RADBMX.CO.UK
Technical & Reference Section => Tech and Restoration => Topic started by: curtispro on March 24, 2011, 08:18 PM
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Now I've built up a fair few bikes over the years and maintained them but my last one is doing my head in, I just built up a mid school rider for the missus and tonight me and the boys went for a cruise around the village, I got about 50mtrs and the chain came off after I gave it some juice, pushed it back home ( much to the amusement of my 3 sons) and re adjusted the rear wheel, tightened it all up and off we went, now every time I give it some it clangs and bangs and feels like the chain is going to come off, it's a BNIB 18 tooth sugino freewheel, NOS chain wheel, NOS chain with a re furbished SR opc, it's all in line but it's this is happening, :wtf: is going on, chain fits the sprocket ok so I think it's the right pitch, any ideas ? do you think chain tugs would help as it must be the wheel moving on the right hand side!!
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Sounds like the chainwheel and rear freeware are not in line properly, had it myself.....the moment you give it big licks it comes off the rear cog. You'll need to move your chainwheel in or out with spacers.
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Do you put the spacers on the spider then? I've not come across this before with a opc, can't adjust the rear wheel alignment unless I change the locking nuts on the spindle that sit inside the dropouts!!
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seems strange with the opc set up..... look from the front from ground level to see if everything is in line! take it the wheel nuts are ft? :daumenhoch:
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would a 16th freewheel not be better?
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Instead of giving it juice , try oil on the chain instead .
works a treat
failing that chain tugs are a must :-\
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Wheel nuts are tight, it's a new chain, I was thinking that the 18 tooth was too big, maybe I need some washers with some grip on them to chew up the dropouts :LolLolLolLol: and a can't beat a good tug on the rear wheel ;D
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If its wrong pitch, chain would jump, Like pickle said more likely out of line, stick some washers on, they go behind the lock nut on chainring side.
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If its wrong pitch, chain would jump, Like pickle said more likely out of line, stick some washers on, they go behind the lock nut on chainring side.
Do you mean the locking nut that holds the spider onto the crank (the bit that sits in the bearing on the bottom bracket) that then would move the chain wheel further away from the frame ?? is that what you mean?
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yeah.......get your camera and take a picture of your chain line from the back and you should see if it's out of line or not? bang it up so we can see
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Is the chainring on the inside or outside of the spider? I've seen a few people put them on the outside of the spider - it works on some bikes but messes up the chainline on others. :-\ A flat power disc with the chainring on the inside would get it closer to the frame if thats which way it needs to go for a straighter chainline...
If the rear wheel is moving then chaintugs should fix it. 8)
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Its not the best picture as I am at work at the moment, the chain wheel is on the outside of the spider (is this correct)
Will double check alignment tonight when I get home, also I have just ordered a 16 tooth for the rear, (the gearing was $hit anyhow)
(http://www.radbmx.co.uk/archive/albums/xx207/curtispro1/Picture.png)
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Its not the best picture as I am at work at the moment, the chain wheel is on the outside of the spider (is this correct)
(http://www.radbmx.co.uk/archive/albums/xx207/curtispro1/Picture.png)
either way is fine - putting it on the inside will probably sort out the chainline if it's out. :daumenhoch:
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oh BOY, I had same problem and it was down to the spider bud, same one you have, I changed it and all was fine....
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was going to say the same ,with the tioga spider its thicker than a normal one +you mount the chainring on the outside,unlike a sugino etc the ring is on the inside
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I think that the chain is too wide, lots of latteral play, it all looks in line though
(http://www.radbmx.co.uk/archive/albums/xx207/curtispro1/478a641e.jpg)
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yeah the chain looks in line okay, are all the chainring bolts done up tight? there's no wobble in it is there? maybe it's just your rear wheel slipping? get some chain tugs :daumenhoch:
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looks like you running a 1/8 chain on a 3/32 chain ring mate, that may not be helping as the chain will move side to side as you pedal, if the chain is under tensioned, that could be throwing it off, as it will never stay true between the freewheel and the chain ring. have you got an 1/8 chain ring you could just throw on and try. :daumenhoch:
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I have just got a slimmer chain from halfrauds and will give that a try :daumenhoch: