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Apr 30, 2010 22:23:28 GMT
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here she is a saracen mantra brought for £50 not to shabby but the crank went today I need help as I'm confused about crank sizes and what not all I know its got a shimano atlus 21 spd gear set I'm calling on bike buddies to help out thanks guys   |
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Last Edit: Jun 4, 2010 10:58:39 GMT by Camp Davy
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awoo
Posted a lot
Posts: 1,506
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nice for £50! looks more like a dual slalom bike. its not retro btw, its probably no more than 5 years old if that
what was wrong with the cranks to make you remove them?
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its probably the bb cartridge thats got worn bearings in it. there might be a size marked on the centre of the cartridge. Probably about 113mm.
I see that youve got a nutted rear axle. does the wheel have a freewheel on it. Instead of a cassette. A cassette will have a flush fitting cap on the end of the cogs. A freewheel will have a reccessed hole in the end of the cogs.
Freewheel hubs have the bearings where the spokes are. so the right side has more strain on it. And they bend or break rear axles. Where as the freehub cassette hubs, have the bearings near the end of the axles. so less likely to break.
Would be worth taking the wheel off and seeing if the axles ok. You can get replacement axles
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TS
Part of things
Posts: 558
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it looks like a freewheel to me.
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I remember selling these new about 3 or 4 years ago. Saracen are notorious for being tightarses and having a freewheel rear hub even on £400 bikes. As explained above, these bend the rear axle in no time at all when built up with good quality stuff, and saracen used the cheapest curse word axles they could sweep up.
If you are lucky, it's been ridden once a month by a 9 year old girl. If not, the rear axle will be slightly bent, and it'll have nipped the bearings up and the rear hub is being steadily ground to pieces.
After seeing how many of these came back, I wouldn't sell these bikes to anyone, simply because of the back wheel - the rest of it is an alright bike really.
As said above, take the back wheel off and make sure the axle spins smoothly. In the very likely even of it being either mega-tight (not had time to wear the hub out) or mega loose (probably worn the hub out), take the axle out and check how bent it is, then replace it with a straight one if the bearing races in the hub are still ok. Any axle you buy will be a lot better than the one saracen supply. In the long term, if you really want to ride the bike properly you'll have to replace the back wheel and rear cassette.
I read this back and it does read as if I'm saying the bike is curse word - It's not, they are a decent bike apart from the fact that some suit at saracen decided to save £10 on a decent back wheel.
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Last Edit: May 1, 2010 22:17:19 GMT by cobblers
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Oh, and the crank will be a square taper and (if I remember right) a 68mm x 113mm bottom bracket.
If the left hand crank arm is hanging off (they usually are), then you can usually just replace the arm (it is aluminium, so it wears out but the steel bottom bracket spindle will be fairly OK)
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