Most online tire pressure guides focus on 22.5-inch highway tires. But a large share of the world’s trucks and buses run on smaller wheels: 17.5-inch and 19.5-inch tires on rigid distribution trucks, vans, buses and trailers. These sizes behave differently. They run at lower pressures, they have narrower load margins and many carry different load indexes depending on whether they are steer, drive or trailer versions. The Goodyear truck tire data book lists them in detail. This guide turns that data into a practical reference for regional fleets, and links to our master truck tire pressure chart for the wider picture.
Why small-wheel tires need their own guide
A 17.5-inch regional tire is not a scaled-down 22.5. It is built for different duty: shorter trips, frequent stops, curb contact and mixed urban and highway use. The load index range is lower, the maximum pressure is lower, and, importantly, trailer versions of the same size often have a much higher rating than the steer or drive versions. That makes the cost of a mix-up high. If a van-trailer tire is fitted to a steer axle because “it is the same size”, the driver may not notice, but the load calculation changes.
17.5-inch sizes: the Goodyear data
Goodyear lists standard-series sizes (8.5R17.5, 9.5R17.5, 10R17.5), 75-series (205, 215, 225 and 235/75R17.5), 70-series (245/70R17.5, 265/70R17.5) and 65-series (205/65R17.5). Selected entries show how the ratings change by pattern and position:
| Size | Pattern | Load index | Max pressure (bar) | Single (kg/axle) | Dual (kg/axle) |
|---|---|---|---|---|---|
| 8.5R17.5 | Regional RHS / RHD | 121/120 | 6.25 | 2,900 | 5,600 |
| 9.5R17.5 | Regional RHS II / RHD II | 129/127 | 7.50 | 3,700 | 7,000 |
| 9.5R17.5 | Regional RHT II | 143/141 | 8.75 | 5,450 | 10,300 |
| 205/75R17.5 | KMAX S / KMAX D | 124/122 | 7.50 | 3,200 | 6,000 |
| 215/75R17.5 | KMAX D | 126/124 | 7.00 | 3,400 | 6,400 |
| 215/75R17.5 | KMAX S HL | 128/126 | 7.50 | 3,600 | 6,800 |
| 215/75R17.5 | KMAX T | 135/133 | 8.50 | 4,360 | 8,240 |
| 225/75R17.5 | KMAX S / D | 129/127 | 7.25 | 3,700 | 7,000 |
| 235/75R17.5 | KMAX S / D | 132/130 | 7.75 | 4,000 | 7,600 |
| 235/75R17.5 | KMAX T | 143/141 | 8.75 | 5,450 | 10,300 |
| 245/70R17.5 | KMAX S / D | 136/134 | 8.50 | 4,480 | 8,480 |
| 245/70R17.5 | KMAX T | 143/141 | 8.75 | 5,450 | 10,300 |
| 265/70R17.5 | KMAX S / D | 139/136 | 8.00 | 4,860 | 8,960 |
| 205/65R17.5 | KMAX T | 129/127 | 9.00 | 3,700 | 7,000 |
Three patterns emerge. First, a trailer tire in the same size carries 22 to 36 percent more than its steer or drive sibling. On the 235/75R17.5, the KMAX T is rated 5,450 kg per axle single against 4,000 kg for the KMAX S/D, a 36 percent difference. Second, the maximum pressure rises from 7.75 bar to 8.75 bar, an extra 1.0 bar (about 14.5 psi). Third, the 205/65R17.5 KMAX T runs at 9.00 bar for 3,700 kg, higher than any other tire in the range, because its low-profile shape needs more pressure to carry the same load.
19.5-inch sizes: the Goodyear data
The 19.5-inch range covers 245/70R19.5, 265/70R19.5 and 285/70R19.5, plus urban and winter patterns:
| Size | Pattern | Load index | Max pressure (bar) | Single (kg/axle) | Dual (kg/axle) |
|---|---|---|---|---|---|
| 245/70R19.5 | KMAX S / KMAX D | 136/134 | 8.25 | 4,480 | 8,480 |
| 245/70R19.5 | KMAX T | 141/140 | 8.50 | 5,150 | 10,000 |
| 265/70R19.5 | KMAX S / D, UrbanMax MCA | 140/138 | 7.75 | 5,000 | 9,440 |
| 265/70R19.5 | Omnitrac MSS II, KMAX T, UltraGrip WTT | 143/141 | 8.50 | 5,450 | 10,300 |
| 285/70R19.5 | standard | 146/144 | 9.00 | 6,000 | 11,200 |
On the 265/70R19.5, the standard steer and drive tires are rated 140/138 at 7.75 bar, while the trailer and mixed-service patterns are 143/141 at 8.50 bar. The 0.75 bar difference (about 11 psi) is the price of 450 kg more per axle. Note how the urban patterns UrbanMax MCA sit with the steer and drive pattern, not with the trailer pattern, because urban buses and distribution trucks have weight limits close to those of the steer and drive rating.
