On a tire sidewall, 126/123R means a higher single load index, a lower dual load index, and an R speed symbol.
That small code near the end of a tire size string tells you a lot in one shot. It gives the tire’s load indexes and speed symbol, which is why it matters so much on pickups, vans, work trucks, and dually setups.
If you spot 126/123R on a tire, you’re not reading a random factory stamp. You’re reading the tire’s service description. That tells you how much weight the tire is rated to carry, whether that rating changes in dual fitment, and the speed class tied to that load rating.
What Does 126/123R Mean On A Tire? Sidewall Breakdown
Read from left to right, the code breaks into three parts. The first number, 126, is the load index when the tire is mounted by itself on one side of an axle. The second number, 123, is the load index when that same tire is used in a dual setup, where two tires sit side by side on one end of the axle. The letter R at the end is the speed symbol.
That slash is the part many people miss. It does not mean “between 126 and 123.” It means the tire carries one rating in single fitment and a lower rating in dual fitment. That’s common on LT tires and other heavy-duty applications.
What 126 Means
Load index 126 converts to 1,700 kg, or 3,748 lb, per tire on the standard load chart. Use that figure when the tire is mounted alone on each side of the axle, like a single-rear-wheel pickup or van.
What 123 Means
Load index 123 converts to 1,550 kg, or 3,418 lb, per tire. That lower figure applies when the tire is used in dual fitment. In a dually setup, each tire runs beside another tire on the same axle end, so the per-tire rating drops.
What R Means
The R at the end of 126/123R is the speed symbol, not the radial-construction letter that appears earlier in the tire size. On Goodyear’s speed rating chart, R means the tire is rated up to 106 mph under its stated load and inflation conditions. That is a rating ceiling, not a target cruising speed.
- 126 = single-fitment load index
- 123 = dual-fitment load index
- R = speed symbol up to 106 mph
Why Two Load Numbers Show Up On Some Tires
Most passenger-car tires carry one load index because they are used one tire per wheel position. Light-truck tires can be different. The same tire may be approved for a single-rear-wheel truck or for a dual-rear-wheel axle, so the sidewall lists both ratings.
That split rating keeps buyers, tire shops, and fleet owners from guessing. A tire that works on a single-rear-wheel pickup may carry less weight per tire once it is fitted as part of a dual set. Heat buildup, sidewall spacing, and real-world load sharing all play into that lower dual figure.
Michelin’s tire sidewall markings page lays out the same format: the service description pairs the load rating with the speed rating, and both need to meet the vehicle maker’s spec. That matters when you replace one tire, a pair, or a full set.
126/123R Tire Meaning On Work Trucks And Vans
On many work-truck tires, 126/123R appears beside other markings that tell the rest of the story. You may also see an LT prefix, a load range letter such as E, a max-load line, and a max-pressure line. Each one adds context, but none of them replaces the load index itself.
That’s where people get tripped up. Load index and load range are linked, yet they are not the same thing. The load index gives the carrying rating in chart form. Load range tells you the tire’s casing class and inflation band. You need both to choose the right replacement.
| Sidewall Mark | What It Means | Why It Matters |
|---|---|---|
| 126 | Single-fitment load index | Used when one tire sits on each side of the axle |
| 123 | Dual-fitment load index | Used when two tires share one axle end |
| R | Speed symbol | Shows the tire’s rated speed class |
| LT | Light-truck tire type | Common on pickups, vans, and heavy-use rigs |
| Load Range E | Casing and inflation class | Not the same as load index, though both affect carrying ability |
| Max Load | Stated sidewall carrying figure | Shows the tire’s top listed carrying limit at stated pressure |
| Max Pressure | Top listed sidewall inflation value | Not the same as the everyday pressure on the door placard |
| DOT Date Code | Week and year of build | Helps you judge the tire’s age |
If you’re checking a used truck or shopping replacement tires online, this table gives you the reading order. Start with size, then service description, then load range. That keeps you from buying a tire that fits the wheel but misses the truck’s carrying needs.
How Much Weight 126/123R Can Carry In Real Use
The raw numbers are per tire. That part is easy to miss. You can multiply them across an axle for rough math, but the truck’s axle rating, wheel rating, inflation spec, and placard still rule. The tire alone does not set the truck’s legal or usable load limit.
Still, the service description gives you a strong first filter. If the truck came with 126/123R tires, dropping to a lower load index may leave you short on carrying margin even if the size looks the same.
| Fitment Setup | Active Index | Rated Capacity |
|---|---|---|
| One tire on each axle end | 126 | 1,700 kg / 3,748 lb per tire |
| Two tires on one axle end | 123 | 1,550 kg / 3,418 lb per tire |
| Single rear axle pair | 126 x 2 | 3,400 kg / 7,496 lb across that axle pair |
| Dual rear axle set | 123 x 4 | 6,200 kg / 13,672 lb across the four rear tires |
Single-Rear-Wheel Trucks
If your truck has one rear tire per side, the 126 figure is the one that applies. That’s the number you compare against the placard, the owner’s manual, and the replacement tire you plan to buy.
Dual-Rear-Wheel Trucks
If your truck is a dually, each rear tire uses the lower 123 figure. That lower number is normal. It does not mean the tire is weak. It means the tire is being rated for a different mounting setup.
Common Mistakes People Make With 126/123R
A lot of confusion comes from how close these markings sit together on the sidewall. Here are the mistakes that show up most often:
- Treating 126/123 as one odd number. It is two separate load indexes, not one fraction-like code.
- Mixing up the two Rs. Earlier in the size string, R means radial construction. At the end, R is the speed symbol.
- Using sidewall max pressure as daily pressure. Your normal cold inflation spec comes from the door placard or vehicle manual.
- Matching size but not rating. A tire can match the size and still be the wrong pick if the load index or speed symbol is lower.
- Ignoring fitment type. Single-rear-wheel and dual-rear-wheel trucks do not read the same part of the code.
Replacing A Tire Marked 126/123R
When it’s time to replace a tire with this code, stick to a clean check list:
- Match the tire size exactly unless your vehicle maker approves a different size.
- Meet or exceed the original load index.
- Meet or exceed the original speed symbol.
- Match the load range when the truck was built around that casing class.
- Check the door-jamb placard before you buy.
That’s the plain reading of 126/123R: one load index for single fitment, one for dual fitment, and one speed symbol at the end. Once you know that pattern, the sidewall stops looking like gibberish and starts reading like a spec sheet.
References & Sources
- Goodyear.“Tire Speed Rating.”Provides the speed-symbol chart used here, including the R speed rating of 106 mph.
- Michelin.“How to Read Tire Markings and Sidewall Codes.”Explains how tire service descriptions pair load ratings with speed ratings on the sidewall.