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Discussion Starter · #1 ·
Looking at a Jamis Sputnik. (jamisbikes.com) The specs show that a 57cm has 175 cranks. I am worried about catching a pedal. BB height is 275, same as a standard road bike I think. My current geared bike has 172.5 cranks. Your thoughts....
 

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Lew 59 said:
Looking at a Jamis Sputnik. (jamisbikes.com) The specs show that a 57cm has 175 cranks. I am worried about catching a pedal. BB height is 275, same as a standard road bike I think. My current geared bike has 172.5 cranks. Your thoughts....

I'm paranoid about catching a pedal and I'm a creature of habit. My fixies have always had 165s, so that's what I run. Lots of folks go with 170s. 175 seems kind of scary, but maybe that's just me.
 

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Lew 59 said:
Looking at a Jamis Sputnik. (jamisbikes.com) The specs show that a 57cm has 175 cranks. I am worried about catching a pedal. BB height is 275, same as a standard road bike I think. My current geared bike has 172.5 cranks. Your thoughts....
My fixed Mountain bike has 175 cranks and I like the leverage for grunting up a climb - cornering at speed isn't a big issue in the dirt. For my fixed Road bike, I use 165 cranks. Besides the pedal strike issue (which is avoidable w/175s) I like the shorter cranks for the ease in high cadence spinning on fast down hill runs.

175s will work but I would prefer 165, epecially if you are used to 172.5.
 

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I don't think catching a pedal will be a big issue. If you've been riding with shorter cranks, you'll definitely feel the difference. I'm a big guy and I usually use 175's. I just bought a commuter bike that has 170's. Felt the diff immediately. Have to spin faster to maintain the same speed. FWIW, I've never touched a pedal down with 175's or 177.5's.
 

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Discussion Starter · #5 ·
Thanks for all the input. I still don't think I will go any longer than 172.5's. I will inquire with Jamis about changing out the cranks, maybe to 170's. Also they bring this to the market as an all around Fixie but it does not come with brakes. I will ask my LBS about adding. How much should I look to spend on brakes?
Lew
 

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Lew 59 said:
Thanks for all the input. I still don't think I will go any longer than 172.5's. I will inquire with Jamis about changing out the cranks, maybe to 170's. Also they bring this to the market as an all around Fixie but it does not come with brakes. I will ask my LBS about adding. How much should I look to spend on brakes?
Lew

The Sputnik catalog says, "Use it as a track racer, or mount up a brake, quit your day job and join the bike messenger ranks," so I'm guessing they're not really selling it as an "all-around fixie," but more as a track bike you can convert for street. While the 73.5/73 geometry is not as steep as some, it's definitely in the "track" range. Also the gearing is big -- 48 X 15 -- pretty typical for an off-the-shelf track bike at 86.4 gear-inches, but probably too big for daily street riding, depending on where you live. Here in Austin, I ride a 70.5 - inch gear, just for comparison.

As for crankarms, it says they spec their smaller frames with 170s and the larger ones with 175s, so it shouldn't be hard for them to swap.

For brakes, I'd personally mount up nothing more expensive than a 105 or a Campy Veloce. If your shop orders through QBP you can buy a single front brake, but you'll have to get the levers as a pair.
 

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Discussion Starter · #7 ·
Fixintogo/all

Thanks for the info. A few other comments. As far as the geometry goes, this is still more relaxed than the other "off the rack" bikes I have been looking at; Pista, Rush Hour. I am happy with the Sputnik specs. As far as the gearing goes, I agree this is steep. I live in S.E. Texas, flat but windy, I was thinking of backing this off to the mid to high 70's range. I guess I will need to play with this. This is my first Fixed bike so I am open to all comments/suggestions. My initial plan is to use the bike for short (1-2 hr) training rides by myself. I will see where it goes from there.

Lew
 

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I don't get it

Mr. Versatile said:
I ....Have to spin faster to maintain the same speed....
Explain how a decrease crank length would increase cadence for a given MPH?
 

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Lew 59 said:
I live in S.E. Texas, flat but windy, I was thinking of backing this off to the mid to high 70's range.
If you ever come up to Austin (TX) drop me a note and we'll go for a fixie spin. Post pics when you get her built!
 

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Lifelover said:
Explain how a decrease crank length would increase cadence for a given MPH?
I think he meant that an increase in crank length correlates to an increase in pedal speed. It wouldn't increase cadence but does increase the speed your foot is moving.
longer crank = larger radius
larger radius : larger circumference
larger circumference = more distance your foot travels per revolution.
 

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FTM said:
I think he meant that an increase in crank length correlates to an increase in pedal speed. It wouldn't increase cadence but does increase the speed your foot is moving.
longer crank = larger radius
larger radius : larger circumference
larger circumference = more distance your foot travels per revolution.
Exactly!
 

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long time listener, first time caller.

fixintogo said:
I'm paranoid about catching a pedal and I'm a creature of habit. My fixies have always had 165s, so that's what I run. Lots of folks go with 170s. 175 seems kind of scary, but maybe that's just me.
I would like some opinions on crank length.

Me: 5'6"
Bike (being built) 49 cm Soma Rush

I don't know if this matters, but my other bikes are MTB's. SS has 180's the geared bike has 175's.


For this Soma build I have the option of 170's or 165's. I rode it today with the 170's and had no problem with toe overlap. It was there, but not a big problem. The final build is this week and I just was interested to hear what others thought.

Thanks,

aLaN at BikeMojo dot com
 
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