[demo 9]

Ok so i have been giving this a ton of thought lately and am not really sure what to do. Currently I ride a Canfield Jedi with 170mm Saints and straitline pedals. Canfield Recommends 165 cranks and a slimmer pedal. For those who do not know, jedis are very low-id venture a guess into M6 territory. I do hit my pedals quite often, however, i am not sure that 5mm (and mayb another 5-10) with pedals would help. I am more worried about the lost power and leverage?

Today:in a Race i rode, i took my first run pinned pedaling as much as i needed to. In my 2nd run, i rode chainless, my time only went down by 1 second. (and this was a slalom course.(same lines, same course) My style is HEAVILY involved with pumping and jumping. I dont(and cant) pedal for ****. I have basically no stamina. However, i do feel that i have some power. I am 6 feet tall with most of it being in my legs, im afraid that smaller cranks (although) 5 mm smaller, will feel like riding a 12 inch barbie bike.

The reason i bring this up, is that it is very likely i will be aquiring a bike with 165 saints, which i would do a frame swap for another jedi. I am curious if i would be able to ride smaller cranks without having any problems. I really dont pedal all that much, usually just the gate, any EASY straights, and the finish, the rest of it is pumping and gapping other stuff-i feel its important to stress that i came off a bmx and trails background, which helps me with carrying speed with minimal pedaling.

Any and all advice appreciated, The bike in question is a 2010 Jamis dakar Bam, frame swap to a jedi-size large. I will be riding Diablo(and probably only diablo)

 

[DirtyMike]

You wont nitice a loss in power, and in my opinion<maybe its the road biker in me, maybe its the mechanic that knows 5mm is nothing> but you also wont notice any extra clearnce when comparing what is about 1/5 of an inch difference in crank length.


Seriously its about 1.5 times the height of the text on my screen......If there was an inch diffrence, Maybe I would buy into it, but we are talking five mm, youll get more out of the pedals than you will teh cranks.


Argue on folks.

 

[demo 9]

Dont Disagree, but ive heard roadies talking that 5mm will cost you the tour de france, something about 15cm around smaller or larger. I would rather keep the 165s that come on the bike, but if i get a barrage of people saying omfglolz terrible idea, ill sell them for 170s

 

[DirtyMike]

Well... the whole idea with road bikes, is to match the crank length with your leg length. That way you dont destroy your knees. Its really a toss up, more torque with longer cranks vs overworking your muscles/joints.

 

[Sghost]

Yup, the roadie thing is all about your knees holding up. A lot of roadies cry a lot though and just want to sound special because they ordered 172.5 mm cranks.

I run 175's on all my bikes, including my road bike, except my DH rig, which has 165's. There is no lack of power, but hitting a rock when you fully expect not to has an impact.

 

[DirtyMike]

I still stand firm that 5mm isnt enough to justify different cranks for clearance reasons on a HD bike, Specially when like on my bike, at full bottom out, your bashguard is in the rocks and dirt. Doesnt matter what size cranks you have at that point, if there not level, your going to hit them. One of the reasons I started cornering with my cranks more level

 

[Delimeat]

Having had lots of time on everything between 165 - 180 mm cranks on different mountain bikes over the years I can say for 100% fact that personally I never once noticed a lack of power/leverage with shorter cranks. And for reference I am also a massive road bike mega-geek, I like to freak over the details, but on the mtb I never noticed sh*t re. crank length.

Here is how I look at it regarding my DH or AM bikes: It doesn't happen often but when I manage to catch a pedal hard enough to take me down it is almost always a bad and very hard type of crash. Maybe it's because you have no idea what happened until you get back up! I do clip my pedals every few rides, but it only takes me down a few times a year I think, but of those that don't take me down I do sometimes wonder that if things were 5 - 10 mm lower would I have crashed? When I do go down from a pedal clip I wonder if things were 5 - 10 mm higher if it would have still been ugly but maybe I could have stayed up?

I know its only 5 mm but the line is drawn somewhere, right? I'd rather you have a bigger chance of staying up, especially if you say you pedal like crap (no offense) and try not to pedal too much anyway!

 

[DirtyMike]

Valid point of coarse, I wouls say going from a 175 to a 165, you might see some improvement, but we are talking 170 to 165.

