172.5 and 175... I can feel the difference-Or can I?
View Full Version : 172.5 and 175... I can feel the difference-Or can I?
I know I've mentioned this before but...I picked up a 2004 TREK 5000 for a good price. One difference between it and my Lemond is that the Lemond has 175 crank arms and the TREK has 172.5. I believe I can feel the difference and I'm wondering if I should just live with it or try to trade for a set of 175s. Some people say 'what's 2.5cm?,' and maybe they're right, but...:confused:
p.s. I'm also thinking of just shutting the hell up and buying a compact crankset (in 175).
I know I've mentioned this before but...I picked up a 2004 TREK 5000 for a good price. One difference between it and my Lemond is that the Lemond has 175 crank arms and the TREK has 172.5. I believe I can feel the difference and I'm wondering if I should just live with it or try to trade for a set of 175s. Some people say 'what's 2.5cm?,' and maybe they're right, but...:confused:
p.s. I'm also thinking of just shutting the hell up and buying a compact crankset (in 175).
I have bikes with 170, 172.5 and 175. I "think" I can tell the difference between the 170s and 175s, but I doubt I can between the 172.5s and the 175.
Some people are probably oblivious enough to ride around with their saddle backwards and not notice. If you can feel the difference, and it's enough to bother you, then it's enough to switch the cranks.
Some people are probably oblivious enough to ride around with their saddle backwards and not notice. If you can feel the difference, and it's enough to bother you, then it's enough to switch the cranks.
HEY, I only did the saddle thing once!!;)
That's just it. Can I really feel the difference or is it just in my head? I guess its just one of those things to figure out. Thanks.
I know I've mentioned this before but...I picked up a 2004 TREK 5000 for a good price. One difference between it and my Lemond is that the Lemond has 175 crank arms and the TREK has 172.5. I believe I can feel the difference and I'm wondering if I should just live with it or try to trade for a set of 175s. Some people say 'what's 2.5cm?,' and maybe they're right, but...:confused:
p.s. I'm also thinking of just shutting the hell up and buying a compact crankset (in 175).
I live in hilly Seattle and regularly ride 175mm cranks. When I recently acquired an older road bike with 170mm cranks to use as a commuter, I definitely noticed the difference with the shorter cranks, particularly on the uphills and switched to 175s with a noticeable increase in perceived power when climbing with the longer cranks. That being said, I do have one bike that has 172.5mm cranks, and I although I do notice the difference between those and the 175s, the difference is barely noticeable. Since I don't ride that bike as much and usually not for long distances, I haven't invested in the switch to 175s. So for me 5mm is easily noticeable and 2.5 mm less so.
I agree with the other post that if you notice and it bothers you, make the switch.
I know I've mentioned this before but...I picked up a 2004 TREK 5000 for a good price. One difference between it and my Lemond is that the Lemond has 175 crank arms and the TREK has 172.5. I believe I can feel the difference and I'm wondering if I should just live with it or try to trade for a set of 175s. Some people say 'what's 2.5cm?,' and maybe they're right, but...:confused:
p.s. I'm also thinking of just shutting the hell up and buying a compact crankset (in 175).
What's 2.5cm?
250mm...
I have both...and yes I can tell a difference ...well especially if I'm conscious about it.
You definitely notice it when your legs are tired.
I have both...and yes I can tell a difference ...well especially if I'm conscious about it.
You definitely notice it when your legs are tired.
I think I'll start looking for 175s.
If anyone wants to swap their Ultegra 175 crank arms for my 172.5s, let me know. These have less than 500 miles.
I can pick the difference b/w 170mm & 172.5.
What's 2.5cm?
250mm...
Note to all: I am an idiot and should not try to make fun of people who get units wrong. 2.5cm is 25mm. Apologies.
Note to all: I am an idiot and should not try to make fun of people who get units wrong. 2.5cm is 25mm. Apologies. feeling guilty?:D
I've been obsessed about crank length this whole year, and I ended up getting 180s (I'm no sprinter :)) -- I'm 6ft.
Assuming you drop the seat 2.5mm to adjust for the longer crank, this means you knee is 5mm lower, relative to your hip joint, at the top of the pedal stroke. This is a lot, and (hip angle) is probably the most noticeable difference. As far as extra power goes, in my opinion, an increase of at least 5mm is needed to notice any difference.
For all the anecdotes you need, check out this thread thread :)
http://www.cyclingforums.com/showthread.php?t=11281
feeling guilty?:D
Nope. Just silly.
perhaps you really are no sprinter, but lookit the short guys who sprint on 165 with a <52 frame, this is equivalent to pushin' some 180's, no?
[QUOTE=531Aussie]feeling guilty?:D
I've been obsessed about crank length this whole year, and I ended up getting 180s (I'm no sprinter :)) -- I'm 6ft.
]
I can tell the difference too but I am not sure I would want to standardise on any one length...
For me the difference is apparent from the first pedal rev but I like the variety and the riding position on each bike still seems just fine. Not much difference in times on my usual route either.
If you think the difference is affecting you negatively, change one or the other to your preferred (but try both on both bikes first to be sure you choose the right one). If the difference is noticeable but not a negative impact, leave them be...
Cheers
I felt a subtle (but positive) difference going from 172.5 to 175 on the roadie. Kinda a similar feeling to when you've been riding with your seatpost a little low, and you move it back up to where it should be. You get the feeling as though you're able to eke just that bit more power out of the stroke.
I felt a subtle (but positive) difference going from 172.5 to 175 on the roadie. Kinda a similar feeling to when you've been riding with your seatpost a little low, and you move it back up to where it should be. You get the feeling as though you're able to eke just that bit more power out of the stroke.
There is a definite difference for me I´ve owned from 170 mm to 177,5 mm.
My rpm is on the low side (90) and I have a 96 cm inseam so the 177,5 is my prefferred lenght nowadays. What your length should be is decided by you of course. It should be based on rider style and inseam if you ask me. If you ride with high rpms rely on quick accelleration in sprints or are an avid climber with high rpm go for shorter cranks and vice versa. Riding style and that what for example a proffesional measurement at a pro bike shop suggest your crank lenght should be and make the decision from the collected data and your riding style. Or even better get a couple of different lenghts and ride them, choose what you like best.
Assuming you drop the seat 2.5mm to adjust for the longer crank, this means you knee is 5mm lower, relative to your hip joint, at the top of the pedal stroke] I typed this in a hurry.....ooops
It should say the knee is higher with a longer crank :o :(
the biggest difference if you were to go up 5mm is the extra hip flexion at the top of the stroke, and therefore, the knees coming up much higher. This is augmented by the fact that the saddle has to be lowered for the extra reach at the bottom of the stroke.
perhaps you really are no sprinter, but lookit the short guys who sprint on 165 with a <52 frame, this is equivalent to pushin' some 180's, no? I would guess so, but I really don't know. It just seems too simplistic to me for these crank forumla guys to say that 20% or 21% of inseam has the same effect for all leg lengths. Maybe it's different for a 6ft6" guy to be using cranks that are 20% of his inseam....dunno. Something tells me that a big guy on 200mm cranks is not the same as a short guy on 165s......dunno
It should be a complicated issue involving biomechanics, muscle fiber types, etc, but too many people simplify it.
Automatic Translations (Powered by
):
vBulletin, Copyright ©2000-2009, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by
vBSEO 3.3.0
