KTM 390 Adventure Tyres: X and R Sizes and How to Choose
Tyres change how an adventure bike feels more than almost any other part, and on the 2025-on KTM 390 Adventure there is an extra step: the X and the R use completely different wheel sizes. Order by bike name and you can easily end up with tyres that will not fit. This guide gives you the sizes, explains the tyre types, and helps you pick for how you actually ride.
Quick answer
- Adventure R: spoked 21-inch front and 18-inch rear. Listed sizes 90/90-21 and 140/80-18.
- Adventure X: cast 19-inch front and 17-inch rear. Listed sizes 100/90-19 and 130/80-17.
- Always check the sidewall of your current tyres before ordering. Sizes can vary by market and model year.
- Most riders: a 60/40 or 50/50 adventure tyre. Mostly road: road-biased. Serious trails on the R: knobbly.
Sizes for each variant
| Variant | Front | Rear | Wheels |
|---|---|---|---|
| 390 Adventure R (2025+) | 90/90-21 (listed) | 140/80-18 (listed) | Spoked |
| 390 Adventure X (2025+) | 100/90-19 (listed) | 130/80-17 (listed) | Cast |
These sizes come from spec databases and dealer listings rather than a KTM spec sheet we could open, so treat them as a starting point. The definitive answer is printed on the sidewall of the tyres on your bike, and in your owner’s manual.
Launch coverage reported Mitas Enduro Trail E-07+ tyres as original equipment on both variants in some markets, with other brands fitted in others.
Why the R and X need different tyres
A 21-inch front wheel is the classic off-road size. It rolls over ruts and rocks more easily and has the widest choice of knobbly tyres. An 18-inch rear is also a common off-road size. The X’s 19/17 combination is more road-oriented: it turns in more readily on tarmac and opens up a wide choice of road-biased adventure tyres.
The four types of adventure tyre
Road-biased (roughly 90/10 to 80/20)
Mostly tarmac with occasional gravel. Longest life on the road, quietest, best wet grip on tarmac, weakest in mud. A good match for X owners who rarely leave the road.
60/40 adventure
The do-it-all choice for most owners. Mitas describes its E-07+ as a 60% on-road, 40% off-road tyre. Good on tarmac, confident on gravel and dry trails.
50/50 adventure
More aggressive blocks for more off-road grip, at the cost of some road manners and life. Mitas describes the E-07 (without the plus) as a true 50/50 tyre.
Knobbly (off-road focused)
For serious trail riding on the R. Excellent grip in loose terrain and mud; noisier and quicker to wear on tarmac.
How to choose
| Your riding | Tyre type | Variant fit |
|---|---|---|
| Commuting and road trips, some gravel | Road-biased | Best match for the X |
| Mixed road and gravel, occasional trail | 60/40 | X or R |
| Regular trails, travel on dirt | 50/50 | R preferred |
| Technical off-road, mud | Knobbly | R |
Tubes, tubeless and pressures
Whether your rims take tubeless tyres decides how you fix a puncture. Tubeless tyres on rims designed for them can be plugged at the roadside. Tube-type setups need tyre levers, a spare tube and more time. Check your owner’s manual for what your variant uses before you buy, because a tubeless tyre fitted to a tube-type rim needs a tube.
Pressures make as much difference as tread. Use the pressures in your owner’s manual for road riding. Some riders drop pressure for loose terrain; if you do, go back up before riding on tarmac, and never go below what is safe for your tyre and rim type.
Carry the right puncture kit
- Tubeless: plug kit, CO2 cartridges or a small pump, pressure gauge.
- Tube-type: two or three tyre levers, a spare tube (a 21-inch front tube can often get you home in the rear in an emergency), patches, pump, bead breaker if you ride remote areas.
Common mistakes
- Ordering by bike name. “390 Adventure tyres” can mean four different sizes across two generations and two variants.
- Going too aggressive. Knobbly tyres on a bike that lives on tarmac wear out quickly and feel vague on the road.
- Ignoring the speed and load rating. Match or exceed what is printed on your current tyres.
Breaking in new tyres
New tyres have a slippery surface from manufacturing. For the first 100 km or so, ride gently: smooth inputs, no hard braking or aggressive lean, and extra care in the wet. Check pressures after fitting, because a newly mounted tyre can lose a little pressure as the bead seats.
How fast will they wear?
Wear depends on tyre type, surface and load more than anything else. Knobbly tyres wear fast on tarmac; road-biased tyres last longest. A loaded bike wears the rear faster than the front. Check tread depth regularly and know your local legal minimum, which varies between countries.
Signs it is time to replace
- Tread at or near the legal minimum or the wear indicators.
- Squared-off profile on the rear from motorway miles, which makes the bike reluctant to lean.
- Cracks in the sidewall or between blocks, often on older tyres even with tread left.
- Chunks missing from blocks after hard off-road use.
- Tyres several years old, even if tread remains. Rubber hardens with age; check the date code on the sidewall.
Changing tyres yourself
Many adventure riders learn to change their own tyres, especially for remote trips. You need tyre levers, rim protectors, a bead breaker or a technique for breaking the bead, lubricant, a pump and a pressure gauge. Practise at home before you need to do it at the side of a trail. Spoked wheels on the R may also use a rim lock, which needs loosening before the tyre comes off.
Three riders, three tyre choices
X owner, mostly road
Choose a road-biased adventure tyre in the X’s 19/17 sizes. You get longer life, better wet-road grip and quieter running, and gravel roads are still fine.
R owner, mixed riding
A 60/40 tyre in the R’s 21/18 sizes is the all-rounder. It handles the ride to the trail and the trail itself.
R owner, trail days
A 50/50 or knobbly tyre, accepting faster wear on tarmac. Some riders keep a second set of tyres for trail trips.
Glossary
- Load index and speed rating: the numbers and letter after the size (for example 54V). Match or exceed the originals.
- Radial vs bias-ply: different internal construction. Fit what your manual specifies.
- Rim lock: a clamp that stops the tyre slipping on the rim at low pressure, common on off-road spoked wheels.
- Date code: four digits on the sidewall showing the week and year of manufacture.
Buying checklist
- Read the size, load index and speed rating from your current tyres.
- Decide on the road/off-road split honestly.
- Check the date code on new tyres when they arrive.
- Book fitting or plan to fit them yourself with the right tools.
Frequently asked questions
What size tyres does the 2025 KTM 390 Adventure R use?
Spec listings give 90/90-21 front and 140/80-18 rear on spoked wheels. Check the sidewall of your own tyres to confirm.
What size tyres does the 2025 KTM 390 Adventure X use?
Listings give 100/90-19 front and 130/80-17 rear on cast wheels. Check the sidewall of your own tyres to confirm.
Can I use the same tyres on the X and the R?
No. The wheel sizes are different, so the tyres are not interchangeable.
What is a good all-round tyre for the 390 Adventure?
For most riders a 60/40 adventure tyre is the best balance of road manners and gravel grip. Mitas, for example, describes its E-07+ as 60% on-road and 40% off-road.
Sources
- 1000PS, KTM 390 Adventure R 2025 vs 2021 (tyre sizes, tank): 1000ps.com
- TRF, 2025 KTM 390 Adventure R and X model reveal (wheels, OE tyres): trf.org.uk
- BikeBD, KTM 390 Adventure R 2025 specifications: bikebd.com
- Adventure Motorcycle, Mitas E-07 release (tyre balance descriptions): adventuremotorcycle.com