Let me see if this works

_____ Lets call this an inch, compare it to this
_ This would be the five MM in comparision to an inch


Really not that much.

 

[Sghost]

So there you have it, straight from DirtyMike:

170 to 165 is half an improvement, and its a free one to boot!

 

[DirtyMike]

No No No... dont twist my wording, I said Might.....its a pretty big might. Of all things, something else to remember, 5mm could be lost from a little more speed, or a little more lean, or a little more push in a corner ETC...Soo Many factors that are really coming into play.

 

[Percy]

Try it and see, you'll never know the real answer about how the difference relates to you, unless you do try them both.

The interwebs can only tell you what other people have done, and unless they are identical to you in every way (which would be really weird!), that still doesnt really help much does it?

 

[buckoW]

With very low bb heights, every mm counts, imo. It also depends on how technical the trails are as well.

 

[4xBoy]

I went from my 175 XTR cranks to a set of 165 FSA gravitys for a few days the difference to me was in the stiffness of the crank, I could barely tell the length had changed.

 

[DirtyMike]

Oh there are benefits to running shorter cranks on a dh bike, its just not clearance. Generally, the shorter cranks will feel better on your knees when your riding due to your lower body position when riding a DH bike. Itll take alot of the pressure of your knees, which is a huge benefit, there<for your knees> 5mm can really make a huge difference. With that youll find it easier to spin higher cadence's as well without burning out as fast. But now we are relating seat position relative to the BB position into the mix....

 

[Delimeat]

For the average rider I don't see why one wouldn't run 165's if given the choice, especially since a lot of us are on these uber-low BB bikes that are probably easier for a pro level rider to really take advantage of.

DirtyMike, if given the choice, would you run longer than 165's and if so, why? Why not get a touch more breathing room?

 

[Alex.]

Well, if you are just clipping rocks on 170 cranks, surely you would only be clipping the last 5mm of the crank anyway? So by that logic switching cranks would make a difference.

Note: That was pure e-speculation, I've never switched from 170 to 165 myself.

 

[redride]

hi guys... i'll just add my experience. I have recently changed from 170 -> 165 and I DID notice a difference especially in powering out of corners earlier. i used to hit my pedals every time i tried to pedal after a drop or a berm... with the 165s i could do it a bit earlier.

i did not notice any loss of pedal power going to 165. other than that, 165 and 170 not much difference!

 

[Brian HCM#1]

I run between a 14"-14 1/4" I couldn't imaging using anything longer than 165mm's.

 

[slowitdown]

Anyone who thinks a 5mm shorter crank arm is responsible for fewer pedal strikes... delusional.

There's a way to demonstrate this, and it's called the scientific method, and it requires controlled situations with variables reduced to ONE -- crank arm length. You would have to take the exact same line, working the bike the exact same way, every time -- and do probably 20-30 runs with each crank arm length. EVERYTHING would have to be identical in each of those 40-60 runs except crank arm length.

Short of that, you're just talking about subjective, personal impressions -- and while that's valuable at one level, it's nothing like proof. Nothing at all.

On the other hand, 5mm longer crank arms are more leverage and a functionally bigger gear, no matter what else you do, simply because it's a longer lever turning over.

Can you change your pedaling style to "feel" as powerful with a 5mm shorter crankarm? Perhaps. But you've still lost the mechanical advantage.

If all you want to discuss is "feel" then that's cool, but please don't pretend you're coming up with proof. You're just talking feel.

On a singlespeed bike, it definitely makes a noticeable difference. The longer crankarm is harder to get over the top of the pedal stroke because it's a functionally larger gear, but if you can get it over the top, you will notice being able to climb further before you lose your wind/power/whatever and step off to walk. Conversely, the "spin" with a longer crankarm is more notchy, not as smooth.

The discussion of what roadies do -- listen, unless you are or ever have been a very serious road rider, you should shut your trap. Okay? The stupid attitude wars where everyone who rides a MTB hates on roadies merely because they're roadies -- ****ing stupid.

 

[P.T.W]

Anyone who thinks a 5mm shorter crank arm is responsible for fewer pedal strikes... delusional..

Can you explain how a shorter crank arm cant make a difference???? It is shorter after all, an there for further away from any object it may or may not strike.
Im not saying there will be a huge or even noticeable difference but there has to be one no matter how small.

 

[Dogboy]

Can you explain how a shorter crank arm cant make a difference???? It is shorter after all, an there for further away from any object it may or may not strike.
Im not saying there will be a huge or even noticeable difference but there has to be one no matter how small.

Precisely. It is like saying going from a shorter to longer crank won't make a difference either. It will make a measurable difference either way you go.

 

[norbar]

Anyone who thinks a 5mm shorter crank arm is responsible for fewer pedal strikes... delusional.

There's a way to demonstrate this, and it's called the scientific method, and it requires controlled situations with variables reduced to ONE -- crank arm length. You would have to take the exact same line, working the bike the exact same way, every time -- and do probably 20-30 runs with each crank arm length. EVERYTHING would have to be identical in each of those 40-60 runs except crank arm length.

Short of that, you're just talking about subjective, personal impressions -- and while that's valuable at one level, it's nothing like proof. Nothing at all.

On the other hand, 5mm longer crank arms are more leverage and a functionally bigger gear, no matter what else you do, simply because it's a longer lever turning over.

Can you change your pedaling style to "feel" as powerful with a 5mm shorter crankarm? Perhaps. But you've still lost the mechanical advantage.

If all you want to discuss is "feel" then that's cool, but please don't pretend you're coming up with proof. You're just talking feel.

On a singlespeed bike, it definitely makes a noticeable difference. The longer crankarm is harder to get over the top of the pedal stroke because it's a functionally larger gear, but if you can get it over the top, you will notice being able to climb further before you lose your wind/power/whatever and step off to walk. Conversely, the "spin" with a longer crankarm is more notchy, not as smooth.

The discussion of what roadies do -- listen, unless you are or ever have been a very serious road rider, you should shut your trap. Okay? The stupid attitude wars where everyone who rides a MTB hates on roadies merely because they're roadies -- ****ing stupid.

Well if a big amount(I mean the majority) of riders share an opinion about a certain change in their gear than there are 2 probabilities. 1st. They are right. 2nd. They are dilusional/Mass placebo and should start the religion. Do your "scientifick" method to calculate what is more probable dear sire.

And about roadies - it very often goes booth way. Also - too much bad vibes man. Relax before posting

 

[DirtyMike]

For the average rider I don't see why one wouldn't run 165's if given the choice, especially since a lot of us are on these uber-low BB bikes that are probably easier for a pro level rider to really take advantage of.

DirtyMike, if given the choice, would you run longer than 165's and if so, why? Why not get a touch more breathing room?

170's.... they fit my legs and my stance better.

Can you explain how a shorter crank arm cant make a difference???? It is shorter after all, an there for further away from any object it may or may not strike.
Im not saying there will be a huge or even noticeable difference but there has to be one no matter how small.

I can, Just to eff with a friend of mine over this subject, when I replaced my last set of cranks, he was all over the I need 165s idea due to hitting his pedals and needing more clearance.....Just to be my normal ass self that I can so wonderfully be, I told him my old set was 165's, we installed them on his ride, he came back swearing how it made all the difference in the world, he stopped hitting his pedals Blah Blah Blah....... I told him to read the inside of the cranks after that..... Nope, not 165's, but 170's.... it was all in his head.


I would be willing to bet that most people, if they were just told that there cranks were 165's over 170's would already notice a difference.

 

[P.T.W]

I can, Just to eff with a friend of mine over this subject, when I replaced my last set of cranks, he was all over the I need 165s idea due to hitting his pedals and needing more clearance.....Just to be my normal ass self that I can so wonderfully be, I told him my old set was 165's, we installed them on his ride, he came back swearing how it made all the difference in the world, he stopped hitting his pedals Blah Blah Blah....... I told him to read the inside of the cranks after that..... Nope, not 165's, but 170's.... it was all in his head.


I would be willing to bet that most people, if they were just told that there cranks were 165's over 170's would already notice a difference.

Ummmm you didn't answer anything.... Your lil story just explained the placebo effect.

