Trek Rail+ tires
The Trek Rail+ runs 61-584 and 61-622 in ETRTO sizing, the width in millimetres followed by the rim bead seat diameter. It is staggered: a 61 section at the front and a 61 at the back, so the two can never be swapped across axles and the rear goes first.
Every fitment
| Generation | Trim | Wheel | Tire size | Inch size |
|---|---|---|---|---|
| Current | Rail+ 5 Gen 5, sizes M-XL (Bontrager Gunnison Elite XR, mixed wheel) | 29in front / 27.5in rear | 61-622 front, 61-584 rear | 29x2.40 |
| Current | Rail+ 5 Gen 5, size S (Bontrager Gunnison Elite XR) | 27.5in | 61-584 | 27.5x2.40 |
Your own placard is the authority. You will find it on the printed on the tire sidewall, next to the pressure range. Where it disagrees with this page, it wins. Match or exceed the size, load index, speed rating and construction class it gives, and use its pressure figure rather than anything printed on the tire.
What changes on this bike
The Gen 5 Rail+ is a mullet on M to XL frames, a 29in front and 27.5in rear, while the size S frame runs 27.5in at both ends; order replacements by frame size, not by model name.
Trek states a frame limit of 27.5x2.60 at the rear, so there is room to go wider than the stock 2.40 but not to a 2.8 plus tire.
The stock Gunnison Elite XR is a wire-bead, 60 tpi trail casing; Trek caps the Rail+ at 136 kg all-up with an 800 Wh battery aboard, so heavier riders on rocky ground may want a tougher casing at the same size.
No tires listed against this fitment yet. Product specifications are published from each manufacturer's own data and that work is not finished for 61-622. Match or exceed every figure in the table above and you cannot go far wrong.
Where these figures come from
- Trek GB spec, Rail+ 5 Gen 5 (Tyre: Bontrager Gunnison Elite XR ... 27.5x2.40" sizes S-XL; 29x2.40" sizes M-XL; Max tyre size Frame: 27.5x2.60"): https://www.trekbikes.com/gb/en_GB/bikes/mountain-bikes/electric-mountain-bikes/rail/f/F344/rail+-5-gen-5/48458/5329013
- Triton Cycles listing, Rail+ 5 Gen 5 2025 (same Gunnison Elite XR 27.5x2.40/29x2.40 split and 27.5x2.60 frame limit): https://www.tritoncycles.co.uk/full-suspension-c325/integrated-c329/rail-5-gen-5-electric-mountain-bike-2025-p46767
- usedbikes-ob listing, Bontrager Gunnison Elite XR TLR 29 x 2.4 (ETRTO: 61-622): https://www.usedbikes-ob.de/en/products/bontrager-gunnison-elite-xr-tlr-29-x-2-4-mtb-reifen
- usedbikes-ob listing, Bontrager Gunnison Elite XR TLR 27.5 x 2.4 (ETRTO: 61-584): https://www.usedbikes-ob.de/en/products/bontrager-gunnison-elite-xr-tlr-27-5-x-2-4-mtb-reifen
Including the manufacturer's own published figure. Neither source is standing next to your vehicle, which is why the placard still wins.
Common questions
- What size tires does the Trek Rail+ take?
- It runs 61-584 and 61-622. The exact fitment for your bike is on Printed on the tire sidewall, next to the pressure range.
- Can I fit a cheaper tire to a Trek Rail+?
- Only at 61-622 or better. That is the figure to hold: a tire below the load index, the speed rating or the construction class is not a cheaper one, it is the wrong one.