idoru2005

Hello, this is my first post in this forum. Been riding geared bikes primarily and recently started riding a fixed gear bike - 42x16 with a 165mm crank. Lately I've been doing my bike commute fixed, and riding the geared bike on the weekends.

The geared bike has a 170mm triple crank. Do many of you switch between fg and geared bike riding? If so, do you have a different length crank on your geared bike?

I can feel the difference in the size of the circle I'm pedaling whenever I change bikes. Furthermore, when I go from Fixed to Geared riding, it is very disconcerting when I feet cease to turn when I let up on my pedal pressure. It always takes me a few blocks to adjust to freewheeling. And it takes me at least an hour for my legs to adjust to turning bigger circles.

I'm just wondering how everyone else adjusts to this. I've been considering swapping my 170mm cranks on the geared bike to a 165mm triple. But since this is also my climbing bike, I'm considering tweaking my drive-train to account for less leverage at the crank. Possibly putting a long cage RD and mountain cassette, so I can spin high cadence with smaller circles on the 165mm crank. Any thoughts on this?

seau grateau

I just run 170mm cranks on all my bikes.

hairnet

Give it time. I have bikes with 180mm, 175mm, and 170mm. While I can feel the difference when I really pay attention to it, it all blends together because I ride differently on each bike and I dont think about it.

Mumonkan

I have the same scenario, 165 on my fg and 170 on my freewheel bike, but i cant notice the difference even when i try

hairnet

FWIW, I can only feel a difference when with my bikes. On other bikes I can't tell the difference.

Jaytron

167.5 on my commuter (lower gi). 170mm on my tark biek. 172.5 on my road bike.

JohnDThompson 

I use 165mm arms on my fixed gear bikes and 170mm arms on my geared bikes. No problem going from one to the other.

Nagrom_

I use 170 on the track and 175 on the road. Can't tell the difference really.

IthaDan 

I have different bike with cranks anywhere from 165 to 180. The bikes are all different, fit different and ride differen. In fact, I like that they're all different, the idiosyncrasies are char,img in a weird way.

hairnet

yep. N+1

Jandro 

You'll get used to it. I wouldn't go longer than a 165mm on a fg unless it's a dedicated track bike (constant turn angles), personally. Need to be able to corner, yo.

IthaDan 

Wow, that's barely legible, I need to start proofreading what the autocorrect on my ipad comes with.

Jandro 

I like how no one corrected you. We just sort of interpreted and ran with it. Rare, given this is the internet, after all.

Jaytron

I just assumed Dan had finally lost it.

IthaDan 

any day now.

max5480

i ride mostly the same length cranks on my bikes.
But I figured this forum was about Q-factor, which I think might be more important to consider regarding joint health. MTN bikes have wider q-factors but that's OK because you need the width to help balance over technical sections. But on a road bike, if your feet are further apart (width wise), it's not like your hips (and somewhat knees) are any wider apart, so you're putting strange stresses on your knees. I'm just thinking here... but I guess what it comes down to is proper bike fit.
I'd probably do some measurements and figure out which length you like better and then make both your bikes the same... but that's just my preference.

europa

You get used to it. When the Europa was fixed, she had 165 cranks because she's a road frame (ground clearance). My geared bike at the time had 172.5 cranks. I could feel the difference in a vague way, the longer cranks felt as though they cramped me a little but it was really vague, just one of those interesting things you ponder while waiting for traffic lights to change. The geared cranks were Octalink and when they went they way of many Octalinks (started working loose), I replaced them with 170s ... and that 'cramped' feeling went away. Then I commissioned the Hillbrick and specified 170s so the BB was raised to suit, and eventually, I converted the Europa back to gears. This gives me a fixed gear bike and a geared bike, both with 170s so you probably won't be surprised to hear that I don't notice any difference in crank length

On your second question though, if I ride fixed only for some period, the geared bike sometimes feels like it's broken when I leap back onto it, I certainly miss the control you have with fixed gear - stopping with brakes is fine but they are a really blunt tool for controlling speed.
Nowadays, I ride both in fairly equal measure so don't notice anything going between fixed and geared ... except when I cop a head wind.

europa

My autocorrect seems to be set to 'malicious gibberish'

BoSoxYacht

I use 175mm cranks on all my bikes. According to most crank length calculators, I should be using 184mm cranks.

dookie

I think it came out as intended...

Optimal number of bikes in the stable = N + 1, where N is the current count...ie: another addition is always welcome. I'm all too familiar with the math...

(Oh, and I have two each 170/172.5/175, w/170 on the fixed, 175 mtb, and a mix of 170/172 on the road. No issues w/strike on the Sputnik. I swear I can feel the 2.5mm difference on the road, in that the shorter ones spin better.)

icyclist 

Difference in inches is what, less than 1/8th?

BoSoxYacht

Wtf is N+1?

N=H+ 1

seau grateau

Numerical representation of the ideal number of bikes, where N is equal to the number of bikes you own. Alternately represented as S-1, where S is equal to the number of bikes that would result in separation from your significant other.

Bat56

You completely missed the point.

Spoonrobot 

You're either missing the point or trying to make a point by being glib.

The measured length difference doesn't matter, it's the % change that is important. 170->165 is a 3% change which can be significant for racing and fit purposes. The difference in frame sizes is generally less than that, usually around 1.4-1.8%, which most people find significant. A top tube that is 3% longer than what is the proper length for an individual will be detrimental to both performance and comfort.

Now, for the OP it appears neither one of those points is an issue and this is more a mental thing. I suggest you just keep doing both and get used to it. Going back and forth was a little disconcerting for me as well but now I just relax and let it happen. I've found the same thing to be true with switching between fixed and freewheeled bikes, regardless of crank length.