The Green Monster; Gearbox
Author: Chris Armstrong | Location: Whistler, BC via/ Whistler Mountain Bike Earlier this season I got a interesting email from the Ryan @ Brodie.
"Hi Chris, do you want to try a gear box bike? I've got the frame sitting here beside me."
Now the inner engineer in my has always be excited by the thought of a gearbox bike. But with the scarcity of them actually being built at most I have seen a fleeting glimpse of one in the chairlift lineup, hence my excitement.
Fast forward a couple days and one UPS delivery later and I was looking at the frame. The gearbox was designed by Suntour and features 9 internal gears actuated by a gripshift. The gearbox can be shifted while under load, stationary, pedaling backwards etc. The gearbox is situated as low as possible in the frame around the bottom bracket area. It has an external cog of 22 teeth that is single speed style setup to the rear cog of 22 teeth. The cranks are unique to the gearbox and are both left hand cranks.
As this is a first generation proof of concept frame it is a little on the beefy side and favours durability & reliability over weight. As such the frame comes in at 18lbs. Double the weight of a high end DH frame, albeit with a shock. Technically all the weight of the frame was a low as possible as it is based around the gear box which is above the bb placement.
Brodie Gearbox Bike. The meat & Potatoes. |
With the frame in front of me I had to decide on what to suspend the bike with. The head tube is 1.5", 7" rear travel and with the chain stays being so short on this bike I think it is better suited for a slopestyle setup instead of a full DH rig.
Enter X Fusion Vengeance HLR & Vector HLR. Up till this point I had seen X Fusion product at the tradeshows, but hadn't had a chance to try any of the suspension out. The Vengeance HLR fork comes in 1 1/8", 1.5 or tapered headtube, has 160mm of travel with 36mm stanchions and a 20mm axle. The weight was 2.2kg (5.3 lbs) and features a twin tube cartridge damper with high & low speed compression adjustments and rebound.
X Fusion Vector HLR. 450 lbs spring. |
The Vector HLR that came shipped with 2012 internals, which have minor tweaks to the 2011 internals. As with the Vengeance, the shock has high / low compression adjustments, rebound adjustments and bottom out.
As the frame was a prototype I didn't really have any baseline for suspension settings, so it took a couple days to get the ride dialed in. I ended up running the fork with 180psi in it, with the compression turned up to 9 clicks out, which was a couple over middle. This made the fork slightly more supple and forgiving than the original settings that I had it on.
For the Vector I have a 450lbs spring with the compression set slightly up to be snappy for increased pop on jumps. Initially I thought that I was under sprung with that setup, but after a couple days on it i found it to be perfect.
The cockpit was spec'd out with a Gravity 50mm Limited Edition AT stem, Answer Pro Taper 780mm bars, WTB saddle & Gravity seat post. For brakes we went with Hayes Strokers with a 180mm front rotor, 160mm rear rotor.
Brodie Gearbox Bike. Cockpit, Gravity 50mm stem, Answer bars, Gravity grips, Hayes Stroker brakes, WTB saddle. |
Once all the suspension was setup the bike was super fun to ride around. It rides like an all mountain bike on high speed technical runs, so you can't really let it fully go, but it really shines on jumpy trails where you can flick it around. Crank It Up, A-Line, Freight Train feel like second homes on the Green Monster and it wanted to hit them over and over again. The short chain stays really help it out in that regard and make it feel like a dj bike.
Opinion: If I had one thing that I would change at this point, it would be to lengthen the front forks a bit to something closer to 180mm. But that could just be my old body complaining too loudly.
Plus: No deraileur. Perfect chainline.
Minus: Heavy, gripshifts suck.
The frame isn't in production, but you can buy from this bike is everything else around it.
Websites:
http://www.srsuntour-cycling.com
Special thanks to Qualitek Collision in Vancouver for the superb paint job; three tone metallic green! Make sure you check them out for all your vehicle repair needs!