Wow, I have posted on the importance of good tires before, but after a weekend on a rental bike with tires very similar to the ones used by many of our xc racing students I have to discuss this again! I had not been on tires like this in years so I forgot how bad they really are! Is lower rolling resistance worth losing 25-50% of your control? On fast, non-technical race courses it may be, but at the Jungle Habit and Ringwood, NJ trails this weekend it was not worth it.
The small (in height and thickness) knobs provided little rolling resistance, but squirmed on rocks (because they flexed, a lot) and didn’t climb or corner well. I would only use these tires on a bike path (or maybe an easy xc race trail involving no skill).
If you are looking for a confidence inspiring tire that will hook up, study what the best downhill racers are using in your area and buy similar tires (if you are worried about weight get the single ply versions, if you hate flatting, like increased control and don’t mind extra weight (double the tire weight) use downhill, double ply tires. Tall knobs work well on softer surfaces like the loomy trails in the Pacific Northwest and in mud. The more hard packed the surface (as in Colorado, Utah, Arizona and much of California) a medium to low height knob with a lot of surface area (blocky knobs instead of skinny knobs) as these tires will put more rubber on the ground (as the surface is too hard for the knobs to push into the ground) and the big surface area keeps the knobs from flexing (flexing makes the tires squirm). My personal favorite tire for Colorado, Utah, Arizona and California is the Maxxis High Roller.
Notice how thick the knobs are! These tires are also Greg Minnaar’s favorite tires. Greg says that they roll fast for an aggressive tire and they are very predictable. Specialized, Kenda and Schwalbe all make excellent tires, do your research and find the ones made for your trail conditions.
Tires also come in different rubber hardness, the harder the rubber the faster they roll and the longer they last. The softer the rubber the better traction they have but they roll slower and where quicker. Many manufacturers offer dual and triple compound tires where the center, rolling knobs that get the most wear are a harder compound than the cornering knobs (which get less use but are vital to cornering control). Tire hardness is measured in Durometer, the higher the number the harder the rubber. Most tires range in Durometer from 42 to 70. 70 durometer tires feel almost like plastic and slide easily, but roll fast. 42 durometer tires are favored by downhill racers but wear really quickly and roll slow, most tires will fall in between. Better, more expensive tires often will have a dual compound of around 55 for the center knobs and 45 for the side. Dual and triple compound tires are my favorite for xc use as they hook up almost as well as a downhill tire, but roll a little faster and last longer.
Tire pressure also greatly effects your ride. Lower pressure hooks up better, smooths out the trail a bit and rolls faster than higher pressure so go lower. For more info on tires check out my older post on this: