Rear D, slow to spin on back pedal, help!

Tracerboy · Nov 8, 2007

Hey everyone,

my rear D is slow to spin when I am back pedaling. For example, when I back pedal the chain goes slack immediately between the front chainring and the rear cogs. My guess would be that the pulleys in the derailler cage are slow due to grunge/grease/whatever. I am planning changing out the bearings and pulleys (shimano XT) but before I did I wanted to ask if anyone else has run into this and if they knew what the solution was. Thanks.

skywaybuzz · Nov 9, 2007

could be but take the wheel off and check the freewheel cassette.

Squash · Nov 9, 2007

Very rarely are....

the jockey wheels on the derailleur the cause of this. Much more often it is the freehub, the part of the hub that the cassette mounts to. A dirty or worn out freehub creates a considerable amount of drag. Causing the chain to go slack when coasting or trying to pedal backwards. This is not a good thing! The jockey wheels dragging might cause enough drag to let the chain go slack, but not likely.

The easiest way to check it is to either put the bike in a work stand or turn it upside down. Then pedal up to a good clip by hand. Once you've got the rear wheel spinning pretty good, let go of the pedal. The cranks should stop moving or at least be barely moving, and the rear wheel should continue to spin freely (thus the term "freehub"). If the cranks continue spinning along with the rear wheel, it's your freehub not your jockey wheels. The freehub either needs to be serviced or replaced. It's either gunked up inside and creating drag or it's worn out and not allowing for free movement. Either way it needs to be corrected as soon as possible. If it's worn out you well could be looking at the freehub freezing up while riding. This turns your bike into a fixy, i.e. you can't stop pedaling and coast without the chain going slack and getting tangled up in things or without locking up the rear wheel. If it does freeze up, depending on the circumstances, it could cause considerable damage to your drive train.

So get it fixed! The freehub may not be serviceable or replaceable. Some low end hubs don't have serviceable/replaceable freehubs. If that's the case then a new hub will be in order. But whatever the case may be, get it fixed! Not doing so and having the hub freeze up can be quite costly.

Good Dirt

A Grove · Nov 10, 2007

Squash said:
the jockey wheels on the derailleur the cause of this. Much more often it is the freehub, the part of the hub that the cassette mounts to. A dirty or worn out freehub creates a considerable amount of drag. Causing the chain to go slack when coasting or trying to pedal backwards. This is not a good thing! The jockey wheels dragging might cause enough drag to let the chain go slack, but not likely.

The easiest way to check it is to either put the bike in a work stand or turn it upside down. Then pedal up to a good clip by hand. Once you've got the rear wheel spinning pretty good, let go of the pedal. The cranks should stop moving or at least be barely moving, and the rear wheel should continue to spin freely (thus the term "freehub"). If the cranks continue spinning along with the rear wheel, it's your freehub not your jockey wheels. The freehub either needs to be serviced or replaced. It's either gunked up inside and creating drag or it's worn out and not allowing for free movement. Either way it needs to be corrected as soon as possible. If it's worn out you well could be looking at the freehub freezing up while riding. This turns your bike into a fixy, i.e. you can't stop pedaling and coast without the chain going slack and getting tangled up in things or without locking up the rear wheel. If it does freeze up, depending on the circumstances, it could cause considerable damage to your drive train.

So get it fixed! The freehub may not be serviceable or replaceable. Some low end hubs don't have serviceable/replaceable freehubs. If that's the case then a new hub will be in order. But whatever the case may be, get it fixed! Not doing so and having the hub freeze up can be quite costly.

Good Dirt

Agreed. Whenever we get that occasional bike at the shop that has a *ghost chain* as we like to call it, it is almost always in the freehub. When this happens, backpedaling is practically impossible.

Check your freehub.

boomn · Nov 10, 2007

Squash said:
the jockey wheels on the derailleur the cause of this. Much more often it is the freehub, the part of the hub that the cassette mounts to. A dirty or worn out freehub creates a considerable amount of drag. Causing the chain to go slack when coasting or trying to pedal backwards. This is not a good thing! The jockey wheels dragging might cause enough drag to let the chain go slack, but not likely.

The easiest way to check it is to either put the bike in a work stand or turn it upside down. Then pedal up to a good clip by hand. Once you've got the rear wheel spinning pretty good, let go of the pedal. The cranks should stop moving or at least be barely moving, and the rear wheel should continue to spin freely (thus the term "freehub"). If the cranks continue spinning along with the rear wheel, it's your freehub not your jockey wheels. The freehub either needs to be serviced or replaced. It's either gunked up inside and creating drag or it's worn out and not allowing for free movement. Either way it needs to be corrected as soon as possible. If it's worn out you well could be looking at the freehub freezing up while riding. This turns your bike into a fixy, i.e. you can't stop pedaling and coast without the chain going slack and getting tangled up in things or without locking up the rear wheel. If it does freeze up, depending on the circumstances, it could cause considerable damage to your drive train.

So get it fixed! The freehub may not be serviceable or replaceable. Some low end hubs don't have serviceable/replaceable freehubs. If that's the case then a new hub will be in order. But whatever the case may be, get it fixed! Not doing so and having the hub freeze up can be quite costly.

Good Dirt

Ahh poop. I noticed that my bike is doing this as well. I bought it used as my first real mountain bike and the first bike I have ridden much in the last 6 years. I had no idea to check for this.

I really don't know if my hub is serviceable. It is some sort of generic hub that came with the bike (Kung Ten??). Does a replacement Shimano freehub only work on a Shimano hub? If I can't replace it, is there any other service I can do?

It looks like my decision will come down to "take it to the LBS" or "buy new wheelset!!" I think I know which option I like better

Rear D, slow to spin on back pedal, help!

Tracerboy

skywaybuzz

Squash

A Grove

boomn

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