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Singlespeed & Fixed Gear "I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!"-- Henri Desgrange (31 January 1865 - 16 August 1940)

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Old 01-24-10, 04:02 PM   #1
cest.wen
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i have a question about crank arm length

would a 175mm crank be okay for someone 5'7?
i have short legs too


--thanks
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Old 01-24-10, 04:23 PM   #2
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depends. whats your gear ratio? whats your riding style? i'm 5'10 and run 170's. but IMHO 175 is a bit much...
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Old 01-24-10, 04:36 PM   #3
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you'll spin squares with 175mm.

actually, the crank should be proportional to your inseam/femur length.
roughly 19~21% of your inseam.
it's not written in stone however.
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Old 01-24-10, 04:37 PM   #4
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Just in case you haven't experienced it full-on yet, pedal strike kinda sucks.
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Old 01-24-10, 04:41 PM   #5
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Just in case you haven't experienced it full-on yet, pedal strike kinda sucks.
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Old 01-24-10, 05:11 PM   #6
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i'm 5'10" and 170 is pretty perfect, but i have 172.5's on my road bike (**** replacing those, wayyy to expensive for 2.5mm) 175 though would be a bit much for me. if you're shorter with shorter legs, i wouldn't advise it. plus pedal strike and toe overlap yada yada
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Old 01-24-10, 06:47 PM   #7
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Are you riding a track frame or a conversion?

Usually 165s are recommended for someone your size on a track bike if you're going to be riding on the street, and you might want to go smaller if you're riding a conversion, since the BBs tend to be lower.

170s are about as big as people generally recommend for fixies of any size on the street.

If I were you, I'd steer clear of the 175s for riding fixed gear.
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Old 01-24-10, 06:54 PM   #8
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I'm 6'2" with a 59cm Frame and ride with 172.5mm cranks. I haven't experienced pedal strike yet. Has anyone experienced any problems with that set up?
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Old 01-24-10, 06:57 PM   #9
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I'm 6'2" with a 59cm Frame and ride with 172.5mm cranks. I haven't experienced pedal strike yet. Has anyone experienced any problems with that set up?
6'-2" 175's are perfect for me.
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Old 01-24-10, 07:01 PM   #10
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I ride 165s on my fixed gears and 175s on my roadie and mountain bikes. 6 foot tall with long legs.
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Old 01-24-10, 07:04 PM   #11
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6'-2" 175's are perfect for me.
I was thinking about going with 175's, but my inseam is 33.5 inches which made me stay with 172.5mm. I was worried about pedal streak which is why I avoided 175mm. 172.5mm seems to be perfect for me.
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Old 01-24-10, 07:54 PM   #12
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yes
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Old 01-24-10, 08:01 PM   #13
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my inseam is about 28.5 inches.
i just purchased a frame from eighthinch.com, its the scrambler V2.
from the site, it says the bb is raised by 10mm to avoid pedal stikes.
http://www.eighthinch.com/scrambler_frame.html

if i buy the 175mm crankset, my gear ratio would be 46:17

i'm just asking because the price of the crank is pretty cheap, if its not going to fit right, i'll just buy a different one
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Old 01-24-10, 08:40 PM   #14
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you can find 165mm cranksets for pretty cheap if you're not looking for amazing quality. origin8 and eighthinch cranks are cheap and durable.
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Old 01-24-10, 09:45 PM   #15
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Is going to be a FG or SS? It might be a little long for you, but if its SS you might find it ok. Depends on your style of pedaling.

FG, I would not just in case you lean into a turn too much.

I am 5'7" as well with normal leg portions. I use 165 on my FG, 170mm on my SS and road bike and 172.5 or 175mm on my MTB.

Depending on that frame, 170mm might work. But if you going FG, go with 165mm. IMO its easier to spin shorter cranks.
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Old 01-25-10, 08:31 AM   #16
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I'm with Dirt Boy. If it's a freewheel, 175s probably won't really matter. But with fixed you're going to be more likely to have a host of problems (pedal strike, toe overlap) with those long cranks.
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Old 01-26-10, 02:13 AM   #17
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remember, it is only a cm.

Yeah, it can make the difference with pedal strike, but the fear is over rated. I've had it happen once or twice and managed a full recovery.

Just ride the bike
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Old 01-26-10, 02:29 AM   #18
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From a bio-mechancal standpoint it has been shown that there is not a lot of difference between 170 and 175 cranks and I use 170, 172.5, and 175 cranks with no issues and if I gave myself time could probably get used to 165's although they feel odd.

On a fixed gear those extra cm could be the difference between striking or not striking a pedal... if you have a more reserved riding style a longer crank arm might no be an issue buut if are going into corners hard and fast is is an important consideration.

My fixed folder runs a 170mm crank and I have never struck a pedal while it has been fixed... it probably has the lowest clearance of any of my bikes. If I did strike a pedal it is also one of the most easily recoverable bikes I ride and I did strike a pedal when it was a 3 speed which was nothing.



