Rear Cassette.

[Doug.]

Hello, is there a difference between a mountain bike and a road cassette ?
I want a lower (hill climbing) gear and can only find M/B cassettes with the higher number of teeth.
The present low gear has 36 T. and I would like about 40 T.
The bike already has a long cage rear derailleur
Yes it is for a road bike.

Thank you for any replies.

 

[Salty seadog]

As long as the derailleur cage size is OK and the cassette fits on your free hub/freewheel then all is good.

 

[TheDoctor]

The only difference is in the number of teeth.
Although, 36T is getting towards the low end of gears already. A road mech may start to struggle with a 40T sprocket.
Can you reduce the size of your small chainring?

 

[DCBassman]

Agreed, change the front set if you can.

 

[Racing roadkill]

Mountain bike cassettes tend to be loaded towards the high tooth number sprockets. They typically need a longer cage rear mech, than is normally found on a road bike set up.

 

[Heltor Chasca]

My cargo bike has 11-36 with a long derailleur (same as my MTB) and both have triples up front so lots of torque.

For balance: My tourer and Audax bike have 11-32 cassettes with triples and long derailleurs. Nursing an old knee injury and I have the hills of the West Country to contend with. And I’m more efficient as a spinner.

A friend fitted a 40T (I think) to his Croix de Feur which he uses for Audax. It looks like a cheese grater. It’s great. But he needed a special adapter somewhere on the back. It escapes me exactly.

I tell you what: He spins away from everyone on the big hills.

 

[screenman]

I am not sure I could spin a 40 back on a granny ring front quick enough to stay upright.

 

[Ajax Bay]

The bike already has a long cage rear derailleur
Yes it is for a road bike.

Assuming the RD is a 'road' RD, then the OP will likely struggle on two counts if they try to fit a cassette with a 40t largest sprocket:
1) Even with a long cage, and assuming at least a 16t difference between largest and smallest chainring, no normal road RD will wrap the 45t capacity that you've implied.
2) The RD cage guide wheel will likely interfere with the 40t sprocket and make changing to it problematic. You can screw the 'B' screw right in or even insert it from the opposite direction but still.
How much space is there now between guide jockey wheel and the 36t? The 40t will be about 8mm closer to the guide wheel.
Given that the OP has already got a 36t sprocket, as others have suggested, if you must have / need a lower low gear, change your chainrings (ability to do this beneficially will depend on crankset and its BCD).

he needed a special adapter somewhere on the back.

Probably this: Wolf-Tooth-Components/Road-Link-Rear-Derailleur-Hanger

 

[Blue Hills]

I don't think the OP has yet said what they have on the front.