7G Legacy Wheel/Tire Fitment

[Mach V Dan]

Today I put some 20" wheels on my 2020 Legacy XT Touring. I thought I'd share a little bit about my experiences, how it fit, and some of the calculations I did. If other people want to add to this thread later with more wheel/tire fitment info, that would be great.

 

Intro:

 

At least in the US, the 2020 Legacy comes with either a 17" wheel (7" steelies or 7.5" alloys) with a 225/55R17 tire, or an 18x7.5" wheel with a 225/50R18 tire. Note that the 18" tire is 0.7% taller than the 17" tire. The speedometer/odometer is calibrated to the tire size the car came with.

 

Even the 18" wheel looks very small on this car, and the big plush sidewalls are not very sporty in appearance or in feel. The wheels and tires are also not very flush with the fenders, although that pushed-in look is not as pronounced as with some Subarus.

 

Calculations:

 

I considered several options for larger wheels/tires. I really felt from an aesthetic standpoint a 19" wheel was the smallest I wanted to do. My XT Touring came with the larger 18" tire, so I used that as the baseline diameter for my tire calculations.

 

225/50R18: 26.9" diameter, 84.3" circumference, 8.9" tread width, 4.4" sidewall.

 

I wanted a wider tire, so I looked at some 245 width options:

 

245/40R19: 26.7" diameter (0.7% shorter), 83.9" circumference, 9.6" tread width, 3.9" sidewall.

 

245/35R20: 26.8" diameter (0.4% shorter), 84.0" circumference, 9.6" tread with, 3.4" sidewall.

 

That's a pretty good match right there, and if I was choosing wheels I would just pick a 20x8.5" wheel with a slightly lower offset than stock, and go with that. However, my friends at Titan7 had some 20x9.5" forged wheels I could get for a very reasonable price, and a 245 tire would have been very narrow on that wheel. Time to go back to the calculations.

 

Specific specs on the wheels: Manufacturer is Titan7, style is called T-R10. Color is Satin Titanium. Size is 20x9.5" 5x114.3 +63. They are forged and weigh 22.1 pounds each. Centerbore on these is 68.05; I think they were originally made for a Lotus Evora? I had to order some custom 68-56.1 hubcentric rings from ebay so the wheels would be hubcentric to the car.

 

Back to the tire sizing:

 

265/30R20: 26.3" diameter (2.2% shorter). The 265 tread width would be a perfect match to the 9.5" wide wheel, but measuring fender and strut clearance, it was looking like a 265 width would be a very tight fit. Plus, I try to keep the diameter within 2% of stock to minimize speedometer/odometer error.

 

255/35R20: 27.0" diameter (0.4% taller than stock), 84.9" circumference, 10.0" tread width, 3.5" sidewall. Not too bad a fit on the wheel, looks like it'll just barely fit between the front strut and the front fender. I think we have a winner. Plus, that happens to be a fairly common size for high-performance sedans, with lots of options in terms of brand and tire type. I ordered a set of Vredestein Ultrac Vorti tires in that size.

 

Fitment on the car:

 

The rear suspension on the 2020+ Legacy is a variant of the same multi-link setup that Subaru has been using on everything since 2008. One nice thing about it is that there's almost infinite rear inner tire clearance, so my super-high-offset wheels worked fine. I only had to worry about the inside of the tire rubbing on the fender liners and the brake line. Both cleared. Note that the lower suspension arm and the rear knuckle itself are now made of forged aluminum.

 

The front suspension is a strut design like most modern cars, and the shock body is the limiter in terms of how far inboard the wheel/tire can go. My +63 20x9.5" wheel bumped into the strut, so we mounted some Mach V 10mm wheel spacers. The stock wheel studs are not long enough to bolt the wheel on then, so we installed longer wheel studs as well. This effectively positioned the wheel/tire assembly at +53 offset.

 

Pressing the old studs out using an air hammer

 

Note that there is a little access from the back of the front brake backing plate, so you can get the stock studs out and pull the new studs in without having to take the whole front hub apart.

 

Longer stud vs original studs

 

10mm spacer in place. Mach V Motorsports (my business) makes these spacers. They are unusual because they are Subaru-hubcentric to both the car and the wheel.

 

Test-fitting the front wheel and tire.

 

So far so good -- looks like it fits and everything clears. The back actually has a little extra room at the fender, so the offset back there could be even lower. The front is pretty tight at the fender, and there's very little room between the tire and strut -- maybe 3-4mm?

 

 

 

 

 

 

 

 

The fenders are pretty much flat/pre-rolled on the inside where the tire would contact, so there's almost nothing to roll. In the back there's just a bead at the top of the wheel well, not even a folded sheet metal lip, so you're not going be rolling that.

