Technical question for stock tire size.

[FIND]

On my 99, the stock size is 255/70R16 on a 7" wheel.

However, tire manufacturers recommend OEMs use either a 235 or 245 wide tire on a 7" wheel, and 255 for 7.5" wide wheels.

Anyone know the reason Ford went with the 255 wide tires instead? Did Ford just choose a fairly narrow 255 for their OEM tire, was it a ride quality issue, something related to the firestone roll-over mess, or was there some other reason?

The reason I ask, is because I am considering just going back to a stock size wheel and tire combination instead of larger wheels from a later gen since I have a full set of stock wheels anyway that I am not doing anything with (though I probably should try and find a set for a limited instead). This is mainly because I want to have my primary tires a good mix of on road and light off-road. I've got snow tires and a set of 15" steelies.

So, I have been looking at two different tires in a 245/75R16 which would give me an overall diameter of 30.2 for one set, and 30.5 for the other... both of which are close enough to what my truck is calibrated for, so if there is no significant reason why Ford went that direction, and since they both exceed OEM requirements for load index, I'm going to choose between one of the two.

 

[J_Train]

with my experience with ford and engineers as well as field service engineers they will tell you that's what ford felt would do best with what they built. plus it comes down to which is cheapest at the time if a 255/70/16 was cheaper then other's, that's why they used it. plus back when the truck was new that was when every one had to have there own tire specifically for a paticular vehicle. At least that's what I've been told by my Field Service Engineer

 

[colintrax]

From what I understand Ford put 235/75r16 and 255/70r16s on there, it might have been for looks. I doubt it had to do with the roll overs, remember most explorers have 15" rims, I would guess those were the roll over prone vehicles.
I wouldn't worry about what is recommended, I'm sure you know that 255 isn't excessively wide for a 7" wide rim, and Ford should know this as well.

My guess is looks, who doesn't love the look of a fat tire? Ford might have used a skinny 255, but that tire is no longer made and good luck finding the dimensions of it.
BTW, I'm probably going with 245/75r16 next so post some pics please

 

[J_Train]

Let me add to it since I had time to talk with my dad since he worked for Ford for 23 years. The 255/70r15 was 2wd with towing package and 4wd/AWD with towing, then there was 235/75r15 for 2wd/4wd, 2wd towing/4wd towing, then there was 225/75r15 for 2wd non towing xl/xls models all depending on certain years

 

[FIND]

Meh, I just went with the 245/75R16s as a replacement tire. They are a more common size anyway and cost me a few bucks less. It is only a difference of 10 millimeters, so it is not like it is really a big deal anyway.

 

[J_Train]

No problem. Yeah there's some many choices (in any over all sizes) anymore you can go up or down a few sizes and it doesn't make much of a difference. just figured I'd give some more info on the subject.

 

[4rd Xplora]

From what I understand Ford put 235/75r16 and 255/70r16s on there, it might have been for looks. I doubt it had to do with the roll overs, remember most explorers have 15" rims, I would guess those were the roll over prone vehicles.

Seems I read somewhere no Explorer with 16's ever rolled, read too no Mountaineer even with 15's ever rolled. I ran a 245/16 since 2008, bought tires the other day and went back to the stock 255's.

 

[FIND]

Seems I read somewhere no Explorer with 16's ever rolled, read too no Mountaineer even with 15's ever rolled. I ran a 245/16 since 2008, bought tires the other day and went back to the stock 255's.

2nd gen 4 door Explorer XLT and Eddie Bauer had an optional tire size of 255/70R16. 2 door, XL, XLT and Eddie Bauer Explorers had the 235/75R15 tire size standard. Limited Explorers came with 16" wheels stock. Mountaineers could be purchased with either the 235/75R15 tire size or the optional 255/70R16 tire size. In higher trim levels, the 16" wheel and tire were standard.

 

[J_Train]

2nd gen 4 door Explorer XLT and Eddie Bauer had an optional tire size of 255/70R16. 2 door, XL, XLT and Eddie Bauer Explorers had the 235/75R15 tire size standard. Limited Explorers came with 16" wheels stock. Mountaineers could be purchased with either the 235/75R15 tire size or the optional 255/70R16 tire size. In higher trim levels, the 16" wheel and tire were standard.

You forgot the 225/70/15 that was on the base of base Explorers. i believe xl and the later xls.

 

[FIND]

You forgot the 225/70/15 that was on the base of base Explorers. i believe xl and the later xls.

Didn't they stop using that size after 1996?

 

[Anime]

Ford went to a 255/70R16 as the optional size because that was the widest (without being too wide) tire that they could fit, and also probably because that was what their OE manufacturers and design engineers had come up with for the new Explorer.

It probably had a lot to do with improvements in braking and cornering over the 235/75R15, which was a pretty standard light truck size at the time. Obviously, Ford ditched the TTB/TIB and went IFS, and did a lot of other things to tweak the Explorer to the soccer moms who were buying them to drive around town. Also keep in mind a lot of other SUVs had come to market to challenge the Explorer, and lots of them now had larger and wider tires than the first gen, so Ford simply did what they needed to, both for looks and for function.

The Firestone fiasco hadn't yet exploded when the second gen came out, so that wasn't too much of a factor, at least publicly. If anything, a wider tire was against what Ford warned for the first gen - that if you used wider, grippier street/performance tires instead of all-terrains, you'd be at greater risk of a rollover because the tires would 'stick' in a turn instead of slipping. I've still got the door panel warning label for this on mine, and it's not too far off. The LTX M/S, when you take a sharp turn, put it up on two wheels. Of course, the new Explorer also had much larger and stiffer anti-sway bars to go with the tires, and the rack-and-pinion steering, and a few other things that made it handle more like a car over the first gen.

A 245/75R16 would have made more sense for an off-road vehicle, with the slightly taller sidewall, but the 255/70R16, with the wider tread and slightly lower sidewall, made more sense for what the SUV was being used for, driving on the pavement. The off-road crowd was putting LT tires on instead of the P-metric sizes, anyway.

245/75R16's make sense if you wanted the slightly narrower width/taller sidewall for off-road use, for slightly better snow/bad weather traction, or just because it's offered in a certain tire or you can get them at a good price. For pavement use though, the 255/70R16 is good, and still a popular size.

 

[J_Train]

Didn't they stop using that size after 1996?

That's what I thought but pts tire sales tool shows it up to 98

 

[FIND]

Ah, thanks Anime. That makes sense now that I think about it.