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:
Rims:
29er
Mavic Xmax XL
WTB I29
Easton ARC 30
Stan’s Flow MK3
Stan’s Arch MK3
Ibis 94127.5:
WTB I 35, I29,
Stan’s flow MK3
Easton Arc 24
Ibis 741Tires:
29er
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 2.227.5
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]
This Post Has 16 Comments
“some companies like Maxxis are trying to “generalize” their sizing”
Maxxis has a long way to go in this effort of “trying”. In 2017 you can guarantee their 2.8’s measure 2.66″, 2.5’s measure 2.3, and so on. While I haven’t measured their 2.5 “WT”, I can bet they’re 2.4″ at best. In an industry obsessed with measurement “standards” and their supposed benefits (35mm handlebars anyone?), you think tire manufacturers could cop to lying about tire widths to please the gram counters.
Very good point with the oversized tires. At least we have good options. ;)
Looking to get some Stan Mk3 Flow’s (with Hope pro 4 hubs as from the UK) with a high roller 2.3 at the front and a 2.4 ardent on the rear. This will be for my hardtail 29er. Currently got some mavic rims (19mm internal) with 2.3 high rollers that have been great over the winter. How did you find the flows? Would you recommend any of the others rims instead on your list? I ride aggressive trails around where i live and looking to upgrade my wheelset. Many thanks for this interesting article.
So which combinations did you prefer?
Last I spoke with Alex, he was really into the 29×2.4WT or 2.5WT Maxxis Minion DHF/DHR’s on Stans Flow MK3. When mixing it up to just play around (ride with slower riders) he was riding a handbuilt set of WTB i35’s with WTB Bridger 27.5×3.0’s.
His point with this post was really to voice his opinion that many folks inducing manufactures are choosing to go too wide with their rims and the tires ability to perform at their best is being compromised. You have to consider the shape of the tire before going wide with a rim since some tires have square profiles while others have round profiles. I agree with this thought 100%. Many manufactures are now recommending inside rim diameters for their tires that I suggest following given your tires of choice.
We now have the 2.6″ trend which looks to be the hot new trend this year. We’ll be testing these very soon to throw into the mix.
Interesting; the i35s looks like a good choice for a wider rim. Maxxis recommend 35mm rims with their WT tyres and I just read that Pivot – after testing – are using that pair on the new 5.5 whereas Ibis have gone for 40mm. Rim / tyre pairings seem to be more important than either in isolation.
Perhaps rim widths will increase as tyre manufacturers design better tyres for wider rims.
Yes! The i35 with 2.6’s seems like a great pairing. We will have a similar setup in a few weeks to start testing. The Ibis internal width is either 34mm for alloy or 35mm for carbon. Their names are actually the external measurements 738/938 = 34mm internal, 742/942 = 35mm internal. The wider footprint of these rim width’s even with true 2.35/2.4’s is quite nice in many conditions – especially rocky/rooty/loose condtions.
It appears as though rim widths are actually decreasing as 2.6’s are on the horizon as the next popular tire size. I personally think many manufacturers went too wide with their rim choice for 2.8/3.0’s, but I am a little more sensitive to all that extra weight of the 40+mm rims as a lighter rider.
Thanks for the article, good read. From my research, 35mm for 2.6 is a bit on the wide side. I’m gonna get wheels with 30mm rims (DT Swiss M 1700 Spline) for Schwalbe Nobby Nic 2.6.
Thanks for reading! We’re really liking our NN 2.6’s and have just started riding some of the new offerings from Maxxis that have impressed. The 35mm internal rims are great for the right tire, but as a trade-off are heavier. 30mm might just be the sweet spot if weight is a concern.
I have a pair of FSA 40mm lightweight rims paired with schwalbe rocket rons that are 2.8 wide. EXCELLENT combination..grip forever, great cornering and without the extra weight. The new addix compound is VERY durable, schwalbe claims 60 percent more durable sidewalls and puncture resistance than its predecessor.
I run a size M/L aluminum hard tail with a 1×11 setup. SRAM NX. Full Boost front and rear thru axles. Large Pedaling innovations alum. pedals. Cheaper Truvativ cranks and Neco BB (going to upgrade the cranks and BB eventually) Not one ounce of carbon on this bike and all up weight is 29lbs. Once I replace the cranks and bb I suspect I will be just over 28lbs. Not bad for a full aluminum setup with 2.8 tires!
what do you think about this size chart Chad? (BTW, may buy one of their carbon wheels and test on the McDowell rocks, price looks good) https://www.lightbicycle.com/newsletter/tire-size-chart-for-bicycle-rim.html
Hi Mike, That chart is pretty good but stretches a little wide especially if you have a particularly round or square profile tire. I have some 2.6″ tires that I think are almost too round of a profile on a 30mm rim but their size chart says you can run a 2.6″ tire on a 25mm rim. I like the charts from Enve and We Are One Composite.
I don’t know too much about Light Bicycle rims/wheels. After my time spent working in the test lab at Enve Composites, I’m a little wary of trusting some carbon rims though. I still see failures that scare me. I would buy wheels from these guys if I were looking right now – https://www.weareonecomposites.com
They have a great lifetime warranty, make their rims in BC and start at $1399 with I9 hubs.
Try a continental trail king 2.2 tire 29er or 27.5 not to wide
Yes, Conti’s that I’ve used in the past were really undersized. I am hearing some rumors that we might see a new line from them this year though.
I have i30 rims and am currently running Mavic Minions/Aggressors at 2,5″ and they are great.
However, as the tires are getting older and need replacement, I’m also tempted to test out 2,8″ Nobby Nics that I got with the bike. But I’m afraid they will be too round for these rims.
As a pure cool factor, 40 mm / 2,8″ would seem great, but after reading your text 35 mm might be better? Anyway, I don’t think I’m ready to spend the cash for new rims just yet, so maybe it would be worth testing with the i30’s?
Hey Mikko, yea the 35mm internal is probably the right fit for the 2.8’s. If you look at most companies sizing recommendations for their rims they recommend a 35 for 2.8’s. The 2.8’s on the i30’s will like you said give a more rounded profile.