The Right Profile

Yesterday was the season's first outing for my Project Singlespeed mountain bike. This was my first ride since installing the Profile bmx crankset and bottom bracket. Holy cr@p!!! I expected an improvement, but was immediately shocked at how much difference it made.

Originally I started this swap to eliminate a pesky creaking/thumping somewhere in the drivetrain. I suspected the stock OEM generic bottom bracket/crankset didn't fit well and wear may have become an issue. With the Profile design the interface is ultra-precise, which eliminates this problem. 

The increase in stiffness was incredible and impacted power delivery and the overall "jump" of the bike. This made hill climbing so much easier. Hills that normally frustrated me weren't an issue. Just powered right up them. A stiffer crankset also provided a handling benefit - a more direct connection to the bike that provides yet one more "steering input". Cool!

My Profile's are a 165mm and replace a set of 175mm stock cranks. The difference in clearance is another benefit. I first noticed it when I didn't need to continually pay attention to my size 12 feet hitting the front tire, but I also found plenty of pedaling ground clearance from the shorter arms.

For those who haven't followed the blog for a while here's some more on Project Singlespeed. The bike started life as stock SE BM Flyer (nice acronym, guys...). My goal was to build up a bulletproof single-speed mountain bike. It started with some simple upgrades - a WTB Laser V saddle and then some Sun Ringle magnesium pedals.  I've always wanted a disc brake-equipped bike and the SE has all the mounts, so I scored a set of Avid BB-7 calipers and discs and installed those. A chat with Steve Sauter, wheel building guru at Great Lakes Cycle, revealed that the White Industries ENO Eccentric rear hub was the solution to effective chain tension, as my bike has vertical dropouts. Plus a 29" wheel with a casette hub is up to 40% weaker than a dedicated single-speed hub, due to the wider distance between flanges. So I had Steve lace up some new hoops with the ENO in the rear and stock Formula sealed hub in front on Mavic TN719 rims. During this process I was also looking to dial in the gearing (when you only have one option, get it right). The final solution was a 31 tooth Graveyard sprocket coupled to an 18 tooth White ENO freewheel (stupidly expensive for a freewheel - and worth every cent). A Wipperman single speed chaing completes the drivetrain.  The Profile cranks and sealed bottom bracket were the final stage.

The resulting bike is amazing. Fairly light for a 29er, handles great, nimble and responsive, and super comfortable to ride for long periods. Sure a single-speed can't go everyhwere, but the appeal of simplicity certainly works for me. Cool ride!

-Sean-