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Urban-X

I originally got into cycling through mountain biking, and then progressed to city biking and commuting, and then finally I got my first real road bike about a year ago.  Meet Blitzen:

bringing the new (to me) bike home

bringing the new (to me) bike home

I totally enjoy riding a lightweight bike on tiny, high-pressure tires.  It’s amazing how much faster the bike is than the rest of my stable, I’ve even seen 40mph on a downhill near the National Harbor.  But…

I noticed immediately that it’s not a very “versatile” bike (okay so I’m not Martyn Ashton).  I found myself riding it less often.  I worried that the rims would get smashed up on the potholed streets, or from hopping up onto sharp curbs.  The factory gearing was ridiculous: a 12-25 cassette and a 30/42/52 triple.  What exactly is that supposed to be optimized for?  Even with the 30T small ring it still had no really useful climbing gear.  So…

I considered trading for a cyclocross bike, but a few preliminary measurements suggested this frame could fit some much wider tires than the 23mm Continentals it had sold with.  And I knew I wouldn’t be worried about mud clearance on this bike so tight clearances were okay.  I didn’t really need a cyclocross bike, I was going more for of an “Urban-X” sort of thing.  I found this review of the Kenda Karvs 28mm mini-cross tire which seemed perfect!  I ordered up a set and have now put several hundred miles on them and they’re great for this application.  Kenda specifies 75-100psi so I can pump them up for low rolling resistance when I want to ride fast, or I can air down a bit and get a little cushion for riding in the city without the fear of pinch-flats or dinging the rims.  The tread is minimal and should not be confused with an offroad tire, but it works great for your standard urban mix of concrete, asphalt, granite, steel plates, etc.

plenty of clearance

plenty of clearance

Just for grins, I tried a 32mm Kenda Small Block Eight on the front, as you can see there is enough clearance on the sides but it rubbed the crown of the fork!  (anyone want to buy a *very* lightly used Kenda SB8?)

no dice!

no dice!

Next up was the drivetrain.  The factory triple was promptly removed and tossed into the parts bin.  I snagged a 4-bolt mtn crankset on clearance and a Race Face 46T big ring.  This also gave me the opportunity to upgrade the original square-taper bottom bracket to an external-bearing.  I removed the 22T inner ring, installed the 46T outer ring, and was left with an awesome 32/46 double.  Combined with an 11-32 cassette out back this provides a 1:1 climbing gear which I think is perfect (I must not be the only one thinking along these lines).

the new Urban-X drivetrain

the new Urban-X drivetrain

Interestingly, the 46/11 high-gear combo is actually faster (by a miniscule margin) than a 50/12 combo which is pretty standard on road bikes these days (46/11 = 4.18, compare to 50/12 = 4.17).  I did have to move one of 2.5mm spacers from the right side of the BB to the left to get the chainline right, so the crank is not perfectly centered on the bike (translation: don’t try this at home unless you know what you’re doing, and maybe not even then).  At any rate, it’s a much more versatile gearing setup that’s still as fast as a standard compact road setup. Mission accomplished!

P1040969222

Blitzen 2.0

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