The load ladder for these sizes
Goodyear’s load capacity table tells you what happens at lower pressures. Here are single-fitment capacities per axle for three load indexes common in small-wheel tires:
| Pressure (bar) | LI 124 (205/75R17.5) | LI 129 (225/75R17.5) | LI 134 (245/70R17.5 steer) |
|---|---|---|---|
| 5.00 | 2,310 | 2,680 | 2,920 |
| 6.00 | 2,680 | 3,100 | 3,370 |
| 6.50 | 2,850 | 3,300 | 3,600 |
| 7.00 | 3,030 | 3,500 | 3,820 |
| 7.25 | 3,110 | 3,600 | 3,920 |
| 7.50 | 3,200 | 3,700 | 4,030 |
| 8.00 | — | — | 4,240 |
The tables show the same behavior as the 22.5-inch sizes. Capacity at 5.00 bar is about 69 to 73 percent of capacity at the maximum. A small-wheel tire has a smaller margin for error, so keeping it close to its working pressure matters more. A 205/75R17.5 at 6.00 bar can carry 2,680 kg per axle, 84 percent of its 3,200 kg rating, and many urban delivery vans operate in that range.
How to choose pressure for a distribution truck
- Weigh the loaded steer and drive axles. Do not use the vehicle manufacturer’s gross axle rating unless that is truly the load.
- Read the load index on the tire and look up its row in the ladder.
- Pick the lowest pressure whose capacity exceeds the axle weight by at least 5 percent.
- Consider the duty cycle. Heavy stop-start urban work generates more heat, so use the higher end of your range.
- Fit the trailer-rated tire only to trailer positions.
This is the same method described in our Goodyear load and inflation table article for 22.5 sizes, adjusted for smaller wheels. For US customers, the equivalent psi charts for common sizes are collected in the Goodyear truck tire pressure chart.
Special cases: winter, urban and coach patterns
Winter patterns such as UltraGrip WTT and coach patterns such as Marathon appear in the same size lines, usually with the highest load index in the family. Winter tires also gain from slightly lower pressure on snow, but not below the load requirement. For urban buses, the UrbanMax MCA 19.5 carries a rating that fits low-floor bus axle limits, and pressure should be checked more often because curb contact is frequent. Rotation and wear patterns are covered in our guide to steer tire wear patterns.
Common errors on small wheels
- Swapping trailer tires onto steer positions to use up stock. The load index is not the problem; the pattern and construction are.
- Assuming every 17.5 has the same maximum pressure. Maximum varies from 6.25 to 9.00 bar between sizes.
- Under-inflating to improve ride on empty vans, which reduces the tire’s margin when the van is loaded.
- Forgetting dual spacing. The data book lists a minimum dual spacing for each size, from 231 mm on 205/75R17.5 to 318 mm on 285/70R19.5.
- Ignoring rim width. A 17.5 tire has a recommended and permitted rim range, and a rim that is too narrow stresses the bead.
Cost implications
Small-wheel fleets often run lighter tires that wear faster in urban conditions. A pressure program that cuts irregular wear and shoulder damage improves both tread life and casing life for retreading. The long-term effect on total cost of ownership is as significant as on long-haul fleets, even though the absolute numbers per tire are smaller.
Quick selection guide for small-wheel fleets
- Urban delivery van or rigid up to 12 t: 215/75R17.5 or 225/75R17.5 in KMAX S/D versions at 6.0 to 7.0 bar, depending on axle weight.
- Distribution truck 12 to 18 t: 235/75R17.5 or 245/70R17.5 at 7.0 to 8.5 bar for steer and drive; trailer versions where a trailer is fitted.
- Light trailers and caravans for goods: 205/65R17.5 KMAX T at up to 9.00 bar.
- Buses and coaches on 19.5: 265/70R19.5 urban patterns at 7.75 bar maximum, checked weekly because of curb contact.
- Mixed fleets: label each tire position with the pattern and index, so that a trailer-rated tire is never fitted as a steer by mistake.
FAQ
Do 17.5 tires need higher pressure than 22.5 tires?
Not necessarily. Their maximums are generally lower (6.25 to 9.00 bar versus 8.50 to 9.00 bar), but low-profile sizes such as 205/65R17.5 can need 9.00 bar.
What does the HL suffix mean on a KMAX S?
High load. The 215/75R17.5 KMAX S HL is rated 128/126 against 126/124 for the standard tire, and runs at 7.50 bar instead of 7.00 bar.
Why do trailer tires have higher ratings?
A trailer axle does not steer or drive, so its tire can be built with a different casing and tread to carry load, and often runs at a higher pressure.
Key takeaways
Small-wheel tires are governed by the same physics as 22.5-inch tires, but the margins are tighter and the differences between positions are bigger. Read the load index, use the correct position, set pressure from axle weight, and check regularly. Continue with our pressure management hub for the rest of the cluster.
