From time to time I get questions on the site in the form of comments, or e-mails that I like to address with a post. Today’s question is about putting road tires on 29 inch rims. Can you do it? Are they compatible? What sizes are recommended? There are a lot of confusing answers floating around out there, so let’s take a look and see if we can figure this one out………..

Easton XC One wheels These Easton single speed wheels are for 29″ers, but have a narrow-ish rim width suitable for road rubber.

The Fit Question- Diameter: Okay, let’ get this cleared up right away. It is commonly thought that 29″er wheels are a different diameter than everything else out there. I suppose the moniker, “29”er” is to blame, but make no mistake, it is 700c. 700c, or ISO 622mm is the rim diameter for both 29″ers and road racing bikes. In fact, the ISO 622 is a very common rim diameter that is used on a wide spectrum of bicycles. The term- 29″er- refers to the total diameter of the tire and wheel together, with the rim size being ISO 622mm, or as it is commonly referred to as, 700c. Okay? That part is the simple part.

Salsa Gordo rims
A wide 700c rim, like these 35mm wide Salsa Gordo rims, are not suited for road going rubber unless it is 50mm wide or wider.

The Fit Question- Rim Width: Now here is where things get a little dicey. To make it simple, you will need to match your tire width to your rim width after you determine that the diameters are compatible. So, what does that mean exactly? Let’s assume we are using only 700c/ISO 622 rims and tires to keep that part of the equation constant.

A typical road tire will measure around 23mm to 28mm wide. To support the tire properly, and to allow it to function in a way that is safe, the rim the tire is mounted to must be within a certain range. Too narrow and the tire will “roll” or squirm in corners, and too wide will cause the height of the casing to be to low in relatioship to the rim walls. This will encourage tire blow offs and more pinch flat problems, not to mention a higher likelyhood of rim damage. To properly support a tire in this width range, I would recommend any rim that was 19mm wide to no more than 24mm wide. Any wider and you will start to see a drastic increase in the problems I detailed above.

Some 29″er wheels have rims in this range. The Easton set, pictured above, has a 23.5mm wide rim, which should work fine with road tires in our 23mm to 28mm range. What about wider 29″er rims? Well, you would by necessity start to have to look at a wider tire.

A 24mm to 28mm wide rim, which covers a lot of 29″er rims, would probably work best with tires 30 to 35mm wide, the wider rims needing the wider tires in this range. Something on the order of the Gordo (pictured above) would require a much larger tire, say at least a 2.0 inch tire and on up.

I suppose some folks will say that these recommendations are too conservative, but in my mind, it is best to match proper components for the job at hand. (Of course, it could be said that running narrow tires on mountain bike rims is not matching up your components properly in the first place!) Putting a 25mm tire on a 28mm wide rim is not fitting that ideal in my mind, and I would not recommend doing that.

Conclusion: So, the answer to our question is a qualified “yes” with the qualification being that your diameters, while matching for rim and tire, are not the sole determination of whether certain combinations will work. Width of the tire and rim must match within a reasonable range also, or you will be inviting trouble.