Mountain Bike Tires 101

Mountain Bike Tires 101 - Blister Review, presented by High Brew Coffee

Tires 101

While it might seem like they’re pretty much all the same, the fact is that the right tire can be the difference between having a very good time and a pretty bad time on your bike.

Bad tires — or even “good” tires that aren’t the right choice for the kind of riding you’re doing — can have you skittering down the trail out of control (while praying you avoid your third flat tire of the day), as opposed to achieving a zen-like flow, railing corners, cleaning climbs, and making it back to the car without needing a pump.

And no matter how nice your bike is, the wrong tires can make a great bike ride poorly, while the right tires can make any bike ride that much better.

So what do you need to know about tires, and how do you figure out which ones will work best for you given how and where you ride?

Before you go spend your money on some random piece of rubber, there are a lot of concepts and features that are good to understand. And in this article, we’ll walk through some of the most important things to look for, then offer some specific recommendations based on different priorities (durability, grip, etc.) and scenarios.

There are five basic elements to consider when shopping for a tire: tire size, tread pattern, casing & construction, rubber compound, and bead type. We’ll get into each of those, and cut through the jargon and talk about what each company’s marketing terms actually mean.

There’s a lot of information in here, so you can use the jump links below to skip around as you like.


1) Tire Size (page 1)
2) Tread Pattern
3) Casing and Construction
4) Rubber Compounds & Bead Type
5) Specific Tire Recommendations

Most tires come in a few different sizes, casings, rubber compounds, and bead types. We’ll help you navigate those options here, but you’ll also want to check out our in-depth tire reviews for longer discussions of specific tires.

Basic Elements of a Bike Tire

Now just before we get into the meat and potatoes, here’s a handy graphic from Maxxis that gives us the basic elements of any bike tire — the tread, the casing, the sidewall, the bead — and some tires will have reinforcements to help with puncture protection or other durability concerns. We’ll talk about all of these below.

Tires 101 by Noah Bodman for Blister Gear Review.
Basic Tire Construction

Tire Size — Diameter & Width

This one’s pretty obvious, but you’re going to need a tire that’s the right diameter for your wheel, and that’s the right width for the type of riding you want to do. So let’s talk about diameter and width:


Wheel diameter measurements are most commonly expressed in inches: 26”, 27.5”, and 29”. Those same dimensions are sometimes expressed using the French sizing system – a 27.5” wheel is the same as a 650b wheel, and a 29” wheel is the same as a 700c wheel.

A Side Note on ISO and ETRTO Sizes

Sometimes, you’ll see tire sizes expressed as a string of numbers; something like 60-622. That’s an ISO / ETRTO size designation that gives both the width (60 mm) and the diameter (622 mm). The International Standardization Organization (ISO) has superseded the European Tire and Rim Technical Organization (ETRTO), but both organizations are still referenced sometimes.

Both the width and the diameter are measured in millimeters. In our 60-622 example, 60 mm would be the width of the tire at the widest point (which, in real life, will vary a bit depending on the width of the rim it’s mounted to). 622 mm would be the diameter of the bead seat of the rim. Expressed in their ISO form – 26” wheels are ISO 559 mm, 27.5” wheels are ISO 584 mm, and 29” wheels are ISO 622 mm.

Regardless of the naming designation that you use, when buying tires you just need to buy the appropriate tire to fit your rim.


Most tires come in multiple widths, and this can be the trickier decision.

  • Knobby tires for “regular” mountain bikes range from around 1.8” in width to around 2.6”.
  • Plus bikes (i.e. 27.5+) usually have tires around 2.8” to 3.0” wide.
  • Fat bikes have tires wider than that, up to around 5” wide.

The delineations between where regular tires turn into “plus” tires, and where plus tires turn into “fat” bike tires are a little vague, but ultimately, it’s just semantics.

Noah Bodman reviews the WTB Riddler tire for Blister Gear Review.
Noah Bodman on the WTB Riddler Tire, Whitefish, MT.

