Pedalling Problem

[Downward]

New Bike New commute - Problem is when I put pressure on the pedals (Pedalling uphill for example) the bottom bracket seems to just go round without transferring the force to the gears.
Any quick tips to help me get home before I can get it back to the to LBS ??

 

[RecordAceFromNew]

Hi Downward perhaps it is the terminology here, to be precise which is the bit that you think was failing to turn when it should while you were pedalling? Was the crank/chainring turning as expected? If so was the chain that hangs on to chainring moving along? If so was the sprockets at the cassette? and if so was the rear hub/rim?

It is not the purpose of a bottom bracket to transfer force to the gears, it simply allows the chainset to hang on to the frame. Depending on the design if the bike wasn't set up properly then it is possible that a chainset can turn independently against the bottom bracket spindle, which would likely have caused irreparable damage to both.



BTW can't help but notice how apt your avatar is to the problem you have described...

 

[Downward]

Yes it's like I'm pedalling and the chains going round but not not transferring power to the wheels. It feels like the the bottom bracket is just literally going around. I'm sure thinking back I had this problem on my last bike and the bottom bracket was faulty. <BR><BR>It only seems though to happen in the highest 2 gears so not sure if the chains skipping without having a look when it's up on the stand.

 

[monkeypony]

Sounds like your free hub is knackered rather than the bottom bracket. As has been said, the bottom bracket is only there to enable the cranks to turn smoothly. If that is happening (which in your case it is) then its fine.

 

[chillyuk]

If the problem only happens in a couple of gears I cannot see how it is the bottom bracket. When you say highest gears, do you mean biggest or smallest cogs. Is it possible that the chain is not precisely aligned with the gears and is slipping between the sprockets rather than seating onto the sprocket. Maybe something as simple as a half turn on the cable adjuster is required, especially as you say it is a new bike. A bit of a pest when you commute but I would go home in what gears I can ride in and take it back to the shop and let them sort it out.

 

[ajb]

I had similar a while back, sat there turning pedals and not going anywhere,
If the chain is in tact then I say it is the free hub, (mine was)
Took it to my LBS and it cost me about £7.50 if I remeber correctly.

 

[ColinJ]

If the chain is moving freely but your wheel isn't and it is the same on all the sprockets (cogs) it is a knackered freehub.

If it works on some sprockets but not others, then you have the problem that CC member 'spline-ripper' colly had on on one ride with me - see when hubs go bad!

 

[Downward]

Cool and of course for such a short commute i left all my tools on my main bike !
I'll check the gears 1st as it was skipping a fair bit.

 

[Downward]

Sounds like your free hub is knackered rather than the bottom bracket. As has been said, the bottom bracket is only there to enable the cranks to turn smoothly. If that is happening (which in your case it is) then its fine.

Yeah I see what your saying, When I got to 4th (Only got 6 gears) its fine but rattling now on the other 3.

I'll give the barrel adjuster a turn see if it stops the gears jumping at least.

 

[Downward]

Quickly adjusted the gears with the barrell adjuster but won't go into 1st gear which isn't too much of a problem at the moment, Did stand on the pedals though in 2nd to see if it was loose and it wasn't slipping.

 

[guitarpete247]

The limit stop/adjusting screw might need tweeking.

 

[Downward]

The limit stop/adjusting screw might need tweeking.

Yeah the barrel screw won't move now so I'll have to have a mess with the screws.
Had to fit mudguards though as the cyclepath is covered in mud.

 

[Maz]

If it works on some sprockets but not others, then you have the problem that CC member 'spline-ripper' colly had on on one ride with me - see when hubs go bad!

The splines on the freehub in that picture look incredibly thin (compared to the freehubs I've seen, at least).

 

[ColinJ]

The splines on the freehub in that picture look incredibly thin (compared to the freehubs I've seen, at least).

They do, don't they! Colly isn't exactly a huge muscle-bound cyclist so it was a bit of a shock when he did that - funny though!

We'd just ridden down a steep descent to a bridge over a river and then it was time to power up the steep little climb on other side. I saw him change down and grind to a halt, his legs spinning round and a very puzzled look on his face!

It was only the one sprocket, all the others worked as normal. He had to work a bit harder on the remaining steep climbs.

 

[gbb]

On the face of it, freehub would seem most likely, but why only in a couple of the gears ?
Check to see the chain IS actually sitting on the sprockets in those troublesome gears, and that its not sitting between two and just spinning. In that case, its really just a cable adjustment in all likelihood.