Its simple math people a bike with a static 343 mm bb height that's compressed 150mm mid sprint through small rocks fitted with 170mm cranks will just clip a 23mm rock....... the same bike fitted with 165 cranks in the same scenario needs a 28 mm rock for contact with the crank arm(a %21.7 bigger rock).
There you go no data loggers or scientific testing needed just simple math a 8 year old could do

Now I'm not saying the OP (or anyone) will notice a worthy difference or any at all....but it is there an it is measurable.
An it sounds like this isnt going to cost him anything to try so i dont get why he just dosnt go do some runs an take some tools an try both back to back???? simple isnt it???
I dont get why the question was asked in the first place when the OP currently has 170mm cranks an is aquiring a bike with 165s to split up...man he could just go out an try the damm things in les time than some of the people (including me) have spent typing out their opinon on this thread.

 

[Mike.rider]

My Blindside sits at about 13.8 bb height wise and I went from 170mm gravity gaps to 165mm gravity lites and immediately noticed a dramatic reduction in pedal strikes. I was up in the air if the 5mm would make a difference but man does it.

 

[demo 9]

An it sounds like this isnt going to cost him anything to try so i dont get why he just dosnt go do some runs an take some tools an try both back to back???? simple isnt it???

as much as i would like to try this, new in box, is usually easier to sell than the pinkbike "it has just 1 run i swear". I did not think it was noticable, but if i got a barrage of answers saying omfg dont do that, i might save some money and be able to sell easier. that was all.

 

[buildyourown]

I run 170s. I have used 165s in the past and I have such long legs, they are really hard to turn over.
My bike is low, but when your cranks are level, it's all the same. You just need to be better at timing you pedal strokes.
For tall riders, I think 170 is just fine.

 

[P.T.W]

as much as i would like to try this, new in box, is usually easier to sell than the pinkbike "it has just 1 run i swear". I did not think it was noticable, but if i got a barrage of answers saying omfg dont do that, i might save some money and be able to sell easier. that was all.

So would you rather try them an find out for your self? Orrrrr not try an have that lil voice in the back of ya head nagging you every time you clip your 170s on a rock????? All for the sake of $50..its up to you. Your asking peoples opinions an as you can see from this thread..opinions are like a$$holes,everyone has one.
It sounds to me like your mainly worried about pedaling issues not clearince issuse with the 165s...you dont even need to try them on a trail, just do sum (timed) sprints up an down your street,that way you wont clip nothing with them.
Oh an the 165s arnt "new in a box" theyre fitted to a bike...so whats different from fitting them to your bike? When i buy a bike as new from my LBS im pretty sure that it could have been test ridden by other peeps,so whats the difference?
Sorry dude but IMO crank length is one of those things that is down to the rider an what suits him....go ask a BMX racer type about crank lenght or a track racer...

 

[DirtyMike]

Ummmm you didn't answer anything.... Your lil story just explained the placebo effect.

Its simple math people a bike with a static 343 mm bb height that's compressed 150mm mid sprint through small rocks fitted with 170mm cranks will just clip a 23mm rock....... the same bike fitted with 165 cranks in the same scenario needs a 28 mm rock for contact with the crank arm(a %21.7 bigger rock).
There you go no data loggers or scientific testing needed just simple math a 8 year old could do

Now I'm not saying the OP (or anyone) will notice a worthy difference or any at all....but it is there an it is measurable.
An it sounds like this isnt going to cost him anything to try so i dont get why he just dosnt go do some runs an take some tools an try both back to back???? simple isnt it???
I dont get why the question was asked in the first place when the OP currently has 170mm cranks an is aquiring a bike with 165s to split up...man he could just go out an try the damm things in les time than some of the people (including me) have spent typing out their opinon on this thread.

You math is exactly my point. Harder pedalling nullifies your math, while softer pedalling backs it up. Too many conditions that are changing at all times when riding DH to have a true difference from just five mm of crank length....How about the difference from Manf to Manf in how much material there is ont he other side of the threads..... Maybe one manf that five mil is really 2mm because they wanted to make sure there cranks were strong???? Have to really look at all of it......

 

[Damo]

My hardtail has one 170mm crankarm and one 165mm arm. It has been that way for years now since I replaced a bent arm with whatever I had laying around. I didn't notice anything while riding, so never sorted it out.

Just saying.

 

[P.T.W]

Now I'm not saying the OP (or anyone) will notice a worthy difference or any at all....but it is there an it is measurable.

You nath is exactly my point. Harder pedalling nullifies your math, while softer pedalling backs it up. Too many conditions that are changing at all times when riding DH to have a true difference from just five mm of crank length....How about the difference from Manf to Manf in how much material there is ont he other side of the threads..... Maybe one manf that five mil is really 2mm because they wanted to make sure there cranks were strong???? Have to really look at all of it......