People have been arguing about the pros and cons of various tire widths for many, many years. I’m not going to fully open up that can of worms here, but there are a few basic considerations when deciding on tire width:

Take a look at your frame and fork clearance. Any given frame or fork is going to have a maximum tire width that it’ll accommodate. If you go too wide, it’s going to rub. On a fork, if you run a tire that’s too big, even if it doesn’t rub you run the risk of the tire hitting the crown on a hard bottom out. That’s a good way to lose some teeth.

Also factor in mud clearance. If you ride in a muddy area and cram the largest possible tire into your frame, things might get gummed up.

Look at your rim width; ideally, the measurement you want is the internal width of the rim. If you put a wide tire on a narrow rim, the tire won’t have good cornering support and might feel squirmy in corners. You’ll have to run higher pressures to counter that. Conversely, if you put a narrow tire on a super wide rim, the bead might not properly engage, the sidewall is more prone to damage, and the tire will have a very square profile that can ride a bit weird.

For the majority of mountain bikes out there, internal rim widths are going to be in the 18-30mm ballpark (which translates to around 21-33mm external widths). If you already have firmly held opinions on tire widths, feel free to ignore the next sentence. But if you’re lost on tire width and don’t even know where to start, I’m of the opinion that 2.1” tires work best on 18-22mm rims, 2.3” tires work best on 23-27mm rims, and 2.5” tires work best on 28-30mm rims, up to around 35 mm. Beyond 35 mm, you’re generally into “plus” tire territory.

Wider tires tend to be heavier.

Narrower tires tend to provide less traction.

In some situations, wider tires roll slower, but that’s not always the case.

Some companies are coming out with tires that are specifically designed to work well on wider rims. For example, the Maxxis Wide Trail series of tires are designed to work well on rims that are over 30 mm wide (internal).

A Note on Front vs. Rear

Plenty of people run the same width tires front and rear. Plenty of people put a wider tire in the front. Both options have their pros and cons, but really, some bikes and riding styles tend to work better with matched tires, and some work better with a wider tire in the front. Generally speaking, the reason for a wider tire in the front is to gain a bit of cornering traction so that the rear tire will usually be the first to break free in a corner. When the rear tire is the first to break free, you get a little bit of oversteer, which can be desirable. But when the front tire is the first to break free, you tend to crash, which is undesirable. For that same reason, you generally don’t want a larger tire in the rear.

NEXT: Tread Pattern

13 comments on “Mountain Bike Tires 101”

  1. Noah, great review.

    Any comment on the Maxxis Rekon 2.8? I know you are not a plus bike fan in general. But I love my Pivot Switchblade setup plus, and am still debating the best tires for all around riding in Park City (almost always dry trails, mostly smooth dirt riding with some decent downhill trails). I blew out my stock Rekon in the back after about 10 rides, ripped through the sidewall. Now I have a DHRII 2.8 (it was all the shop had at the time) in the back and stock Rekon in the front. It sort of feels mismatched with the meaty tire in the rear.

    Get a DHF upfront? Switch back to Rekons front and back as a good all-arounder for PC? What would Noah do (WWND)?

    • Hey Dan,

      I’ve spent a bit of time on the 2.8 Rekon, but probably not enough to make a super confident assessment. But given the tires that you have, personally, I’d just switch them – put the Rekon on the rear and the DHRII on the front. That way you’ll get the meaty traction up where you want it, and the slightly looser feeling Rekon in the back where a bit of skittering about isn’t a big deal. Then, if you slice up the Rekon again (which seems somewhat likely – those things are a little too thin I think), then you could get a DHF to put up front and stick the DHRII back on the rear.

      I suppose that involves lots of swapping tires around, but that’s not too big of a deal.

