I am looking at purchasing a used Specialized Rockhopper with an XL frame. Everything is exactly what I'm looking for on this bike with one exception...the tire size. It currently has 22" tires/rims and I'm curios if I can upgrade those to 26" tires without having them rub against the frame?

Thanks in advance! msindle

  • 2
    Basically, a "22-inch" wheel is unheard of, so either the seller is talking about 22-inch diameter rims with 26" tires as Emyr states, or 2.2 inch wide tires as Batman states. The standard tire sizes are 20, 24, 26, 27, and 700c (28). Commented Nov 6, 2014 at 12:04

2 Answers 2


MTB rims branded 26" measure 559mm to the bead seat, which converts to... 22 inches.

You already have 26" wheels.

They're called 26" because when you put an ordinary 2" wide tyre on them, the outside diameter is about 26".

  • 1
    This seems more plausible than my answer, but it seems weird that someone would have sold the bike saying ISO 559 or actually measured the diameter instead of just reading the tire size off the tire sidewall.
    – Batman
    Commented Nov 6, 2014 at 15:00
  • You guys nailed it, I dont know what number he was giving me but when I asked him to double check it he came back with 26". Thanks everyone!
    – msindle
    Commented Nov 7, 2014 at 1:20

I doubt it has 22" tires/rims - more likely the rims are 26" or 29" (in which case it should be listed as a Rockhopper 29) and the tires are 2.2" (and the seller forgot the decimal point).

22 inch wheels on bicycles are pretty much a botique item for BMX, and certainly wouldn't be found on an adult sized bicycle (and the kids bikes from Specialized are sold as the Hotrock in sizes 12, 16, 20, 24). For general reference, there are some juvenile bikes with 22" tires, but the Rockhopper is not one of them.

Also, in general, switching the rim size is difficult with rim brakes (since the rim brakes have to line up - one special case is 27" to 700c which requires a 4mm brake adjustment), but sometimes doable with disc brakes (700c -> 650b is not uncommon) provided the setup clears. Its generally a ymmv/you're on your own option.

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