Results 1 to 39 of 39
  1. #1
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    634

    Tandem drive chains

    Have been using SRAM 951 chains since 2007. We've had no issues with them until recently. I change out the drive chain every six months as a precaution (in the main) and due to some chain stretch (~1/16 over six months, but chains are much cheaper than chainrings and cassettes).

    Out yesterday on the bike and snapped a chain. This chain had 1.5 rides on it from new, as we'd snapped a chain two rides ago that had been on the bike only since August. I have two more new-in-box SRAM 951 chains that I'm hesitant to install on the bike. It would seem that there is/was a bad batch of SRAM chains out there, but from all appearances on the chain and packaging, there's no way to identify when it was made. Chain failure occurred with the side plates separating. The first was while shifting, the failure yesterday was in low-torque flat riding with no shifting, but we had just spent a half-hour climbing a switchback singletrack.

    Two questions - 1. Is/has anyone else experienced unexpected failures of SRAM chains recently? 2. Are there suggestions for another manufacturer? We'll need a new drive chain for next weekend.

    Chain failure is NBD; since I swap out chains relatively frequently I carry my stash of SRAM powerlinks. More the principle of the thing, especially on that 1.5 ride chain from yesterday.

  2. #2
    mtbr member
    Reputation:
    Join Date
    Aug 2008
    Posts
    32
    Don't know if you have cross posted, but the Drivetrain section may be more fruitful for responses?

    How many hours riding do you do in 6 months?

  3. #3
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    634
    More of a tandem-related thing, so I thought I'd stick it here. MTBTandems spec all their stuff with the same chains I use. Doubt even Clydes on singles put as much power through the drive chain as a tandem team.

    Typical riding in 6 months is ~600 miles or so. The Aug-Dec chain probably had half that due to other factors.

  4. #4
    "the big red train"
    Reputation:
    Join Date
    Apr 2007
    Posts
    114
    Julian, I had the same issue with chains this August when we were heading to Mammoth. I like to use the 7701 XTR chain and I put a new chain and cassette about a week before our vacation and got 2 rides then up in Mammoth we broke the chain. Thank goodness for the Sram powerlink, no problem and I happened to have a spare new chain.

    You know its just like tubes, you go for years without any issues them it you get a flat everyother ride?

    I'd just check everything and make sure chainrings and cassette are good and install the new back-up chain you have.

  5. #5
    mtbr member
    Reputation:
    Join Date
    Jun 2010
    Posts
    299
    Most of the chain issues I have had on the tandem have been the result of bad shifts( one or both of us not letting off the power when shifting).Some result in immediatly peeling a link and others may take a day or two. We use SRAM PC991 chains. The most inconvienient one occured last year during AORTA. We had just arrived at DuPont SF, I unloaded and assembled the tandem, we got on to ride over to the group and the first pedal revolution separated the drive chain. Some digging around for quick links solve the problem but not my choice for starting a ride. I have switched to KMC chains on the road tandem and am considering them for the Ventana.
    The price of the SRAM chains is much cheaper though and I also switch drive chains about 2-3 times a year on the Ventana.
    Ed and Pat Gifford
    the Snot Rocket tandem

  6. #6
    mtbr member
    Reputation:
    Join Date
    Mar 2007
    Posts
    143
    Gave up on SRAM chains years ago for tandem use for the same reasons. Knock on wood but with nickel plated Wipperman chains I have had no tandem chain issues for going on maybe 5 or more years now. Seem to wear very well too.

  7. #7
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    634
    Up until these most recent failures, I haven't had any issues with 951s going back to 2007. From the looks of mtbtandems.com build specs, Alex uses 'em as stock.

    However, it may be a non-issue if you can go 3x on a Wipperman vs. a 951.

  8. #8
    Schipperkes are cool.
    Reputation: banks's Avatar
    Join Date
    Feb 2004
    Posts
    4,091
    If the SRAM chain broke somewhere other then the Power Link, it is a fault of the chain. I see a Lot of SRAM chains break at the pin/outer plate. There have been many bad batches of SRAM chains in the last 12.5 years. I rarely see Shimano chains have that break on a link that was Factory installed.
    Also, for the best shifting, keep the rear derailleur and the chain of the same manufacturer. ie Shimano rear derailleur & SRAM chain is the sloppiest shifting possible & SRAM rear derailleur with a Shimano chain is the fastest shifting, but the most anal.
    Quote Originally Posted by mikesee
    Better suited to non-aggressive 125# gals named Russell.
    I ride so slow, your Garmin will shut off.