  2. Great article! Love when you guys get into the details even if some of them are fundamental. From company to company there seem to be a dizzying array of terminology and special tech that each offers and often times, reviews and comparisons really don’t answer the question. FWIW, I’m one of those guys that had to buy about a dozen different tires and went through the trouble of swapping them out after about 6 rides on each. I ride a Niner SIR9 so its nothing downhill worthy or bad ass but its what I’ve got and does what I need it to do. I followed the hype for a while and even tried a DHF 2.5 up front. Awesome going downhill and it looked cool but pretty much everywhere else it was a lot of work. My favorite combo turned out to be a High Roller 2 up front and an Ikon 2.35 rear. Been loving that pair for the last 2 yrs and have yet to find a strong enough reason to change it. Compromise? Yes. But I’ve got one bike to do it all and these tires seem to get 90% of it done. Keep up the great work!!

  3. Thanks for this great overview on mtn bike tires. Very helpful as it is so confusing. Keep up the awesome mtn bike related reviews!

  4. Really amazing article!!!

    Have you ridden the vittoria morsa?
    I would appreciate it if you could share your experience.

    How does it compare to aggressor?

    • I currently have a 2.6 dissector on25 rim on the front and a 2.4 rekon and the back on a 30mm rim. I’ve got an enduro coming up and want a better tire on the back. So I don’t know if I should just get a 2.5-6 dissector/aggressor for the rear or put the big tire at the back and get a 2.4-2.5 for the small rim at the front.

  5. Hey Noah ,

    Thanks for the informative reviews. I like them a lot. Proper rider opinion is so useful – there’s a lot of gear out there!
    Tyres especially so this o e is much appreciated.
    I’m a Maxxis DHRII fan too. (And a Mojo Geometron owner. Very long slack and low, used as a UK trail bike).
    Do I remember right that in an early review you made some recommendations about trimming the width of the wider DHRII center knobs to open up the channel?
    I can’t find that article of yours in a search, frustratingly
    Any chance you could link to it please?
    And what tool to use? Plain sidecutters perhaps.

    MAYBE I dreamed it ‘;~}.

    Thanks lots.

      • Hey Neil,

        Personally, I don’t spend much time cutting tires, but that’s mostly a laziness thing. I’m with Kevin though – trimming a bit off the center knobs of the DHRII would increase cornering grip a bit, and would still probably preserve most of the DHRII’s fantastic braking abilities. I’ve run an uncut DHRII in the front on a few occasions and I like it, although I like the DHF better for the front (because it corners a bit harder). Also consider a Bontrager G5 – they run a little bigger than the Maxxis tires, but the tread pattern isn’t too different than what you’d get with a cut DHRII.

  6. Hi Noah,
    great to know, thanks for the reply.
    as well as being hard work, cutting is risky too, it would be just like me to get it wrong ‘;~}, it WAS great to read about Kevins experiments though. Helps in understanding treads.
    That G5 sounds like it would make one great alpine uplift tyre
    Thats one good write up from Kevin:
    Shame Trek don’t do a trail-bike weight version. Even the 2.35 seems a bit of a “man-up weight” for “pedal up” sessions.
    My next non mud front’ll likely be your recommended DHF in WT on a DT471 or even a 35 internal rim. Maxxgrip maybe even.

    I do like the Mavic Claw though (on a 34 internal rim), maybe you’ll get to try one of those.
    Gwin’s signature Onza Aquila certainly looks an interesting project, not least inasmuch as he lined up the centre and sideknobs.
    Maybe he can ride like that on pretty much any tire though ‘;~}

  7. MM,
    I see that for “Enduro” there is the Bontrager SE5 Team Issue though.
    It’s based on the G5 apparently.
    shame they made it of harder rubber (if it was going on the front) might make an OK rear for trail bike use I guess.

  8. Noah, thanks to your recommendation I’ve been running a G5, originally 27 x 2.3, now 29×2.5 upfront a few years now. Its fabulous. So calm and confident.
    Pleased I didn’t have to cut the tread and risk ruining a DHR2.
    I enjoyed Kevin’s review of the G5 too.
    thanks for all ‘the good work guys.

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