Andeee Posted July 9, 2012 Report Share Posted July 9, 2012 (edited) Ok so i was working on my bike tonight after getting my steerer height for my forks set up perfect etc. To then realise i needed to re-adjust my chain ( After following tartys method for setting snail cams) When i turn my crank arms back wards by time it gets to the 6-7 o'clock position they seem to stiffen up to the 4'oclock position where it will release back to normal. So i checked crank bolts re adjusted my chain tension and i still have this problem! Could the chain tensioner be causing pressure on the rear hub? I need Tarty Adam to help me resolve this horrible situation! Anyone ever had anything similar i may have to strip down the drive area tomorrow on my day off and investigate. Help? Set up is: Ozonys curve v2 frame trialtech sport cranks trialtech b.b hope pro2 rear hub monty snail cams Edited July 9, 2012 by Andeee Quote Link to comment Share on other sites More sharing options...
monkeyseemonkeydo Posted July 9, 2012 Report Share Posted July 9, 2012 Only time I've had something like you've described it was when my freewheel was catching my BB cup. A bit of grinding was required to aid clearance but if you're running a Pro2 I doubt that's the issue. If you loosen the chain off does it still happen? Could be the tight spot in your drivetrain stopping things if the chain becomes super tight at that position... Quote Link to comment Share on other sites More sharing options...
forteh Posted July 9, 2012 Report Share Posted July 9, 2012 (edited) Guessing either bent BB or front sprocket teeth. Overly tight chain will result in increased chain/sprocket wear as well as causing uneven loads on the BB and hub driveshell bearings, none of which is good. Edit: if it is always stiff at the same point of the crank rotation then it won't be a tight section of chain, that is unless you have reset the chain tension with the chain at it's slackest point. Edited July 9, 2012 by forteh Quote Link to comment Share on other sites More sharing options...
Andeee Posted July 9, 2012 Author Report Share Posted July 9, 2012 (edited) Just had another mince around it does it lightly with chain really slack. Also if i go to spin the pedals/cranks back with my feet they stop half way :/ I looked at sprocket it spins reasonably straight (with chain off) I havent got a wide enough crank puller tool to take my cranks off due to them being isis. I have a feeling my b.b may have a slight bend to it even worse the 6 month warranty expired last week FML! EDIT: Also i have only been on the isis scene for around 6 months after previously using square taper for 8 years. So if the b.b is bent i am gonna be very dissapointed i have never had a square taper b.b bend on me and i have used mix brands like onza's , shimano and neon. We shall see what the verdict is in the morning when i get my hands on a crank tool! Edited July 9, 2012 by Andeee Quote Link to comment Share on other sites More sharing options...
harmertrials Posted July 9, 2012 Report Share Posted July 9, 2012 You have a thread on the sprocket on your cranks, as well as a thread where the bb goes into the frame. This is a common issue mainly on mods where you tend to have the thread of a freewheel, bb and sprocket meaning that you can almost always get a 'stiff spot' Quote Link to comment Share on other sites More sharing options...
Mark W Posted July 9, 2012 Report Share Posted July 9, 2012 The BB threads usually aren't that much of an issue in that sense, it's just the fact it's pretty hard to get the freewheel/sprocket threads perfectly concentric with the BB interface on the crank arm. Some cranks are better than others, but it's pretty much luck of the draw really. I've had a set of Trialtech cranks that were bang on, but I've also had one that was a bit off. My Atomz ones were ridiculous... Quote Link to comment Share on other sites More sharing options...
harmertrials Posted July 9, 2012 Report Share Posted July 9, 2012 My worst setup for this was my middleburns on a profile hub. My current set up of try alls on an echo hub doesn't have the slightest hint of a stiff spot which is luxury Quote Link to comment Share on other sites More sharing options...
Andeee Posted July 9, 2012 Author Report Share Posted July 9, 2012 So would you say this can be a natural fault? Quote Link to comment Share on other sites More sharing options...
harmertrials Posted July 9, 2012 Report Share Posted July 9, 2012 Yeah of sorts. There's not a lot you can do about it. It's all very hit and miss. I tend to find the tight spot, tension my chain so it's perfect there and live with the slack and nasty noise. Quote Link to comment Share on other sites More sharing options...
