K2 / Proflex Riders Group
General => Tech Forum => Topic started by: jeffhop on June 21, 2008, 04:25:59 am
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Ive just replaced the bushes on my oz and also replaced the pivot face inserts to try and cure the annoying cracking noise when pedaling. When i had the cranks off i checked the bb insert to make sure that was tight, it was, ive tried the paint round the dropouts trick to see if theyre coming apart, theyre not, it makes the noise seated or standing so its not the post, saddle or post insert. I noticed on the instructions for the bushes that the pivot bolt needs tightening to 250 inch pounds, am i right in thinking that would be about 21 foot pounds? My question is with a normal allen key how tight is 250 inch pounds is it one grunt or two? and is it possible to over tighten the bolt causing the pivot faces to bind on each other causing the cracking noise? Ive tried different wheels, different chainset and bb`s only thing i havent tried is different knees! hmmmmm maybe thats what it is, whatever it is its driving me mad.
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Are you sure its not the back of the saddle rails??
My Oz creaks and after a few rides it turned out to be the saddle, I was worried about the pivots or drop outs, but abit of tipex showed no movement.
Seriously considering doing the sealed bearing conversion , as a small machine shop has opened on the tiny industrial estate where i work, and they have CNC lathes.
Trying to find a DHX5 or SPV air to replace the SPV coil, as i am sure it occaisinally gets stuck down, when cycling along it feels like the rebound is wound up real high and the shock is packing down. I am thinking it may eb overheating as both times its been on hard rides on hot days.
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I had an annoying creak - when I looked over my bike I noticed that one of the chainring bolts had gone entirely and the other 4 had worked themselves loose!!
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I think thats about 17 to 18lbs ft still more than a grunt on a normal allen key. Over tightening wont make them bind, all it will do is strip the threads so be carefull.
I'd still be tempted to think a dropout is loose (ever so slightly loose)
Have you checked your pedals ?? A little lube on the axle threads into the cranks can do wonders.
How's the pivot insert in the frame there have been issues raised about that recently.
Simon.
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the pivot inserts seemed fine when i had everything apart, i used a couple of the inserts i had made so everything was nice and snug and no play, ill try a different set of pedals as it only does it when im pedaling either stood up or sat down, funny thing is its as quiet as a mouse when im coasting even on the rough stuff with the suspension working overtime and it doesnt do it when i trackstand and bounce up and down :) im even tempted to go back to the square taper bb and crankset i used when i first got the frame off simon. in fact i might change it over later today and have a run out again tomorrow.
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I crank the pivot bolt as tight as possible by feel. I have the specs somewhere, but got the feel eventually.
The loose drive side pivot face insert was my big creak recently. About 2 years ago it was the Hollowtech crankset BB and chainring bolts. Blue locktite on all those surfaces cured that problem.
At some point the dropout screws got loose and was creaking. I take that back, it was a missing screw.
Lastly, my derailleur cable housing squeaks on occasion just above the BB, and on the frame coming from the shifter. You might grease them just to check.
Good luck!!!!
Terry
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well i changed the bb, chainset and pedals back to the ones i had on when i first built it and it is quieter, it still cracks on hard efforts out of the saddle but its noticeably quieter on long fireroad climbs, think im going to have to live with it and wait for the offending item to drop off or at least give me a bigger clue as to what is wrong. thanks for all your help.
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Couple or three things to check, see my previous posts on "cracking" noises.
1) Shock bushes - if they have seized and are not rotating easily then this could be it, but would happen when the suspension moves rather than pedalling, but can creak in sympathy with pedalling frequency.
2) Bottom bracket - sounds like you've replaced this, but is it a brand new one? I had a cracked bearing cup causing a really nasty cracking noise when pedalling.
3) Worn square tapers on the cranks, so not sitting tight even when bolt is done up fully.
Col.
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the bb isnt new its been in about 4 bikes now ;) i last had it in my roadbike with an adapted mtb chainset on with no problems, its probably the best bb ive ever owned for longevity its still silky smooth compared to the isis i took off that felt grainy even when new! hmmm suspension bushes, i made these myself and never thought about them needing to rotate easily i thought they had to be fairly snug, thanks for that colin im off now to do a bit filing and will report back in a couple of days or so with the result ;D
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Yeh, my understanding is that the shock bushes should clamp tightly between the frame holes, but the shock should be able to pivot on the bushes (without any sideways slop).
You can check this by undoing one end and seeing if the shock pivots easily, then do it up again and repeat for the other end.
Col.
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Just finished my build of an OzM and as Terry pointed out in previous posts it was the lower cable housing on the drive side just above the BB. It was driving me nuts trying to locate but the big clue was when I ran thru a puddle the bike went silent... I greased/lubed the cable housing ends and "poof" sound was gone... Could not believe the cable covers could make that much noise!! If I start hearing a squeek on a ride, I drip a little water out of my camelbak on the cable end and it goes away for most of the day- of course I make a mental note to relube when I get off the trail! It looks as if you are getting to the heart of the matter with the cranks but you may want to see if it is those cables are contributing too. Chain ring bolts and pedals are pretty good advice. If squeeks are still there you will have to move on to seat post and headset/headtube and handlebar/stem? :D
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SUCCESS!!! :D ive got rid of the creaks, squeaks and my occasional groans ;D ive basically done everything that has been suggested above and also made myself a couple of new shock bushes .3mm wider (.012" for our american friends) ive greased the cables wherever they go through a cable guide ive changed the pivot bushings obviously as thats part of the title, ive changed chainset and bottom bracket, ive greased pedal threads and ive made sure its not a loose drop out and.............................its silent. think i need a nice cold one now to celebrate ;)
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That's a result then, 'cos it sounds like the only things left to change were the frame and/or the rider!
I'm convinced a rythmic creaking/grinding/knocking noise is my left kneecap running dry on lubrication......................must keep drinking more.....................<GRIN>
Col.