Jamis Trail X I am new to cycling. I recently got Jamis Trail X with 27.5x2.25" tires. This is a bit hard (not easier) on city roads. I was thinking about replacing the tires with max 1.5" wide hybrid or road tires. I researched a little bit and learned that 27.5 is not actually 27.5 rim. It's 26.5" or 584mm in diameter. My question is, can I replace these tires with any 584 or 650b tires?

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    What makes you think that narrower tires would be less "hard on city roads"? Have you tried lowering the tire pressure in your existing tires? Commented Aug 30, 2018 at 7:36
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    @GrigoryRechistov Irfan might mean "hard" as in "not easy", rather than "hard" as in "not soft". Commented Aug 30, 2018 at 8:58
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    I'd try less knobby tires since knobs cause more than resistance than width (to my mind)
    – k102
    Commented Aug 30, 2018 at 10:58
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    I disagree with @AndyP - I run 35mm almost-slicks and the difference between those and the gravel/road tyres of the same width (that came with the bike) is noticeable both in the legs and the clock
    – Chris H
    Commented Aug 30, 2018 at 16:19
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    Once again, there are huge differences inside tire categories, so much that a fast XC knobby may have lower rolling resistance than poor road slick.
    – ojs
    Commented Aug 30, 2018 at 20:45

2 Answers 2


Yes, you can replace your 27.5 tires with 650b tires as long as they fit your current rim. You need to get the internal rim width (B on the next picture) and use the following table to see if you can use the tire that you want on that specific rim. As long as the combination of internal width (in mm) and tire section width (in mm as well), then you should be able to use a narrower tire. Keep in mind that the table is fairly conservative, but when it comes to safety, it's always better to do things properly to avoid personal injury.

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Rim tire chart


My question is, can I replace these tires with any 584 or 650b tires?

as long as it fits on your rim, yes. fitting on your rim means that your new tire has to be wide enough for your rim. if this fits, so every 584 tire will be fine. how wide is your rim?

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