[CaptAmerica]

Hello! New here, so I believe this is the right place for this. Correct me if I’m wrong… just looking for some help:
Cover Trunk swap question -
I recently bought my first Subaru, and first brand new car - 2022 Forester Limited (Woo Hoo! Love it!) Well, I plan on daily driving this baby and taking it out on adventures. With those adventures, I’ve been looking at options to get a full-size spare and ditching the stock, temp. spare. (I do not plan on getting after-market wheels, at this moment, so I would buy a fifth OEM wheel and tire to match what I currently have.)

I have done a good amount of research, but cannot find the answer to my question (maybe it’s too new of a model, or maybe I’m missing the answer posted somewhere) - I know that a full-size spare, some aired down and some with slight modifications that I’ve seen online, can be made to fit in the spare-well of the trunk in a non-Wilderness Forester. What I’m specifically curious about, is the Wilderness’ Cover Trunk Standard (the foam tray to cover the spare under the trunk floor.) To my knowledge, and the limited research I’ve done, the Wilderness edition does not have a different size trunk/spare-well. It is essentially the same chassis/base as a non-wilderness edition. So, if I were to order the Wilderness’ Cover Trunk Standard (PN#91141SJ040), does it fit/interchange in the non-Wilderness layout and accommodate a full-spare, essentially swapping with Cover Trunk T. (PN#91141SJ000), and let the trunk floor lay flat? Does anyone have any insight/experience with this, yet? Based on the Subaru parts schematics, they look like they are an interchangeable part and fit, but I could be totally wrong?

Link to parts listing: MAT. REAR.. 2022 Subaru Forester | Subaru Parts Online

 

[Shilo]

All Forester models from 2019 - present have the same chassis. This means the wheel well is no different in any of them (apart from the E-boxer of course as the battery is there). So a full OEM size tyre will fit, the only thing stopping them in the US models is that foam cover. So you just need to do away with that cover or alternatively replace yours with either a Wilderness one or one from overseas like Aust / NZ.

 

[FozzieBalou]

One thing to keep in consideration - original tire size.

2022 Forester Wilderness - 225/60-17
2022 Forester Limited - 225/55-18

Checking on a tire size calculator - the 2 different sized tires do have similar outside diameter (which is one-half of the battle) - just .1 inch different. The width is the same.

The basic "will it fit" is a yes.

Now for the real issue - the Wilderness full size spare does not appear to have a TPMS sensor in it, but even if it does, from what others have reported and seen, that 5th tire does NOT show up on the TPMS sensor/system and if you do a 5-wheel rotation (bringing the 5th in), you would need to either have the system reprogrammed for the 5th TPMS unit OR you would have to be aware that one tire will never have that tire pressure reading on your display.

This brings another question to mind... how does the TPMS unit "know" where the tire is? We have people doing tire rotations all the time and never reprogramming the TPMS set up, right? I mean, the last time I had my tires rotated, the guys at @Discount Tire never had to flash or reprogram the TPMS receiver. So then how does it know that LF is just that - left front?

 

[FelineFreddie]

My understanding is the vehicle does “location checking” to determine each wheel location. Think of it as checking only one wheel pressure at a time. There are at least 2 methodologies in use… direct and indirect.

Now, how that is accomplished, I really can’t say. But that’s why when the tires are rotated the pressures are still accurate.

I looked this very thing up on Wikipedia a while back, and the various tps system technologies and implementations are discussed in detail…

WHAT IS TPMS & HOW DOES IT WORK?

www.bridgestonetire.com

 

[jjjjsuba]

@FozzieBalou re: TPMS
As I understand it, it’s a combination of individual receivers for each wheel + rotation sensors to ensure the spare isn’t picked up inadvertently. Some folks have reported needing an initial dealer setup for their full-size spare, but other than that, it should all just work automatically, same way it knows when you rotate around four tires.

 

[Black21Limited]

You could use a cloneable sensor in the spare. But you would always have to just use the two that are the same in a 5 tire rotation. Not 100% perfect, but it should work. Since the spare doesn't spin, it shouldn't get picked up as an active tire.

 

[CaptAmerica]

Thanks for all the feedback! Really like that you shared the tire comparison tool, @FozzieBalou. I will have to remember that for the future. Saved!

I did contact my local Subaru dealer, this morning. The guy I talked to wasn’t sure about the tire being fully inflated vs somewhat deflated to fit, but confirmed the spare-well/trunks are the same for Forester vs Forester Wilderness. I also asked about the TPMS sensor. You can get a TPMS sensor for the spare wheel (sold separately, but that may be obvious to others. I wasn’t sure…) It may have to be “programmed” at first, but the employee confirmed that the car knows which wheel is mounted based on the wheels spinning, similar to what others have stated. If a wheel is switched out with the spare, the car will “recalibrate” and start reading the mounted tire pressure because that wheel is spinning.

All in, this was a big help. I just wish Subaru offered a “full size spare setup” as an option. For my car, I want this setup to look clean/factory (that’s just my personal preference) so I’m ultimately going to get the alternate cover for the trunk/spare, fifth wheel, TPMS sensor, and a tire. (I think the center cap logo in the wheel is considered an extra part/cost, but I may be wrong. Haha) Just not ready to get off-road tires, eventually want to look at a 2” lift, and then I might be looking at different size wheels; but I’m not there yet. This helped me out, and I think I have a good plan.

 

[FozzieBalou]

The full size spare option has dwindled pretty much with everybody - either by continuing with temp donuts or using "run-flat" technologies or self-sealing tires. The last two will do nothing if you have a sidewall failure but will work for minor punctures in the tread.

One of the biggest reasons for the change is MPGs - the extra weight of a full size spare (even if only a few pounds) is bad for higher MPG requirements. This is the same reason many cars are getting louder - because sound deadening adds weight and can drop MPGs across a lineup. Another reason is ease of manufacturing; limiting options (especially individual options) is not great because of overhead and complexities in production lines.

Subaru (and others) have gotten past this by offering "accessories" as dealer or port installed options. Yes, a full size spare could be added here, but part of the issue then becomes the "take rate" - how many people will buy it. Tires are more problematic because of aging of rubber and degradation of the rubber. If Subaru has 1500 full size spares in stock for use as an optional accessory, and only 300 are sold, that's 1200 tires that need to be written off - after a certain amount of time - and destroyed. Sure, there are ways that they could easily swap these out into production lines to keep the rubber fresh, but that goes back to point 3 above - the complexity. Now you have a program in place to swap full size spares to a production line, but that needs to be coordinated and it needs to happen.

Keep us informed on if you go forward with this and your experiences.

 

[SESubie]

(I think the center cap logo in the wheel is considered an extra part/cost, but I may be wrong. Haha)

The center cap will need to come off anyways to allow the threaded rod in the spare tire well to come through the wheel to clamp the wheel down. I replaced my 18" wheel with 17" wheels and 225/60/17 tires. I added a full size spare and will just use the center cap from whatever wheel becomes the spare after a rotation.

This thread may have some interest for you: ('19+) - 2022 - Full-Sized Spare for Forester Sport?

 

[CaptAmerica]

The center cap will need to come off anyways to allow the threaded rod in the spare tire well to come through the wheel to clamp the wheel down. I replaced my 18" wheel with 17" wheels and 225/60/17 tires. I added a full size spare and will just use the center cap from whatever wheel becomes the spare after a rotation.

This thread may have some interest for you: ('19+) - 2022 - Full-Sized Spare for Forester Sport?

Great point! Duh… haha. You’re right. Thanks.

 

[CaptAmerica]

Keep us informed on if you go forward with this and your experiences.

Absolutely will!
Great points on the inventory stock and rotation, and MPG performance. I am not really worried about the difference in MPGs. I’m thinking about maybe just having the full on hand and putting it in the car when I know I’m going on a trip or off-road. But, I’ll be the first to admit, I can easily say that I’ll switch it out each time, but the reality of actually doing that is easily something I will not keep up with. Haha

In the long run, I definitely appreciate the benefits of having a full spare rather than run flat, seals, patches, etc. Having a sidewall rupture is a great example. I will definitely follow up on my experience to help others.

 

[Shilo]

The full size spare option has dwindled pretty much with everybody - either by continuing with temp donuts or using "run-flat" technologies or self-sealing tires. The last two will do nothing if you have a sidewall failure but will work for minor punctures in the tread.

One of the biggest reasons for the change is MPGs - the extra weight of a full size spare (even if only a few pounds) is bad for higher MPG requirements. This is the same reason many cars are getting louder - because sound deadening adds weight and can drop MPGs across a lineup. Another reason is ease of manufacturing; limiting options (especially individual options) is not great because of overhead and complexities in production lines.

Subaru (and others) have gotten past this by offering "accessories" as dealer or port installed options. Yes, a full size spare could be added here, but part of the issue then becomes the "take rate" - how many people will buy it. Tires are more problematic because of aging of rubber and degradation of the rubber. If Subaru has 1500 full size spares in stock for use as an optional accessory, and only 300 are sold, that's 1200 tires that need to be written off - after a certain amount of time - and destroyed. Sure, there are ways that they could easily swap these out into production lines to keep the rubber fresh, but that goes back to point 3 above - the complexity. Now you have a program in place to swap full size spares to a production line, but that needs to be coordinated and it needs to happen.

Keep us informed on if you go forward with this and your experiences.

In the case of Subaru of America, I think it is purely a case of cost.
Using a temporary spare or doing away with one all together is cheaper then a full sized. Remember that all Foresters come from the same production line in Japan and here at least in the NZ / Aust market (and probably others), a full sized spare is standard in all but the E-Boxer. There is no option of a doughnut, in fact we don't have an "option list" when ordering as everything is standard for each model.

The culture of the marketed buyer here in NZ demand a full size spare, thus it is ordered by SONZ and SOAus to lift sales. The same would apply to the fact that the Wilderness model you get over there also comes with a full size. The marketed buyer of a Wilderness would also demand a full size. I would assume in the US a full size is not considered as important by SOA for sales and thus not supplied as standard or offered as an option in your other models.
Because it is standard in other countries outside the US & the Wilderness within the US, I would say stock etc is not a problem for the factory. But it is not supplied because it is an extra cost and SOA regard the market for a full size spare to be very small.

 

[FozzieBalou]

There is some truth to your statements for sure. But the North American market (US and Canada) is very different from markets in other countries/regions. Sometimes it may be related to regional / national laws and requirements; like in the US the CAFE EPA standards and the required MPGs for manufacturers to meet. Those same standards do not exist in AU/NZ and other regions.

So yes, SoA is responsible for it, but it has to do more with the requirements imposed.

 

[supasta]

I have considered an alternative solution to carrying a spare tire.

Amazon.com: CURT 31006 24-Inch High Trailer Hitch Spare Tire Mount for 2-inch Receiver , Black : Automotive

Buy CURT 31006 24-Inch High Trailer Hitch Spare Tire Mount for 2-inch Receiver , Black: Spare Tire Carriers - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

A roof rack mount is another option:

Spare Tire Carrier

Leave your bulky spare to the elements and make room inside your vehicles for more precious cargo. This carrier mounts spares up to 35” to your LoadWarrior, MegaWarrior, or OffGrid and features quick release for easy installation and removal.

yakima.com

It may be worthwhile to consider these options if you find that the installation of the Wilderness parts are limited.

 

[jjjjsuba]

In my dream version of the FW, it would come with a side-opening rear hatch and a built-in spare tire holder there. Won’t likely ever happen, since it’s a way more significant change than swapping out the fascia, and that style of rear hatch seems wildly out-of-fashion right now (compare to late 90s crossovers like RAV4 and CR-V). But it would give people the ability to run bigger tires and still keep the full-size spare, makes accessing the spare a bit quicker (especially if you have cargo), and opens up a not-insignificant amount of additional interior cargo space.

All that to say… I like the hitch-mounted spare tire carriers, and just wish they didn’t interfere with the rear hatch so much.

 

[aggie113]

For 14-18 versions the only way to get a full size spare was to somehow purchase the rear cargo setup from an Australian model Forester. I tried contacting a few local dealers but could never get one to respond about shipping the parts to the US.

 

[SESubie]

All that to say… I like the hitch-mounted spare tire carriers, and just wish they didn’t interfere with the rear hatch so much.

Though expensive, you could get one like this: Swing-Away spare tire mount

 

[jjjjsuba]

Though expensive, you could get one like this: Swing-Away spare tire mount

yeah, I’ve seen those, and it’s better. But it’s still something you gotta do. Every. Single. Time. you open the hatch. They’re also heavy and expensive, but it’s the annoyance that would really get at me in the end.

 

[FozzieBalou]

One of the reasons so many SUVs no longer have rear mounted spares (and also an issue with these aftermarket systems) is the potential damage caused by low speed crashes. My brother had the 1st or 2nd gen RAV4 with the spare tire on the swing out door. He got rear ended at a light, the hood of the car behind hit the spare and the window shattered and the door was toast.

It's the same with the hitch-mounted spares - somebody hits you from behind and you get major damage that would not be as bad if not for the rear mounted spare.