Mountain Bike Reviews Forum banner

29er SS Crank Arm Length?

1441 Views 8 Replies 6 Participants Last post by  ia_ss157
I have always ridden long cranks. 177.5 road. 180 MTN 26.... My 29er came with 175s and I rode it like that for some time

I took the 180's off my 26 and put them on the 29er expecting to feel a big difference up from 175. For whatever reason I did not feel it on the 29 with the 180. For the first time I felt like I was pedaling squares and the momentum just doesn't feel right.


2 weeks and about 6 rides. Sustained climbing. 32/21 on a 175 felt much better to me geared as well and I was frankly surprised. I felt the need to spin more and am not sure where to go with a new build in the works



I am just wondering if there is a logical engineering explanation that is over this non-techie nerds head

From my new and limited 29er experience 29er riding to me lends itself to spinning more it seems.

I couldn't wait for the 180s on the 29 and it just didnt feel like I wanted it too. maybe my legs were bad those 2 weeks:madman:
1 - 9 of 9 Posts
Personally I don't see any reason why a certain crank length would work better with a certain wheelsize (provided that the bottom bracket height is acceptable, of course!). Crank length has to do with leg length: pure biomechanics, really, and a topic that has been debated to death. If 175s feel good to you, then there's nothing wrong with that. You may just have stumbled upon your best crank length by accident. Maybe you should try putting some 175s on you road and 26" bikes too, to see what it feels like. You may find that you prefer spinning on those bikes as well.
I appreciate that O. I am not worthy

Perhaps "spinning" was not the right word choice as related to SS and climbing. There are other issues Frame sizing and fit are likely key here. I must say that the 29er thing is a real trial and error discovery, which I love about it at the moment...

All the yearsand miles I am set in stone on the other rides

I wont touch the roadie as that is a science and another level altogether.

but I might put the 175 on a 26 ss just to see whats up. I think what I was trying to say is that the added leverage on a ss 26 that a 180 gave me was not significant on the 29.
I should have know that all roads lead to GT ;)

Good article. Thanks for the post and thanks to GT as always
Interesting thoughts all around, here. Guitar Ted's musings seem to correspond with what Matt Chester wrote some time ago (he rides fixed, of course) about the advantage of 'shorter than recommended' crank arms.
Ike Turner said:
I have always ridden long cranks. 177.5 road. 180 MTN 26.... My 29er came with 175s and I rode it like that for some time

I took the 180's off my 26 and put them on the 29er expecting to feel a big difference up from 175. For whatever reason I did not feel it on the 29 with the 180. For the first time I felt like I was pedaling squares and the momentum just doesn't feel right.

2 weeks and about 6 rides. Sustained climbing. 32/21 on a 175 felt much better to me geared as well and I was frankly surprised. I felt the need to spin more and am not sure where to go with a new build in the works

I am just wondering if there is a logical engineering explanation that is over this non-techie nerds head

From my new and limited 29er experience 29er riding to me lends itself to spinning more it seems.

I couldn't wait for the 180s on the 29 and it just didnt feel like I wanted it too. maybe my legs were bad those 2 weeks:madman:
Ike, I had the same experience. Rode 180's on my 26" SS for years, believing that that added leverage was helpful - and it might have been.

On the 29", it didn't feel quite right. I had read and believed that the bigger wheels were harder to get spinning initially, but keeping them spinning was where the magic was. So, I geared down a bit, put the 175's on it, concentrate on pedaling circles and it has felt great. The bike seems to fly spinning at a higher cadence :thumbsup:

(Full disclosure: I'd also been battling some knee pain, so I figured the easier gear and spinning would help - so far, it has)

E
I ride 180s on my SS 29er, I'm 6'2", they feel great. I like not having pedal strikes with the longer cranks. The 180s on my Turner Flux (26" wheels) tap the ground several times a ride. I'd like to try 185s or 190s.

Morgan
I would definitely try running a cog taller than you are running now, or maybe run a 33 tooth chainring. With that extra leverage, you may as well use the benefit of it, which would be a little extra torque. Also it will lower your cadence range so on flats and downhills, you don't feel like you are spinning out with the longer arms.

I know that is a kind of obvious idea, but I run a lower gear on my Karate Monkey than I would on my Superfly, weight aside. I ride 170 on the KM and 175 on the Superfly. I definitely notice the shorter length and lack of torque that goes with it.
1 - 9 of 9 Posts
Top