Did you just skim read my post????
Oh ann looking at "all of it"..... longer cranks will allow the rider to pedal harder causing more bobbing while shorter cranks encourage spinning a lower gear this equals less bobbing an yet more clearance
Really this could go on for ever...an really its all down to personal preferance (as iv said before).

 

[Percy]

I like tree's, specially the green ones, but not the ones that PTW has bounced off, they are mean tree's, nasty even.

And that post is about as much use as 98% of this thread.
I reiterate my original call, that is the only way to tell if 5mm will make a difference to you ( or anyone for that matter) is to try it, ther is no other way grasshopper.
And if it costs you $50 loss on selling the "new" cranks, then that is $50 well spent.

 

[Sghost]

If it makes no difference then why are you guys running 170's instead of 175's?

 

[Sandwich]

thread tl;dr

I switched from 175s to 165s on my brooklyn to my sunday and the difference is not hugely noticeable but it is there. With the amount of ground stomping I do on the sunday, I wouldn't want anything but 165s. They are super stiff and I don't feel as though I'm at any kind of a disadvantage by riding with them.

If you don't have a problem with your cranks, keep them. If you're clipping stuff, you may as well grab the shorter ones. I'm with stupid, and every MM counts, especially when BBs continue to drop.

 

[DirtyMike]

Did you just skim read my post????
Oh ann looking at "all of it"..... longer cranks will allow the rider to pedal harder causing more bobbing while shorter cranks encourage spinning a lower gear this equals less bobbing an yet more clearance
Really this could go on for ever...an really its all down to personal preferance (as iv said before).

No, I read it well. the longer cranks wont be the deciding factor in how much a bike is bobbing when pedalling, how smooth the rider is will. As far as the power output change, again, we are only talking five mm here, to really see that, youll need to be checking power output, and comparing the Data between the two.

I like tree's, specially the green ones, but not the ones that PTW has bounced off, they are mean tree's, nasty even.

And that post is about as much use as 98% of this thread.
I reiterate my original call, that is the only way to tell if 5mm will make a difference to you ( or anyone for that matter) is to try it, ther is no other way grasshopper.
And if it costs you $50 loss on selling the "new" cranks, then that is $50 well spent.

I will still drop back to another one of my posts.... There are more benefits for most riding downhill going to 165's than just clearance. Stiffness, leg length, seat height compared to pedal height, stance on the bike ETC.
Than again, the other part why you see sooooo many peopls wearing by the 165's......is because soo many others are swearing by, and when you just spent a grip of money, you really want to not feel like you wasted your cash, so your looking for it to be better
.


Theory, and I repeat theory.....Maybe people are seeing such an improvement because of a better feel on there stance, and the shorter cranks are allowing them to be more comfy keeping there pedals lever while cornering. I have no scientific proof or indication that this could be true, more just making a point that the different cranks could be inducing a slightly different riding style, that is all.








The one big point I want to make in this thread is, there is def a place for 165's int he DH world. In no way am I trying to say we shouldnt be using them, selling them, or pushing them for, well alot of the riders out there. But my reasons are alot different than... Youll notice more clearance. My reasoning is more of the fact that most people riding stuper fast, 1)are not exactly tall, and not exactly big either, 2) increased stiffness 3)better stance, more balanced stance for tech riding.








For those that truly belive its a clearance issue, I have a challenge for you, I have a few nice rock gardens over by my place, they are actually pretty rough, like to eat derailluers ETC.....
I will pick up an extra set of cranks same brand and model, we will take my blindside out, I will put on one set of cranks, you go ride the garden five times, I will swap them for the others, take five mroe runs....You tell me which one were shorter after taking five runs each.

 

[P.T.W]

No, I read it well. the longer cranks wont be the deciding factor in how much a bike is bobbing when pedalling, how smooth the rider is will. As far as the power output change, again, we are only talking five mm here, to really see that, youll need to be checking power output, and comparing the Data between the two.

Ummm where did i say that longer cranks where the deciding factor???? I was actually being a smart ass with regards to your "must look at all of it" line.The big cheesy grin should have told you this.

