Kids DH Bike Part 2: Specialized SX Trail

Part Two:  Picking Up Speed

There was this day on the trail in 2012 - I remember it very clearly.  My son was ahead of me on the Ball-n-Jack trail at Snowshoe Mountain, flying down the mountain on his Stinky 24.  At the time, the trail had a very high speed, long straight section of old double-track trail bed littered with loose rocks.  Watching him, I had no idea how he was holding on.  This was fun, but he was on the edge.  It was time to get him a bike with more travel, a longer wheelbase and suspension that could help keep a bike under control at 30+ mph.  This would also be the bike we would take to Whistler 2012

Ben Richter, Age 8.  Staring down the start of Whistler's Dirt Merchant

Ben Richter, Age 8.  Staring down the start of Whistler's Dirt Merchant

The move from the Kona Stinky to the Specialized SX happened a lot faster than I would have guessed. Ben was still small; he was 8, weighed about 72 pounds and was about 4'7".  At the time there was no way to buy a complete 24"(wheel) kids DH bike that was any fundamentally different than the Stinky.  With the goal to build the best bike we could, but still use 24" wheels...this was the starting point of bike building for us.

The first choice to make with a bike build is the frame.   For us, we didn't have a brand preference - we had requirements for simple things that mattered for a small rider like:  does the bike have a low 'standover'.  We found the SX line from Specialized - it fit our basic requirements and we opted for the coil suspension version (at the time I was still a coil spring proponent). This bike would have a slightly lower standover but have 180mm of travel vs. the 100mm on the Stinky.  A slightly longer wheelbase would give some added stability at speed and the head tube angle was a bit slacker.  We would build the bike with a Fox Van RC2 FIT fork (coil spring) and get the lighter spring for <120lbs. rider.  We would also use Avalanche Suspension as experts to tune the rear shock.  This frame geometry and suspension would give him the control he needed at increasing speeds and technicality.  The complete specs looked like this:

The other challenge with the 24" Bike Build is getting the wheels right.  Pre-built 24" wheels are available, but they must have hubs that fit the frame.  In case you haven't researched this variable - at the time of this blog there are 3 different size hubs that are common for the rear wheels (150mm, 142mm, and 135mm).  There are also two common sizes for the front (15mm x 100m and 20mm x 110mm).  The end result is - it is highly likely that you will have to build a custom wheel vs. being able to pick up a set of 24" wheels from a dealer.  With a custom wheel, there are over 10 choices to make. You'll have to choose a reliable and cost effective hub with the proper spec, have an idea of what rim you want, make a decision on what kind of spokes and whether or not you're running tubeless.  These choices should be based on what your preferred riding style and trail conditions are - as well as the kind of tires you will use.  Needless to say, this 'exercise' of determining the wheels for Ben's SX Trail was quite the learning experience.   After a bit of research we went with Hope Pro 2 Evo 32h hubs (we have these on all of our bikes), DT Swiss spokes/brass nipples, and the only 24" black wheels we could find at the time with 32h.

The rest of the build wasn't quite the headache. With a balance of price-shopping and brand preference for Shimano we set off to get the rest of the bike together. Let me confirm for all of you out there: the Shimano M785 XT Brakes are very strong and with metal pads they are very durable. We used these same brakes on Ben's Demo 8, and even as a very fast downhill rider weighing close to 120lbs.  These brakes will do anything your little shredder needs them to do - on any trails.

From a style standpoint - I would like to say we pulled it it all together with red anodized color for the hubs, the seatpost collar, the stem and a portion of the seat.  We got style points for the Chromag Seat and Handlebars too.

This bike build gave Ben the tool he needed to pick up the speed.  While he only rode it for a year - I was able to catch some good footage of a day at Snowshoe Bike Park, WV.