Changing Crankset, need some advice.

cjpowl6818

I need some help, I am wanting to change my Crankset out on my 05 Jekyll. I have already bought new 596 brakes and 590 shifters and a 591 R Derailleur, my question my crank says that the BB is a 68mm, I have found a 9 speed shimano Deore that has the same BB 68mm, is that the only thing I have to worry about and does it make a big difference between 170 and 175 for crank arm length, This is what I found on my bike.
Frame Jekyll
Fork Manitou Splice Super 100/130 w/ RTWD
Rear Shock Fox Float RL Pro Pedal
Rims Sun Black Eye Disc, 32 hole
Hubs Cannondale Fire Disc
Spokes DT Champion
Tires IRC Serac XC, 26 x 2.1"
Pedals Wellgo alloy cage w/clip and strap
Crank TruVatiV IsoFlow, 22/32/44
Chain Shimano 9-speed
Rear Cogs SRAM PG-950, 11-34
Bottom Bracket Shimano 4-taper
Front Derailleur Shimano Deore
Rear Derailleur SRAM X-7
Shifters SRAM X-7 Trigger
Handlebars Cannondale Earth, 15 mm rise
Stem Cannondale 3-D Forged
Headset FSA Converter
Brakeset Avid BB5 Disc
Brakelevers Cannondale Earth

This is the Shimano deore 590
Hyperdrive SG-X chainrings
Dual SIS front index shifting
SG-X aluminum outer rings and steel middle and inner rings
Item Specifications
Color Black
Genre 175
BB/Frame Interface English
Spindle Interface Type Hollowtech II
Pedal Spindle 9/16"
Chainring BCD 104
Chainring BCD 64
Rings 22/32/44
Crank-FD Type Mountain Triple
BB Shell Width 68
BB Shell Width 73
BB Included Yes
Crank Intended Use Mountain
Chain Compatibility 9-Speed

This is the other crank I was looking at besides the shimano Deore 590.

Number of Chainrings:
3
Brand:
Shimano
Bottom Bracket Interface:
Octalink V1
MPN:
FC-M443-8L/BB
For Bike Type:
Hybrid/Comfort Bike,Mountain Bike
Crankarm Length:
175mm this also has a BB-68mm
Any help would be greatly appreciated.
Thank you

jimothy78

68mm is the width of the bottom bracket shell (the part of the frame that houses the bottom bracket) - the crankset doesn't have any impact on this, really. The important thing to get right is the correct amount of spacers when fitting the new bottom bottom bracket. You'll need two driveside and one non-driveside (unless you have a bottom-bracket-mounted front derailleur or chain guide, in which case this takes the place of one of the driveside spacers).

As for the crank arm length, you're unlikely to notice the difference between 175mm and 170mm - it's the sort of thing a roadie or an XC racer might obsess about, but your average mountainbiker probably wouldn't even be able to tell you which they have without looking

poah

you'll have to adjust your saddle slightly up - I went from 175 to 165mm. better for my hight but I can't say I actually notice a difference

The Rookie

My daughter got 170 cranks when buying new as she is 5'3" and short of leg length even for that height, she'd previously had 175's though.