When I first got the call from desert racer Greg Row, he was raving about these new 12-inch wheels he received from Douglas Wheel and how they flattened out terrain and mentioned a bunch of things about how trophy-truck wheel sizes had really increased and ... did I want to come ride them?
After the excitement he was obviously feeling, how could I say no?
When I first saw Row's little fleet of quads all sporting these insanely big polished-aluminum wheels, I was floored. Screw how they work; riders should roll these on principle. They give a quad such a huge attitude and completely change the look of the machine. But Row wanted some feedback, so riding was in order.
He brought to Southern California's Plaster City OHV Open Area a few machines mounted with his new setup: a Yamaha YFZ450, a Suzuki QuadSport Z400 and his own Bombardier DS650 racer. We had an opportunity to ride the Z400 and the Bomb. The 450 and 400 were shod with standard Douglas 12-inch rims with 25-inch Titan 489 X/T tires. Originally designed for a utility quad, the bias-ply units adapt well to both soft sand and hardpack.
I was concerned with how much the added weight of the big wheel/tire combo would affect suspension action. It seems the advantage of a big rolling surface more than makes up for the extra weight, and the shocks (Works Performance on the Z and Elka on the DS) did a good job of keeping all four wheels on the ground.
The first one we tried was the Suzuki. It seemed the greater spinning mass of the wheel/tire combo made acceleration a little soft, but boy, did it soak the ripples! In the flat-out world of desert riding, it was in its element; smallish bumps and rocks barely register, while even whoop absorption (a far tougher test of the suspension) seemed right on par with what we'd expect. The taller ride seemed perfectly composed in corners, as one of our concerns was that the higher ride height would sacrifice some stability. With aftermarket shocks that actually lower the overall center of gravity, the resulting effect is still better than a stock machine.
Hopping on the DS, we found it even more natural. Row's success on DS-based desert machines is legendary, and he thinks this one mod should give him an extra edge.
Still, physics dictate that you will pay a price for switching to heavier equipment, especially of the "unsprung" variety. We whipped out our Stalker radar gun and proceeded to test the difference between Row's DS and another with stock-sized wheels that he had brought along. They were set up pretty similarly, other than the necessary gearing changes for the larger tires. The verdict? Half a second slower 0-60-mph times. While that seems like a lot, and in a short-distance motocross race it's an eternity, out in the dez with 250 to 1000 miles to cover, half a second accelerating versus less fatigue, or even getting hung up one time in a rut, is more than worth it.
While we probably wouldn't recommend using this heavy setup on a high-flying motocross machine, for a C-class amateur in a really screwed-up and rutted place such as Southwick, another couple of inches of clearance might just be the winning ticket and edge you need to propel you to victory.