My Rides

Sunday, February 19, 2012

Mountain Bike Shifters on a Road Bike

My new "Road Bike" can best be described as a hybrid.  Cyclocross frame, fork, wheels & tires, with a mountain bike drivetrain.  I'm a fan of bullhorn handle-bars, most comfortable/familiar with SRAM mountain trigger shifters, wanted to give reverse levers a try, and didn't want to spend the money on road combo brake/shift levers.

I knew the new(er) SRAM shifters have detachable clamp, which gave me the idea to find a way to use them.  I picked up a pair used, on ebay for $35, which is about 50% of the street price.  The total price for brake/shift levers is about $65, compared to $200 for an entry level road combo lever.  
I tried finding a larger clamp, for this purpose, but had no luck.  I had some 1/2" thick aluminum in the garage, and ultimately the clamp I need is a refinement of a piece of aluminum with a 23.8-26.0 mm hole in it.  
That's how the machining (on a drill press) started - I drilled a couple of 1" holes in my 1/2" aluminum plate.  I added the through-hole and counter-bore for the clamp/fastener bolt.  Then I trimmed away some excess material.
It's not finished.  I still need to make a groove where it mounts to the shifter mechanism (keeping the shifter from twisting), trim away more material, and generally clean it up.  But a quick mock-up illustrates that it's on it's way to doing the intended job.

Update:  June, 2013

I've had these on the bike for over a year now.  

As you can see I cleaned them up, rounded them off, etc.  
There's not a lot to say - life with them has been uneventful.  They work well, feel comfortable and "right" on the bike.  As you can see they're pushed in pretty close.  A mountain bike bar is a lot wider than the 40cm bullhorn I have on these.  The up-shift levers hit my bar tape a little, and sometimes the lever sticks in the forward position. 
From the front you can see that the shifters overlap each other.  The shifter for the front 3 rings is cocked at an angle to clear his neighbor (the shifter for the rear 9).  That was something I sorted out when mocking it up.  In the time I've ridden them, I haven't really longed for a different shifting system.

Recently, I signed up for a century, and in training I realize that my hand discomfort on the bike starts to bother me after about 3 hours of riding.  That motivated me to try out aerobars (with a wider, 46cm, bullhorn bar) - for one more riding position, and secondarily to make those 100 miles go by a little faster (presuming I'm going alone a few times throughout the day).  
As it turns out, those areobars will fit the mountain shifters, with their original brackets.  I've only done a few rides with these, but I can't say there are any real draw-backs, related to them being mountain shifters, and given my goals & expectations.