275/70R18 on a Toyota Tacoma.

275/70R18 is an 18-inch size, so the generations it can go on without new wheels are the ones our size families run on 18-inch rims: 2nd gen Tacoma (2005-2015), 3rd gen Tacoma (2016-2023), and 4th gen Tacoma (2024-2026). Two sources in this repo have an opinion about 275/70R18 on each of them — the per-generation clearance matrix behind our max-tire estimator, and the per-size candidate table behind the recommender — and where they disagree, the stricter of the two is what you read below.

Every tier above is modeled output of our own fitment rule-set applied to 275/70R18, not an install anyone here measured: wheel offset, alignment, mud flaps, and the tire model's real moulded width all move where 275/70R18 starts rubbing. Where the two sources behind those tiers disagree, the number you see is the conservative one.

These are the 4 sizes closest to 275/70R18 in overall diameter that also run 18-inch wheels, so every swap in the table is a tire change rather than a wheel change. The set runs from 265/65R18 at 31.6 in to 285/70R18 at 33.7 in, and 265/65R18 and 265/70R18 are factory Tacoma sizes. Speedometer error is calculated against 275/70R18 at 33.2 in — the size the truck would be calibrated for if it wore this page's tire.

That last column is the error you would carry after the swap, before any recalibration: fitting 285/70R18 in place of 275/70R18 puts true speed at 61.0 mph when the speedometer still reads 60. 265/65R18 sits outside the 3 percent window our speedometer calculator treats as the safe band against 275/70R18, so that one is recalibration territory. Width moves on its own axis: the widest of them, 285/70R18, is 0.4 in wider than 275/70R18, and section width is what reaches the fender liner and the upper control arm first.

Our tire research dataset lists 33 models offered in 275/70R18. No Tacoma ships the size, so the shortlist leads with the category our candidate table's trail fit rating points at rather than with a factory fitment. Below are the 3 best-ranked all-terrain models offered in it, plus the mild all-terrain Yokohama Geolandar A/T G015 for contrast — built for a different job, so it scores on different axes.

Scores are a 0-10 editorial synthesis of published reviews, manufacturer specifications, and retailer fitment data — not tires we tested ourselves. Which models are offered in 275/70R18 is the research dataset's own size catalog, which is why a thinly-catalogued size returns a short list here rather than a padded one. The order above is that dataset's editorial rank; the 0-10 badge is the blended score behind it, so a higher badge on a lower-ranked model is the two measures disagreeing rather than a mistake. How we source and score.