Wider is better… Not always. In the past couple years, we have seen the arrival of wider rims for our trail bikes. With the rise of Enduro, the Carbon Technology excitement and the growth of fat bikes, it was a logical snowball effect to see more of them.
We went from 21mm internal width (that was a wide rim 3 years ago!), to 30, 40 and even 50+mm for the fat bikes. The tires though, didn’t change very much, but some companies like Maxxis are trying to “generalize” their sizing, so there is no “big 2.4” or “small 2.3”, like it was in the past. Sometimes the tire sizes are not always the same even within the same company. We also start to see some tires coming with “wide rim specific” labels, like the Minion DHF 27.5×2.5.
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Just like a race car, the tires are your contact with the ground, and having the right rim/combination for the use is critical. Combining a rim too wide or too narrow for the tire you want to use, can affect the way that same tire is going to function. As an example, if you use a 2.0 tire on a 25 or 30mm internal rim width , it s going to look big enough, but not going to have the profile that this same tire was designed for. The side knobs will be too high, and the rolling resistance different. Also the sidewall will be affected. In result, you won’t have grip in corners, you may have more rolling resistance, and you re giving up the volume that will take away the comfort.
A tire mounted on a rim has a “light bulb” kind of shape. You want to find the compromise where the difference between the base and the round shape of the bulb is right. If you use a 2.5 or more tire on a narrow rim (less than 23mm internal), the base of the light bulb will be too narrow, compare with the round shape. That tire will not function properly, it will look more triangular on the rolling band, and pinched at the base. It will result in the tire rolling off the rim under pressure, and chances to burp it or even popping out off the rim completely. Not a fun thing to experience!
It is actually pretty simple. We can classify the rims in 4 internal width categories. Under 23mm, 24-30mm, 30-40mm and 40+, which actually will be only reserved to Fat bikes going over 4.0 tires. Any tire up to 2.25 can be use until 23mm. Most tire between 2.3-2.5 in the second category, and 2.5-3.0 in that third range of width. Now, if we look at the types of riding Mountain biking is offering, on the same base classification, it will be : XC , Trail/All mountain, Enduro, DH, Fat bikes.
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The weight of the wheels and tires are obviously growing on the heavy side, the wider you go, and vice versa. So choosing that combination related to your use is the logical way to look at it. Just like you do for picking what bike you are going to ride.
Not to mention, riding style and comfort preferences come into play as well. I hear from pro friends, that the added traction of being able to run the lower pressures (not necessarily cornering traction), really found this to help in very leafy conditions ( east cost, northwest, BC…) where, the lower pressures allows to keep a little better traction on the rooty and rocky leaf covered trails, but the risk to dent or break your rim is also bigger.
I played with lots of set ups, from 24mm inner rims to 30 mm on 29er, and 35-38 on 27.5 for plus tires. I have used Minion DHF 2.3, 2.5, and 2.8 in the front and back. The high roller II 2.3 29 on 29 mm rim is one of my favorite tire for the front. The minion DHF 2.5 29 on 30mm is a great front tire too The new Minion SS 2.3 is smaller volume than a DHF or IKON, the side knobs are already high on the 24mm rim. I would not use it on wider than 29mm. For the 27.5 plus size, after almost s year of testing, I found that the 35-36 mm internal is ideal. The 2.8 and 3.0 have a perfect profile, and the rims have been staying clean of any damages.
List of what I’ve tried:
Mavic Xmax XL
Easton ARC 30
Stan’s Flow MK3
Stan’s Arch MK3
WTB I 35, I29,
Stan’s flow MK3
Easton Arc 24
Mavic Charge XL, Roam XL, Quest
Maxxis : High roller 2, dhf 2.3, dhf 2.5, dhf 2.5WT, DHR 2.4WT, Shorty 2.5 WT, Aggressor 2.3, Minion SS 2.3, ardent 2.25, ardent 2.4
Vitoria saguaro 2.2
Wtb Trailblazer 2.8, Trailboss 3.0, Bridger 3.0
Maxxis : Chronicle 3.0, dhf 2.3, dhf 2.5WT, dhf 2.8, DHR 2.8, ardent 2.4
It is hard not to get drawn towards the newest and latest equipment in this industry, and I’m seeing people everyday with illogical combination. Ask your local professional about it before making decision. Adapting your equipment best for your use is critical to enjoy riding your bike efficiently. It is even more important when you are seeking top performance for racing, and when it comes to tires/rim combination, it s even a matter of safety. Check out the numbers on your equipment before you say “oh, this tire sucks!”
There are a lot of tires and rims out there, and the point of this is not about being right or wrong, but to bring awareness to consumers, and have them try to be logical with their combinations.
Author Alex Petitdemange is an enduro racer from Annecy, France now living and training in Sedona, AZ. He raced as a XC JR and U25 pro for 5 seasons while mixing it up with some moto. After 9 years with no racing he jumped back into the sport while living in Moab, Utah and finished well enough for a podium position and was hooked back into racing as a pro in enduro.[/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]