[skiwithcharlie]

Im 5'11 and weight 185pounds and have a new intense m3 large frame. What size Diabolus cranks should i run on this beast considering it has a pretty low bb height. I run 175mm RaceFace Atlas cranks on my Ellsworth Specialist hardtail and it works well for me but i guess 170mm cranks would also work nicely. To me, running shorter cranks on a dh bike sorta seems weird, doesnt it usually go like: the taller-heavier the rider or the bigger the bike the longer your cranks should be (in theory). Does it really make a difference in the riding feeling, im not all that good anyways..thanks for the advice..chuck

 

[Bicyclist]

Definately 170mm. 5mm will make a surprisingly big difference in how much you hit your pedals, and with the sag you should be running on a 9+" bike, your BB will be low when it's sagged out. Maybe even think about some 165mm cranks?

 

[Zark]

170mm FTW.
Clipping crank arms is not fun at speed.
Its been argued that it is the number of crank revolutions that matter the most in DH racing, and a shorter crank that is quicker to turn over and able to be pedaled through rocks will help achieve this

 

[jvnixon]

I'd go with 170's esp at 5'11".

How do you find that large m3 frame for your height?

 

[big-ted]

Its been argued that it is the number of crank revolutions that matter the most in DH racing

It might well be argued, but I highly doubt it's merit.

One look at the results sheet of the Welsh Dragon series will show you that, between the "fun" chainless race, and the main event, regular winner Dan Stanbridge is something like 7 seconds slower over a 4 minute course. Granted, 7 seconds can easily separate the top 5, but when that's the kind of loss that not being able to pedal at all gives you I'm highly doubtful that races can be won on "number of crank revolutions". FWIW the Dragon course are usually pretty technical too.

That said, clipping crank arms is NOT fun, and I'd agree that 170/165s are where it's at.

 

[rigidhack]

I'm 6'4" with super-stork legs and I had always ridden at least 175mm cranks until I got my fully. I've got 170's on there and I don't notice a difference at all except for the fact that I don't clip my pedals nearly as much as I used to. The 5mm really does make a difference in that regard.

The logic of longer crankarms for taller riders makes a lot more sense in the roadie, BMX racing or XC world than it does in either the FR or DH world. The priorities are just different.

 

[tlproject7]

but if you have longer cranks when your turning with one pedal down. you have a lower center of gravity. well thats how i make myself feel better about having 175s

 

[skiwithcharlie]

The large frame works fine for my 5'11 frame. The bike has a lot of sag and a pretty enclined seat angle so when I slam the seat it really feels like a medium frame in terms of height and lenght ...id prefer to have the
1inch shorter wheelbase lenght of the medium m3 but i felt sorta cramped on the medium!

 

[skiwithcharlie]

Ok, so here comes the big difficult Question!!! I have 2x170mm and 1x175mm RaceFace Diabolus cranksets and also a set of Atlas 175mm cranks which im keeping for sure. Which lenght Diabolus cranks would you try to get rid of considering they are all in the same condition?? Im losing sleep tring to decide!

 

[jake133]

I have 175's on my EC-d. I would prefer 170's but i can't get myslef to replace perfectly good cranks for the 5mm difference.

 

[Superdeft]

I run 170s on my med m3, not much trouble with hitting stuff yet, but I don't have a full season of testing it out yet.

 

[Transcend]

It might well be argued, but I highly doubt it's merit.

One look at the results sheet of the Welsh Dragon series will show you that, between the "fun" chainless race, and the main event, regular winner Dan Stanbridge is something like 7 seconds slower over a 4 minute course. Granted, 7 seconds can easily separate the top 5, but when that's the kind of loss that not being able to pedal at all gives you I'm highly doubtful that races can be won on "number of crank revolutions". FWIW the Dragon course are usually pretty technical too.

That said, clipping crank arms is NOT fun, and I'd agree that 170/165s are where it's at.

Well i don't know if it has merit or not, but 7 seconds at the level of a rider Dan is, is a HUGE difference. Like you said, not only can it seperate the top 5, at world cups it can be the top 10 or more.

 

[SPINTECK]

not sure if you're a road rider or not, but for every 5mm of crank length, the entire leg (acting as a lever arm and all stuff) moves around 15 cm. This can make a difference in RPM and lactic acid tolerance.

 

[EuroNewbie]

I would say 170mm. I have 175mm on my large, and seem to be hitting them a lot. I have some 170's on the way, will let you know the difference when I get them on.

 

[LFB]

Thanks for this thread!

I am 5'11" and I just got a really good deal on a large M3. I wanted a medium, but I couldn't pass it up. I haven't built it up yet, but I've been a little concerned with the size. I've been riding a medium VPX, and most of the time it feels perfect, but there are occasionally a few instances where I want something larger (and certainly longer!). But the large wheel base will be nearly 3 freakin' inches longer!

I've been also debating about the cranks. I have been debating between 170 and 175 as well, and I think I'll go with 170s on this bike.

 

[downhillracer]

i have a large m3 and i believe that 175mm cranks won't fit because of clearance issues. i have 170 middleburns on my m3 and they work great.

 

[EuroNewbie]

i have a large m3 and i believe that 175mm cranks won't fit because of clearance issues. i have 170 middleburns on my m3 and they work great.

There is some clearance issues, I have been running Shimano XT Cranks, and had to grind down the backside some to overcome that. (Not the best situation, especially as they hit the ground so often)

 

[LFB]

There is some clearance issues, I have been running Shimano XT Cranks, and had to grind down the backside some to overcome that. (Not the best situation, especially as they hit the ground so often)

If you have XTs on an M3, you likely have an older M3 with a 73mm bottom bracket. The newer M3s all have an 83mm bottom bracket, which eliminates your the clearance issue you mentioned.