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Hi. I like to know what am I doing wrong? I have now changed twice my deore XT double crankset as the non drive is getting loose after a few months riding, roughly 50km per week end. I always tightened them up firmly, alternating between bolts. Is too tight an issue? Is that set an issue? Should I go for Zee or SLX instead?
Thanks
I've thought this in the past. And had similar problems but I'm guessing it's down to user error. Have a read of this thread.
[url= http://singletrackworld.com/forum/topic/shimano-xt-crank-keeps-falling-off-is-the-little-plastic-bolt-necessary ]http://singletrackworld.com/forum/topic/shimano-xt-crank-keeps-falling-off-is-the-little-plastic-bolt-necessary[/url]
Get a sram one, easy to fit and tighten and hard to over tighten. Not looked back since I left shimano stuff behind.
Are you torquing the bolts correctly? These cranks are incredibly common and there isn't a widespread issue with them so I'm forced to conclude that you are doing something wrong.
I was just going to link to my old thread, ta Darrenspink. I did buy an alloy one from ebay, (which is tightened with an allen key rather than a silly plastic shimano tool) and the crank has never come off since. Everyone on that thread said it's not needed to keep the crank on and just to preload but having a metal one on has kept my crank arm on and has saved me buying new cranks since it's been faultless.
The reason the tool is really hard to put any pressure on is that the torque needed is tiny. More and you overload the bearings causing the bb life to fall.
Definitely need to get your torque right
Even buying 2 new shimanos, still better vfm than SRAM!
Excluding $$$$ carbon cranks, no one really makes anything better than SLX
Never had a problem with my XT's, 1000's of km's on them ... but I have seen it happen.
- remove the arm (and the bolts from the arm) and clean everything!
- clean it again
- check the splines, if they're worn it's junk
- apply a decent waterproof grease everywhere where metal touches metal
- fit the arm, make sure it hits home
- preload the bearings (just a small amount of drag, no "gritty" feeling)
- tighten the allen bolts alternating a quarter turn at a time
- when snugged up use a torque wrench for final tightening
- nip up the preload
My 3 year old x9's bet to differ...
I discovered on the Zesty that because the pressfit BB had been re-bonded back in, the BB was a couple of mm too wide. This is enough to allow some flexing and then play to occur.
A sanding of the surface solved it...
Op, what happened to your old cranks? may I have them if you haven't binned them? perhaps for a donation to charity? 🙂
email on profile.
I think people are getting the preload tool mixed up with attaching the cranks to the axle.
The NDS crank should fit virtually the whole way onto the splined axle with only 2-3mm space at the end of the splines.
I've never properly torqued the mounting bolts, just made sure they are evenly tightened up between them.
The plastic washer that fits in the slot between the clamping surfaces of the crank arm has a small pin which should only engage with the hole in the axle when the crank is properly installed and allow you to push the washer in flush with the crank.
llatsni - MemberNever had a problem with my XT's, 1000's of km's on them ... but I have seen it happen.
- remove the arm (and the bolts from the arm) and clean everything!
- clean it again
- check the splines, if they're worn it's junk
- apply a decent waterproof grease everywhere where metal touches metal
- fit the arm, make sure it hits home
- preload the bearings (just a small amount of drag, no "gritty" feeling)
- tighten the allen bolts alternating a quarter turn at a time
- when snugged up use a torque wrench for final tightening
- nip up the preload
All good apart from the last point.
No point nipping up the preload, it wont do anything. Once you've set the preload prior to tightening the arm, leave it alone.
Never had a problem with [s]my XT's[/s] any cranks coming slack, 1000's of [s]km's[/s] miles on them .
Never used a torque wrench on any pushbike stuff.
mikewsmith - Member
My 3 year old x9's bet to differ...
POSTED 3 MINUTES AGO # REPORT-POST
In what way? My current XTs are older than that, and should keep on going for a lot longer yet. Shimano's crank design is absolutely spot on imo, easy to install and work on whilst plenty stuff and strong even for big biffers
It fits with 1 tool, it can't be over tightened, the splines are big enough not to be damaged by it coming loose (which it doesn’t) I've retired shimano for worn splines, pedal inserts and being heavy. Just not having any issues on the sram stuff. It gets a bad rep but it really does just do the job.
Suspect your bb is too wide somehow.
SRAM cranks are really good tbh, but they're not very competitive on price even before you take into account the shit BBs, which are shit.
I've had this problem loads - probably 4/5 crank sets killed. It's obviously user error somewhere (as others say it isn't a widespread problem) however I've now moved to RF Aeffect which seems to remove the risk of user error
I think bb being to wide, too many spacers might be a potential cause.
Even a fully paid up SRAMboy like mikew has gotta admit they are way overpriced at rrp and realworld prices.
It's more obvious at the budget end, I've had from deores to saints and they are all great, but I'd never* known a crank flex until I got sram s1000 on a new bike and found they could clip the stays if leant on with hand strength
* I'll ignore some awful truvativ shit I once had
No one has mentioned the little plastic nib that sits in the split gap. You pull it out to take the cranks off and push it in to seat them. If it won't push in the crank is not correctly positioned on the splines.
Gilles, just use a bigger spanner 😀
Mine did this,it came loose and I finished a ride with it loose which wore the splines which caused it to keep coming loose.I ended up using some loctite on the splines to 'fill in' the wear and they have been OK since!
adsh - MemberNo one has mentioned the little plastic nib that sits in the split gap. You pull it out to take the cranks off and push it in to seat them. If it won't push in the crank is not correctly positioned on the splines.
Ahem!
bigyinn - MemberThe plastic washer that fits in the slot between the clamping surfaces of the crank arm has a small pin which should only engage with the hole in the axle when the crank is properly installed and allow you to push the washer in flush with the crank.