Bicycle Mechanics - Serious problem with a HUB(rear)
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I have serious problem with rear hub, sometimes I spin pedals, bike don't move. Sometime when I spin pedals backward and then forward it make half circle to pedals start to move the bike.
If you understod problem, I think that problem is in rear hub, and how should I fix it, or I must change whole hub?
I forget to tell that I have Shimano FH-RM30 hub
10-16-10, 02:16 PM
If the hub has been sitting it probably just needs to be ridden, but don't stand on it in case it doesn't engage. It sounds like the freehub body might be bad and would need to be replaced as about a 40-80 dollars and is not a rebuild able part, but they can be oiled if you take it off the wheel first by removing the axle there is a 10mm hex bolt to remove this part. New wheel might be cheaper.
10-16-10, 03:22 PM
the freehub need oiling , try that first , if that doesn't work yes time for a replacement.
10-16-10, 05:12 PM
Yep, time to oil the freehub or freewheel.
Take the wheel off the bike and lay it on its side with the drive side up. If you have a freewheel you do not need to remove the axle. If you have a freehub then you need to remove the axle to find this joint. To find out which you have if you do not know go to www.parktool.com/repair (http://www.parktool.com/repair) and click on the rear wheel on the bike. Go to the parts on the freewheel and freehub and look at the pictures so you can figure out which you have. If it is a freehub body then you need to take the axle out because the flushing and oiling job will also flush out the grease from the wheel bearings if you do not do this.
Now turn the gears or freehub backwards and find the joint in the center near the axle where the outer part is moving and the inner part is not moving. That is the crack that you want the oil to go down into. To help the oil go into the inside and spread around easier it can help to mix the oil with a little bit of mineral spirits or lacquer thinner. The solvent will evaporate over the next day or two and leave the oil where it needs to be. Use enough of the oil and solvent mix that it flushes out the gunk and gets the spin nice and smooth. You should also hear ticking of the ratchet pawls sounding a lot more smooth and consistent now.
After it has been flushed out with a few good squirts of the oil and solvent mixture turn the wheel over and let the excess drain out for an hour or so. To ensure you flush it well use about 10cc's of the mix and then turn it over and drain it out unless it runs out by itself. If you have to drain it then repeat with another 10cc's. If it just runs out keep putting in the mix slowly until you have used a whole 20cc's. Then you can put back on the axle and cassete if it is a freehub. If it is a freewheel and if you did not get much or any of the mix into the wheel axle opening then it should be fine. No need to wait, you can go and ride right away.
If you flush it out like this and it is still not working then your freehub or freewheel needs to be replaced. You do not replace the whole hub. Just the part that has the sprockets on it for a freewheel or the splined inner part if it is a freehub.
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