Chevrolet Colorado 2nd gen: height, no width

The starting points

255/65R17 at 30.05 in, 265/60R18 at 30.52 in and 265/65R17 at 30.56 in. Half an inch covers the range, and the two larger ones are within 0.04 in of each other.

Two of the three share the same 265 mm section width on different wheels, so the difference between them is entirely in sidewall: 6.78 in on the 17, 6.26 in on the 18. Same width across, same height overall, and half an inch less casing standing between the rim flange and whatever the tire hits.

Zero width, one inch of height

The most interesting move available on this platform is 265/65R17 to 265/70R17.

Both are 265 mm wide — 10.43 in — so section width changes by exactly zero. The aspect ratio goes up five points, the sidewall grows from 6.78 in to 7.30 in, and the overall diameter rises 1.04 in to 31.61 in. A 3.41% change, entirely in one dimension.

For a truck whose front suspension and inner liners are packaged tightly, that is a rare clean option: nothing moves toward the control arm or the liner, and the tire still stands an inch taller. It also means a set of factory 17-inch wheels needs no change at all.

The bigger steps, and what they cost across

• 285/70R17 at 32.71 in — +2.15 in from 265/65R17, a 7.02% change, and +0.79 in of section width.
• 33x10.50R17 at 33.00 in — +2.44 in, 7.97%, and only +0.07 in of width. The flotation size reaches higher than the metric one while adding almost nothing across, because a 10.50 in casing is barely wider than a 265.

That second row is the one worth sitting with. A nominal 33 that is narrower than the 285 most people compare it against, on the same wheel, is a genuinely different trade — and the reason narrow flotation sizes persist on midsize trucks long after full-size trucks abandoned them.

At 7.97%, an indicated 70 mph is 75.6 mph and 100 miles of odometer is 108.0 travelled.

Starting from the base tire changes the figures

255/65R17 is the shortest recorded fitment, and from there 33x10.50R17 is +2.95 in and 9.81% rather than 7.97%. The same tire, a materially larger change, because the starting diameter is half an inch smaller.

Anyone reading a fitment thread about this platform has to know which of the three factory sizes the writer started from, and most threads do not say.

Two blanks in the record, and only one of them matters here

The factory wheel diameters recorded for this generation include a 16, and no 16-inch tire size sits against it in the three above. The axle ratio column is empty too. Neither gap touches a figure on this page — diameter, section width, sidewall and speedometer error fall out of the size code and nothing else.

Engine speed is the one calculation that needs a ratio, and unlike the missing 16-inch size, that number is recoverable from the truck itself: this manufacturer prints an option-code label listing the axle among the rest of the build, and the code is on the axle housing as well. Read it off, put it into the gear ratio calculator against a 3.41% or a 9.81% step, and the answer is exact rather than assumed.

Geometry, not fitment

Nothing here says a tire clears. On a midsize truck the binding constraint is usually at the inner edge of the front tire at full lock, which is why the zero-width 265/70R17 step and the 285/70R17 step are not variations on one another. One of them puts nothing new in front of the control arm; the other adds 0.79 in of casing across, and on an unchanged wheel and offset roughly half of that lands on the inboard side, where the control arm is.