Sometimes the pedals spin but the bike goes no where... what is it?

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Sometimes the pedals spin but the bike goes no where... what is it?
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flag nyrider15
Posted: Feb 26, 2009 at 15:43 Quote
sometimes my pedals will just spin but the bike will not move and sometimes it will just skip and throw me off the bike pretty much

i need to know why its doing this and how to fix it??

can someone please help me!
flag lexx
Posted: Feb 26, 2009 at 15:46 Quote
hub engagment has gone bad? bearings dead? try rebuilding the hub and checking for problems.
flag manicmastiff
Posted: Feb 26, 2009 at 15:49 Quote
There is a catch in the hub with a spring. The spring pushes into the catch to pull, sounds like you're hub is full of dried muck / oil or something. I had the same problem not too long ago. Go to you're LBS, it's a 10 min fix.
flag rotato
O+
Posted: Feb 26, 2009 at 15:50 Quote
99% of the time it's the chain or cassette (or both) that is worn out.
flag manicmastiff
Posted: Feb 26, 2009 at 15:52 Quote
It's the paw spring. 100% sure.
flag nyrider15
Posted: Feb 26, 2009 at 16:01 Quote
willshiels wrote:
It's the paw spring. 100% sure.
what is a paw spring?? sorry im kinda new to this stuff
flag Gsnickets
Posted: Feb 26, 2009 at 16:03 Quote
take it to a bike shop then, this repair will be over your head.
flag nyrider15
Posted: Feb 26, 2009 at 16:06 Quote
Gsnickets wrote:
take it to a bike shop then, this repair will be over your head.
alright... would it be an expensive fix??
flag cloverleaf
Posted: Feb 26, 2009 at 16:10 Quote
nyrider15 wrote:
willshiels wrote:
It's the paw spring. 100% sure.
what is a paw spring?? sorry im kinda new to this stuff

It depends what hub it is. If it's something high end like Hadley/Hope etc then the pawls & springs are seperate pieces which can easily be replaced. On something with a one piece freehub such as Shimano, it's an entirely new freehub that's required. Basically, pawls are sprung paddles which dig into a ratchet and allow the hub to drive (when they're engaged) or freewheel (when they're not). The pics in this article show what I'm meaning:

http://www.gravity-slaves.co.uk/?a=300

What can cause drive slip? Cassette/chainring teeth being worn down to mounds so that when you put pressure through the pedals, instead of pulling the chain, the chain lifts up and slips into the next set of teeth. It takes a lot to get it to that stage though and it's likely that there would be other symptoms. If it's intermittant and virtually impossible to replicate until it suddenly goes again at an innoportune moment then the chances are that it's the freehub mechanism, whether that's pawls, slack springs or a worn ratchet. What rear hub is it that you have on? That will also help pinpoint the best course of action for you to take to get it all fixed so you don't keep smacking the jewels on the stem!
flag nyrider15
Posted: Feb 26, 2009 at 16:20 Quote
cloverleaf wrote:
nyrider15 wrote:
willshiels wrote:
It's the paw spring. 100% sure.
what is a paw spring?? sorry im kinda new to this stuff

It depends what hub it is. If it's something high end like Hadley/Hope etc then the pawls & springs are seperate pieces which can easily be replaced. On something with a one piece freehub such as Shimano, it's an entirely new freehub that's required. Basically, pawls are sprung paddles which dig into a ratchet and allow the hub to drive (when they're engaged) or freewheel (when they're not). The pics in this article show what I'm meaning:

http://www.gravity-slaves.co.uk/?a=300

What can cause drive slip? Cassette/chainring teeth being worn down to mounds so that when you put pressure through the pedals, instead of pulling the chain, the chain lifts up and slips into the next set of teeth. It takes a lot to get it to that stage though and it's likely that there would be other symptoms. If it's intermittant and virtually impossible to replicate until it suddenly goes again at an innoportune moment then the chances are that it's the freehub mechanism, whether that's pawls, slack springs or a worn ratchet. What rear hub is it that you have on? That will also help pinpoint the best course of action for you to take to get it all fixed so you don't keep smacking the jewels on the stem!
It is a shimano not sure what kind exactly but the one that came on the bike. It is a trek 3900
flag cloverleaf
Posted: Feb 26, 2009 at 16:34 Quote
nyrider15 wrote:
It is a shimano not sure what kind exactly but the one that came on the bike. It is a trek 3900

In that case it'll be a whole new freehub, and it certainly sounds like that'll be what's causing the problem as it won't be a high end hub on there and the lower level Shimano hubs aren't as tough as some of the high end cartridge hubs. They usually do this once they suffer from excessive wear. Chances are that it'll be cheaper to buy a whole new hub and transfer the bearings/freehub/axle etc over onto the old body. That way, you get effectively a whole new hub in there but without the hassle of having to rebuild a wheel. If you pop it into your local shop they should be able to sort it out for not a lot of cash. The alternative would be to work out what hub it is, order the parts and tools needed online and pick up a repair manual like the Park Blue Book which will have everything in it that you'll need to get it all fixed up.
flag Hombre3000
O+
Posted: Feb 26, 2009 at 16:36 Quote
Dude. Just go to the shop.
flag nyrider15
Posted: Feb 26, 2009 at 16:36 Quote
cloverleaf wrote:
nyrider15 wrote:
It is a shimano not sure what kind exactly but the one that came on the bike. It is a trek 3900

In that case it'll be a whole new freehub, and it certainly sounds like that'll be what's causing the problem as it won't be a high end hub on there and the lower level Shimano hubs aren't as tough as some of the high end cartridge hubs. They usually do this once they suffer from excessive wear. Chances are that it'll be cheaper to buy a whole new hub and transfer the bearings/freehub/axle etc over onto the old body. That way, you get effectively a whole new hub in there but without the hassle of having to rebuild a wheel. If you pop it into your local shop they should be able to sort it out for not a lot of cash. The alternative would be to work out what hub it is, order the parts and tools needed online and pick up a repair manual like the Park Blue Book which will have everything in it that you'll need to get it all fixed up.
ok thanks. So if i bought a new hub do you think i would be able to do it myself?
flag nyrider15
Posted: Feb 26, 2009 at 16:37 Quote
well i take it it would be easer to just take it to the shop lol
flag nyrider15
Posted: Feb 26, 2009 at 16:49 Quote
nyrider15 wrote:
cloverleaf wrote:
nyrider15 wrote:
It is a shimano not sure what kind exactly but the one that came on the bike. It is a trek 3900

In that case it'll be a whole new freehub, and it certainly sounds like that'll be what's causing the problem as it won't be a high end hub on there and the lower level Shimano hubs aren't as tough as some of the high end cartridge hubs. They usually do this once they suffer from excessive wear. Chances are that it'll be cheaper to buy a whole new hub and transfer the bearings/freehub/axle etc over onto the old body. That way, you get effectively a whole new hub in there but without the hassle of having to rebuild a wheel. If you pop it into your local shop they should be able to sort it out for not a lot of cash. The alternative would be to work out what hub it is, order the parts and tools needed online and pick up a repair manual like the Park Blue Book which will have everything in it that you'll need to get it all fixed up.
ok thanks. So if i bought a new hub do you think i would be able to do it myself?

so around how much would a new hub cost?
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