6 feet 2, Size 48 shoe - what crank length?

[tv_vt]

I seem to be going back and forth between 175's and larger cranks. Just wondering if forumites have any experience regarding changing cranklength and performance. One might feel more comfortable, but which one works better for speed, mainly on climbs?

Thanks,

T

[David Kirk]

The is no one "correct length".

that said I think you'd benefit from going longer than the 175's.

I'd try 180s to start.

I'm 6'4' and have long legs for my height and I use 190's and love them.

Dave

[jhcakilmer]

I'm no fitting expert, but I'd stick with the 175.

I'm 6'3" and I use 175, I would like to try 177, but there not easy to find.

Personally, I think unless your 6'6", that 175-180 would fit anyone fine. This is no preformance advantage, but some feel like it allows their legs to spin more freely.

The longer the crank arm the larger the circle, so your candence will decrease, as compared to shorter arms. Accelerations might not be as quick. Also, the longer crankarms accentuate the "dead spot".

Not a huge deal since going from 175 to 180 is only a 3% increase, I believe. But anything longer I personally think is overkill. There are several pros that are 6'3"....Boonen, Hincapie, Backstedt.....and they don't use custom crankset (to my knowledge).

Definitely is a personal preference, but as a person that has a lot of education in the sciences, and currently in medical school spinning seems easier on you joints/connective tissue, then mashing which is a tendency with longer cranks.

Just my laymans oppinion, maybe give them a try, and see how they feel

[RPS]

I like Sheldon Brown’s Gain Ratio for estimating gearing, which takes crank-arm length into account.

If one spins a longer crank slower in RPM but with the same pedal speed, is one really mashing?

[William]

I run DA double 180's. Admittedly I could go longer but for now, the 180's do me just fine. When I switched from 175's to 180's I felt an immediate improvement in my climbing. Instead of always feeling like I was fighting to stay on top of the gear, I was motoring away after the switch. The increased leverage really suited my power output.

David Kirk on the feel of going to 190's:

Me:
Hi Dave,

How does your climbing technique/power application feel with the 190"s? Any changes? Better, worse, same?

I know when I went from 175's to 180's I felt that I could apply a little more torque and stay on top of the gear easier. I would imagine that at my height a move from 180's to 190+ would possibly be beneficial.

Thanks,

William

DK reply:
http://forums.thepaceline.net/showpost.php?p=96735&postcount=11

[musgravecycles]

I'm with Dave, there is no 'right' answer but I'd look into longer arms.

I'm 6'3" wear a 49/50 and use 180's.

[Bradford]

I'm 6'3" and ride 175s. I bought a used bike with 180s on it and hated them. I didn't know they were 180s when I first started to ride it but knew I hated how it felt. Once I switched back to 175s, everything was sunshine and ravioli again.

To qualify things, I have bad knees and if I don't spin, I can really feel it.

[regularguy412]

I think your fore/aft saddle position relative to the BB has some bearing on what crank length you may find comfortable to use when climbing. Admittedly my own experience is both personal and anecdotal, but when I went from being 'on top' of the BB ( saddle nose 3 cm behind ) to 'well behind' the BB ( 7.5 cm behind) my climbing improved. At the same time that I made the position change, I went from 170's to 172.5's. I decided on all these changes when I got 'properly' fitted during my purchase of my CSi.

Granted, I'm not a tall person, only 5 ft 8. However, I found that with the more 'behind' position combined with the slightly longer cranks, I could climb MUCH better and was still able to turn the gear. My most comfortable climbing cadence is from 80 to 84 rpm. My most comfortable cadence for cruising on the flats is slightly higher ,, around 94 rpm. I wear a 43.5 shoe with the center of the cleat slightly behind the ball of my foot. With the slightly longer crank and 'behind' position, I can drop my heel at the top and 'kick' the pedal over. I use the push /pull method of pedaling instead of the the 'up / down' method (for lack of a better way to describe it). I try to imagine my foot moving in an elliptical orbit around the BB spindle, with the pointed ends of the ellipse at the front and rear wheel hubs.