  9. #9
    mtbr member
    Reputation:
    Join Date
    Jan 2006
    Posts
    1,936
    I rarely have had problems with SRAM chains, run them on all of my bikes, except for my Campy equipped road bike, in which I use a Wipperman chain.
    I switched from Shimano chains to SRAM, because I was breaking the Shimano chains and you had to use that stupid pin system Shimano was using(maybe they still the pin) but have been very happy with SRAM chains.

  10. #10
    mtbr member
    Reputation: ds2199's Avatar
    Join Date
    Sep 2008
    Posts
    842
    Quote Originally Posted by Hurricane Jeff View Post
    I rarely have had problems with SRAM chains, run them on all of my bikes, except for my Campy equipped road bike, in which I use a Wipperman chain.
    I switched from Shimano chains to SRAM, because I was breaking the Shimano chains and you had to use that stupid pin system Shimano was using(maybe they still the pin) but have been very happy with SRAM chains.
    + 1 or 2 on the SRAM chains. Busted Wipperman chains on road tandem. Great results with SRAM, did not like the pins on Shimano.

    991 and 951 have both worked well. Agree about SRAM with SRAM etc.

  11. #11
    PMK
    PMK is offline
    mtbr member
    Reputation: PMK's Avatar
    Join Date
    Oct 2004
    Posts
    2,501
    All the bikes for us, all SRAM chains.

    For experienced teams, schoolboy mistakes can still happen. Is there maybe just a few highly loaded shifts possibly causing the concern?

    Maybe they are just a bad batch of chains as mentioned.

    AORTA 2011 was a year for the Powerlink...there were some broken chains, most appeared to be caused by a heavy load downshift during a climb.

    Hope it gets resolved.

    PK
    Reps! We don't need no stickin' reps!

  12. #12
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    634
    Quote Originally Posted by PMK View Post
    For experienced teams, schoolboy mistakes can still happen. Is there maybe just a few highly loaded shifts possibly causing the concern?
    On the 5-month chain that broke - perhaps. It did break while shifting and going uphill, but honestly the shift wasn't anything out of the ordinary.

    On the 1.5-ride chain? No shifts when it broke - flat fire road, light loading. As mentioned, we'd just spent a half-hour climbing singletrack before topping out on the flat, but that's nothing out of the ordinary.

    I called SRAM. They didn't admit to any issues with chains, even though there are sufficient reports on the intertubes to indicate a bad batch here and there (mostly pointing to poor/insufficient hardening). But as SRAM don't deal with end users, I'd have to submit the chain to a bike shop and have them submit it to SRAM. For a $15 chain, I don't see the point, nevermind I don't have a LBS I frequent.

    I ordered a Wipperman, and will keep the new SRAM chains in reserve.

  13. #13
    mtbr member
    Reputation:
    Join Date
    Jun 2010
    Posts
    299
    [QUOTE=Okayfine;

    On the 1.5-ride chain? No shifts when it broke - flat fire road, light loading. As mentioned, we'd just spent a half-hour climbing singletrack before topping out on the flat, but that's nothing out of the ordinary.
    [/QUOTE]

    With the chain that broke at AORTA in Dupont we had not ridden at all that day and had just put the front wheel on and turned the pedals once. I assumed I had made an errant shift the day before and it was just catching up with me, but now you have me thinking. There were a lot of broken SRAM chains at AORTA last year. Some of them you could hear the teams shifting going uphill under load but we are experienced enough not to do that. Who knows! We always carry 2 or 3 extra links and a chain tool on the Ventana anyway.
    Ed and Pat Gifford
    the Snot Rocket tandem

  14. #14
    Schipperkes are cool.
    Reputation: banks's Avatar
    Join Date
    Feb 2004
    Posts
    4,091
    Power Links work great with Shimano chains, but the Link is softer then the Shimano plates.
    Shimano pins are Super easy with the right chain tool. The chain tools that do not push the pin all the way out obviously will not work.
    Quote Originally Posted by mikesee
    Better suited to non-aggressive 125# gals named Russell.
    I ride so slow, your Garmin will shut off.

