Best crank arm length

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Best crank arm length
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Posted: Dec 16, 2007 at 21:46 Quote
Hey I am not to sure on which sized crank arms I should get for my Giant Reign x1. Currently I have 175mm saints, but i feel that they will be to long and I could hit something while pedaling. So my question is 175, 170, or 165mm cranks arm for downhill racing. The races will involve alot of pedaling.

Thanks, Ryan.

PS: If you need anymore info, just ask. I would willfully give you an answer.

Posted: Dec 16, 2007 at 22:00 Quote
hey, ive found I hit stuff just the same with shorter cranks, but what it really makes a difference with is your pedal stroke. I felt like my legs werent working right with the shorter cranks.

Seriously, going to a shorter crank increases ground clearance by how much :-) 5mm, 10 mm? thats at most the thickness of your pinky finger!

Of course, when I hit, i hit hard, so that might be why it didnt make much difference to me.

Posted: Dec 17, 2007 at 8:38 Quote
well i've kind of noticed that with my 175 cranks compared to my friends 170 (this may sound very picky) I tend to bob a lil with my cranks. Then again it could be bce i have low profile pedals, and he has some block pedals. But still, I feel a slight difference.

Posted: Dec 17, 2007 at 8:52 Quote
the last bike had 170 when i bought it - i replaced them with 175 and felt the difference immediately: i felt i have more control in curves and over bumps - well generaly more control - it's easier to steer with my legs with longer crankarms.

but my knees heart more often now Confused

Posted: Dec 17, 2007 at 9:42 Quote
c-v-tich wrote:
the last bike had 170 when i bought it - i replaced them with 175 and felt the difference immediately: i felt i have more control in curves and over bumps - well generaly more control - it's easier to steer with my legs with longer crankarms.

but my knees heart more often now Confused

In my opinion, this is a 'placebo' effect. What would be interesting is if someone changed your cranks without you knowing, and then heard these reports, but I am not a believer that 5mm could have such an effect on someones ability. You guys need to get out a ruler and refresh your memory what 5mm's looks like.

nate

Posted: Dec 17, 2007 at 22:00 Quote
165 is the way to go

Posted: Dec 20, 2007 at 8:53 Quote
-nate- wrote:
In my opinion, this is a 'placebo' effect. What would be interesting is if someone changed your cranks without you knowing, and then heard these reports, but I am not a believer that 5mm could have such an effect on someones ability. You guys need to get out a ruler and refresh your memory what 5mm's looks like.

nate

ya man, 5 on each side : )
if it wasn't much than the companies wouldn't bother putting so little difference. for example on road bikes you can get cranks in 2.5mm increments. my opinion is that 175mm just work better for me, and i have 34˝ inseam and 19 years experience on mtb (i think that's why i have knees problemWink ).

Posted: Jan 30, 2009 at 18:05 Quote
i have 165mm cranks on my dj atm but im going to be racing dual slalom and i have a pait of 175mm should i keep the 165's on or put on the 175's? and what are the pros and cons?

thanks

Posted: Jan 30, 2009 at 18:39 Quote
|...| The length between those lines is about 5mm...you are not going to notice that.

|......| that's about 10mm, the difference between a 165 and 175mm crank.


Common sense will tell you the rest. ( Unless of course you have your browser zoomed in a crap load and those are huge haha.)

Posted: Jan 30, 2009 at 22:01 Quote
jettj45 wrote:
|...| The length between those lines is about 5mm...you are not going to notice that.

|......| that's about 10mm, the difference between a 165 and 175mm crank.


Common sense will tell you the rest. ( Unless of course you have your browser zoomed in a crap load and those are huge haha.)
No..it's double what you said for both measurements. 5mm more on EACH crank arm.

Posted: Jan 31, 2009 at 7:57 Quote
fishboy67 wrote:
jettj45 wrote:
|...| The length between those lines is about 5mm...you are not going to notice that.

|......| that's about 10mm, the difference between a 165 and 175mm crank.


Common sense will tell you the rest. ( Unless of course you have your browser zoomed in a crap load and those are huge haha.)
No..it's double what you said for both measurements. 5mm more on EACH crank arm.

Yes I know but I was not talking about total rotational arm length.

Posted: Jan 31, 2009 at 8:18 Quote
For the most part, DH guys will run 170mm cranks, most DH bikes have a lower BB, so the shorter cranks do help a bit with not hitting as much, but you'll still hit your cranks once in a while. Most 4X riders will run 175mm or longer (180mm) cranks to get more power out of the gates. As said earlier, a longer crank gives you more torque, but will have a larger pedaling circle (if you think about it, each crank is 5mm shorter, but that means that the circle your pedaling in is 10mm smaller) I would suggest to ride a 170mm crank for DH. Some bikes require a 165mm, but I find that these cranks are way too short, and just feel weird. As you gain more experience, you will not be as likely to hit your cranks, it still happens to me now and then, but a lot less than when I first started riding DH.

Posted: Jan 31, 2009 at 14:55 Quote
kopp-productions wrote:
For the most part, DH guys will run 170mm cranks, most DH bikes have a lower BB, so the shorter cranks do help a bit with not hitting as much, but you'll still hit your cranks once in a while. Most 4X riders will run 175mm or longer (180mm) cranks to get more power out of the gates. As said earlier, a longer crank gives you more torque, but will have a larger pedaling circle (if you think about it, each crank is 5mm shorter, but that means that the circle your pedaling in is 10mm smaller) I would suggest to ride a 170mm crank for DH. Some bikes require a 165mm, but I find that these cranks are way too short, and just feel weird. As you gain more experience, you will not be as likely to hit your cranks, it still happens to me now and then, but a lot less than when I first started riding DH.

Pretty much aced that. I ride 170's.

On a side note though, O-Cups Eh? What are you planning on hitting you cranks on? A berm, ahaha. I'm not going to lie, for kelso and such 175 would be nice to feel like a can pedal so much harder, but it would all be psychological at the most.

Posted: Feb 1, 2009 at 17:41 Quote
if you have a 73mm shell go with the xtr 167.5 mm cranks. best of both worlds!

Posted: Feb 1, 2009 at 17:46 Quote
I now have 170s, but used to run 165. I honestly couldn't feel any difference

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