Friction in drivetrain

[Dan79]

I've noticed friction in the drivetrain on my Carrera Banshee that I haven't been able to solve for a couple of years. I had the bottom bracket serviced professionally last year ( for the first time since new in 1996) and I replaced the pedals this month (the bearings of one of which were badly worn), and I have personally replaced the chain, sprockets, gears and jockey wheels in the last 1000 miles. However there is still a bit of friction I feel when pushing the pedals whilst riding, and I'm not sure what else I should check. I only perceive this whilst pedalling, so would not have thought that the rear axle is at fault. Both front and rear derailleurs appear to be in perfect alignment.
Any thoughts much appreciated,
Thank you.

 

[jack smith]

Brakes rubbing? Tyre rubbing on frame?

 

[cyberknight]

You havent routed the chain wrongly around the deraillier cage ?, says someone whos done it .

 

[Citius]

Friction is inherent (and inevitable) in any mechanical drivetrain. Do you have anything to compare it to which suggests the friction is higher in this case?

 

[Tim Hall]

What happens when you lift the rear wheel clear of the ground and spin it? How soon does it stop? How does it compare with someone else's bike?

 

[ColinJ]

I had a similar problem on my mountain bike. It turned out that I had overtightened the quick release and that was causing significant friction in the bearings of the rear hub. (Clearly, you do not want to UNDERtighten a QR, but it is possible to have them too tight.)

 

[Levo-Lon]

Turn bike upside down and pedle it..
push the mech forward a bit to lesson chain tension..does this ease the resitance much?
Pop the chain off the front and spin the crank..do they spinn freely?
Does the wheel freewheel..does it stop quickley? Bearings may be tight or rusty..
is this a cup and cone wheel or press fit bearings?

 

[Dan79]

Thanks for all the responses, sorry but i don't check very often !
There's definitely no contact between tyre and frame or rubbing brakes, the friction definitely feels like a drivetrain problem. That said, I cannot replicate it with the bike turned upside down and pedalled by hand with chain engaged in any gear.
The freewheel spins perfectly freely; the friction is only felt when pedalling whilst riding.
Crank spins perfectly fine with chain disengaged.
Haven't tried the following:
1.moving gear mechanism; is the suggestion to push the bottom of the rear mech' forward slightly effectively reducing the tension placed on the chain by the spring in the chain tensioner? Sounds like it could cause the problem as an overtensioned chain would create resistance and noise/friction.
2. tweaking quick release (which it does have); worth a try.
3. don't know the difference between cup and cone / press fit bearings!

 

[Smurfy]

I had a similar problem on my mountain bike. It turned out that I had overtightened the quick release and that was causing significant friction in the bearings of the rear hub. (Clearly, you do not want to UNDERtighten a QR, but it is possible to have them too tight.)

I have some thick washers for checking cone adjustment. After adjusting the cones I add them to the spindle, and do up the QR real tight. If the spindle won't rotate easily the cones are too tight.

 

[goody]

Is it possible to distinguish between friction in the drivetrain and resistance from aerodynamics, rolling restistance and gravity? I have my doubts.

 

[ColinJ]

Is it possible to distinguish between friction in the drivetrain and resistance from aerodynamics, rolling restistance and gravity? I have my doubts.

I put the bike on a stand and there was so much friction that I could barely spin the back wheel!