FAQ: Fat Tires & Wheels
How wide will X model tire be on X size rim?
- It can be difficult to know what tire and rim combinations will fit various frames and forks. The links below provide data for the resulting width of various tire model and rim size combinations.
- For reference when using the links above, rim widths for various popular models are listed below, from lightest to heaviest:
|Rim Data||Width (mm)||Weight (g)||Material|
|HED Big Deal||85||445||Carbon|
- When comparing tire weights, be sure to match up parameters exactly. Some tires of the same model name are offered in two TPI grades which will be different weights. For example, several particular models come in either 27 TPI (threads per inch) or 120 TPI. The 27 TPI uses fewer internal threads of larger diameter, making the sidewall thicker and more cut-resistant. As a result it uses more rubber and is the heavier option. The 120TPI has more internal threads of finer diameter, making the sidewall more supple (less rolling resistance at low pressures). As a result the wall is thinner and less rubber is used, so the tire is lighter.
- Keep in mind that even tires of the same brand and model will vary by weight. The molding process is such that the weight of identically-labeled tires can vary by 5% or more.
- Here is a handy listing of actual weights reported by tire owners: Tire Weights for Fat-Bikes
What's the deal with front and rear disc spacing?
- There are two standards for where the disc rotor mounts on the front hub. "Front" spaced hubs put the rotor about 5mm farther from the hub center than "rear" spaced hubs.
- A rear-spaced hub CAN be adapted to a front-spaced fork with an adapter, which basically puts a 5mm shim between the rotor and its mount. Problem Solvers makes one, and there are various DIY solutions out there as well. Keep in mind that using a spacer usually requires longer bolts.
- A front-spaced hub CANNOT be adapted to fit a REAR-spaced fork. At least not by adapting the hub or rotor. People have found ways to modify the fork caliper mount, but it involves machining a custom bracket.
- Some helpful links on the topic: