goes through chains and none of the standard answers seem to apply.

But like I said earlier, I quit worrying about it and just change chains. I don't think this is a problem that's going to leave me stranded.

Chains wear primarily in the bushings that fit around the pin, not on the pins themselves. In a severely worn chain there may be some slight wear on the pin, but this is typically due to grit having gotten into the bushing area rather than normal wear. As you point out in the first quote, the side plates don't stretch; however, since the holes in the bushings elongate, the pitch of the chain (the spacing from one pin to the next) becomes longer. When this happens, the chain no longer matches the pitch of the chainring or sprocket (assuming that they matched in the first place), all the drive tension is placed on one or two rollers, and the wear accelerates.

You can't accurately measure all chainring or sprocket wear with the naked eye. You could use a pitch gauge, but in practice it's easier to replace the chainring and sprocket than it is to find a gauge to measure them.

The probable solution to your problem will be to replace the chain, the chainring, and the sprocket as a set, preferably with high-quality replacements. The other option will be to live with the bike going through chains quickly, although in that case I'm not sure why you asked the question in the first place. :)

I'll check the axle nuts and washers. At least some of the pile is brand new (when I first got the bike -used- I couldn't tighten the non-chain side because the nut was stripped) but I'll look into the rest. There's no rusting on it though. If there isn't any issue with the nuts/washers I'll probably wait until I move (endo of the month) and then try and find a good LBS to take a look at it. Soonish I need to get new wheels built up anyway.

Surly and a couple other companies make tensioners for holding axles in place. You could install one those. Here's a pic of the Surly:

http://www.surlybikes.com/parts/popu...rodTuggnut.jpg

Well, I didn't really intend to. All I intended in my first reply was just to let Joel know that he's not alone in having loose chain issues.

I'd forgotten about those, something to think about

Doh! I guess that's what I get for being AFK too long at a mind-numbing meeting - I forgot you weren't the OP. :o

For the OP, +1 on new axle nuts with sharp serrations, and don't forget to put a little lube on the threads so the turning force really goes into clamping the nut against the dropout/fork end, not into friction on the threads. It might not be a bad idea to take a close look at the threads on the axle to make sure there isn't any damage (or gunk packed into the threads) that's causing the nut to bind before it's tight.

'Gunk' is a definite concern. The bike had been sitting in some guy's garage for ~10 years without riding before I picked it up. I've cleaned it but don't really have the space to take it apart and do the job right (fully carpeted studio with a TINY bathroom) but will soon when I move.

If I've followed all the recs right than what I have is - 1) clean the threads and inspect everything for any rusting or other damage, 2) replace nuts and lube before reapplying to tighten down but good, 3) if it still slips look into the Surly (or other) tensioner.

Thanks for all the info.