Zero FX tires
The Zero FX runs one fitment, 90/90-21 54S. It is staggered: a 90 section at the front and a 120 at the back, so the two can never be swapped across axles and the rear goes first.
Every fitment
| Generation | Trim | Wheel | Tire size | Load index | Speed | Construction | Marking | Pressure |
|---|---|---|---|---|---|---|---|---|
| Current | FX | 21in front, 18in rear, spoked | 90/90-21 front, 120/80-18 rear | 54 | S | SL | none | see plate |
Your own placard is the authority. You will find it on the the specifications section of the owner's manual. 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 machine
Dual-sport knobbly sizes, a 90/90-21 front and a 120/80-18 rear on Pirelli Scorpion MT-90 A/T, both S rated for 180km/h. Michelin lists the fitment as tube type, which is what spoked rims usually need.
Michelin's data also carries a narrower 90/90-21 and 110/90-18 pair for early FX models. Zero's 2022 and 2025 manuals both give the 120/80-18 rear, which is the one to match on a recent bike.
No tires listed against this fitment yet. Product specifications are published from each manufacturer's own data and that work is not finished for 90/90-21. Match or exceed every figure in the table above and you cannot go far wrong.
Where these figures come from
- Zero Motorcycles 2025 FX/FXE owner's manual (25 XMX OM NA), Zero FX specifications: Pirelli Scorpion MT-90 A/T 90/90-21 54S front, 120/80-18 62S rear: https://zeromotorcycles.learnupon.com/r/yeso10keqwt54uqysn1hr1tzi1s3xke (linked from https://www.zeromotorcycles.com/owners)
- Zero Motorcycles 2022 FX/FXE/FXS owner's manual, Zero FX specifications: same 90/90-21 54S and 120/80-18 62S: https://zeromotorcycles.learnupon.com/r/23s07v113zsklcqysynhnxtkijslq94 (linked from https://www.zeromotorcycles.com/owners)
- Michelin US motorcycle fitment tool, 2025 Zero FX, 90/90-21 54S front and 120/80-18 62S rear (TT): https://www.michelinman.com/motorcycle/browse-tires/by-vehicle/2025/zero-motorcycles/zero-fx/-/90---90-21-54S-F-TT_120---80-18-62S-R-TT
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 Zero FX take?
- It runs 90/90-21. The exact fitment for your machine is on The specifications section of the owner's manual.
- Can I fit a cheaper tire to a Zero FX?
- Only at 90/90-21 54S 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.