Front and rear tire sizes on an XC bike

There is some good info on here about tire choice for XC racing and I interested in hearing everyone’s experience with running mismatched tire sizes on their XC bikes.

2.25 rear and 2.35 front seems to be pretty common, would a 2.1 and 2.35 combo on a XC bike that also sees moderate trail bike terrain be weird?

I think the tire/rim combo I have in mind will mount up slightly oversized and looking to the 2.1 to give better mud clearance in the rear.

Part of that depends on the internal width of your rims for sure, but from a pure performance perspective, I personally wouldn’t want to run something as narrow as a 2.1 unless I was riding gravel or something similar to Leadville-type terrain, and unless I had internal rim width less than ~23mm.

That said, I’d run whatever tire I needed to avoid a broken or damaged frame from tire clearance issues, hehe.

FWIW, I like matching my tire sizes and tread patterns front to rear for typical XC riding. Having similar handling characteristics and tendencies front to read makes me feel more confident in what my bike is going to do. I’m still not sure what I’ll use most frequently next year between the 2.4 and 2.25, but in almost every case I’ll be riding Aspens.

When it comes to heavier duty trail / enduro riding, I like treating each tire uniquely for different purposes. In those circumstances, breaking traction strategically is a regular occurrence for cornering and line selection, so I like my back end to break loose easily and my front to still be glued to the ground. That said, I still try to find 2 tires that behave similarly when they are leaned over and my traction depends on the side knobs.

My go-to for gnarly stuff is a 2.5 Assegai front and a 2.5 DHF rear. Assegai simply does not want to let go and the DHF out back adds a fun playful element with that wide empty channel between the center and side knobs.

For mellower trails on my trail bike I like 2.4 Rekons front and rear. Grip is still predictable, but the rolling resistance and weight is reduced a ton.


@Jonathan thank you for the input!

I dug around for some more info and it looks like I should be able to mount up the 2.25 tire with good clearance. Seems like less of a mullet :grin:

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