Classic & Vintage - How long your chain?

Which is to say, how long a distance would you expect one to last?

The reason I ask is that on several occasions lately my commuter UO8 has thrown the chain from the chainrings, sometimes inside on a downshift, sometimes outside on an upshift. The chain is an SRAM PC870 with about 700 miles and a reasonable number of shifts (I guess). The crank is a VeloOrange compact double. When I first installed this chain back in April it shifted impressively promptly with no trouble whatsoever. I suppose it is possible that the RD (a Suntour Vx w/GT-cage) is keeping it under less tension. But I'm thinking that the chain is now worn and more laterally flexible.

Yea or nay? Comments?

Thanks,
Jim

doubtful.

realistically you can get 5000 miles on a chain easily depending on conditions. a chain checker will tell if you if it has stretched. kmc makes an anti-stretch chain as well.

youd have to be cross chaining, riding through mud, etc to kill a chain in 700 miles. especially an 8speed one.

realistically you can get 5000 miles on a chain easily depending on conditions.
Thanks. That's how I remember it, riding for years, no, decades, on the same chain. Of course, that was back when bikes were bikes and chains were chains, as if today's chains might be, ah, more shall we say fragile.

Which leaves me wondering why the change in chain/chainring behavior. Oh well, I'll ride it again tomorrow and see how it behaves. Maybe tighten up the FD stop screws a bit though.

Chain is fine, you may have alignment problems, which could be anything from a misaligned frame to a bent derailleur hanger to a poor chain line to the FD limit screws. It's all cables and pulleys, not rocket science.

It's French, so what could possibly go wrong?

It's possible you wore it out by riding it while it was very dirty. But not likely, since you've been around bikes for a long time.

I'm quickly becoming fond of thick chain lubricants. They don't attract as much dirt and don't need reapplication as frequently.

Are your chain rings and/or crank arms still true? I have seen some bikes that shift themselves just because the rings are wobby. These days, I always check my rings to ensure they run straight and true. I never have shifting problems anymore and can't remember the last time I dropped a chain...

My first Legnano Gran Premio offered me the opportunity to show how I inspect and repair out of true rings (http://www.mytenspeeds.com/My_TenSpeeds_1/Feature_Bicycles/Feature_Bicycles_Itlay/Legnano_Tipo_Roma/Legnano_Tipo_Roma_6_CrankSelection.htm)...
http://www.mytenspeeds.com/My_TenSpeeds_1/Bicycles_Table/Italian_Bicycles/Legnano_Bicycles/Legnano_Brian/Legnano_Repairs/Legnano_Repairs_Cranks_S_Measure_2.jpg

I, too, would go with checking any runout from the vertical on
your chainrings. Otherwise, I got nothin'

The important thing is that my chain is longer than yours.:o

I have had cheap chains wear out quickly on my commuter bike, like less than 1000 miles. That was on my old folding bike, with 16" wheels; I think the smaller wheel with its lower axle gets more exposure to dirt and therefore shorter chain life; but I was also using $6 Walmart chains. I recently replaced the chain on my newest commuter bike, which has 20" wheels, because the chain had stretched to the point of unreliability after about 3500 miles. I sprang for a more expensive chain this time. Note that a derailleur system is much more forgiving of a 'stretched' chain than a single speed / IGH system (which is what I run).

I'm quickly becoming fond of thick chain lubricants. They don't attract as much dirt and don't need reapplication as frequently.

What are you using?

What are you using?

I don't remember what the LBS has. I think it's something that Pedro's puts out.

I also have a sample bottle of Chain L which I've been meaning to try. I guess today is a great day to try it, since it's time to lubricate. I left a few bikes out in the torrential rains. Duh.

... if you are going to evaluate chain wear by a gauge, you may wish to measure the chain when it is new on the bike to gain confidence in what the gauge tells you. I found the ProGold Chain Wear Gauge doesn't read 0% wear for some new chains.... as much as 30% "worn" with some new chains.

Thanks for all the input. Today's ride was fine inbound but I used the FD sparingly. At the office I screwed in the FD stop screws just a bit but probably not enough to make any real difference. On the ride homeward it threw the chain once on an upshift.

I've been so busy that chain maintenance has been neglected for a few months so I know one thing I'll be doing tomorrow evening...

Spent some quality time with the chain yesterday. I measured out okay, no measurable stretching. It seemed more laterally compliant than I remember but that could be a problem with what I remember. I never measured anything like that when it was new, didn't again yesterday. Anyway, when I bench-shifted it I could see how it might twist over from the small chainring across to the outside of the large. It's all a matter of how it was pedaled and shifted, I suppose. So I just cleaned and lub'ed it and re-installed. We'll see how it works this week.

Thanks all for your comments and your patience.