The Question: Should I run a 255/80/17 in the spare location or will a 285/70/17 be okay on a TRD PRO Suspension? I'm concerned with the 285's hanging too low.

I'm heading out to Colorado/Utah for some hiking and off-roading (Alpine Loop and Ophir Pass to be specific). I run 285/70/17's on a TRD PRO suspension and I'm getting a fresh set for this trip.

I was hoping my Eibach coil-overs would come in (after 7 months of waiting) for a 2" lift all around; however, the trip is upon me and I'll make due without the lift.

Thanks for your help!

I assume you aren't planning a 5 tire rotation. Since a 255/80R17 has a slightly larger diameter (33.10") than a 285/70R17 (32.76") when new, and won't be used as part of a regular rotation, the difference in diameter will only become greater as your 285s wear. If you have to use that larger diameter tire for an extended trip, your wheels will turn at different rates. It may not harm your differential, but why take that chance? I would just get the same size and brand for your spare.

Ah, I'm a new guy so I didn't think about wheels turning at different rates. I hate the look of "skinnes" or "pizza cutters" but if damage if using the spare is an issue, I may just go for 255/80/17's all around.

Thanks for your help!

I run 285’s all around on my Pro with a 1.5/1” spacer lift. I have a matching 285 on a Pro wheel that I do a 5 tire rotation with. As far as clearance, I did scape the bottom side of the bumper and probably my spare in this pic, but did not see any damage to the tire. And the face of the wheel points upward so it won’t get scraped. The differential still hangs lower than the 285. Go with a 285.

Attached Images

     

Spare Skid Plate - Skid Plates, Off Road Tires, 4x4

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I do Ophir and Alpine loop every summer (my dad was born in Ophir). You will do just fine with a 285 spare. Only two places to stay away from without a substantial lift: Black Bear and Poughkeepsie (the local rentals prohibit you from those two). I would also suggest you stay off the lower end of Engineer pass (Mineral Creek), were it meets US 550, with out at least a two inch lift. Thus to get to Animas Fork from the west side, go over Corkscrew, Hurricane, and California.

Check in with with the visitors centers in Ouray or Silverton for current local conditions and a free map.

The scenery is spectacular in that area. Enjoy!

I really appreciate your input! Thank you.

There are so many different things I hear about Black Bear. I'm in CO and the locals (with 4runners) tell me that Black Bear is a breeze with exception of one or two spots.

Go with the 285's (they're an inch wider than the 255/80's). I run the same setup as TRD Panther and while it has hit the ground plenty of times with the many trails I've ran in several states including Utah, there's no damage to the spare at all. If anything it's kinda like a bumpstop lol. I just did Valley of the Moon a week ago, and going down the gatekeeper it slammed the spare and hitch really hard, and still nothing wrong at all with the spare.

Maybe keep the spare at 20psi (if you have an air compressor) so it flexes more than being at full pressure when it contacts the ground.

That’s some good info. Next time I make it back to Colorado I will try some of these.
I did one in my old 3rd gen about 12 years ago. Beautiful area.

I'm glad to read that the 285s will fit in this location. I thought they would have been too big to squeeze into the 265 space.

Any mods or adjustments needed?

Nope. I think if you have KDSS it is really close and may rub slightly, but will not interfere with the function.

Agreed 285s rub slightly on the Kdss sway bar BUT doesn't interfere with the function. I tested my 285s first under it then tried it with my 255s which cleared with plenty of space to spare.

Yeah, Corkscrew--Hurricane-California is my favorite offroad route along with the White Rim Road.

Some of the comments surprise me because I would put it the other way round: for Black Bear, you need wheel travel above all, not extra ground clearance. Some folks drive Mineral Creek (and Black Bear) in Foresters or XVs (downhill only).

I just use a 265 70 SL Wildpeak as a spare. It has served as a skid plate multiple times, including on Black Bear, with no issues at all.

In CO, I would just stick to 265 70 17 to minimize on road impact of larger tires. It is not like a 33" will really make any difference on trail, but it will be felt on the road which is 90% of the time even for those of us who offroad a lot.

Or, I would go 34" and up with re-gear so as to know I really have more clearance.

But that's me. Different people like different things. Except for front wheel travel. It matters a lot and lifts above 2" only rob from capability, don't add to it. I am on like 1.25" and with stiff suspension, it is plenty. With a soft suspension, it would hit a lot.

EDIT: to be more specific, the rolled Toyota videos and pics I have seen on Black Bear come down to wrong line plus lack of front wheel travel, particularly on one spot before the rocky switchback. I have also seen Jeep pictures roll at the start of the switchback were they hug the wall too closely on the right (easier mistake to make than one may think). So if the OP is headed there, don't do Black Bear without prior offroad experience and understanding of how to handle off-camber spots.

Either way is fine. Your trailer hitch is going to take by far the most abuse as it is at the back end and the departure angle limit.

An open differential doesn’t care one bit about difference in tire circumference. You could run a 31 on one side and a 40 on the other, forever, and the diff wouldn’t even know. ABS/traction control might mind.

A bone stock SR5 will have no problem with the Alpine Loop and Ophir Pass; a stock RAV4 would have no problem. The only trail in the San Juans that you need* more than a stock SR5 is Poughkeepsie Gulch.

Even Mineral Creek is pretty mellow lately, I think they did some improvements for equipment to clear some avalanches and smoothed out a lot of the lower section.

*need - as in you won't make it through in a stock SR5. Some of the other trails you are going to scrape skid plates, frame, trailer hitch, etc and maybe take a bit of trail damage, but you'll make it through unless you do something stupid to get stuck.

Headed down that way in a few hours for the weekend, like most weekends for the next 4 months.