  15. #15
    PMK
    PMK is offline
    mtbr member
    Reputation: PMK's Avatar
    Join Date
    Oct 2004
    Posts
    2,501
    Quote Originally Posted by giff07 View Post
    With the chain that broke at AORTA in Dupont we had not ridden at all that day and had just put the front wheel on and turned the pedals once. I assumed I had made an errant shift the day before and it was just catching up with me, but now you have me thinking. There were a lot of broken SRAM chains at AORTA last year. Some of them you could hear the teams shifting going uphill under load but we are experienced enough not to do that. Who knows! We always carry 2 or 3 extra links and a chain tool on the Ventana anyway.
    Ed and Pat Gifford
    the Snot Rocket tandem
    Some of the failed AORTA chains were obvious downshifts under heavy loads. I watched a couple of them.

    After reading this topic again from the first post, I now notice the chain model is the 951 series that failed for okayfine.

    For comparison,

    Our Ventana ECDM 26" wheeled machine runs
    Surly stainless chainrings on the timing side with a SRAM PC850 chain
    Rear drive is Salsa front ring, SRAM cassette and SRAM PC971 chain

    The Fandango has installed on it
    Shimano tandem timing rings and a SRAM PC850 chain
    Rear is a Middleburn Hard Anodized with pins / ramps front ring, SRAM cassette and SRAM PC971 chain

    The Fandango drive train is getting replaced probably this weekend.
    The following is the stuff picked up for the task
    Timing rings will be Middleburn Hard Anodized with no pins / ramps, SRAM PC971 chain
    Rear plan is another Middleburn Hard Ano with pins / ramps same PN SRAM cassette, and SRAM PC991 Cross Step chain

    The Co-Motion runs Race Face timing and drive chainrings. The Cassette is SRAM. Timing chain is a SRAM PC870 and the drive is a SRAM PC 991

    Don't know if that helps anyone or not.

    PK
    Reps! We don't need no stickin' reps!

  16. #16
    mtbr member
    Reputation:
    Join Date
    Jun 2010
    Posts
    299
    Yeah I also noticed a lot of that type of shifting at AORTA. FWIW we also run Sram PC 991 chains and Middleburn hard ano rings.

  17. #17
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    634
    From a brief search on the internets it would seem the 951 and 971 chains are the same, except the 971 gets nickle plating (perhaps only on the outside links). The 991 has full plating and hollow pins, otherwise the same.

    We currently have Middleburn coated chain rings (pins and ramps) and an XT cassette. We have a Raceface chain ring set in reserve, and a SRAM 990 cassette in reserve. FWIW, the 990 cassette only has one rivet per arm attaching the 34T cog, while the XT has two rivets per arm. Subjectively the XT piece feels much more substantial, and we've had zero issues with the cassette in over a year of abuse. Uh, I mean use.

    The Wipperman replacement won't arrive until next week, so one of my back-up SRAM chains will go on so we can ride this weekend. Wish me luck.

  18. #18
    PMK
    PMK is offline
    mtbr member
    Reputation: PMK's Avatar
    Join Date
    Oct 2004
    Posts
    2,501
    FWIW, the PC991 is available in both formats of hollow pin and solid pin.

    Checking the SRAM site last night while posting, their site stated the PC991 Cross Step is their strongest chain.

    Somehow I also thought that PC991 regardless of labeled Cross Step or not were all that style. Don't know how they peen the hollow pin stuff.

    PK
    Reps! We don't need no stickin' reps!

  19. #19
    mtbr member
    Reputation:
    Join Date
    Jun 2010
    Posts
    299
    Quote Originally Posted by Okayfine View Post
    From a brief search on the internets it would seem the 951 and 971 chains are the same, except the 971 gets nickle plating (perhaps only on the outside links). The 991 has full plating and hollow pins, otherwise the same.

    We currently have Middleburn coated chain rings (pins and ramps) and an XT cassette. We have a Raceface chain ring set in reserve, and a SRAM 990 cassette in reserve. FWIW, the 990 cassette only has one rivet per arm attaching the 34T cog, while the XT has two rivets per arm. Subjectively the XT piece feels much more substantial, and we've had zero issues with the cassette in over a year of abuse. Uh, I mean use.