It goes really fast in straight lines and I have to be mindful in corners whereas my old Peugeot had nearly 12 inches of clearance at the bb and there was no way I'd strike a 170 unless I was already on my way down.
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Old 01-26-10, 03:12 AM   #19
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Quote:
Originally Posted by cest.wen View Post
would a 175mm crank be okay for someone 5'7?
i have short legs too


--thanks
I've asked a similar question to athletes and scientists in the cycling arena and it boils down to what you feel. Studies have shown that riders produce the most on their crank length of choice and there was no direct correlation between leg length or height to crank length.

I'm 6'1 and I ride 167.5mm cranks on my track bike and 170mm on my road bike and they feel perfect. With my height, 170mm and 175mm would be considered ideal.

Conventional wisdom would say that "spinners", those who cruise with higher than normal RPMs using lower gears, go for shorter than normal crank arms. And "Mashers" those who slowly pound high gears go for normal or longer than normal crank arms.

This is sort of like buying a guitar. Everyone told me to, "JUST GO TO THE STORE. Pick up every guitar in there and buy the one that feels right." I laughed at the idea. I did all kinds of research on this spec and that spec. I bought and sold about 6 guitars before I settled on "the one". The one that felt right.

I know this is a "buy everything online because it's cheaper" forum. But, it's not very cheap to buy several different cranks online to try them. Go to your local shop and tell them that you want to try to find the crank arm length that FEELS right to you. Don't let them tell you what you *should* ride (inexperienced guys will do this. Not their fault. They don't know everything). Try a bike with 165s, 170s, and 175s no matter if the bike fits you or not. You can feel the difference. It WILL be noticable. Once you decide, ORDER THE CRANKS FROM THE SHOP. This is important. They helped you make an important decision. It's the least you can do, plus you are supporting bike shops in your town. You like having bike shops in your town, right?
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Old 01-26-10, 12:46 PM   #20
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[QUOTE=carleton;10319194]I've asked a similar question to athletes and scientists in the cycling arena and it boils down to what you feel. Studies have shown that riders produce the most on their crank length of choice and there was no direct correlation between leg length or height to crank length.
[QUOTE]

I completely agree. Gear accordingly.
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Old 01-26-10, 02:44 PM   #21
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Originally Posted by cest.wen View Post
my inseam is about 28.5 inches.
i just purchased a frame from eighthinch.com, its the scrambler V2.
from the site, it says the bb is raised by 10mm to avoid pedal stikes.
http://www.eighthinch.com/scrambler_frame.html

if i buy the 175mm crankset, my gear ratio would be 46:17

i'm just asking because the price of the crank is pretty cheap, if its not going to fit right, i'll just buy a different one
So I guess the 10mm BB raise would make 175's just fine. I ride 165s because I was told of the horrors of pedalstrike.
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Old 01-26-10, 06:17 PM   #22
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This is sort of like buying a guitar. Everyone told me to, "JUST GO TO THE STORE. Pick up every guitar in there and buy the one that feels right." I laughed at the idea. I did all kinds of research on this spec and that spec. I bought and sold about 6 guitars before I settled on "the one". The one that felt right.
A bit OT, but I'm gonna QFT. I remember when I was buying a guitar, I laughed at the prospect but I eventually went through about 5 guitars through the course of a month or so. Now I'm a believer. And +100 points to Guitar Center's return policy.
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Old 01-26-10, 06:24 PM   #23
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So I guess the 10mm BB raise would make 175's just fine. I ride 165s because I was told of the horrors of pedalstrike.
I mean that really depends on what kind of BB drop you're used to. Someone who corners hard is still going to pedalstrike with 175 crankarms, higher BB or not.

Oh and BTW, the Scrambler V2's BB drop is 55mm, which is more or less standard for fixed gear frames. Their V1 had a nightmarish 65mm drop, which sent people flying from their bikes then complaining, to which Eighthinch responded with the V2.
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Old 01-26-10, 08:16 PM   #24
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Quote:
Originally Posted by cest.wen View Post
would a 175mm crank be okay for someone 5'7?
i have short legs too


--thanks
It is long for your height but the pedal strike danger is more important. Especially if you are riding a road conversion. I'd go with 165mm. On a geared road bike, 170mm. Going with shorter crank arms, you'll notice an increase in your cadence.

When I first got my San Jose, I took it full speed around a corner, just as I'd do on my roadie. Pedal hit the road hard enough to lift the me and the bike completely off the ground and move me sideways a couple of feet. Sideswiped the curb and barely managed to stay on the bike.

Get shorter cranks.
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Old 01-26-10, 09:29 PM   #25
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the difference between barely not pedal striking (with 165mm) and barely pedal striking (with 175mm) would be drivetrain shudder and a scrapping noise. pedal strike only matters if you're gonna crank the **** out of a high curb or dig a hole out of the pavement because you're leaning a lot. do you really think 1 cm would save you then?
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