172.5 vs 175 cranks
05-15-02, 03:36 PM
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172.5 vs 175 cranks
I'm 6-0 172 lbs and was considering changing to carbon cranks. I currently have ultegra 172.5's. Is there any advantage to getting 175's? Any disadvantages?
05-15-02, 03:52 PM
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Read this thread: https://www.bikeforums.net/showthread...&threadid=6719 (Also check out the links that MichaelW has posted in that same thread).
I have 167.5mm cranks on my mtn bike, and 180mm on my road bike. I feel much more comfortable with 180mm cranks. The difference is amazing, I have no idea why i had such small cranks on my mtn bike to start with.
BTW, I'm 6'4" tall, with long legs. YMMV!
I have 167.5mm cranks on my mtn bike, and 180mm on my road bike. I feel much more comfortable with 180mm cranks. The difference is amazing, I have no idea why i had such small cranks on my mtn bike to start with.
BTW, I'm 6'4" tall, with long legs. YMMV!
05-16-02, 06:48 AM
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if you lengthen the crankarms , and lower the seat - what about the clearance issues?!
05-16-02, 08:09 AM
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Originally posted by RiPHRaPH
if you lengthen the crankarms , and lower the seat - what about the clearance issues?!
if you lengthen the crankarms , and lower the seat - what about the clearance issues?!
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Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
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"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
05-16-02, 09:10 AM
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I have 167.5mm cranks on my mtn bike, and 180mm on my road bike.
crank length as I have seen it.
Usually you see longer cranks on mountain bike than road
bikes. My understanding of this is that
for mountain bikes where cadence isn't much of an issue
a longer crank gives more leverage to power up hills etc.
On a road bike its more difficult to maintain cadence through the
top of the crank rotation (10 o'clock to 2 o'clck) so less
length translates to higher cadence.
Does 2.5mm make a huge difference? not sure.
If you can maintain cadence with longer cranks you get
the additional leverage plus the benefit of high cadence.
Marty
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05-16-02, 10:58 AM
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Marty, I understand what your saying. I think I have always had the wrong size cranks on my mtn bike, its now 7yrs old, I purchased it when I was just 17yrs old and 5'5" tall
The bike is way to small for me now, as are the cranks. I have changed out the stem, and have quit a bit of seat post sticking out as well, to somewhat fit the bike to me.
Overall, my new road bike is a much better fit, and I feel much more comfortable spinning on 180mm cranks then my mtn bikes short 167.5mm cranks. My LBS has some older DuraAce 175.55mm cranks, I may give those a try for a few weeks, to see if it makes a difference.
BTW, on my road bike, I have no problems spinning at 110rpm, but feel most comfortable at 85rpm.
The bike is way to small for me now, as are the cranks. I have changed out the stem, and have quit a bit of seat post sticking out as well, to somewhat fit the bike to me.
Overall, my new road bike is a much better fit, and I feel much more comfortable spinning on 180mm cranks then my mtn bikes short 167.5mm cranks. My LBS has some older DuraAce 175.55mm cranks, I may give those a try for a few weeks, to see if it makes a difference.
BTW, on my road bike, I have no problems spinning at 110rpm, but feel most comfortable at 85rpm.
05-16-02, 02:51 PM
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I found a bunch of different "formulas" for determining
crank length by doing search of Google groups.
The basic "formula" (palms?) is:
L (mm) = 2.16*I (cm)
where L= crank length in mm,
I= inseam measurement in cm.
or:
L = 6.07 * I
where I= inseam measurement in inches
and finally
Edmund Burke, PhD gives these guidelines :
<5'0" 160mm
5'0" - 5'5" 165mm
5'5" - 6'0" 170mm
6'0" - 6'2" 172.5mm
6'2" - 6'4" 175mm
using these formulas I get the following recommendations
based on a 30 inch inseam
1) 164.59
2) 182.1
3) 170
thats really assuring, isn't it?
Marty
crank length by doing search of Google groups.
The basic "formula" (palms?) is:
L (mm) = 2.16*I (cm)
where L= crank length in mm,
I= inseam measurement in cm.
or:
L = 6.07 * I
where I= inseam measurement in inches
and finally
Edmund Burke, PhD gives these guidelines :
<5'0" 160mm
5'0" - 5'5" 165mm
5'5" - 6'0" 170mm
6'0" - 6'2" 172.5mm
6'2" - 6'4" 175mm
using these formulas I get the following recommendations
based on a 30 inch inseam
1) 164.59
2) 182.1
3) 170
thats really assuring, isn't it?
Marty
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05-17-02, 08:12 AM
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...and then there's the formula provided here: https://www.peterwhitecycles.com/fitting.htm
Let us know what length that gives you Lotek
Let us know what length that gives you Lotek
05-17-02, 09:27 AM
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I went from 170 - 175mm cranks on my commuter and noticed a very slight improvement in leverage on hills, but it was so slight it could have been psychological rather than physical...
Richard
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05-17-02, 08:52 PM
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It depends on your height and your pedal cadence.
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05-20-02, 06:01 PM
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Here is my crank length story:
I have 175s on the mountain bikes and they feel fine.
Until recently I've had 170s on the road and tandem. Just started riding 172.5s on the single road bike. I hate to be "princess and the pea" but i *swear* i can feel that my cadence has dropped, especially while climbing, with the 172.5s.
The 172.5s are DuraAce and my 170s are Ultegra. I'm considering going back to the Ultegra thinking the loss of "spin" offsets the weight advantages.
Thoughts?
I have 175s on the mountain bikes and they feel fine.
Until recently I've had 170s on the road and tandem. Just started riding 172.5s on the single road bike. I hate to be "princess and the pea" but i *swear* i can feel that my cadence has dropped, especially while climbing, with the 172.5s.
The 172.5s are DuraAce and my 170s are Ultegra. I'm considering going back to the Ultegra thinking the loss of "spin" offsets the weight advantages.
Thoughts?
05-21-02, 06:02 AM
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For a person of your size, a 2.5mm change is fairly minor and both are within the correct size range.
You may want to try a cheaper crank of that size before investing in an expensive one. Going to the larger crank, you may find yourself using a lower cadence and a higher gear. Although we often say pedal at the fastest cadence, really that should read optimum cadence.
You may want to try a cheaper crank of that size before investing in an expensive one. Going to the larger crank, you may find yourself using a lower cadence and a higher gear. Although we often say pedal at the fastest cadence, really that should read optimum cadence.
