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165MM cranks what do I need to know?

717 Views 6 Replies 3 Participants Last post by  bdbloom
I've acquired a set of new XTR 165mm cranks set up for DH(garage sale special). There was a machined aluminum spider to convert them to 3 rings included. Bearing in mind that I am 61 years old, 5'8", 160lbs, and ride 55miles a week xcountry(no jumping dropoffs, etc) with some climbing involved. What would I notice if I switched to 165mm instead of my Hollowtech 4 bolt 175mm cranks. Seems like there would be easier pedaling for an old guy like me. Do I lose too much in leverage to counteract any gains? Thanks in advance.
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Given the same number of teeth on the chainrings, it'll be slightly harder to pedal. You'll have a little more clearance over obstacles, but you say no jumping/dropoffs, so maybe that's not much of an issue.

Usually cranks that small are used for people with short legs (at least in an XC scenario - dunno about DH, where the clearance may be paramount.)
Depends on your Pedaling Style

browns110 said:
I've acquired a set of new XTR 165mm cranks set up for DH(garage sale special). There was a machined aluminum spider to convert them to 3 rings included. Bearing in mind that I am 61 years old, 5'8", 160lbs, and ride 55miles a week xcountry(no jumping dropoffs, etc) with some climbing involved. What would I notice if I switched to 165mm instead of my Hollowtech 4 bolt 175mm cranks. Seems like there would be easier pedaling for an old guy like me. Do I lose too much in leverage to counteract any gains? Thanks in advance.
At your age I'm going to guess that you pedal at a moderate to slow cadence. The super short cranks you just bought are suited either to riders under 5' tall or riders that like to pedal around 120rpm all the time, so they're probably not a good fit for you.

The big difference will be in climbing. I know the 10mm difference doesnt sound like much but it makes a huge difference. The 175's offer more leverage so its a bit easier to grind up climbs. With 165's you will have to use a lower gear and spin much faster when climbing because you dont have the leverage to push a big gear.

I can notice a big difference between 175mm and 172.5mm cranks.
Actually shorter cranks are easier to pedal....

...in a nice smooth circle. Great for flats and downhill. Where they are more difficult is when climbing.
Shayne said:
...in a nice smooth circle. Great for flats and downhill. Where they are more difficult is when climbing.
True, I was only coming at it from a leverage point of view (probably because my spinning isn't that great.) With the same number of gear-inches (is that the technical term?) the added leverage of a larger crank makes pedalling easier.

We're saying the same thing. :)
being as I am already...

Shayne said:
At your age I'm going to guess that you pedal at a moderate to slow cadence. The super short cranks you just bought are suited either to riders under 5' tall or riders that like to pedal around 120rpm all the time, so they're probably not a good fit for you.

The big difference will be in climbing. I know the 10mm difference doesnt sound like much but it makes a huge difference. The 175's offer more leverage so its a bit easier to grind up climbs. With 165's you will have to use a lower gear and spin much faster when climbing because you dont have the leverage to push a big gear.

I can notice a big difference between 175mm and 172.5mm cranks.
pushing a fast cadence climbing, small chainring and 32 tooth cassette, it doesn't sound like it would be a detriment. Most of the climbs I do are very short, but very steep. I try spin up those hills maintaining a faster cadence.
browns110 said:
pushing a fast cadence climbing, small chainring and 32 tooth cassette, it doesn't sound like it would be a detriment. Most of the climbs I do are very short, but very steep. I try spin up those hills maintaining a faster cadence.
As long as you don't feel like you've bottomed out your gears, it might work. You'll have to push harder on each pedal, but since you're already spinning, it might be by a small enough amount that it wouldn't matter.

Heck, you've got the cranks, give it a shot. You may find you like it, you may find you hate it - either way it's worth a ride.

(BTW, need some 8spd 94mm chainrings for those cranks? I just found out that they won't work on mine. :( )
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