Just broke the 9-spd SRAM chain on our DaVinci @800 miles on a climb. Now we're at 340lb. team, but also senior citizens so I'm not sure we're overtaxing the drivetrain. Fortunately, I had a quick link (and some latex gloves) so I was able to get up back on the road. The chain doesn't show excessive wear and I do lube regularly. My LBS said "still looks good", but I'm inclined to replace.

I've searched the archives and find posts that have bad things to say about most brands of chain commonly used; Shimano, SRAM, Wipperman. I'd like to hear from anyone who has either personal experience or tandem-related product knowledge.

I'd replace it. I do that as regular practice. I feel it reduces the number of on-ride part failures. If you leave it on there it will fail again. Maybe in a week, maybe in 3 months but it will fail again. A new chain is just a much safer bet.

We are running about 3000mi/drive chain and just put the 3d chain on after the KMC blew out at the
bottom of a 15% climb. Thinking back I would estimate around 150 ft-lbs torque. Exam of the chain
showed a side plate had broken across the pin hole. OTOH the timing chain still shows less than 0.75%
wear at 6500mi. Drive chain is 10 spd.

Back in May, on a 500mi 6day tour the KMC came apart on an 8% grade at the quick link. We were able
to find the pieces and after exam reassembled the chain and rode up a nasty hill ~1mi long with 16% hairpins
and a quarter mile of 12% grade and finished the tour with no further problems. The quick link was not
apparently damaged. The later failure was on a standard link.

I have always used Shimano Dura Ace 9 speed chains and never had one break.
I don't carry a quick link or a chian tool but maybe I should.

I think I'm going to try a Wipperman chain. My LBS carries these in the extra-length configuration I need for the DaVinci. I'd have to splice together two ordinary drive chains. I'll size the Wipperman for my 11-32 cassette which I'm going to try for a while and re-size the SRAM for the 12-27.

I don't recall what inspired me to have a quick link on board, but I'm real thankful. I probably could have used my chain tool to make a temporary repair; don't know if SRAM chains can be reassembled legitimately w/o a quick link. Definitely want a "quick link" that can be assembled/disassembled by hand!

There is a discussion in the road forum about what you carry in your wedge bag. Not so much on a half bike, but it think this is a good idea!

Thoughts?

We run all SRAM chains on the Co-Mo.

SRAM makes several levels of quality in the product lineup. I installed PC991 and 870's for timing chain.

Hope this doesn't jinx me, but so far so good.

The tool kit does have a chain tool and a 8sp and 9sp link.

PK

I would definety toss that chain...I could never trust the other links. No way any chain should break at 800 miles. I don't know what caused it or why but it had to be a pretty freak deal.
Brand wise, I can't pitch one over another as I've used Shimano and Sram with complete satisfaction. On our tandems I use 9 speed Dura Ace/XTR cn 7701 on both sides of the bikes...carry a spare link, pin and mini chain tool. To date they have been dead reliable. On the tandems I use the best stuff I can afford for reliability's sake and tend to replace suspect parts early...I may fudge a bit on my singles but not the Tandems.
Good luck with the replacement.
Bill J

I'm currently running Campag 8-speed on the tandem. 8-speed chains are still reliable. I'm thinking of going to 9-speed, but of course the chain would cost a lot more, and I'm not sure the extra cog would be that useful. No way would I run a 10-speed cassette and chain on a tandem; they even break on singles. This is bleeding-edge racing equipment. Our team weight is 320#, and I'm an ex-racer. A very smooth sub-300# team might be able to get away with 10 speeds, but even then I'd be careful any time I was out of the saddle...

(I guess running 10-speed chain on a tandem is sort of equivalent to running a single-bike carbon fork or similar critical component not certified for tandem use.)

With 8-speed, you can use cheap 8-speed chain, which has wider rivets and a lot more tolerance for the chain flexing across the cogs. The timing chain doesn't bend laterally at all, so it should last far longer and you can use the cheap Nashbar recumbent chain, or even 1/8" track chain, which is designed not to flex laterally.

I normally replace the drive chain on my bikes at between 3,000 and 4,000 km (I don't like wearing out the cogs). The timing chain can go twice that.

L.

Only ever broke two chains on rides and they were Dure Ace. And both went pretty quick- within 100 miles and within 500 miles. But that is what I got for fitting them to the mountain tandem used off road.

Luckily- I always carry a spare Run-in chain and chain breaker in the top bag.

In 225,000+ miles of tandeming since the mid 1970s, we have never (so far!) broken a drive chain in any of our tandems.
Did break about 4 or 5 cross over chains; stoker had to pedal us home while pilot steered.
Have used all sort of chains (except Campi or Wippers). Currently SRAM PC991 for drive chain and KMCs for crossover, all of them 9 speeds.
Agree, the narrower the chain the more likelyhood of failure.
So be prepared all you 10 and 11 speed afficionados!
Pedal on TWOgether!
Rudy and Kay/zonatandem

We broke our new SRAM 1090R (drive chain), on a steep descent that suddenly became a steep climb, during the Mt Tam double century. This thing was literally a "V." The chain was only on maybe mile 200 of it's life. It was my fault, due to a poor shift.

