Jump to content

Crank arm Length for 29er


Jaco-fiets

Recommended Posts

I used a 175ml crank on my 26er. When going over to a 29er, do i stick to 175ml cranks or should one go shorter?

 

Sorry if this is a stupid question. Just need to make sure

Link to comment
Share on other sites

  • Replies 34
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

I used a 175ml crank on my 26er. When going over to a 29er, do i stick to 175ml cranks or should one go shorter?

 

Sorry if this is a stupid question. Just need to make sure

NO .
Link to comment
Share on other sites

In theory , you should probably go longer, to compensate for the greater torque required to rotate a bigger wheel, but this can be addressed by gearing a bit lighter, so, stay with what you have.

Link to comment
Share on other sites

I used a 175ml crank on my 26er. When going over to a 29er, do i stick to 175ml cranks or should one go shorter?

 

Sorry if this is a stupid question. Just need to make sure

 

Just about every bike comes standard with a 175mm crank length, incl 29rs.

With many 29rs having a bb closer to the ground though, you can occasionally knock rocks on rougher terrain. If that's an issue for you, then maybe consider shorter cranks.

DG ran 170mm or 172mm crank lengths.

Link to comment
Share on other sites

I heared Kevin Evins also uses 172.5mm while he used 175mm on his 26er. This is all hear say so one can't always believe that. If the bikes come standard with 175mm i will be happy. Thought about it last night. Find it strange that they did not ask me what size cranks when i ordered the bike

Link to comment
Share on other sites

I used a 175ml crank on my 26er. When going over to a 29er, do i stick to 175ml cranks or should one go shorter?

 

Sorry if this is a stupid question. Just need to make sure

 

Have your legs grown since you bought a 29er? Are you a big boy now? If so, you might need longer crank arms.

 

If not, and your legs are still the same, then stick to the same crank length ;)

Link to comment
Share on other sites

I heared Kevin Evins also uses 172.5mm while he used 175mm on his 26er. This is all hear say so one can't always believe that. If the bikes come standard with 175mm i will be happy. Thought about it last night. Find it strange that they did not ask me what size cranks when i ordered the bike

 

It's not hearsay entirely, DG and Evans run very similar setups. The shorter length helps with clearance, if 175 works for you though, stick with it.

175 is generally the standard crank length on all bikes, so no reason for them to ask.

Link to comment
Share on other sites

The theory is that crank arm length is a function of leg length, not wheel size

 

The man speaks sense, your frame is not longer or higher, your wheels are bigger, and your rear stay is a bit longer to to accomodate the bigger wheel, So the answer is no you stay with 175mm,

 

Simple way to look at the logic in crank length:

Pick 10 random 29"ers from 10 random manufacturers and look at their specs. you will notice they all come with standard cranks.

Link to comment
Share on other sites

Jaco this is not a stupid question as many may think. It depends a lot on the type of terrain and riding you are most likely to do. My 29'ers bb sits 10 mm closer to the ground than my 26". I find it quite annoying hitting my pedals on rocks, roots and the sides of some deep cattle track with the standard 175 mm cranks on the 29'er. Will be changing to 165 mm in the near future. Do your own measurements and consider the type of riding you are likely to do and then make your decision.

Link to comment
Share on other sites

The area where i stay (Wellington) is mostly jeep track and lots and lots of singletrack. I don't do open roads much and not too many real rocky areas around. If i think about the races here in the Cape i don't recall them being too technical. Think the most technical is Lourensford.

 

Friend of mine also use to ride 175mm on his 26er but is currently riding 170mm on his 29er. He is shortish with short legs and says that 175mm just does not feel right on the 29er. I will be getting 175mm cranks and see how it goes

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Settings My Forum Content My Followed Content Forum Settings Ad Messages My Ads My Favourites My Saved Alerts My Pay Deals Help Logout