MTB Crank length (Pro's and con's of going shorter)

[Sniffie]

Hi Hubbers.

 

I was wondering if any one has experimented with shorter cranks on their Mtb? I am riding a Giant Anthem 29" dual suspension. Nice bike, somewhat on the heavy side, but what bugs me the most is that my pedals gets caught on rocks, roots and other stuff way more often than with my previous bike (Raleigh MR 9.0 26" dualie). The reason for this is that the Giant's BB sits about 10 mm lower than that of the Raleigh. Both bikes have the same crank length of 175 mm.

 

I understand that going shorter will mean less torque, but then you could down shift to an easier gear if your power fails you on a steep technical section right? Or am I missing something here. When dropping to an easier gear to still apply the same force on the pedals you will have to up your cadence to maintain the same speed or power up a climb, am I right? My question is how will this effect endurance or is it just a question of conditioning at higher cadences? How will it affect my technical ability, as I find it easier keeping my balance up a gnarly section pushing a slightly heavier gear?

 

For the record: I am 1.87m tall and most of my riding is marathon events, but I do enjoy the technical single track type of event more than just riding on district roads.

 

I would appreciate any advice on this matter.

[Dustbug]

Hi Hubbers.

 

I was wondering if any one has experimented with shorter cranks on their Mtb? I am riding a Giant Anthem 29" dual suspension. Nice bike, somewhat on the heavy side, but what bugs me the most is that my pedals gets caught on rocks, roots and other stuff way more often than with my previous bike (Raleigh MR 9.0 26" dualie). The reason for this is that the Giant's BB sits about 10 mm lower than that of the Raleigh. Both bikes have the same crank length of 175 mm.

 

I understand that going shorter will mean less torque, but then you could down shift to an easier gear if your power fails you on a steep technical section right? Or am I missing something here. When dropping to an easier gear to still apply the same force on the pedals you will have to up your cadence to maintain the same speed or power up a climb, am I right? My question is how will this effect endurance or is it just a question of conditioning at higher cadences? How will it affect my technical ability, as I find it easier keeping my balance up a gnarly section pushing a slightly heavier gear?

 

For the record: I am 1.87m tall and most of my riding is marathon events, but I do enjoy the technical single track type of event more than just riding on district roads.

 

I would appreciate any advice on this matter.

 

have a look at the compact crank threads basically they are the shorter length but there is a substantial power loss until you build up the strength.

[goya-goya]

Hi Hubbers.

 

I was wondering if any one has experimented with shorter cranks on their Mtb? I am riding a Giant Anthem 29" dual suspension. Nice bike, somewhat on the heavy side, but what bugs me the most is that my pedals gets caught on rocks, roots and other stuff way more often than with my previous bike (Raleigh MR 9.0 26" dualie). The reason for this is that the Giant's BB sits about 10 mm lower than that of the Raleigh. Both bikes have the same crank length of 175 mm.

 

I understand that going shorter will mean less torque, but then you could down shift to an easier gear if your power fails you on a steep technical section right? Or am I missing something here. When dropping to an easier gear to still apply the same force on the pedals you will have to up your cadence to maintain the same speed or power up a climb, am I right? My question is how will this effect endurance or is it just a question of conditioning at higher cadences? How will it affect my technical ability, as I find it easier keeping my balance up a gnarly section pushing a slightly heavier gear?

 

For the record: I am 1.87m tall and most of my riding is marathon events, but I do enjoy the technical single track type of event more than just riding on district roads.

 

I would appreciate any advice on this matter.

 

I ride 170mm... I noticed no difference in power...

 

In Fact the jury is still out on this in the scientific testing community.... lots in google that go either way

[SeaBee]

Compact cranks (in my mind) has nothing to do with crank length, but with the amount of teeth in the blades. (Which allows you to spin easier up inclines.)

 

Sniffie, I think best is to get a decent bike fit - I've used Ergofit guys in the past. Or even just a chat to a good bike fitter. This will allow you to understand the science behind the longer and shorter crank arms and the effect it will have - not only on torque, but also knee angles, etc. You may try to address one problem and create a far bigger one.

[RocknRolla]

is your rear shock pressure correct?

 

what could be happening is that on the downstroke, the downforce on the bike causes the suspension to compress, making your pedals hit the floor.

 

10mm is not THAT much of a height difference.

[Azonic]

I'm 1.88 - 1.89m and ride 180mm on my MTB's. I find the extra leverage works nice with the big wheels. However, I also have longer legs than most people my height.