35mm rims are normally combined with 2.8″+ tires. Nonetheless, a 2.4″ tire can still be installed on a 35mm rim. In some cases, the fit could be a bit tight, and the user may have to use “excessive force” to mount the tire.
Understanding Rim Width
A rim has two widths – internal and external. The external width is the distance from one outer wall to the other.
The internal rim width is the distance between the closest inner parts of the rim. (Those would be the so-called bead hooks as shown in the image below.)
In most cases, the indicated rim width is the inner one. The greater the inner width, the larger the tire can be. Respectively, rims with narrow inner widths are used with narrower tires.
The Downsides of Using 2.4″ Tires On 35mm Rims
- Installation could be difficult
In some cases, a 2.4″ tire could be a bit too narrow for a 35mm rim, and the user may experience some difficulty putting it on. That said, it’s perfectly doable.
- Flat Shape
An excessively wide rim stretches the tire sideways and makes the contact patch flatter than usual. This effect is known as “squaring the tire” as the tire’s side walls get closer to a 90-degree angle.
As a result, the tire assumes a shape that could hurt the expected performance of the treads. The degree to which this effect will manifest depends on the tire and rim models.
FAQ: Is there a formula for calculating the ideal rim width for a tire?
The general rule is to multiply the inner rim width by 2 to 2.3. For example, if the inner rim width is 35mm, this formula gives us a range between 70 and 80.5mm or 2.75 to 3.2 inches.
A tire in that range will be ideal for a rim of such inner width. That said, some deviations are allowed without facing degraded performance.
It’s also worth noting that tire sizes aren’t incredibly accurate. For example, a 2.4″ model from one brand could be narrower or wider than that of another.
Based on the formula above, we get the following table for rim and tire compatibility:
| Inner Rim Width | Tire Width |
| 19mm | 1.5″-1.75″ |
| 25mm | 1.95″-2.3″ |
| 30mm | 2.35″-2.7″ |
| 35mm | 2.75″-3.2″ |
| 40mm | 3.2″-3.7″ |
Summary: What You Need To Know
- 2.4″ tires can offer satisfactory performance when installed on rims with a 35mm internal width. However, it’s still recommended to go for a narrower rim (25-30mm) or a wider tire to avoid “squaring out” the 2.4″ unit.
The deformation could hurt the grip of the tire. The extent of this effect depends on the tire and rim models.
