A customer needed a new front wheel for the new Straggler fork on his Cross Check. He wanted a disc brake on front for single track riding and the Straggler fork is very close to the Cross Check fork geometry-wise. I built up the wheel using a Surly Ultra New hub and the DT Swiss E512 rim which at 30mm wide is a full 11mm wider than the DT Swiss R450 rim on the wheel he was replacing.
A significant width difference!
Why did I use such a wide rim? For a couple of reasons. The same tire, in this case a 700 x 35 Continental Cyclocross Speed, on a wider rim will have a wider contact patch than when mounted on a narrower rim and this means more traction. The tire will also have a cross section which will be a little more “square” and less balloon like. What this means, in theory, is that the tire will have less tendency to roll sideways when the wheel is angled into a turn and the handling should be more firm and confidence inspiring with no squirming. This idea is visually represented in the following two pictures:
Wide rims provide optimal grip and allow a thinner carcass combined with increased traction and tracking ability. Photo: syntaceusa.com
Narrow rims provide little guidance for the tyre. The tyre “folds” and can even jump out of the rim.
Photo: syntaceusa.com
When it was done, we gained about 4mm in width to the inflated tire, a little over 1%. While that doesn’t sound like a significant increase it should stiffen up the sidewalls of this tire and contribute to better handling and cornering. The combination of a little bit of extra width in the tire and a deeper rim profile make the wheel and tire look quite a bit bigger then the original setup on this bike. Neither a Cross Check nor a Straggler now. Monster Crossler?
The tire on the top is on the 19mm rim and the one on the bottom is on a 30mm wide rim.