    The Wipperman replacement won't arrive until next week, so one of my back-up SRAM chains will go on so we can ride this weekend. Wish me luck.
    Well, good luck with that. Let us know how the Wipperman chain works out. the ones I looked at seemed pretty pricey. We pay around $29 for the PC991. Ours does not have hollow pins or plates. I like the shifting reliability we have had using Shimano XT cassettes.
    I generally keep a Sram on the spare set of wheels we take with us when we travel. I have returned a couple of Sram cassettes that were so out of alignment that they wouldn't fit the splines on the rear hub.
    Ed

  20. #20
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    634
    Jenson had the Wipperman at $40, -$10 for a previous missed delivery by Jenson, and $30 is cheap enough for a test. If I get a year out of it without undue stretch, I'll be happy and probably switch for the drive chain. I get much longer life on the sync chain, so I'll figure out what to do once it gets to 1/16" stretch.

  21. #21
    PMK
    PMK is offline
    mtbr member
    Reputation: PMK's Avatar
    Join Date
    Oct 2004
    Posts
    2,501
    Quote Originally Posted by giff07 View Post
    Well, good luck with that. Let us know how the Wipperman chain works out. the ones I looked at seemed pretty pricey. We pay around $29 for the PC991. Ours does not have hollow pins or plates. I like the shifting reliability we have had using Shimano XT cassettes.
    I generally keep a Sram on the spare set of wheels we take with us when we travel. I have returned a couple of Sram cassettes that were so out of alignment that they wouldn't fit the splines on the rear hub.
    Ed

    FWIW, we don't run Shimano cassettes, every one has folded on us.

    Ed, in regards to those SRAM cassettes not being aligned for the splines, not defending SRAM, bur FWIW, there is a long allen headed fastener that ties the set of sprockets together. Often for us, this will loosen slightly with use. The fastener does not fall out just loosen maybe a 1/4 turn or less. Then the sprockets sort of float or pivot out of alignment on the fastener.

    To control this, actually deal with it, I have an old freehub body that I slide the loose cassette onto. Then without a hub flange in the way, I re-tighten the fastener.

    Also, for anyone with an aluminum freehub, to remove the cassette, you may need two chain whips so you can unseat the sprocket from the notch cut into the aluminum. Trust me, they wont come off with easy persuasian.

    PK
    Reps! We don't need no stickin' reps!

  22. #22
    mtbr member
    Reputation:
    Join Date
    Jun 2010
    Posts
    299
    Quote Originally Posted by PMK View Post
    FWIW, we don't run Shimano cassettes, every one has folded on us.

    Ed, in regards to those SRAM cassettes not being aligned for the splines, not defending SRAM, bur FWIW, there is a long allen headed fastener that ties the set of sprockets together. Often for us, this will loosen slightly with use. The fastener does not fall out just loosen maybe a 1/4 turn or less. Then the sprockets sort of float or pivot out of alignment on the fastener

    PK
    Good to know, thanks Paul. FWIW these were brand new , never installed on a wheel cassettes. We have never folded a Shimano cassette. You 2 need to stop eating your Wheaties.(LOL)
    Ed

  23. #23
    ballbuster
    Reputation: pimpbot's Avatar
    Join Date
    Dec 2003
    Posts
    12,702
    I have no tandem experience, but the only chains I ever broke were SRAM chains. I use XTR chains almost exclusively with a SRAM Powerlink (9 speed) and have had zero issues.

    We're not talking about the sync chain, are we? I don't see any reason to use anything but a good singlespeed chain for the sync chain.

    Yeah, with twice the torque being applied to the drive chain, keep a very careful eye on it. Check it often with a chain checker, and use good thick chainlube. The thin stuff has no film strength. I use Finish Line Synthetic wet lube or DuMonde Tech thick lube year round. So my chain looks dirty... so what? My chains last me for frickin' evar.

  24. #24
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    634
    Wippermann chain came in last night. Installed it today. Looks very pretty all plated, but the master link isn't as easy to work as the SRAM piece. Proof will be in the pudding, so hopefully I won't be updating this thread for at least a year

  25. #25
    mtbr member
    Reputation:
    Join Date
    Mar 2007
    Posts
    143
    SRAM quick links work fine on Wipperman chains if needed.