Andeee Posted July 9, 2012 Author Report Share Posted July 9, 2012 Hmmm. I dont like running slack or tight chains :/ Will it stop me from riding this tight spot? if i keep on riding as normal? Quote Link to comment Share on other sites More sharing options...
forteh Posted July 9, 2012 Report Share Posted July 9, 2012 How old is the chain? Was it at its slackest when you tensioned it? The natural kicking action of trials will stretch the chain only in a certain point. Quote Link to comment Share on other sites More sharing options...
Andeee Posted July 9, 2012 Author Report Share Posted July 9, 2012 Chain is only a month old believe it or not. :/ Quote Link to comment Share on other sites More sharing options...
Mark W Posted July 9, 2012 Report Share Posted July 9, 2012 The natural kicking action of trials will stretch the chain only in a certain point. How does that work? Surely the chances of your chain happening to be in the same spot each time you kick is going to be minimal? 1 Quote Link to comment Share on other sites More sharing options...
harmertrials Posted July 9, 2012 Report Share Posted July 9, 2012 Also that would essentially make the chain slack all round Quote Link to comment Share on other sites More sharing options...
forteh Posted July 10, 2012 Report Share Posted July 10, 2012 Oh yeah, bit of a brain fart moment there :$ But that said, with a fixed front sprocket you will by loading the same section of chain repeatedly each time you kick until you you rotate the cranks enough to pull the lower chain run up to the top. Obviously it will eventually even itself out all around the chain though. If the chain is only a month old then it is feasible that it has just stretched in a portion of it whilst it beds in, if you have a chain stretch gauge you could easily measure it; you may be able to find one on the net that you can print off. Quote Link to comment Share on other sites More sharing options...
RobinJI Posted July 10, 2012 Report Share Posted July 10, 2012 If it's doing it with the chain slack, then the problem's not a tight spot in the chain. Either something's catching, or the BB bearings are binding, which would support the idea of a bent BB axle, although it could just be knackered bearings. When you say your cranks stop half way when you spin them, was this with the chain on or not? The best bet will be to take the chain off the front sprocket and see if there's still any sign of a tight spot with the cranks rotating with no chain on them at all. If there is, it's something up with the BB, if the tightness is gone with the chain off, then it's likely a tight spot in the chain*. The best bet if it is a tight spot in the chain will be to tension the cranks in the position where you have the tight spot, then see if when they're rotated away from the tight spot the chain still manages an acceptable tension. *(When I say a tight spot 'in the chain' I mean in the whole assembly relating to the chain. As others have said, the most likely cause is a lack of concentricity between the BB interface and sprocket threads on the cranks, although it could also be a damaged part.) Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted July 10, 2012 Report Share Posted July 10, 2012 Does it do the same thing if you take the chain off / slacken it right off? Quote Link to comment Share on other sites More sharing options...
Andeee Posted July 10, 2012 Author Report Share Posted July 10, 2012 (edited) Does it do the same thing if you take the chain off / slacken it right off? No it runs very smooth with chain off. Stripped drive area down today to find my bottom bracket was a tad a loose so i took out the b.b axle runs straight and it runs reasonably smooth put it back in my problem is solved. Thanks for everyones help n suggestions etc Also i cracked my bb7 today too >.< Edited July 10, 2012 by Andeee Quote Link to comment Share on other sites More sharing options...
Andeee Posted August 22, 2012 Author Report Share Posted August 22, 2012 Actually found out what the problem was as it returned on me again. A while ago i had a 3mm carbon single speed spacer crack/split on me so i replaced with a 5mm so when the lock ring was tightened it had more pressure on one side which caused the lock ring to look not straight so when the cranks were turning back the lock ring caught on my frame to give off a tight spot in the cranks. So i rang tarty last night n got a 3mm carbon spacer on its way. Quote Link to comment Share on other sites More sharing options...
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