I'm slowly upgrading things on my 26" Scott Aspect, I now need/want to get some new tyres.

I think the tyres on there at the moment are 26 x 2.1

Scott Aspect

Firstly, is that 2.1 Inches? - what are these things even measured in!?

Secondly, I'd like to maybe go for a slightly wider tyre, say 2.25, how and what should I measure to ensure there will be clearance?

Thirdly, does anyone have experience upgrading tyres on these kind of stock MTBs - whats the limit size wise, should I just go for like for like?

Any tyre recommendations also welcome.

  • Easiest and least likely to cause grief option - like for like. Nearly as easy - take bike to LBS and buy from them with right of return if it does not fit. Mostly like to cause grief - buying cheap off the net. In the middle must be a "beg, steal or borrow" a tire (ideally fitted to a wheel) from someone to try.
    – mattnz
    Feb 1, 2017 at 0:56
  • Look at the tires that are on it. They have markings on the side that tell you what size they are. They will have both an inch size (eg, 26 x 2.1) and an "ISO" size (eg, 53-599). The first number in the ISO size is the width in millimeters. Feb 1, 2017 at 3:57
  • The width is the sidewall-to-sidewall dimension when the tire is fully inflated on an "average width" rim, so it's a bit vague. Plus, it doesn't account for the added width due to the tread on a mountain tire with lugs. To judge how large a tire you can use, measure clearances at the sides and "top" of a tire of known size, and then understand that a tire that is supposedly 0.2 inches wider will be about 0.1 inch wider on each side but 0.2 inches taller on "top". But that doesn't account for any difference in tread knobbiness, etc. Feb 1, 2017 at 4:01

1 Answer 1


We can't recommend a specific tire, also there are very similar questions already on this site but i will do my best to answer your questions.

First: it is indeed inches, although not all tire are measured that way, it is rather common for MTB tires to be listed as such. Other tires, say road tires are listed in a millimeter* sizing such as 700 x 40*

Secondly: Clearance measurement will be inside the fork/frame triangle, both on the side and the top near the crown of the fork, and between the stays on the rear. It's hard to say from the image but it looks like 2.25" tires would be doable but not much larger, one issue to keep in mind is that if the tire is extremely close to the fork but doesn't rub, it may do so under a big hit or heavy load.

Third: The size limit is decided by two things, inner rim width and frame clearance. It is likely that 2.25" would be acceptable as a 2.1" tire is compatible with inner rim widths from 19 to about 28mm widths. 2.25" falls very near to this, and i would imagine the rims that came on that bike are right around 19mm inner width.

So i wouldn't go any larger than a 2.25" i think it would likely work, but cant tell you for sure without seeing more or knowing more.

Tire choice should be based on you budget, and the type of conditions you most often ride in, whether it be on a trail or tarmac.

I tried to keep this answer short, but their are a lot of more in depth explanations available if you search the site.

Hope this helps

  • 1
    Should add that 2.1 and 2.25 are nominal values. Just because one 2.25 fits does not mean another will.
    – mattnz
    Feb 1, 2017 at 0:52
  • Thanks this was helpful, I've ordered some well priced knobbly conti 2.2's
    – Wez
    Feb 13, 2017 at 15:33

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