    Also, make sure your Wipperman connex link is oriented properly. There is a slight curvature to the link. That curvature needs to be the same as the rings an/or cogs. If it is upside down you will skip on your smaller cogs and it just is not happy that way. The Wipperman instructions have a tiny picture of the curvature matching the drivetrain.

    Once you have installed the connex link a couple of times to get the hang of it I found it the easiest of all quick links to use. It is a tad unusual though.

  26. #26
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    634
    Quote Originally Posted by Stevoo View Post
    If it is upside down you will skip on your smaller cogs and it just is not happy that way. The Wipperman instructions have a tiny picture of the curvature matching the drivetrain.
    Funny you should mention that. After two rides, the Wippermann doesn't like the 22T front ring. It hangs up and clatters all about. I verified the Connex link versus their diagram and it was correct. The hanging-up was over the whole chain length, anyway, and not just wherever the link is/was.

    New SRAM chain doesn't hang up, so I don't expect it is worn teeth, but will also compare to a new 22T ring for giggles. Will clean the granny ring and try again.

  27. #27
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    634
    That didn't take long. Wippermann failed today. Climbing an asphalt road, shifting down in back. Maybe half torque, maybe less. Unexpected, I've tried to be as kind as possible due to the previous failures.

    This is (only) the third ride with it, and it busted early, so really only the second ride.

    I'd put the blame all on my shifting, except my shifting hasn't changed (for better or worse) in the six years we've had the Ventana. We've only snapped chains starting in October of last year.

  28. #28
    mtbr member
    Reputation:
    Join Date
    Jun 2010
    Posts
    299
    Thanks for the update (I think). Sorry to hear it. I just purchased the spring edition of cassette and chains. I bought Sram 991s for sync/timing chains and a 991 cross step( which is supposed to be stronger than standard)for the drive chain. Went with a Sram PG990 cassette instead of our usual Shimano XT cassette. We will report back on any issues. Take it as no news is good news. The chains are 2011 models I paid $30 ea for at Price Point FWIW.
    Ed and Pat Gifford
    the Snot Rocket tandem

  29. #29
    mtbr member
    Reputation:
    Join Date
    Oct 2010
    Posts
    39
    OK giff07, now I am thoroughly confused.

    Let me start by saying I have ridden a Wipperman 908 (drive chain) for about a year now w/no failures. It replaced the original chain on our Fandango which broke w/less than 10 miles on it. When that happened I was completely new to all tandems, had never even seen anyone ride a MTB tandem, didn't know to be careful shifting, and consequently will leave any disparagement of the brand and model out of this conversation unless pressed.

    Last weekend during the TdF I discovered just how worn out our cassette was. Cogs 4, 5, and 6 would pop as we applied any torque to the pedals. We could limp on those gears across flat ground but if we gave her the pork it was ugly.

    After getting home I inspected the cassette to find the backside of the teeth on those cogs to be flattened and curled forward forming sharp edges. Wow, I have never seen one wear like that on a single bike. Lesson learned: drivetrains wear faster on tandems than on singles. I need to be more diligent. I have a couple cassettes around as spares but I decided to take a look for a blowout on a new one. I found the same deal you did.

    Now my question to you. Did you really get a 990 cassette? I thought it was verboten to use cassettes w/spiders on a (MTB) tandem. If that is the case it looks like the highest end SRAM cassette we should be using is a 970? Is there wisdom in using a 991 over a 971 chain? I like what you said about the cross step.

    In the end I am thinking about using an 11-34 970 cassette, 991 cross step drive, and 2 971 for timing chains.

  30. #30
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    634
    Drivetrains do wear faster on a tandem. Sure, it took me wearing out a complete drivetrain to realize it. That's why I got into my bi-annual chain replacement, whether they needed 'em or not. Failure of parts on the tandem is 1,000,000 times worse than on my single bike.

    We use an XT cassette and have had zero issues. It's been on the bike for almost a year and a half. In the past we've regularly imploded White Industries rear hubs (6 months per event), so we're not a light/finesse team. I personally like the XT cassette over the SRAM (I have a SRAM in the spares bin, just in case) because the big cog is attached with two rivets per arm, where on the SRAM piece the cog only gets one rivet per arm.

