[Medic Zero]

.

Anyone riding longer cranks? I inexpensively picked up a set of 180mm ones from a Craigslist seller and am about to either put them on my tourer or my new commuter (both old rigid MTB's), and I've got a couple of questions:

Is it harder to climb hills with longer cranks? I haven't decided which bike to try them out on and I live in a very hilly area. Related to that, should I maybe adjust my gearing down a little? I'm in the middle of building both these bikes up (finally!) and so have a choice of maybe using a 46 tooth big chain ring instead of a 48 for example. Otherwise, I'm nearly at the bottom end of gearing already (48-32-22, and 11-32).

FWIW, I'm 6'2", with fairly long legs. I'm excited to try these out, I've been curious about longer cranks for a while, but new they are very expensive, and from what I recall when researching them a few years back, opinions were mixed as to whether many folks felt any benefit or even noticed much a difference.

Any other advice? I know I'm going to have to be more carful about pedal strike, anything obvious I may be overlooking?

Many thanks!

 

[asphaltdude]

Longer cranks make your effective gearing lower. (Google Sheldon Brown on 'gain ratio') so no need for smaller chainrings, and climbing won't be more difficult.

Crank length is nothing magic. A longer crank only makes the gain ratio of your entire drivetrain (by which I mean from pedal to tire) a bit lower, and slightly changes the joint angles in the knee and hip.
I presume you currently ride 175? 180 is only a 3% increase.
Chances are you won't even notice.
It's just not that big a deal.

 

[Saul Lumikko]

I'm 188 cm tall (6'2") with long legs (92 cm / 36" inseam).

Crank length fit is a bit like bike fit: we can make general guidelines, but in the end there's a lot of subjective matter at play. Our anatomic, mobility and muscle nerves are different even if our measurements are the same. I've heard about tests where taller riders were more efficient on shorter or longer cranks depending more on the individual than their measurements.

I'm not entirely in agreement with Sheldon Brown over the issue of Gain Ratios. If one were to build two otherwise identical bikes with 170 mm and 180 mm cranks, and had gear ratio matched to compensate for crank length (to achieve the same gain ratio), the bikes would be very different to pedal and various riders would probably report preference of one over the other. Respected and knowledgeable forum member Shiggy has also written about this subject and agrees that there's more to it than the plain physics Sheldon suggests.

I found going from 170 mm to 175 mm cranks an immense improvement: I could go as fast as before with less effort. Of course I can't say which part was an actual difference and how much is placebo, but for me the only thing that matters is enjoying the ride. (If I was more race-oriented, I'd probably find my optimum crank length on a wattbike.) Now all of my bikes have at least 175 mm cranks and one has 180 mm cranks. Going to 180 mm was more noticeable in a way that the circle I produce with the pedals feels larger. I'll have to give them more time to say for sure if I like them or 175 mm better. Either way, going to longer cranks has helped me especially in situations where the pedals are in 12 and 6 o'clock positions and I have to push forward.

Obvious tip: lower the saddle by as much as you extend the crank.

Short summary: you're tall, you might like them. Give them a try and don't give up immediately, but if you can't get to terms with them after a while, just go back to what worked better for you before.

 

[Realslowww]

My whole entire problem where I could not get gear selection right or my cadence right was the cheap 175mm stock cranks, I bought a set of 180mm road race cranks and all my drive problems went away and I just ride the bike now.

I was snapping chains and everything because I could not find the right gear that felt right.

It is like he said, it's all rider dependent but if your big and have strong legs a good crank set in my opinion is mandatory.

 

[ou2mame]

I would think that a longer crank would increase your ability to create torque exponentially, to a certain point obviously because the pedal would eventually hit the ground upon rotation lol.. The torque is more than just gearing because you can use your weight more effectively to push down on the crank.

Sent from my SPH-L710 using Tapatalk 2

 

[Glenngineer]

I would think that a longer crank would increase your ability to create torque exponentially, to a certain point obviously because the pedal would eventually hit the ground upon rotation lol.. The torque is more than just gearing because you can use your weight more effectively to push down on the crank.

Sent from my SPH-L710 using Tapatalk 2

Linearly.

 

[NYrr496]

I have 180mm cranks on two bikes. Noticed a small difference on the first ride when I switched from 175. Now it just feels normal to me.

 

[Realslowww]

Where did your old avatar go, I like Gamera.

 

[edubfromktown]

Disclaimer: I am not an SS vs geared or crank length zealot

I run 180's on my single speed rigid 29er (XTR 952's with an XT 4-banger 104 spider), 175's on 3 other 29er's (two hard tails and one FS) and 170's on a 1995 MTB that I did a lot of road miles on too.

I am 6'2" w/ 32" inseam and ran 175mm cranks on my SS for about a year before switching to 180's. I notice a slight difference on climbs (a bit more leverage on the power stroke), otherwise nothing dramatic. I would not run 180's on a full suspension bike for fear of increased pedal strikes. My other fear was that I would like them so much that I'd have to get them for all of my bikes... didn't happen.