 

So there you go. That's about as wide a tire as I think I can fit on this car. If you wanted to make it easier and avoid the front spacers, I'd probably do a 20x8.5" wheel at +48 or so, and a 245/35R20 tire, or a 19x8.5" +48(ish) wheel with a 245/40R19.

 

Dan

Mach V

FastWRX.com

[Stuff]

Nice mod/looks good. What I would like to know is how the handling is affected. Most of the early reviewers stated that Subaru's choice of tires wasn't good and stickier tires would help a lot. What is it like with your lower profile and better tires? I realize the geometry is changed and it wourld be hard to say what had more of an impact. Edited October 26, 2019 by Stuff

[Mach V Dan]

What I would like to know is how the handling is affected... What is it like with your lower profile and better tires? I realize the geometry is changed and it wourld be hard to say what had more of an impact.

The handling is a little better -- there's basically no tire squish and squirm, which is a big change from the big doughy stock tires. But the springs and shocks and sway bars are unchanged, so there's still the same soft ride and overall body roll/dive/squat is the same. There's definitely some more vibration and impact transferred into the body that was absorbed by the OEM tires.

 

Dan

Mach V

FastWRX.com

[Humble Rumble]

Looks great, and thanks for doing the legwork early on with this chassis. You mentioned that the rear suspension seems to be relatively unchanged, which would lead me to believe that all of the popular rear sway bar fitments from Gen 5 and 6 may still fit this car as well (2015+ STI RSB, Whiteline 22mm & 24mm, etc). That could definitely pick up the slack on some of the body roll.

[Falcor]

If it's on the same platform as the 2019 Forester, the rear swaybar is now in front of the rear axle.

[YeuEmMaiMai]

If it's on the same platform as the 2019 Forester, the rear swaybar is now in front of the rear axle.

 

 

question is can you get it out with out dropping the drive shaft?

 

 

 

 

as for tires

 

 

 

17" are about right in terms of ride comfort and handling.. doing larger wheels = increased harshness as the sidewall will not absorb as much,, get on some rough pavement and you will immediately know what is up.

[Mach V Dan]

17" are about right in terms of ride comfort and handling.. doing larger wheels = increased harshness as the sidewall will not absorb as much,,

Tire diameter alone does not dictate ride comfort and handling. The 7th-generation Legacy has a significantly larger tire diameter than, say, the 5th-generation, and if you make the tire diameter larger while keeping the wheel size the same, the sidewall has to get bigger.

 

The stock 17" tire on the 2014 car was a 215/50R17. The 2020 car has a 225/55R17, which has a 17% taller sidewall than the older car. Even the 2020 car's 18" wheels have a 5% taller sidewall than the 2014 car's 17" wheels. Because of the sidewall difference, the 2014 Legacy 17" tire would feel firmer/harsher than the 2020 Legacy's 18" tire.

 

So, yes, going to larger-diameter wheels does mean a shorter tire sidewall, but what is "ideal" is going to depend on your starting point and what you are trying to achieve.

 

Dan

Mach V

FastWRX.com

[whitetiger]

lol at the fact that the 2020 legacy now uses the same wheel and tire sizing(diameters) as a BL/BP outback. at this rate the 2025 outback will be using Light truck tires.

[YeuEmMaiMai]

Tire diameter alone does not dictate ride comfort and handling. The 7th-generation Legacy has a significantly larger tire diameter than, say, the 5th-generation, and if you make the tire diameter larger while keeping the wheel size the same, the sidewall has to get bigger.

 

The stock 17" tire on the 2014 car was a 215/50R17. The 2020 car has a 225/55R17, which has a 17% taller sidewall than the older car. Even the 2020 car's 18" wheels have a 5% taller sidewall than the 2014 car's 17" wheels. Because of the sidewall difference, the 2014 Legacy 17" tire would feel firmer/harsher than the 2020 Legacy's 18" tire.

 

So, yes, going to larger-diameter wheels does mean a shorter tire sidewall, but what is "ideal" is going to depend on your starting point and what you are trying to achieve.

 

Dan

Mach V

FastWRX.com

 

 

 

 

Those are practically rubber bands. you are going feel it when you run a fly over... and compared to 17's on the same car they are definitely harsher...

 

 

 

Yes, I have 17's on my 14 and they are demonstrably harsher riding than a 13/14/ legacy with the stock 16". The wheels have to be the same overall diameter so more rim = less side wall which equates to less flex and shock absorption

 

 

 

Also, comparing different generations of said car is pointless as there is suspension changes as well often within the same generation.

 

 

 

My old Acura CL-S rode on 225 50R17 and you felt it over harsh pavement.

