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Discussion Starter · #1 · (Edited)
Note: the previous was written in a rush after a really good ride. I have toned down things a bit since then...

I'm not trying to start a crank war, but I needed to get a somewhat strange experience off my chest.

I went for a ride today: a fairly short, one-hour tour with some nice climbing. It had a bit of road (icy asphalt, most of the time, considering the light snowfall and subsequent freezing temperatures of the past few days) and some snowy singletrack.

Normally, I'd be riding my trusty On One Inbred, equipped with 2.2 (rear) and 2.4 (front) tyres, platform pedals, 195mm cranks, 33:21 gearing and Jones H-Bar. A beast, so to speak.

Today, however, I had been tinkering in my garage with my On One Il Pompino frame. I'd built it up with 35c Schwalbe Marathon tyres (slick ones), platform pedals, 170mm cranks, 32:16 gearing and my old Azonic Double Wall Riser plus bar ends.

Over the past few years, I've read just about anything I could get my hands on concerning crank length. I've got a 37” (94cm) inseam, and the 195mm cranks are just about proportional to me. I've been riding them for about half a year now and I like them. (So far, I've run everything from 165s up to the current 195s.)

Imagine my surprise today when the Pompino flew. Of course, the tyres (and bike) are lighter than my Inbred, but they were inflated for road duty. It made the ride pretty harsh, but it was harsh in a bouncy, skippy way.

The biggest surprise, though, came from the cranks (a cheap, second-hand set of Shimano Alivio, by the way). The 32:16 gearing was a bit much, obviously, but I was astonished at the ease with which I could keep pedalling in rough terrain. Because the motion of my legs and hips was much less pronounced, I seemed able to keep the whole thing together much more easily. My core muscles were less 'disturbed', as it were, and could concentrate on keeping everything tight.
For the same reason, I seemed better able to deal with shocks transmitted through the bike.
Another element was climbing: I don't know if I lost a lot of leverage (physics would say yes, I guess), but with the shorter cranks I didn't 'sink' as deep down, nor did I have to 'lift' myself as high up. I know that being 'in' the bike is a nice feeling when riding seated, but when you're doing standing climbs (a major element in singlespeeding, as we can no doubt all agree), I like to feel 'on top' of the bike.

All in all, the word I'd use to describe the impression the 170s gave me, is efficient.

For what it's worth, I quickly hopped onto the bike with the 195s as soon as I got back, just to get the 'feel'. It was odd, but not as odd as one may think.

I have to say that I'm somewhat at a loss. I thought I'd just about figured everything out about bike fit (proportional cranks: yes please! - thank you Sparty, Shiggy et al.), but now I'm leaning towards the 'shorter than recommended for your inseam' again (the Matt Chester approach, as it were).
 

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Get yourself some rollers and practice your spin with the longer cranks. It's easier to spin and be smooth with short cranks. Doing so with longer cranks is a skill. I can do 180rpm with 175s on my track bike on the rollers smoothly after just a week of having them. Working up to 200+rpm.
 

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Longer cranks may give you more leverage and in theory more power, but it's much easier to spin on shorter cranks. Look at the guys riding track where even some the tallest riders spin 165mm cranks.
At 6'5" I've tried 180mm, but I still prefer 175mm cranks as a happy medium between leverage and spin. I didn't even know you could get 195s.
 

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Woah, 195mm? Newbie here, I find those really long. :eek:

My bike stance is generally lowered by my Project 2 kona fork. Hence, even with my 170mm cranks I have generally pretty low clearance. Its troublesome at eroded, narrow sections of the track but generally still fine.
 

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i also have pretty long legs, and i run a 175. I find that a smooth rythm is the key to being able to reach and maintain a high cadence. Much easier to maintain that smooth rythm if you dont have to move your legs as far. I never had a problem on the hills as far as power goes, so it just made more sense to run the shorter crank.
 

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Discussion Starter · #6 ·
Woah, 195mm? Newbie here, I find those really long.

My bike stance is generally lowered by my Project 2 kona fork. Hence, even with my 170mm cranks I have generally pretty low clearance. Its troublesome at eroded, narrow sections of the track but generally still fine.
If you have clearance problems, I suggest using a slightly longer rigid fork. The headangle of the bike will be slightly slacker (slowing the steering somewhat) but you won't have to worry about pedal strikes that much anymore.
 

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The sensation you had on the shorter cranks of being easier to turn on rough terrain is something that's been known in mountain unicycling for a while. In that setting, you're essentially riding a fixed gear, forcing you to keep turning over all terrain.

