Tuesday, November 17, 2015

Pugsley to 9zero7 upgrade finished with a Vee Rubber Bulldozer

I have enjoyed working on the Pugsley to 9zero7 upgrade. But I have the lingering thought that I still need greater floatation. The trouble is that to gain clearance for wider tires you need a bigger frame and when I started this project I was not thinking way up to 4.7/5.0" tires I was still trying to improve the original 3.6", which I did. But the snow is always whiter on the other side of the trail right?

The problem is that it is a big jump to gain the clearance for real 4.7" tires. If you go to a wider spaced frame you need to get all new wheels with wider axles. It really becomes not cost effective to try and upgrade a frame with 135mm rear spacing to one of the newer frames with 170mm spacing or 195mm spacing because you just have to change too many parts.

But I do have the advantage of not using a derailleur for my drive train. Using a planetary hub means the chain does not move in closer to the center of the hub and back out during gear changes. This gives more clearance than a deraileur equipped bike because the chain is always as far outboard as possible.

When I tried the Vee Rubber Snowshoe XL it gave me the increased width I wanted, over the standard Snowshoe, and extra floatation but the side knobs where just to far out and could touch the frame depending on how I inflated the tires. So they were just a hair too wide for my 135mm frame.

Then Vee Rubber came out with the Bulldozer. Also claiming a width of 4.7" but with side knobs that were not quite as aggressive. I decided it was worth a try and see if I could get a bit more floatation. The volume of a sphere goes up as the cube of the radius so every extra bit of width really does make a big difference in the volume of air in the tire.

Here I put all three tires together in the same image.
Left to right the Vee Rubber Snowshoe XL, standard Snowshoe, and Bulldozer.

It is pretty easy to see the difference in clearance between the three tires.

Unlike the XL the Bulldozer does not hit the frame under any inflation and it is a good .25 inches bigger than the Snowshoe that I was running. Hence the Vee Rubber Bulldozer is a winner for me in the frame clearance game. It will allow me to get more life out of my 135mm frame.

Part two of this article: Pugsley-to-9zero7-upgrade-part-2
Part one of this article:Budget-pugsley-fat-bike-upgrade-to-9zero7

No comments: