I use 5 matching wheels and tires on my 2001. 5 tire rotation. Note also on my 2001 there is a FWD fuse I can insert if I need to turn off the AWD.

 

Not a difficult question. Your AWD wants a tire that is as close as possible in rolling circumference to the other 3.

Of course we prefer the same tread and design for everyday driving so that all 4 tires will have identical traction. But any normal sized tire will be closer than the donut.

 

+1 on @YoGeorge

I've been considering a little-known Subaru alternative for our two Foresters: A 'middle ground' wheel and tire that can be purchased for SJ & SK models. It uses a mildly narrower 17" wheel and a "REAL" tire in 185 or 195 width. It fits in the well, and with minor modification to the divided storage foam the trunk floor will fit as it would with the space-saver.

Advantage? You aren't limited to about 50 miles of available tread, and the diameter is a 'tweener' so less harsh on the AWD system. This is important to us as there's limited services and cell phone coverage for our kid who drives across the Adirondacks (130 miles).

 

Addendum: I was running a 1" oversize (215/70x16") oversize tire on my '09 Forester when it was nearly new. It was a stick so no AWD fuse.

I got a flat on the freeway (yuk) and had to drive about 30 miles during ultra hot weather with the donut which did go on the rear. My son is still driving the car with 200k miles, and no apparent damage to the AWD system.

 

Umm, You do know that Donut tires are only Recommended for speeds under 55 and NO distances greater than 50 Miles!!

Your Dad or Granddad was supposed to teach you that!!!

 

Umm, You do know that Donut tires are only Recommended for speeds under 55 and NO distances greater than 50 Miles!!

Your Dad or Granddad was supposed to teach you that!!!

Totally unrealistic. Subarus should all come with full size spares. This donut nonsense is mostly about playing games with weight and mileage numbers.

 

The only things that a donut spare does better than a full size tire are consume less space and save weight.
Donut spares are intended to allow you to limp to the tire shop to repair or replace the bad tire - preferably 50 miles or less in decent conditions.

Systems for AWD, traction control, etc. expect that all tires will be very similar. The donut won't be similar, which isn't ideal - but shouldn't be a big deal for the short distance that is expected of the donut.

 

@Fibber2 , careful about that statement about SJ and SK wheel purchases. The two generations SJ and SK have different lug stud circle diameters (100mm vs. 114mm I believe) so a wheel purchased for an SJ absolutely will NOT fit on an SK, or vice versa. You may know that, but others reading your statement might get the wrong idea.

 

In case you aren't aware of it, Subaru does list part numbers (YES, DIFFERENT NUMBERS) for 17 x 6" black steel wheels intended for spare tire use for both the SJ (2014-2018) Forester with 5 x 100 lugs, and for the SK (2019-2024) Forester with 5 x 114.3 lugs. Tires that fit both rims are 185/65-17. It's still smaller than the stock circumference, but better than the space saver spare (145/80-17).

It's even in the owners manual!

I posted details previously here: https://www.subaruforester.org/thre...4-largest-full-size-spare-that-fits-in-donut-spot-sj.852403/page-2#post-7900824

Sorry if my short statement in Post #4 above caused anyone confusion.

 

some facts and data for the discussion: the more-than-half-worn OEM-size 225/55-18 all-season tires on OEM rims sitting in my basement today have a rolling diameter of about 27.5 inches. The never-used OEM T145/80-17 donut spare in my spare-tire well today has a rolling diameter of about 26 inches. So Subaru must have determined in engineering development testing that it is OK to drive 50 miles and 50 mph or slower with tire diameter differing by 1.5 inches or slightly more (accounting for spare and regular tires both being new). So clearly it is not as bad to drive around with a tire diameter difference smaller than that. But impossible from that fact by itself to endorse any particular diameter discrepancy as acceptable for unlimited speeds and distances. It's a separate question, and significant I think, that a donut spare's traction and speed capability is much different than full-size speed-rated tires, so I will never drive more than minimum distances in an emergency with a donut spare. My personal intent is to keep my 4 road tires rotated about annually, and match each other. I haven't ever planned or used a full-size full-speed spare on a long trip, but my hunch is if I had one in matching size (e.g. OEM 225/55-18) I would use it as a spare when needed after a flat, for the speeds and distances needed to get home from vacation, but then swap it back out of my rotation when things are back to normal at home.

 

The choice these days is a donut (space saver spare) or NO spare tire. My '16 Grand Caravan has the optional extra spare tire.

Your car will not blow up if you use the space saver for a day or two, once or twice during the car's lifetime. The spare is a "just in case" measure, not something that really matters that much.

One relevant anecdote, my wife's 2nd cousin, who has passed on, was involved in auto advertising with GM and other car companies. (I think he was at Campbell Ewald.) He participated in the One Lap Across America one year, which was 3000+ miles. He and a buddy drove some kind of nondescript sedan WITH A SPACE SAVER DONUT SPARE ON IT FOR THE WHOLE DISTANCE. No speed limits. I think they got some promotional $$$ from Uniroyal or something.

My son was a bicycle racer when he was younger, and was known to go down 2-lane mountain roads at 65 mph, no guardrails, on 1" wide tires. I would not recommend this to anyone except a skilled bicycle racer.

I've been looking at hybrids for my next daily driver, and am angry that Honda leave a spare tire off the CR-V. I'll take a donut over nothing any day.

 

Full size spare - don't leave home without it

 

Full size spare - don't leave home without it.

