Chain life?

[graham]

Sorry about the length of this post...

On the Rohloff equipped tandem, we seem to get about 2000 miles out of a drive chain, and not much more from the timing chain. I do tend to change the chain slightly before 1% wear, because I don't like the noise it starts to make. Since the tandem has now done over 6500 miles, we're on the fourth drive chain.

We use SRAM PC99 chain, which I can be split and rejoined as often as you like without needing tools or replacement parts, because of the power link. And we've never broken one. But it's not cheap and so I reckon the bike costs us 2p a mile in chain degredation.

I've tried various chain lubes and now use the 'purple extreme' stuff, reapplying about every 100 miles instead of the 400 quoted. Chain wear seems no less with it than with other alternatives, but it is cleaner than most.

Are we particulary heavy on chain, or is 2000 miles about right? Or should we be using another make of chain or lubricant? I had considered using Rohloff chain but can't work out which one to get. Also, since I have a chainring guard on the outer spider position, chain ring in the middle and timing ring on the inner, the two chains run on adjacent rings and only miss each other by about 1.5mm. Would any 9 speed chain be the same width or would I get trouble with the chains clashing?

Your thoughts, please.

[TonySmith]

I get 3500 out of a PC48 on a solo. While I sometimes carry/tow heavy loads/children there's only one of me putting power through it so perhaps that's why it lasts longer.

[sothach]

Not quite on-topic, but a question about chain sizes: I've just replaced the chain (Thorn Raven) with a PC99 I had in stock (spare for my MTB).  Last night I actually read the manual, and found that I should have used an 8-speed chain, not a 9-speed.  It seems to fit and work perfectly, but could the difference in width between the PC48 and the PC99 makes the 9-speed wear faster?

Here's a summary of various 8/9 speed chains - the SRAM only differs by .2mm between the 8 and 9 speeds, whereas Shimano goes a whole .8mm.

Code: [Select]

     8 speed    9 speed
SRAM      7.1        6.9
Rohloff   7.1        6.8
ShimanoHG 7.4        6.6
Campy     7.1        6.8


[sothach]

After checking Rohloff's FAQ & downloading specs for SRAM chains:
Rohloff state that a 3/32" chain should be used, and the PC99 is
11/128", so it's 1/128" narrower than Roholff specify (< .2mm) -
would this cause the accelerated wear the OP is experiencing?

[graham]

Thanks for your input.
Of course, traditionally single speed/ hub geared bikes seemed to use 1/8" chain - whatever that is. 1/8" is about 3.2mm, so I can only assume this is the clear space between the plates rather than the overall width of the chain.
One thing you have shown is that I'd probably get away with most 9 speed chains without them clashing, but whether any of the others are more wear resistant than PC99 is another question.
I'm running Thorn Alloy single rings so there is no machined away bits or pins to allow shifting. From that point of view there is a maximum amount of tooth in contact with the chain rollers at all times compared to derailleur rings.
Perhaps we just try too hard on the tandem and don't clean the chain enough.

[PH]

Sheldon Brown has recently posted an item on extending chain and sprocket life on non derailleur drives. Worth a read.
http://sheldonbrown.com/chain-life.html

[Ratty]

I have also been disapointed by the chain wear.  I ride in harsh conditions, lots of salt, but I do care for the chain.  I feel that chain wear is no better than on a deraileur bike.  This is disapointing and I would now like a complete chain guard which I feel would help a lot.  It is tricky to find one to fit a raven however.

Regarding which chain to buy I have e-mailed Robin Thorn and (I think) he feels that a more expensive chain will last longer and give you the tiniest fraction more performance but not enough to be worth the extra price.  He (cryptically) recommended sticking with the cheapest chain that is £8: Sram/Sachs 3/32" PC48 7/8 speed grey chain.

Anthony

[Eric]

Your chain wear figures sound about right to me. I use the trick of having three chains for every bike (with five bikes - that's a lot of chains!) and rotate them every 500 miles or so - cleaning the dirty ones in white spirit and re-lubing. It's the dirt which exagerates the wear.
Although sounding expensive in 'up front' cash, it's actually cheaper in the long run because the stretching chain tends to wear and hook sprockets and chainrings quicker.
I believe I got this idea originally from Chris Juden (CTC equipment supremo). he seems to know more about bikes than anyone else on the planet!

[freddered]

I've used Motorcycle Chain Wax (and similar Motorbike products) for years and I never snapped a chain in my life (many thousands of miles).  

I admit my derailleur looks like a black and greasy mess but it keeps going OK year after year, takes 5 minutes effort a week and a tin lasts for years.

Anyway, it's worth a fiver down at Halfords.  Just spray it slowly into the links while rotating pedals backwards until chain can't hold any more. Then leave it an hour and run chain through an old rag to wipe off excess.

In theory the solvent/carrier gets the grease in the nooks and crannies, evaporates and leaves 'solid' lubricant that dust/grit doesn't sink through the same as oils. Check for the blurb that mentions this characteristic.

I spray it on pivots of derailleurs and anything else in the house that creaks.  A shiny bike is a bike that needs more grease applied.

Tip.  Put a rag over your wheel.  Confucious say "You will always manage to spray Chain Wax on Braking Surfaces".