165mm cranks

Discuss light weight issues concerning road bikes & parts.
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BRM
Posts: 817
Joined: Sun Mar 16, 2014 3:43 pm

by BRM

I'm curious what is height and inseam is of the TS.

Hexsense
Posts: 460
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

aside from Sram crankset instead of Shimano that i mention in this thread, this post is about sizing because i'm also a short rider.

I'm 5'6.5 (169cm) with inseam=78.5cm. I start biking with 172.5 crank length which i felt fine because i never experience anything better (for my height). Once i built my second bike with 165 crank length, that is the day i know that i hate 172.5 very much. Basically i lose nothing since 172.5 are simply too long to be efficient for my body size. I didn't have to relearn pedaling motion as my cycling experience was so low that it didn't stick hard in my nerve yet.

then i got a good deal on a better, lighter crankset but it was only available in 167.5 (common size like 165 are out of stock because the deal was so good on that time.). I took it. And as expected, 167.5 give me more leverage, i spin slower but with more torque so i can use harder gear. I also happy with this size. Then i go lower and lower on my handle bar while also gain big chunk of muscle on my leg through weight training. I think i'm less flexible with my leg 2cm larger in circumference than before. I start to feel a bit uncomfortable so i put 165 on and bingo! i can pedal better and go lower on the bar again. My now bigger leg and more efficient pedaling are more than offset the lost in leverage. I wonder if someday i would need 162.5 or shorter but hopefully not, as it means i am even less flexible and need shorter crank to solve my fitting again.

PS. aside from cranklength, did you try to move your cleat a bit toward midsole? i find that i like to move my cleats a bit closer to mid sole so it will open up my knee a tiny bit further at 9 o' clock angle. But that cancel out the less toe overlap that short crank arm offer.

[edit out PS2. which i typed it for other topic but somehow mix it up here. so i move it out to place where it belong]

by Weenie


peted76
Posts: 242
Joined: Mon Jun 23, 2014 10:30 pm

by peted76

Thats more like it, thank you AJS914, Hexsense and Grover!
It's good to hear real world feedback, of course everyones experience is different, but is good to hear.
I've played with my cleats quite a bit in the past and would be interested to see what a shorter crank does to them.

The Giant TCR BB is BB86 (this is where my lack of mechanical know-how shines) so the consensus is that I should stick with Shimano 9000 for, ease, weight and aesthetics right?

mattr
Posts: 3538
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

TBH, if you by another 9000 crank, swap the rings you could probably get back a good chunk selling the new rings (the bit that wears) and the old crank (the bit that doesn't wear).

peted76
Posts: 242
Joined: Mon Jun 23, 2014 10:30 pm

by peted76

mattr wrote:TBH, if you by another 9000 crank, swap the rings you could probably get back a good chunk selling the new rings (the bit that wears) and the old crank (the bit that doesn't wear).


Good idea!

peted76
Posts: 242
Joined: Mon Jun 23, 2014 10:30 pm

by peted76

BRM wrote:I'm curious what is height and inseam is of the TS.

I'm 165cm in height with a 77.5cm inseam (apparently).

grover
Posts: 1126
Joined: Mon Jul 26, 2004 1:06 pm

by grover

Yes BB86 is first and foremost designed to be native to Shimano cranksets.

mattr
Posts: 3538
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

Just to add a brief (ish) note to this.

I've started Zwifting with my CX bike on a tacx trainer, it's had 172.5 cranks on it since i built it (thought they were 175s, but checking is obviously more reliable!) i'm using the CX as then both the wife and i can use the same cassette.
Done about a dozen sessions over the last 3 weeks and after about 20 minutes i start getting a mild stinging in my right knee and the muscles above and inboard of it, 10 mins later the left knee starts to do the same. At 35 minutes i have to stop as the right knee hurts too much. Pain goes almost instantly when i stop. 2 minutes later and i wonder why i stopped!

Never had this issue when actually riding the CX bike on the road, done ~3 hour road rides before now, and 2+ hours on mixed terrain. Wouldn't want to do more as it's a proper CX bike, short, stiff and abrupt! Never had it on the 170 equipped road bike either. Even when doing 45 minutes on the turbo (long time ago though!). The new longer cranks on the road bike do give me an issue, as per my earlier post, takes a while to come on though.

Anyway, swapped to some 170s i had kicking around, nothing else has changed. Same pedals, rings, bottom bracket. Even the same 6500 model crank arms. Just done a quick 35 minutes, no issues at all. Could happily have carried on, except i wanted to die.

So yes, it has made a difference in my case, and i will be shopping around for some 165s for my "best" bike and trying to find a home for my 3 month old 172.5 6800 cranks....... probably the cx bike! (for racing though, not turbo work........)

dereksmalls
Posts: 2027
Joined: Tue Aug 02, 2011 9:20 pm
Location: New Zealand

by dereksmalls

What about Lightning crankset?

WhyZ
Posts: 15
Joined: Wed Feb 15, 2017 2:08 pm

by WhyZ

I am 173cm / inseam 80.5.
Presently I used 170 size crank arm. But next week I'll change 165.
I'll test and let you know. What is different.

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