I got one for my 2008 when it was new. Unlike the compact spare, it does not limit capabilities of speed, range, towing, or off-road.

 

If you follow the other thread, you can buy those tires directly from Subaru. And there is an independent source.

 

28121SG120 Genuine Subaru Tire - Spare 185/65R17

Genuine 28121SG120 Tire - Spare 185/65R17 fits 2018-2021 Subaru Forester. SubaruPartsDeal offers 28121SG120 with great deal.

www.subarupartsdeal.com

 

Ah, I misread that, thinking more of a regular tire, and not still being rated as a spare.

 

On my 2010, I had to once drive 160 miles with the space saver spare on the rear and the AWD system deactivated with the fuse. As of almost 279k miles my 2010 has never experienced an AWD system issue.

 

There is still a source for a 'real' tire in that size: Cosmo RC-17 185/65R17 88H I0067212 And at $50 plus shipping it's a bargain. The description says Passenger Car Radial.

An issue is the speed rating of 88H.... 1230 lbs. It's barely adequate for the GVWR of 4891 lbs, best in the rear with less than max axle weight.

But even the 'spare' that Subaru is selling that I posted above is only 90M. But an M rated tire is up to 80 mph use, so is it a REAL tire or still a LIMITED Service spare????

Here's another tire from Subaru. This one is 90S, so maybe a full tread depth tire? 28121FL140 Genuine Subaru Tire 185/65R17 Xv

 

This one is 90S,

It does state it has a 12.000 mile warranty in the fine print

Genuine Subaru Part 28121FL140, the Right Choice
Your vehicle deserves only genuine OEM Subaru parts and accessories. To ensure reliability, purchase Subaru part # 28121FL140 Tire 185/65R17 Xv. Our Subaru parts and accessories are expedited directly from authorized Subaru dealers strategically located all across the U.S. and are backed by the manufacturer's 12 month, 12,000 mile warranty.


I wonder if they would actually back that.

It also doesn't have "Spare" in the description like the other one.

 

@john12774

This and/or very similar discussions have occurred in the past: https://www.subaruforester.org/sear...t=post&c[child_nodes]=1&c[nodes][0]=72&c[searchProfileName]=control&o=relevance

 

For ANYONE who has a Donut spare!!! PLEASE get a full-size the ONLY reason the Donut Spares EXISTS in the first place is because the Manufacturers used them to make money off you!!! $50 Donut VS $115 Short math time 115-50=65!! They make $50 off you and leave you in a CRAP situation where hopefully if you NEED that donut you don't have to go far!!

P.S. Life isn't about Avoiding Bruises but Collecting Scares to prove you SHOWED UP!!!

 

It mostly comes down to how you use the car, if you like the added cargo space, or can live without it.

Depends on which side of the compromise works best for you.

 

... if you like the added cargo space, or can live without it...

The added cargo space with the compact spare bering in its rigid foam filler tray under the floor, for tools and stuff.

 

I've always considered it a choice between 5-wheel rotation or a commitment to drive straight to the garage on the donut. If I expected to realistically be farther from civilization than the donut can carry me, or to be using the car for long, time-critical trips, I would equip myself with 5 identical wheels and tires. But I don't, so I don't. The donut does what I need (which, so far in 9.5 years with my Forester, is nothing; never had a flat).

 

I actually carry two spares; one in the well and the other on the rear carrier.

 

@Kevin,
Sure, but you live in Australia. Always farther than a tank of gas from civilization.

 

Another temporary spare option:

Yokohama Y870 165/80R17

tiresize.com

6.5" wide, 27.4 tall 737 revs per mile, vs 772.

0.6" more sidewall.

Still not a real tire, but would be more AWD friendly.

 

What is with the 50 mile limit? Is that the max to prevent overheating the front/rear coupler? Could I drive 50, wait an hour and drive 50 more?

 

I believe that the true answer is a mashup of all of the above. Well, maybe minus the Conspiracy Theory - The Government Did It reply.....

Second only to Audi, various mechanical analyses over the years have shown that the Subaru AWD system is among the tightest in the industry. The system tries hard to determine wheel slippage and quell it.

Years back many models had limited slip rear differentials along with the "Duty C" solenoid in the center diffy to balance torque distribution to the rear. Today the LSD has been replaced by wheel speed sensors and braking action to force torque. VDC also forcibly reduces power as needed when slippage becomes excessive.

Net is that if one wheel (the spare) is way smaller and turns more per mile, the system can attempt to even that out. That's hard on the system.

Subaru still advises in Service Bulletins to check for tire uniformity before attempting repairs in the case of wheel hop, binding, center clutch wear, etc., as even small differences in wheel rotation apparently do add up over time to system damage.

Use the spare when you have to. Knowing that you are asking the system to work harder (verging on abuse...) should be sufficient to get you to not overdo it.

 

If you consider that an automobile is turning about 60% of the miles it logs, to think that Subaru designs their power transmission equipment to last hundreds of thousands of miles, with a good 20% margin, and to worry about odd sized tires within reason is ridiculous. If you are driving in Baja at top speed and temperatures, then there might be cause for concern.

 

Not a problem to use donut

 

@HarryP I am pretty sure the 50 mile limit is based on the fact that any car's emergency handling, wet and dry braking distances, handling stability in panic stops, etc. etc. with donut spare mounted are significantly worse than the as-new OEM-equipped car. Saying "50 miles max" translates to "this is not a good idea if you don't have to".