Do 27.5" wheels fit a 29" mtb? The 29er is with disc brakes. If they fit, is there any other problem

  • 1
    Refer to Sheldon. A 27.5" inch tire has a 584 mm rim, the same as 26 x 1 1/2 (650B). 29" tires have a 622 mm rim, the same as 700C road tires. A 27.5" tire will not fit on a 29" rim. Commented Nov 12, 2016 at 19:13
  • 1
    You'll need the same size rotors on both as well.
    – Móż
    Commented Nov 12, 2016 at 22:08
  • 4
    I believe the question was about wheels, not tires.
    – ojs
    Commented Nov 12, 2016 at 22:20

3 Answers 3


They fit, in the sense that you can install them in the frame (if the axles are correct, hub width is correct, etc). The problems are:

  • The bike stands a few centimeters closer to ground. Which means less ground clearance for obstacles and cornering. Frames designed for smaller wheels take this into account
  • Less trail at front, which affects steering
  • Lower gearing because of smaller wheel radius
  • You still have the long rear fork of frame designed for 29" wheels and the associated weight distribution and clumsiness.
  • You forgot to mention the need to obtain new wheels. Commented Nov 12, 2016 at 19:14
  • 3
    "If the axles are correct" - needs highlight, few people have any idea how many axle types and widths there are these days.
    – mattnz
    Commented Nov 12, 2016 at 20:15

Yes and no. Installing them with normal sized (2-2.3") tires will result in that much less ground and pedal clearance as well as tweak the geometry of the bike. So that's not likely to work out well.

However, 27.5+ tires (2.8-3") get the tire outside diameter into the ballpark of normal 29", so the bike's geometry and clearances still work as intended. For example, there are now bikes intended to be swappable between the two, and conversions have become common on older bikes. Many 29er frames and forks have the clearance to take a 27.5+, although it's something you'd have to experiment with yourself.

  • It shouldn't change the bikes geometry at all. The smaller tires don't cause the frame to be tilted forward or back, just down a little bit.
    – Jonah
    Commented Feb 3 at 23:05
  • @Jonah The ground is closer to the axle. It changes the trail. Commented Feb 3 at 23:53

You can install almost any smaller wheels so long as the axles aren't too wide, I rode this 29'er bike around for a few days while trying to get my front rim fixed. But brakes would be misaligned if they're rim brakes, and since the bike is not designed for other sizes it's not ideal. But it will work.


  • Why does rim size change alignment of brake disks?
    – ojs
    Commented Nov 13, 2016 at 12:01
  • if you look at my picture, the brakes are not useable at all, they're nowhere near the rim, same with any smaller rim and these sorts of brakes, disk brakes would be better.
    – Kilisi
    Commented Nov 13, 2016 at 12:49
  • The question explicitly mentions disk brakes.
    – ojs
    Commented Nov 13, 2016 at 12:59
  • @ojs thanks, I can also read, it mentions disk brakes on the 29'er, not on the replacement wheels
    – Kilisi
    Commented Nov 13, 2016 at 13:01

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