    Went to XT because our LX cassette (individual cogs) was digging into the stainless Chris King drive shell. Cheaper to go through cassettes than R&R the hub shell, but it hasn't been an issue.

  31. #31
    mtbr member
    Reputation:
    Join Date
    Jun 2010
    Posts
    299
    Hi Jamie,
    We are in about the same situation as OKayfine in that I have always used XT cassettes with good sucess. The best price I could find was in the $90 range. I also keep a Sram cassette on our spare wheels. When I saw the Sram 990 cassette for $59 I decided to give it a try. We generally get a year out of a cassette. The worn out XT was installed before AORTA 2011. I have never been dissatisfied with XT but thought I would try Sram. Both are spidered cassettes and I have heard the opposite of you in that the individual cogs tend to chew up the carrier. I believe Chris King eludes to that on their website.
    As far as chains go I generally replace the drive side chain 2x per year and I measure the timing chain and replace as needed. The 971 has plating on the side plates only I think and the entire 991 is coated. I have experienced some rust issues with the 971. So, call me lazy but my solution was the 991. We break drive chains several times a season and if its got some life in it I clean it up and use it on the timing chain side . I dont think we are that strong and I am careful shifting but it does happen. This will be the first 991 cross step we will try so we will report back with any breakage. We try to replace the drive chain after it has 3 quick links in it.
    I have replaced the middle and granny rings on the crankset with the hard anodised rings from Middleburn and they seem to be working fine. Also just put Panaracer Rampage tires on and really like them also. They shed mud well and seem to roll better than the WTB Moto Raptors we used previously. Our regards to both you and Jen.
    Ed and Pat

  32. #32
    mtbr member
    Reputation:
    Join Date
    Mar 2007
    Posts
    143
    Too bad about the Wipperman experiment. Let us know what ends up working for you.

    Broke a spider arm on the last XT cassette. Currently using the new offering from Shimano that has a 36 tooth big cog. It has individual cogs and digs into our stainless steel Chris King hub. I wish King would change the alloy, heat treat or both to eliminate the problem. Had some interaction with Chris King from time to time and they have always been real nice and helpful but won't acknowledge the shell problem for some reason. If it gets real bad I will TIG weld the cogs together to eliminate the problem.

    Good info on the Rampages. Will give them a try next as the back tire is due for replacement.

  33. #33
    PMK
    PMK is offline
    mtbr member
    Reputation: PMK's Avatar
    Join Date
    Oct 2004
    Posts
    2,501
    FWIW, Jamie and others, our Fandango had the majority of a lazy on my part and not done a while ago rebuild done the week prior to TdF.

    Basically the entire bike was torn apart except hub bearings, fork, headset bearings, and thudbuster.

    The rebuild had me replace all chainrings, cassette, and chains.

    Our worn / removed setup was a SRAM PG970 11/34 with a 971 chain, Middleburn 36t pinned and hard anodized front ring, granny was a Shimano steel ring, the timing rings were Shimano Tandem with 8 speed 851(?) chain. This setup served us well with a bunch of miles and no broken chains. This still has life in it and was offered up.

    The new install was still a PG970 11/34, another Middleburn 36t pinned and anodized front, timing rings are now Middleburn non pinned but anodized, installed a new Shimano steel granny, chains are a 991 cross step for the drive and 971 for the timing. This is with Shimano 4 bolt cranks and DT 540 rear hub.

    The bike was finished, had a couple of short runs up the street to make sure it shifted and stopped. Tossed it in the van and rode TdF. We had two instances of chain suck, both times I undid the chainsuck by a serious pull the chain out with force by hand. I am not certain but want to blame the new granny for some of the problem.

    Also, we will almost always run Finishline Wet chain lube. No doubt nasty and dirty, but does lube well. Cleaning involves removing both chains and washing them in solvent, dry, then install and relube.

    In the past we have folded Shimano spider and non spider cassettes while climbing.

    I honestly don't know what is best, but will say that good shifting technique, and finding the gear a few feet early may make a difference.

    I hope you guys get it sorted out.

    PK
    Reps! We don't need no stickin' reps!

  34. #34
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    634
    Waiting on parts so I thought I'd give the bike a once-over. With the rear chain off, there is some side-to-side play (2-3mm) at the tip of the pulley cage.

    We have a SRAM x9 on the back of the tandem. Been there since 2007. Still shifts fine. Each section of the RD has a tiny amount of play in it and it adds up by the time you get to the end of the pulley cage to 2-3mm. My NIB X9 spare has no play anywhere. Starting to wonder if this wobble might be partially responsible for snapping of chains.

    So, when is a rear mech bad?

  35. #35
    mtbr member
    Reputation:
    Join Date
    Mar 2007
    Posts
    143
    Just saw this posted today on the Drivetrain Forum. Saw the pictures. The side plate are actually broken. Interesting anway. Seems single bike folks also have some challenges and opportunities when it comes to drive chains.

    "SRAM Chain Failure!

    --------------------------------------------------------------------------------

    Can't believe what happened yesterday. Second outing after regular chain replacement using a SRAM PC-991 CrosStep...a link broke in half across the pin after less than 20 miles of use! Upon closer inspection there are 8 other links that were about to break when this one did. Never seen anything like it. Either SRAM needs quality control or something I have never seen is happening.

    Any ideas? Will SRAM warranty this?
    Attached Images"

  36. #36
    mtbr member
    Reputation:
    Join Date
    Jun 2010
    Posts
    299
    Well thats not good news!

  37. #37
    PMK
    PMK is offline
    mtbr member
    Reputation: PMK's Avatar
    Join Date
    Oct 2004
    Posts
    2,501
    The 991 shown in the drivetrain forum is a problem with the manufacturer cracking the chain side plates when peening the rivets. Reading the entire topic, the guy admits it's on a SS he is 180 pounds and just an average rider.

    Our 991 cross type chain has survived the 60 plus miles of TdF, including every climb, and another 12 miles drudge sand ride last night.

    I read about the snapped side plates after our ride last night, gave ours a quick look. No defects noted, but I will give it a more intense inspection before our next ride.

    PK
    Reps! We don't need no stickin' reps!

  38. #38
    mtbr member
    Reputation:
    Join Date
    Mar 2007
    Posts
    143
    Lots of variable in manufacturing and stuff happens. This is true especially with heat treat. I have quite a bit of experience with the variables related to heat treated parts. It is certainly possible to get batches that are to hard (brittle) and /or some that came out too soft. Sometimes things just get by even when it seems there is reasonable quality control in place. Usually the defects are caught before getting to the consumer but not always.

    That is why some folks may have great success with brand X and other folks maybe have some problems. Sometimes you just happen to buy parts made from a bad batch. It happens.

  39. #39
    PMK
    PMK is offline
    mtbr member
    Reputation: PMK's Avatar
    Join Date
    Oct 2004
    Posts
    2,501
    Quote Originally Posted by Stevoo View Post
    Lots of variable in manufacturing and stuff happens. This is true especially with heat treat. I have quite a bit of experience with the variables related to heat treated parts. It is certainly possible to get batches that are to hard (brittle) and /or some that came out too soft. Sometimes things just get by even when it seems there is reasonable quality control in place. Usually the defects are caught before getting to the consumer but not always.

    That is why some folks may have great success with brand X and other folks maybe have some problems. Sometimes you just happen to buy parts made from a bad batch. It happens.

    Agree!

    And then there are the bikes / chains that run virtually no real type of lube because the owners want it always clean. The broken side plates are not a lubrication failure, but it seems that with all the "clean" or "green" chain lubes these days, somebody along the way forgot it had to lubricate also.

    PK
    Reps! We don't need no stickin' reps!

Similar Threads

  1. Replies: 0
    Last Post: 07-30-2011, 10:23 PM
  2. Tandem Quiz: Who made this tandem???
    By First Flight in forum Vintage, Retro, Classic
    Replies: 13
    Last Post: 06-17-2009, 08:39 PM
  3. Nicolai, Gates Carbon Drive, worm drive, and NuVinci
    By vmajor in forum Internal Gear Hubs
    Replies: 4
    Last Post: 03-17-2008, 02:12 PM
  4. Replies: 44
    Last Post: 03-05-2006, 06:16 AM
  5. stolen tandem; need new tandem for century ride
    By gooseguy in forum Tandem Mountain Bikes
    Replies: 0
    Last Post: 08-23-2005, 01:14 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •