Question about tire size

"WesBarton89 - The Way to Santa Fe" (wesbarton89)
08/24/2015 at 12:22 • Filed to: None

So, we’ve got two Durangos. Both are first-gen models with the 4.7L V8. One’s a 2000, and one’s a 2002. The 2000 has a 4-speed A/T, and the 2002 has a 5-speed auto, and is a higher trim level. (Heated leather seats, power driver and passenger seats, overhead console with different readouts, compared to the 2000 which has cloth, power driver’s seat only, no seat heat, no overhead console). But the thing is they both have different tire sizes.

The 2000 has 235/75R-15 I believe, and the 2002 has 265/70R-16 tires. I mean, both of them have the same engine, putting out the same HP and torque, and the only powertrain difference is the transmission. The tires on the 2002 were shot, so we swapped the smaller 15s onto the red Durango, as the tires on those maybe had only 5,000 miles on them. I don’t think I’d run into any issues, right?

DISCUSSION (10)

HammerheadFistpunch > WesBarton89 - The Way to Santa Fe
08/24/2015 at 12:27

Minimal overall diameter difference , it shouldn’t be a problem at all, but they bigger tires will be slower and your speedo may read slightly off.

ChooChooMotherFudger > WesBarton89 - The Way to Santa Fe
08/24/2015 at 12:28

I am no expert, but given they have a diameter difference of over an inch (by the calculations i found online) that might be pushing what you want to do.

jariten1781 > WesBarton89 - The Way to Santa Fe
08/24/2015 at 12:30

Should be fine.

I’ve heard (rumors and anecdotes, no personal experience) of some trucks having brake cooling issues with smaller diameter wheels so you may want to watch for that if you’re doing a lot of towing at the rated load.

Twingo Tamer - About to descend into project car hell. > WesBarton89 - The Way to Santa Fe
08/24/2015 at 12:33

Slight speedo miscalibration but otherwise should be fine.

WesBarton89 - The Way to Santa Fe > ChooChooMotherFudger
08/24/2015 at 12:34

Ok. Wasn’t sure, because the tires I put on are OEM size to the same make and model, only two years previous. Same body style, mostly same powertrain and weight.

WesBarton89 - The Way to Santa Fe > jariten1781
08/24/2015 at 12:35

Ok. I’ll keep watch on that.

WesBarton89 - The Way to Santa Fe > HammerheadFistpunch
08/24/2015 at 12:35

Ok, I can deal with that.

MontegoMan562 is a Capri RS Owner > WesBarton89 - The Way to Santa Fe
08/24/2015 at 12:42

Shouldn’t be that big of a deal. the main difference in the tires is because of the wheel size being different. IT’s not like you couldn’t mount 265/70R-15’s on to the 15 inch wheel.

One person made a comment about brake heat, that’s a wise thought, I’m not sure if the brake sizes are different from one to the other. If the brakes are actually bigger on the one that originally had the 16” on it, it may be a concern. If they are identical brake set ups, I wouldn’t stress.

Speedo a touch off, not a big impact on the truck overall imo.

ChooChooMotherFudger > WesBarton89 - The Way to Santa Fe
08/24/2015 at 12:49

Tires and wheels in my expedience have always been fucky. So I tend to be carefull. If you are worried ask a dealer or mechanic about it.

And if you want to know what those tire sizes mean in terms of size, just google tire size calculator. (if you hadn’t already).

Needmoargarage > WesBarton89 - The Way to Santa Fe
08/24/2015 at 13:53

You won’t have any issues so long as the brake calipers clear, and you’d know it by now if they didn’t. The slightly greater sidewall height on the 15’s will help make up the wheel diameter difference between the two sets. Depending on your transmission gear ratios and final gear ratio, your engine will probably change by a few hundred RPMs at a given speed, but not by enough to make a noticeable difference. Your speedo/odometer might be slightly inaccurate as well.

I wouldn’t worry about it.