Bontrager XR4 27.5x2.35in MTB tire review$75.00

Outstanding and affordable mountain bike rubber

BikeRadar score4.5/5

These flagship tires from Trek’s component sub-brand are top performers in a wide range of trail conditions.

Once you’ve wrestled the relatively tight beads onto the rim, the XR4 (and all of Bontrager’s other tires) bang into place very positively and securely once you get track-pumping.

Carcass size is ample for a 2.35in tire and it’s taller than most so there’s a good depth of air cushioning between rim and trail. The Inner Strength sidewall protection doesn’t feel particularly tough or stable when you’re fitting it, but the XR4 handles low pressures really well with no crumpling or roll even when you’re turning in very aggressively on high-grip rock surfaces.

We've scored them highly in the past, but returning to these tires the overall performance of the wide-spaced, but sloped and siped tread was still a revelation.

Whether we were flicking from berm to berm, carving fresh loam or flat-out across wet, off-camber root spreads, the XR4s stayed outstandingly surefooted and predictable, often letting us turn in tighter mid-corner than we dared hope on entry. They roll quickly enough to leave on all year and wear life is good, confirming their performance credentials.

[Editor’s note: Bontrager recently overhauled the XR4 with a new tread pattern. Stay tuned for an updated review.]

Guy Kesteven

Freelance Writer, UK
Guy started filling his brain with cycle stats and steaming up bike shop windows back in 1980. He worked the other side of those windows from '89 while getting a degree in “describing broken things covered in mud" (archaeology). Dug historical holes in the ground through the early '90s, then became a pro bike tester in '97. Guy has ridden thousands of bikes and even more components the world over since then and can remember them all in vivid, haunting detail. Can't remember where the car keys are, though.
  • Age: 45
  • Height: 180cm / 5' 11"
  • Weight: 68kg / 150lb
  • Waist: 76cm / 30in
  • Chest: 91cm / 36in
  • Discipline: Strict sadomasochist
  • Preferred Terrain: Technical off-piste singletrack and twisted back roads. Up, down, along — so long as it's faster than the last time he did it he's happy.
  • Current Bikes: An ever changing herd of test machines from Tri bikes to fat bikes and everything in between.
  • Dream Bike: His Nicolai Helius AM custom tandem
  • Beer of Choice: Theakston's Old Peculier (not Peculiar)
  • Location: Yorkshire, UK

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