Nothing wrong with giving them a try- particularly if you can score a reasonably priced set of used ones.

 

[Cloxxki]

This lack of longer cranks seems to persist.
Anyone interested in designing a burly crankset perhaps with modular pedal mounts that can be bolted or even welded in place? How hard can it be to have decent cranks made with a 190-210mm range? Any local hero could weld it together when the ideal gearing is decided upon. That is, if the bolt-on solution is not good enough.
It would take some machining of the arm and pedal inserts to make a strong spline and stop to get it work, but the rest would be relatively straightforward. Not easy to meet every BB standard in the world but some solutions can be found to serve a decent variety.
Then either make it a group buy, funds raiser or a commercial exercise of commissioning a production series and selling from stock while it lasts. Sell from a country without crazy safety/liability regs.
I've never pedaled longer than 195 mm (990 mm or so inseam), but that did take some getting used to.
185's on daily bikes was just fine.

Running fat tires andnot too chunky pedals (or trim the edges) might make decently long cranks workon bikes we already own. I'd like to get to try 200 mm and have room to adjust if possible.

What would the money down be to get to some sort of a series run?

 

[Sparticus]

This lack of longer cranks seems to persist.
Anyone interested in designing a burly crankset perhaps with modular pedal mounts that can be bolted or even welded in place? How hard can it be to have decent cranks made with a 190-210mm range? Any local hero could weld it together when the ideal gearing is decided upon. That is, if the bolt-on solution is not good enough.
It would take some machining of the arm and pedal inserts to make a strong spline and stop to get it work, but the rest would be relatively straightforward. Not easy to meet every BB standard in the world but some solutions can be found to serve a decent variety.
Then either make it a group buy, funds raiser or a commercial exercise of commissioning a production series and selling from stock while it lasts. Sell from a country without crazy safety/liability regs.
I've never pedaled longer than 195 mm (990 mm or so inseam), but that did take some getting used to.
185's on daily bikes was just fine.

Running fat tires andnot too chunky pedals (or trim the edges) might make decently long cranks workon bikes we already own. I'd like to get to try 200 mm and have room to adjust if possible.

What would the money down be to get to some sort of a series run?

Good to see you again, Cloxxki, seems like you've been absent from MTBR for a while.
Either that or you & I hang out on disparate sub-forums.

Anyway I'd like to throw a personal observation about crank length into the conversation because I've had so much experience with various length cranks.
I started out with 202mm Bullseye cranks on a custom Co-Motion hardtail back in '94. The frame was designed around long cranks to avoid things like pedal strikes, bad STA, ETT geo, etc.
I loved that bike BITD.

I loved the long cranks, although it didn't take long before the Bullseyes bit the dust and finding long cranks to replace them wasn't exactly easy.
I bought a few pairs of High Sierra Cycles custom cranks in 195mm length. This was back in the days of square taper cranks and the HSC cranks worked great.
When eventually I wanted to move to integrated cranks (rather than square taper), I moved to Surly's 185mm Mr. Whirlys.

But I digress. I'm getting to my point.

Back in the days that I employed longer than typical cranks, mountain biking was more about climbing than it was about doing drops, hitting jumps, getting creative on bonus lines and generally finding ways to get our wheels off the ground and looking for trail entertainment. It was about epic rides. About being strong in the saddle. Hundred mile races were on the rise -- that's the kind of riding people did back then.

Long cranks are great for making power, IMO. (This comes from someone with long legs, so I like long levers.)
But now that I do mix it up so much while coming down the trail, I've found that there's a trade off with employing long cranks.
I don't like my feet that far apart while I'm jibbing. In fact non-offset motorcycle pegs would probably be best (once a rider got used to them) for descending.
BUT (big but) -- we still have to pedal. So today I ride 175mm cranks.
It's a compromise. I'm a stronger climber with 185-195mm cranks but I like descending and jibbing much more with shorter cranks.

Pick your poison.
=sParty

 

[Sasquatch1413]

I've had some interesting experiments with crank length. I'm 6'4" and usually always ran 175 cranks. My Sentinel has a low enough BB and trails are rocky enough that I wanted more pedal clearance. Switched to 170 and it was a very small change. No better, no worse, just different. After a few rides I didn't know the difference. For a host of reasons I started running 155 cranks on my 36er and that was a biiiig change. I had to get a cassette with a bigger cog to compensate for lower pedal torque, felt very spinny and while it wasn't something I really liked, it was acceptable. My conclusion is that for an average rider, crank length doesn't really matter, pick one that makes you the happiest.

 

[bingemtbr]

Wrong or right, I was always told longer cranks are for longer femurs and shorter cranks were for shorter femurs. This is data is circa early '90's.

Recently in the last 4-5 years, shorter cranks have become more common due to lower BB height. Shorter cranks = less pedal strikes.

I'd check with the manufacturer of your bike to verify if its compatible. If they give you the go ahead, try it.