I will still drop back to another one of my posts.... There are more benefits for most riding downhill going to 165's than just clearance. Stiffness, leg length, seat height compared to pedal height, stance on the bike ETC.
Than again, the other part why you see sooooo many peopls wearing by the 165's......is because soo many others are swearing by, and when you just spent a grip of money, you really want to not feel like you wasted your cash, so your looking for it to be better
.
Dude i had 165mm cranks on my m1 back in 97 ......before there where "so many other swearing by" them.

Theory, and I repeat theory.....Maybe people are seeing such an improvement because of a better feel on there stance, and the shorter cranks are allowing them to be more comfy keeping there pedals lever while cornering. I have no scientific proof or indication that this could be true, more just making a point that the different cranks could be inducing a slightly different riding style, that is all.

Dude its only 5mm remember(theres that grin again)

The one big point I want to make in this thread is, there is def a place for 165's int he DH world. In no way am I trying to say we shouldnt be using them, selling them, or pushing them for, well alot of the riders out there. But my reasons are alot different than... Youll notice more clearance. My reasoning is more of the fact that most people riding stuper fast, 1)are not exactly tall(you've seen the world chaps results haven't you?, and not exactly big eitherummmm Canberra podium again, 2) increased stiffness 3)better stance, more balanced stance for tech riding(sheesh its only 5mm as you keep saying.

For those that truly belive its a clearance issue, I have a challenge for you, I have a few nice rock gardens over by my place, they are actually pretty rough, like to eat derailluers ETC.....
I will pick up an extra set of cranks same brand and model, we will take my blindside out, I will put on one set of cranks, you go ride the garden five times, I will swap them for the others, take five mroe runs....You tell me which one were shorter after taking five runs each.

I'm up for it....will you stump up for a airline ticket too???? but i would prefer a proper DH race bike for the test(sorry couldn't resist)

An I'm over arguing this...As I fully expect another even longer winded post to pop up soon, that still gives no real advice to the OP

Oh an I hope you don't mind but i shrunk the unnecessarily long spaces between your paragraphs to a sensible amount

 

[William42]

This thread got real ugly real fast.

My 170mm race face evolve DH cranks were actually longer in total length then my 175mm gravity lites. I do notice fewer pedal strikes with my 170mm diety's, because they have way less wrap then either the gravity lites or evolves. I think the total crank arm length is about 7-10mm different, which translates.

Its not huge though, spinning is a little different, and I still bash my pedals from time to time, I just do it sightly less frequently and generally less hard.

Also, do the dude throwing out math about how 5mm makes a 21% difference, while thats a cool idea, I rarely hit my cranks when I'm at full bottom out. My cranks tend to be quite level if I'm hitting anything that puts that much force into my bike. Maybe thats the difference between me and the pro's, but I don't ever see any of them mashing pedals through huge rock gardens or pedaling as they are landing a big drop. Realistically, most of my pedal strikes are slow speed pedaling through tech stuff that I'll come to a stop on if I don't pedal (13.7BB with 8 inches of travel), or I'm going fast and I'll smack a crank and come to a complete stop (which would happen with any crank regardless of arm length).

I don't think 5mm of difference will be huge in terms of pedal strikes. You'll notice a bigger difference in arm length alone, and not a big one at that. But you might notice fewer pedal strikes.

 

[Damo]

Fightfightfightfightfightfightfightfight

 

[SylentK]

Haha, so much drama

I used to have 175mm cranks on my Sunday. I went through 2 sets of clipless pedals in one season and generally remember smacking them a lot. I was also just starting DH racing, although I've been XCing for a loooong time. Then I got proper 165mm cranks and I'm on the same pair of 646's since I got the shorter cranks (several years ago). And generally, I think I hit a lot less stuff w/ my pedals/cranks.

We go over a lot of gnarly stuff at mach 5 speed where mm's count. Def go 165mm on a DH bike.

I also like the feeling of the shorter cranks combined with the plush suspension. You don't feel like you are "sinking" as much with each stroke, than with the longer cranks.

Short cranks 4 life! LOL

 

[IH8Rice]

im running into the same issue with my Revolt.

since i cant get the rear flip chips out, i cant change the 13.7"BB to 14.2"(or whatever it is) and my 170mm cranks and pedals are smashing everywhere.
im not thinking a 5mm shorter crank would help, but in combination with a .5" higher BB and shorter cranks it should.