Mike in AR

[rnhood]

I am 6'2", 48 shoe, 82cm saddle height and ride 175's. But, I constantly wish they were 180's. If in doubt, go larger.

[jhcakilmer]

I like Sheldon Brown’s Gain Ratio for estimating gearing, which takes crank-arm length into account.

If one spins a longer crank slower in RPM but with the same pedal speed, is one really mashing?

Cadence doesn't necessarily dictate "spinning" vs. "mashing" but the longer the lever arm, the larger the circle, and the larger the dead spot............so some, not all, might excentuate the power stroke, and neglect the upstroke, producing a "mashing" type cycle.

I think with a little adaptation, this wouldn't be a big deal, but it's just to keep.

Another thing to keep in mind is that even though you might produce more torque, your overall power production hasn't changed. So again, I would say riders choose based on feel, not based on suggested preformance gains. I would actually recommend that if two sizes feel equality compliant, that you go with the shorter of the two.

[Jeff N.]

Stick with 175's. Jeff N.

[David Kirk]

When I was racing BMX I rode 190's and could easy spin 140 rpm's on the dirt and a good 160 on rollers.

My inseam is 95ish and I run 190's. I have no trouble at all spinning 90-95 rpm's all day long. It's just not as simple as saying that if you go with longer cranks your rpm's will drop.

That's no different than saying if you switched to 150's that you automatically spin 130 rpm's all the time. It just doesn't make sense and it's not how it works in the real world.

Folks can line up here and tell you that they think you should ride 175's or 177.5's or what ever because that is what they use and it works for them. It's what works for you that is important........not them. Experiment and see what works for you. You'll be a better cyclist for it.

I'm not saying that you SHOULD use longer cranks. I'm saying you SHOULD TRY them and see how they feel. If you don't like them.......ditch them. If you do like them then you learned something new about yourself that no one here, or anywhere else for that matter, could tell you.


Davis Phinney - 175's
Greg Lemond - 180's
Miguel Indurain - 190's

Tell any of those guys that their cranks are too long.

Dave

[scrooge]

What Dave K said--And make sure to give them time.

I ride 200s (yeah, that's right) and like them--I can turn them around 85rpm without any problem (I'm a pretty relaxed rider so haven't really tried to go faster. Plus, when you consider footspeed, that isn't that slow, is it?). I like them. But it took time.
That being said, I personally think that the body can get used to most things...

[William]

When I was racing BMX I rode 190's and could easy spin 140 rpm's on the dirt and a good 160 on rollers.

My inseam is 95ish and I run 190's. I have no trouble at all spinning 90-95 rpm's all day long. It's just not as simple as saying that if you go with longer cranks your rpm's will drop.

That's no different than saying if you switched to 150's that you automatically spin 130 rpm's all the time. It just doesn't make sense and it's not how it works in the real world.

Folks can line up here and tell you that they think you should ride 175's or 177.5's or what ever because that is what they use and it works for them. It's what works for you that is important........not them. Experiment and see what works for you. You'll be a better cyclist for it.

I'm not saying that you SHOULD use longer cranks. I'm saying you SHOULD TRY them and see how they feel. If you don't like them.......ditch them. If you do like them then you learned something new about yourself that no one here, or anywhere else for that matter, could tell you.


Davis Phinney - 175's
Greg Lemond - 180's
Miguel Indurain - 190's

Tell any of those guys that their cranks are too long.

Dave

Yeah, what DK said.

I have no problem spinning them at all. It's all in the technique. Add to that many sprint wins in my racing days....I can spin em.

Just saying.

William

[RPS]

Cadence doesn't necessarily dictate "spinning" vs. "mashing" but the longer the lever arm, the larger the circle, and the larger the dead spot............so some, not all, might excentuate the power stroke, and neglect the upstroke, producing a "mashing" type cycle.
I’m not trying to push the idea of total proportionality; rather just implying that taller riders shouldn’t discount longer cranks just because they can’t spin them at the same cadence. Maybe looking at foot speed is a better indicator than looking solely at RPM.

While on the subject, what’s so wrong with the following proportional picture?

Rider “A” who is 5’-8” tall spins 170s at 95 RPM while pushing a 19T cog.

Rider “B” who is 6’-4” tall spins 190s at 85 RPM while pushing a 17T cog.

In both cases the riders have the same foot speed, same bike speed, and similar leg angular range of motion. And both have the same gain ratio also.

[Too Tall]

I seem to be going back and forth between 175's and larger cranks. Just wondering if forumites have any experience regarding changing cranklength and performance. One might feel more comfortable, but which one works better for speed, mainly on climbs?

Thanks,

T

Change is bad.

Everyone who responded that they hate 180 cranks. PM me I'll give you my address so you don't have to put up with their mocking glances anymore. :cool:

[regularguy412]

In both cases the riders have the same foot speed, same bike speed, and similar leg angular range of motion. And both have the same gain ratio also.

Hey,Ricky! Can you please 'splain what 'gain ratio' is? It's the first time I've heard that term.

Thanx,
MIke in AR

[RPS]

"Gain Ratio" is the ratio of how far your bike travels compared to how far your pedal travels in its orbit around the bottom bracket. It has no dimensions, so you can do the math in any units you want and come up with the same answers. Makes a lot of sense to me. It's a better indicator of total effective gearing IMHO.

You can find more information in Sheldon Brown's web page.

http://www.sheldonbrown.com/gain.html

[regularguy412]

Ah! Otay. Muchas gracias.

Mike in AR

[t. swartz]

i'm 6'4", 36" inseam. i've used 180's, 177.5's and 175's. i now have 3 bikes w/175's and one w/172.5's. i prefer the 172.5's-quite frankly, they're easier to push.

[93LegendTG]

!'m 6-1.5 and after reading on-line articles by Zinn and K. Palm, I tried a set of 180 and 185 TA's and have never looked back. A common thread on these sites of taller persons' reviews of longer crankarms seem to be, "they suddenly felt right." This was my immediate reaction. I also found that I actually increased my spin with longer arms, the exact opposite of conventional wisdom. I would definitely recommend trying longer arms.

[tmanley]

I'm 6'9", size 46/47 shoe, and use 185mm TA's on my Serotta and 180mm on my s-works race bike (i like the extra clearance for crit corners). Both suit me well and I don't plan on trying anything longer.

[Ahneida Ride]

I'm 6"4 and run 172.5 :confused:

Yes they are short. I can feel the power loss at times.
But I have Knee issues. And the 172.5 keep my Knees happy and I can spin
like a Hurricane fan which is my goal.

Happy knees = Happy rider. :banana:

I am looking forward to some day trying Big Uncle William's Zank Crank.
This will be interesting. :D

Problem is ... Cost of experimenting with new equipment can be prohibitive.
One could spend a small fortune just on finding a seat that works.
:eek:
172.5 work for me and they work well. I am not saying they are optimal. :)

[tv_vt]

Thanks to all of you who responded. I've got 175's on one bike and 177.5's on another. Last year, I ran 180's on one and the 177.5's on the other.

What I noticed this winter is that I could really spin the 175s when I was in the drops pushing it. Felt a little more square with the 180s. I sense that it's one thing just to pedal cranks, but a different when really trying to hammer, either on the flats or climbing. My best time up Mt. Ascutney (VT) is still with 175's, even though I've used 177.5 and 180s, too. When push comes to shove, I'm not sure if there's a performance benefit to one length or the other - and that's what I'm trying to find out. Cuz I want to climb faster, dammit! ;-)

Cheers,

TV