Widest Tire

Hello,
I recently got an '05 Mountaineer with the stock 17"x7.5" wheels and 245/70R17 tires (stock should be 245/65R17, so mine are slightly taller). I have a good set of 275/60R17 Hankook Ventus that I like much more that I took off my now-totalled '98 F150 that are still like new. They are actually a little closer to stock height than the current tires. My question is: will the 275's fit without rubbing the inside sidewall on the top? It looks like it could get a little tight. I didn't know that I might have to run spacers to mount my cool tires. What is the width limit on these trucks (by the way, it's an AWD, if that makes a difference). I sure hope I don't have to add spacers. Any advice/pointers? Thanks.

I think they'd be fine without rubbing, they aren't crazy wide or anything. Your hankooks are 30" tires, some say 31" may or may not rub, and 30.5" will not rub (that's what I have, stock is 29.5"). Yours are about 1.5" wider than stock, but only about 1/4" wider than my tires. So comparing them to mine, 1/2" smaller diameter but 1/4" wider... I bet they'd be fine.

The closest thing to a worry that I see is that a 7.5" rim is probably the minimum width to mount those on. Not sure what implications that might have.

The two main places to worry about rubbing is the steering knuckle, 275 is going to be very tight and the frame on full lock. You will probably need wheel spacers until you can source some new rim's that have less back spacing. There are alot of guy's running 285's (with lift spacer's) so width limit should be ok. I'd get one mounted on your spare and fit that to the front and make your decision's from there.

Thanks for the pointers. I had the same thought, mounting my 275 spare on the Mountaineer's spare rim and checking it out. As it is now, the Mountaineer's spare is still the stock 245/65R17, which is a 29.5" tire, and the 245/70's are 30.5", so I've already got a slight issue if I ever do have to mount the spare (I don't like having mismatched tires on a truck/SUV). Is that actually a real problem on a vehicle with what I assume is an LS rear end? Can I even run a smaller tire safely without doing damage to the driveline, etc? At least if I did mount the 275's, I have a complete set, spare and all. I think I can already hear the 245/70's rubbing the inner fender liners on hard turns, which I'm not worried about, but it's a little unsettling. If I have to get spacers, what is the minimum thickness available? I've seen 1" and 2"; 2" seems way too much. Do spacers cause any other issues, like faster/uneven tread wear, alignment issues, ball joint issues, etc? You know I love spending $500 to $600 on a set of front ball joints! Sorry for the amount of questions, but hopefully there are people here with a lot more experience than me. Thanks again.

Just try it on for size mate, DON'T drive it. Like you said all types of problem's drivng an awd with mismatched tyres! Jack up your truck and just test how it fit's lower her back down and turn full lock and see if it rub's, no driving! From there you should get an idea of what you need to do. Spacer's need to be hub centric ones (they have a lip for your rim to sit on so your hub takes the weight of your wheel, not the stud's. No wear issues on the tyres but you need an alignment after they are fitted. 1" would be the minimum I reckon. Extra stress on the hub's is the same as putting on rim's with less backspacing. There will be more stress but not over the top, expect them to wear a little quicker. I have run spacer's for a while with no issue's as yet (touch wood)

The fender liner's can be trimmed so no biggie there, frame cant so please check that.

Thanks again! So I take it that these Explorer/Mountaineer wheels have considerable backspacing? I remembered that my '98 F150 had the hub-centric style wheels, but I didn't know the Exp/Mntr's did, too. Does my '99 Explorer have hub-centric or lug-centric wheels? Will wheels swap from gen 2 to gen 3? I had also thought about putting the '99 Limited wheels on the '05 Merc if they were the same style, then putting the 275 Hankooks and 17"-ers on the '99. By the way, the Explorer wheels are 16" with 255/70R16's. All kinds of possibilities, maybe! And here's a wild hair; does anybody make a spacer/adaptor that would let me mount my '98 F150 wheels (5x135mm, which I also like and what my Hankooks are still mounted to) on the Exp or the Merc (5x4.5")? Now that would be cool! Again, sorry for so many questions at once, but this is starting to get interesting. Thanks.

15" wont clear the brake caliper's on the '05 but 16's will so you should be right with the swap, should be hub centric and if you look hard enough you may be able to find a hub centric adapter from 5x4.5 (114.3mm) to 5x135mm. It's going to be a hard slog tho' to find them but you might get lucky. Those 275's should fit the '99 with only minor trimming. Question's are good mate, if we never ask we never learn!

Lynchy,
I'm so grateful you're willing to keep indulging me. I think I found a set of 5x4.5 to 5x135 adaptors. Here's the question that makes me "think"; does the adaptor need to have both male and female hub features? The ones I found appear to be hub-centric from the 5x4.5 Explorer hub to the adaptor. But the 5x135 F150 wheel appears to have to be supported by the lugs. Something just doesn't seem right about that. I haven't seen any adaptors that look like I think they should for combining 2 hub-centric sizes. Again, thanks for all your valuable info.

No worries mate, when dealing with the adapter spacer ideally you would want the effy wheel to sit on the lip and the spacer to sit on the hub's lip. The back of the spacer where it sit's against the hub could be flush and fit over the lip or recessed for the lip to fit into it, either of those would be ok (does that make sense?). Safety first tho' if you can't find an adapter that is hub centric then you will be better off swapping the tyres to the X's rim's

Thought I'd chime back in, for what it's worth. I was replacing my front diff oil this morning and snapped a pic while I was under there.

My tires are 265-70/16 and this pic shows how close the front tires come to rubbing, horizonatally. I'd guess it's <1/2" from that support... *maybe* you could run 275s without spacers, but it would for sure be real close. At a quick glance this is the only place I can see that it'd be a problem.