Also, I'm not convinced that there's an 'anatomically correct' crank length for cycling. I've ridden 165-180s on bikes and 125-150s on unicycles and never experienced any hint of improved biomechanics or efficiency. One thing I think people often don't consider is the relative gain of a change in crank length...going from 180s to 165s should be accompanied by switching from 32:16 to 32:17-18, but how often is that done?
 

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Discussion Starter · #8 ·
An interesting comparison, Mewmewmew.

I have to say, though, I just completed the same ride I did this morning on my Inbred, and I think my raving that started this thread was a bit over the top... I'm not giving up on the longer cranks yet...
 

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Orkje said:
An interesting comparison, Mewmewmew.

I have to say, though, I just completed the same ride I did this morning on my Inbred, and I think my raving that started this thread was a bit over the top... I'm not giving up on the longer cranks yet...
it happens. I changed my water bottle cage once and i swore i saw jesus.
 

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Discussion Starter · #10 ·
it happens. I changed my water bottle cage once and i swore i saw jesus.
Hilarious.

It's strange how sometimes you get the feeling that, because something totally different also works, it is automatically better.
 

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Interesting thread. I've certainly read a lot about longer cranks and have wanted to give them a try- mountain biking, longer makes good sense. I am hoping to land some 180s as soon as I have money for it.

Still prefer shorter for road though. Right now, 175 for mtb and 170 for road, both SS. After the week of road riding, it takes me a good fifteen minutes to be happy with the 175s on the weekend mtb ride.
 

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Orkje said:
Hilarious.

It's strange how sometimes you get the feeling that, because something totally different also works, it is automatically better.
I've had this experience too and have wondered if the 'improved' feeling is simply a result of enjoying a new and different setup. You know, the old 'variety is the spice of life' thing. Once the newness fades, the new and different might seem not so great.

Come to think of it, maybe singlespeeding works the same way? :p
 

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Discussion Starter · #14 ·
Come to think of it, maybe singlespeeding works the same way?
I don't think so. Every time I ride a geared bike, I like it, but there's always the "mmmmmm, something is missing" feeling. Every sane person would state that something is missing in a singlespeed, of course :)
 

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Old thread...fresh topic for me.

http://vintageone.blogspot.com/2010/04/feeling-cranky-and-confused.html

I have been running 180s for 20 years or so, all on geared MTBs. When I began the SS thing, I naturally used 180s.

But I have been riding 175s on the latest geared bike (no 180mm XX cranks) and although at first I noticed less leverage, I made up for it with a better spin and an easier pull over the top of the pedal stroke.

Then I began riding an SS with 175s. Man, I swear that it felt snappier and easier on the legs, like I could bring the cranks around faster, even on steep, short climbs, and it felt awfully good. I was intrigued.

But a 10 mile climb on the 175s/SS seemed to really work me and it felt like I was really lacking power on sustained climbs.

So, back on the 180mm equipped SS last night and the steep grinders were great on the 180s, but anytime I wanted to spin and snap the cranks around, I felt the 180s working against me.

34" inseam BTW.

Interesting thought on running a shorter crank and lower gearing. Maybe that is the answer/magic combo. I was running a 32/20 on the 175mm SS bike and 34/21 on the 180mm SS bike. Maybe a 32/21 on the 175s? Man, that sure sounds low to me.
 

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mtroy said:
... Maybe a 32/21 on the 175s? Man, that sure sounds low to me.
I'm currently liking 33x21 on 175s. 34x22 was too much & I couldn't keep momentum & a reasonable cadence up the short, steep hills. How much flat stuff do you ride, what is your favorite cadence, & how fast can you spin? There are guys much faster than me on 34x22. YMMV
 

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ruppster said:
I'm currently liking 33x21 on 175s. 34x22 was too much & I couldn't keep momentum & a reasonable cadence up the short, steep hills. How much flat stuff do you ride, what is your favorite cadence, & how fast can you spin? There are guys much faster than me on 34x22. YMMV
Very little flat stuff, usually post ride (back to the car, etc), very digital where I ride....uuuuppp, dooowwwnnn, repeat. But we have long climbs here, often measured in hours of climbing.

I am not a particularly gifted spinner AFAIK, but on the 175s I can wind them up pretty well. 180s, I get to pogoing pretty quickly.

33x21 may be a good compromise.
 

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Discussion Starter · #20 ·
When most of your riding is all up or down, with climbs going on for hours (DEAR ME!), I'd gear quite low. It's the flat bits that kill me when I'm running a small gear. I really have to focus on not going 'into the red' then, heartrate wise.
 
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