My Fuel EX 9.9 was ordered with Bontrager XR3 tires, and I’ve used them for a year, and a year’s worth of mileage.
Over the weekend, I replaced them with a set of Continental Trail King 2.2s.
This post represents my thoughts on the XR3s, and the reason for the change.
First, I ran my XR3s on ENVE XC rims, taped with ENVE tape, tubeless. As far as tubeless goes, these tires set up the easiest of any tires I’ve ever used. For reference, Chad threw a pair of XR3s on a tubeless wheelset and just pumped them up–leaving them in the shop for a few weeks–and they held air perfectly. The tires are just fantastic at tubeless. For my purposes, I was running 2.2″ tires, and used 2 ounces of sealant per tire. Over the course of the year I ran them, I cleaned them out one time and replaced the sealant. I never had any issues with them–even if I went a month or two without riding the Fuel, they’d hold air amazingly well.
The tread pattern on the XR3s is good for midwestern conditions. Good, aggressive knobs, but close enough together that they roll pretty smoothly on hard surfaces.
The knobs on the edge of the tread get knobbier, for better grip when yanking and banking.
I tend to use the Stan’s formula for determining starting pressure with mountain tires. In short, rider weight divided by 7 = x. X -1 = starting front pressure, x+2 = starting rear pressure. For me, that suggests around 23 up front and 26 in the rear. After some time on the bike, I tended to set them around 24-25psi front and rear, with good results.
Over the course of a year, they saw varied terrain in several states, and also some gravel and some pavement. While they were not fond of wet leaves (what is?), they acquitted themselves admirably in most conditions. They really did not like sand, but that may be more a reflection of my riding ability than their traction. They self-cleaned surprisingly well in mud, were great on hardpack, did well on loose over hard, and most other conditions. In most conditions, they would slide progressively and let you know when you were exceeding available grip. To a point.
The “to a point” is a critical note. I’ve tried to up my game with mountain biking–increasing my speed, braking less, having more confidence, riding harder lines. It’s hit or miss, in all fairness, as my skill still needs a lot of improvement. My concern about the XR3s is that they have a finite breaking point where your cornering speed exceeds available traction, and at that point, you’re gone. They go from gradual, controlled drift to low-side, sliding on your leg and wondering what happened, instantly. Before these, I spent a lot of time on Maxxis Ikons–which had less ultimate grip, but which were more recoverable. If they cut loose and slid, you could reestablish traction and carry through a corner. The XR3s have more grip, but once they go, they’re gone–and in a snap. I don’t know how much of that to attribute to the tires, and how much to my skill or absence thereof, but I’ve low-sided enough times with these–and in a snappy, instant fashion, for it to be observable and disconcerting.
The XR3s were not fast-wearing; they still show a lot of good tread on them. The reason that I’m swapping them out is because of a flat I had on the Chubb trail. I was climbing an obstacle and heard that disheartening hiss of air leaving the tire. I stopped, rotated the hole down, and tried to get the Stans to seal…a little blast of CO2 and a second try…no dice. On the trail, we tubed it quickly and continued on. Back home, I dug in for the post-mortem.
I don’t know what caused the hole (rocky trail with 12-18″ rock lips that we were climbing up), but it is a neat, round hole. There is a chunk of rubber about 2-3mm across that is just missing (perfect circle), and around that, an area about the size of a pea that is deformed. The weird part is that on the inside of the tire, the casing in the area of the hole was delaminating–whatever punched the (relatively small) hole also cut the tire casing at the (relatively small) hole, and the fabric inside the tire started pulling apart around the hole. I was hoping to boot the tire and continue tubeless, but that’s a non-starter.
I threw on the Trail Kings for a few reasons. First, in full disclosure, I had them sitting on the shelf from my old El Mariachi. Second, I loved them on that bike, and have wanted to try them on the Fuel for some time, as the side knobs on them are super-gnarls, and I remember them being very predictable (even on a rigid SS bike). Third, I remembered that they set up super easy tubeless, and held air well–and never let me down with a flat on the ElMar, even rigid, with my ‘not so delicate’ riding style.
When I ordered the Fuel, you had to pick a Bontrager tire (obvs). Out of the available options, the XR3 was the clear choice, and I enjoyed my time with it. Generally speaking, a good tire for many conditions. I chose not to replace just the (failing) front with another XR3, as I wanted to see if I could cure the snap low-siding I’ve experienced with a different tire, and I’m hoping the Trail Kings will solve that problem. Again, my complaint isn’t that the XR3s ran out of traction, but rather the fashion in which they did–snapping from a controlled skid into complete loss of traction low-siding.