This ride was awful for tandems, in the fact that it was endless so-called "Italian rollers." I have never shifted so many times in my life!! It was around mile 160 or so and we were pretty fatigued at this point. I got lazy and/or just from being tired I shifted too late, executed a nasty front shift, and then put the power down before the chain was fully seated on the next gear... SNAP!

Thankfully, I carry an extra powerLink. I used my chain tool (on my nice little muti-tool), popped off the snapped links and installed the powerLink in it's place We are still riding it now, I don't see why not.

PS- It was a standard link that snapped (not a powerLink).

There's always the chance that when the chain was installed the connector pin was not pushed in all the way. This can happen when your local shop hires a 17 year old snott nosed rookie mechanic to assemble your prized tandem. That is why I do all my own work.

John R - ""....that is why I do all my own work.""

+1

Bill J

SRAM has had problems with embrittlement in the past.

There was a recall on the PC-41 8-spd chain, but the SRAM PC-41 on my bike was a later date-code.
They replaced it anyway, after I took it to my LBS for a wear measurement (it passed), and pestered them about it. Broken chains can hurt people, and they don't want a lawsuit.

The more expensive SRAM chains are prettier because they have plated sideplates, but I'm not sure that makes them shift better or last longer. I've been using what the manufacturer installed on the bike; PC951 for the drive chain and PC850 for the timing chain.

We have not yet broken a chain. I had installed a new drive chain a while back and developed a "skip" after a few miles. It turned out that there was a stiff link in the chain and it wasn't bending over the smaller cogs. This is a frustrating problem to diagnose since the first thing you suspect is a mis-adjusted derailleur. We pulled into a bike shop, had the mechanic loosen up the link for us and it worked fine after that.

I'm finding that we don't get much more than 1000 miles on a drive chain. Cassettes are not doing so well either; I find that if I don't replace the cassette with each new chain we have skipping issues in our "favorite" cogs.

"No way would I run a 10-speed cassette and chain on a tandem; they even break on singles. This is bleeding-edge racing equipment."

I have never understood this thinking, hence my rant . Greg LeMond once said that he used Campi because it was indestructible. He could bend a rear derailleur back into approximate position and continue the race. Pro racers use Campi and beat the heck out of it. Race testing and outcomes eventually find its way into our daily lives, Campi included. Where do you think your anti-lock disc brakes came from? (Formula 1 and LMP racing).

I have used Campi for 35+ years on my single bike and never had a failure. (Granted, when they moved from friction shifting to index shifting, they didn't get it right the first time.) I am running Campi 10sp Record on both our tandem and on my single bike and have never had a problem. We also live and ride mostly in the hills.

My question is - how did your chain blow? Was it during the climb, under continuous pressure? Did you have a transition from flat/downhill to hill and mis-time the shift, and/or jump too many gears during the shift? Did you grab a lower gear during the climb and not back off your cadence (pressure) during shifting? If it was option 1, then it is probably a chain defect. Any of the other three options can blow a chain.

We are running a Shimamo 10 speed on our tandem. While I must say that I got a little lazy and did not change it in time recently, and it cost me a middle chainring in process, I don't find the 10 speed to be less reliable or measurably less durable than a nine speed.

We ride long distances and tend to go through stuff more often than most people so we have opted to go with a single speed chain for the timing chain. Since the timing chain is a single speed, it makes sense to me to use a single speed chain. The fact that I can pick one up for less than $15.00 makes good financial sense to me too. I don't seem to be able to notice the weight differential.

Since switching to the 10 speed we have completed two brevet series (200, 300, 400 & 600 kilometers) plus training as well as keeping our R-12 alive for almost two years (on the ten speed). We have not broken anything - yet... We are working on another series and have a 400k coming up next Friday, I let you know if we have any trouble. By the way, we are not by any stretch a lightweight team.

Your results may vary.

I too use a 10 speed chain and run a Campy Record drivetrain on our Tandem. Never had an issue with wear or breaks. We live on a 14% hill and have to ride that thing up after all of our rides. [It is sure fun coming down on the begining of every ride]. We did break a rear freehub going up one time. Sucks but we did not crash even though we were going 5mph up the 14% grade.

Haven't broken a chain on our tandem yet, but we did come upon a couple with a Santana on a local climb who were trying to get their chain back together by pounding on it with rocks. Needless to say, it wasn't going well. They were very glad to find that our party was equipped with a chain tool and could get them back on the road. They were in an area with no cell reception and still had a couple miles of climb left and about 15 miles total to get to the nearest town so it would have been a lengthy walk.

+1.

IMHO, these are the questions you need to ask when a chain breaks. Until you know the root cause, you won't necessarily be able to preclude future occurrences. Sometimes there's just a bad batch of chains, sometimes the pressed-in rivet isn't seated properly but most times on a tandem it's caused by a shift under load / operator-induced problem.

The original SRAM chain did fail on a climb, but not on a particularly steep portion. Nor was I shifting, but it's always possible an earlier shift may have caused a problem. My stoker is very good about unloading the drive chain when I call a shift, especially important on the Davinci since without a rigid connection between captain and stoker I can't directly control the chain load. I'm going to stick with SRAM chains and see how it goes. My LBS stocks the longer lengths I need for my drive chain so I don't have to use two quick links. While I don't carry a spare chain I definitely have a good chain tool and quick links.