Surly Endomorph Fat Tyre

It was inevitable that Pugsley was going to need a new pair of shoes. To this point, the current offerings of high-volume, large-footprint bicycle rubber has consisted of downhill specific, or homemade, or scarce out-of-production tires designed for specific out-of-production rims. Though downhill tires are readily available, they are heavier than we need. We ultimately desire a tire that fits the following criteria: 1) The ability to crawl over and through a wide array of soft and loose surfaces and materials without packing up. 2) A size that will fit within the confines of the Pugsley frame and fork. 3) A weight less than 26 x 3.0" downhill tires. 4) Full compatibility with 26" Large Marge rims and other wide bicycle specific rims. Our only option was to design our own tire.

The Endomorph 3.7 is the product of our effort. It's 94mm wide (3.7") x 740mm tall (29") on our rims. It's the highest-volume production bicycle tire on the market at this point. And, at 1260 grams, our 60 tpi tire weighs 300–400 grams less than lower-volume 3"-wide DH tires. Most 3" DH tires hover around 1600 grams.

The center portion of the Endomorph's medium durometer (60a) tread is comprised of widely spaced chevrons made up of small, low-profile knobs. Higher-profile knobs, at the outer edges of the tread, provide cornering traction and lateral stability in the loose stuff. No tread pattern is going to be perfect in every condition, but the Endomorph's tread tends to perform quite well on a variety of surfaces. Truthfully, the casing volume has as much to do with our tire's performance as the tread pattern does. High volume allows the use of low pressure without much risk of pinch flats. The use of low pressure allows the tire casing to spread out on the ground, providing greater traction and floatation due to the increased footprint. We've run our tires as low as 5 psi in deep snow, but 8-10 psi is generally low enough for most snow and sand riding. Want to ride on harder surfaces? Pump ‘em up to 15 psi, if the surface is hard, but rough….up to 28 psi, if you're riding pavement or smooth, hard dirt. Of course, this is just a guideline. Trial and error/success is the best way to determine what pressure will best compliment your riding style, trail (or lack thereof) conditions and your weight.

Embrace the fat. Ride more. Walk less.