Theologic Bear

I ride a new Gary Fisher Piranha for exercise and fun. I'd say I've put about 700 miles on the bike so far. I couldn't be any happier with the durability of the bike, especially at my uber-clyde weight and considering the rough terrain that I ride. The only problem is, I've broken two Sram 971 chains in only 700 miles. They're not breaking at the master link either. Both times, the sides of one link have simply bent out sideways, breaking the chain. I keep the chain regularly lubricated, and my drive train has only 700 miles on it and does not have any alignment issues.

Anyway, to my point. What chains don't break that often?? I hear that I'm supposed to get at least 2000 miles and up to 10000 miles per chain. I need a 9 speed chain that will last with my extreme weight and burly strength.

Suggestions??

bautieri

Maybe you aught to try not to be so burly and mashing the pedals so hard or throwing your weight into the pedal stroke. Sit down and pedal as terrain permits and spin up climbs in a lower gear if your not doing this already.

I humbly suggest a multi tool with a chain breaker and a handfull of powerlinks being added to your seat pack.

flip18436572

You must do some major mashing and not much spinning to do something like that. I can't help you as I don't have that problem. I was at over 2500 miles before I had enough chain stretch to make a difference.

Theologic Bear

If you look at the reviews for this chain, they are terrible. Is it possible that this problem is ALSO a function of the bad chain?? The reason I ask this question is that both times this has occurred, I was in the lowest gear spinning up a really steep hill. I am not at all a pedal masher. In fact, if anything, I am often shifting into too low a gear because I'm lazy. Does it make a difference that I can leg press 750 pounds??

CliftonGK1

I've been using PC971 chains on my commuter/brevet bike for the past year without any problems.
I weigh 250 pounds, ride tons of hills, and have never broken a chain even while standing and stomping the pedals to get up some of the 20% grades around here.

If you're peeling the side plates off, it sounds like you might be cross-chaining and putting a lot of unnecessary sideways stress on the chain.

Mr. Beanz

I agree. I had 13000 miles on my last chain, same model, no problems. Insatalled same model this time, lots of climbing and no problems. I've never had a problem with any chain, SRAM or Shimano, 7, 8 or 9 speeds.

Crosschaining or maybe a bad tooth on your chaingrings that might be causing the damage.

flip18436572

[QUOTE=Theologic Bear;8597884]If you look at the reviews for this chain, they are terrible. Is it possible that this problem is ALSO a function of the bad chain?? The reason I ask this question is that both times this has occurred, I was in the lowest gear spinning up a really steep hill. I am not at all a pedal masher. In fact, if anything, I am often shifting into too low a gear because I'm lazy. Does it make a difference that I can leg press 750 pounds??[/QUOTE]

Nope 750 pound leg press is not that impressive for broken chains. I can also leg press 750 pounds and also could do that in 10th grade almost 30 years ago. No big deal.

I have never broken a chain, but that doesn't mean that it can't happen. Maybe you have some bad chain? Maybe you have a messed up tooth on one or more of your chain rings?


I am also pretty sure Mr. Beanz can leg press more than 750 pounds and he has more hilly miles than I have ever seen.

Theologic Bear

I have completely inspected my drivetrain for problems--nothing. Also, I am not a roadie. I ride mountains which are much harder on chains (dirt and short bursts up steep hills). I am good about being aware of my chain configuration. In addition, the way the chain breaks seems to indicate that it simply has been pulled too hard in a linear fashion. Personally, I think that it is the chain's fault as I have gone through two of them on a new bike.

No reason to start an argument about leg pressing, but let me just mention that most people count the weight that they put on the machine and fail to consider the fact that the weight is on a slide. In addition, very few people actually bring the legs all the way into a 90 degree angle. So, on the 45 degree leg press machine that I use, the actual weight on the machine is over 1000 pounds. I doubt there are any 10th graders that have ever done that down to a 90 degree!!

Sixty Fiver

Bicycle chain is designed to handle load stresses well beyond anything a human being can generate but the reviews on this chain from the mtb community would indicate that it is very poor chain and is prone to breaking.

Whether this was an issue with a production lot or endemic with this type of chain is still an unknown and I'd suggest PC59 / PC951 (same product) as it gets far better reviews.

Pay attention to your shifting habits as even a little runt like me can snap a chain if he is pointed straight up and is shifting under load... PC68 chain is my favourite for intense 8 speed applications and has never cause me any problems on geared and ss mtb's that see some huge chain stresses.

Mr. Beanz

Like I said, I've never boken a chain. Short bursts? How about long bursts up mtb trails?

So you're saying shorts burst on an mtb are more punishing on a chain than climbing 62 miles up into the mtns, some grades of 22%. Done on a 39/25 standard double when your mtb is geared with a superlow gear of, maybe a 22/27?

This is where I ride offroad. A 5 mile loop, the first 2.5 miles very steep. I must say I've never seen an uberclyde climb this hill. I do 3 loops when most do 1. Believe me, mtbing up these hills with a low gear isn't any tougher than climbing 10-22% grades on a standard roadie.

lambo_vt

Oh, you're one of those guys irritating everybody at the gym by using all the big plates. Trust me, those looks everyone is giving you aren't "Wow, look at all that weight", they're "Wow, what is that guy even thinking?"

If you really think you're so strong, you should be squatting. Done correctly, it is not harmful to your knees. The "leg press" is an extreme waste of time compared to a proper low squat, and bragging about your leg press max is like new cyclists bragging about their "average speed".

andymac

Telling people on this or any other forum how strong your are will generally not result in much in the way of helpful advice….
There is a chance that the chain you have tried twice is problematic, so try another brand next time, simple as that. There is no miracle, “cannot be broken” chain out there. They are all very similar in construction, I personally like the nickel plated ones to keep the rust at bay.
Your posts suggest that you think you are doing everything right but repeatedly breaking even a weak chain would suggest otherwise. A chain where the side plate has bent out and broken was likely one that was weakened by something you did earlier. Spinning up a steep hill probably just put a little more stress on the already damaged chain causing it to break. The most likely “actual” cause of a broken chain is something that happened, even days earlier, that has caused the chain to be twisted under force and spread the link out. This could be something like shifting one or more gears while under load or dropping the chain off the front ring or into the spokes and having it jam. If you ever hear a crunching noise while you are shifting into an easier gear under load, or had to pry your chain out of your spokes or from between your frame and cranks you can bet you are messing up. Dropping the chain can be mostly addressed by adjusting your derailleur limit screws but inappropriate shifting is all on the rider.

Mr. Beanz

Good postAndymac!... So many riders don't now how to shift gears. Not suggesting the OP is in the same boat but I've heard riders grind the heck out of the gears while shifting on a climb under load. Easing up on the pedals for a split second to ease the load on the shift works great!

CliftonGK1

Grind 'em 'til you find 'em! It's just like driving a stick shift.

bautieri

To address the original post, I use the chain that came stock on my bike. I haven’t had to replace it yet due to stretch or something else nasty happening to it.

Andymac hit is spot on with the chain getting caught between your frame and bottom sprocket when it's over thrown. It happens every now and then so make sure you come to a complete stop and manually put the chain back on. Don't upshift and grind until it catches. Maybe you aught to stop out to your LBS and ask them to check and see what is going on. If it's a defective chain then they can probably give you a new one under warranty, course that assumes you bought the chain from them in the first place. They will also be able to check your drive train for wear, it's not always easy to spot. If the chains had been damaged awhile before they failed it's very possible they have caused some premature wear. Either way I hope it works out for you, if you're having trouble with a SRAM product give Shimano a try. Fortunately chains aren’t all that expensive.

Keep up the good work in the gym, at least your cross training and working out . When your ready move on to straight bar open grip dead lifts, straps are cheating. Squats are very good too, no smith machine and no pad.

Wogster

You shouldn't need to replace a chain that quick, and probably didn't need to. Chains are made longer then they need to be. So there are usually a few extra links, always keep those, get and learn to use a chain tool. When the chain breaks, simply take out the damaged link(s) and put in the same number of spare links, then ride on. This is a side of the road repair, so get a portable chain tool.

Probably should get a shop to look at the drive train, 700 miles is a little short. One problem with reviews, especially mountain bike reviews is that often the reviewers expect extraordinary performance out of ordinary components. You can try a different model or brand of chain, see if that helps. If you get a Shimano chain, get a few of the replacement pins that Shimano uses, so you can repair the chain.