 

 

on smooth roads, yeah not really a difference....but on broken roads or !!! dirt, you gonna notice...and on my 14 I wear 225 55 R17 a slight improvement over the original 215 55 R17

[M. Schneider]

Our 2020 Outback Touring XT came through with tire size 225/60/18" and 7"x18" et55 alloy wheels. Without a doubt the most gawd awful, ugliest factory wheels to come along.

 

There has to be a wheel from the Subaru wheel palette, maybe a silver 10 spoke forged WRX wheel?

[Mach V Dan]

There has to be a wheel from the Subaru wheel palette, maybe a silver 10 spoke forged WRX wheel?

Maybe there's something suitable over in my wheel department?

 

Dan

Mach V

FastWRX.com

[gibjer]

I wonder how the 19in STI wheels would look on there.

[Falcor]

I wonder how the 19in STI wheels would look on there.

 

Awesome.

[M. Schneider]

Hey Dan -

Any interest in selling your OE 7.5x18 et55 alloy take-offs? The 2020 Legacy Touring XT's alloy wheels would suit our 2020 Outback XT's summer tire just fine.

 

Cheers, Mike

 

 

Maybe there's something suitable over in my wheel department?

 

Dan

Mach V

FastWRX.com

[Mach V Dan]

Hey Dan -

Any interest in selling your OE 7.5x18 et55 alloy take-offs?

I think we can probably come to some kind of arrangement. I can't seem to PM you. Email me at dan@machv.com.

 

Dan

Mach V

FastWRX.com

[Mach V Dan]

I just weighed the stock wheels. They are 27.9 pounds each. I saved almost six pounds a wheel with my +2 upgrade...

 

Dan

Mach V

FastWRX.com

[gibjer]

Wow, reminds me of the 08 STI wheels

[Mach V Dan]

I put the stock tires on some 18x8.5" +44 Flow-Form Rota Grid wheels. Even the regular cast Grids are a good bit lighter than stock at 22.0 pounds, but the flow-form ones are another three pounds lighter than that.

 

Switching back to the 18" wheels/tires from the 20's, the car definitely feels floatier in terms of handling, and more vague in the steering. The tall sidewalls definitely are good for ride comfort, though. Even major potholes just sort of get sponged up, whereas with the 20's I tried to avoid them.

 

 

 

Dan

Mach V

FastWRX.com

Edited December 4, 2019 by Mach V Dan

[daffod]

I had 2015 legecy limited and had 16” winter tires. I try to move same steel rims to 2020 legecy premier as winter replacement and I see not enough clearance....is there a change from 2015 front brakes to 2020. I could not mount those 16” wheels

[Mach V Dan]

.is there a change from 2015 front brakes to 2020. I could not mount those 16” wheels

The front rotors are new for 2020. I haven't been able to measure them yet, but they look like the 2015+ WRX brakes, which are 316mm x 30mm. (12.4" x 1.2"). If that's what they are, they require minimum 17" wheels to fit over them.

 

Dan

Mach V

FastWRX.com

[subimp6u08]

Do you know if 2008 sti wheels fit 2020 legacy? I have winter wheels but I'm not sure if they fit legacy.

 

Sent from my SM-N950U using Tapatalk

[gibjer]

Those should easily fit. If they are the 5 spokes they are extremely heavy though.

[subimp6u08]

Those should easily fit. If they are the 5 spokes they are extremely heavy though.

I meant these wheels.

 

Sent from my SM-N950U using Tapatalk

[rvnmaniac]

I put the stock tires on some 18x8.5" +44 Flow-Form Rota Grid wheels. Even the regular cast Grids are a good bit lighter than stock at 22.0 pounds, but the flow-form ones are another three pounds lighter than that.

 

Switching back to the 18" wheels/tires from the 20's, the car definitely feels floatier in terms of handling, and more vague in the steering. The tall sidewalls definitely are good for ride comfort, though. Even major potholes just sort of get sponged up, whereas with the 20's I tried to avoid them.

===============================================================

 

Did you notice any difference in gas mileage

[M. Schneider]

For Sale: Like New OEM Tires, 225/60/R18 100H, production 07/2019 Like new. Sold.

 

FS,,, 4ea - 18" take-off tires from our November delivered MY2020 Outback Touring XT on day one @ 56 miles; Have all documentation. The 4 tires continue to have printed color stripes on there tread. We had mounted 4 dedicated winter snow tires on day 1 of new OB T XT ownership.

 

Located north of the greater Atlanta area with delivery a possibility. A cross country road trip is planned for the 1st week in February. Atlanta to Vail: day one ATL to Nashville to St. Louis to Kansas City to Denver to Vail. Basically a Hwy I-24 to I-70 Road Trip. Willing to rendezvous along the route within reason for a forum member, avoiding costly shipping $.

 

 

Gotta Zoom ....

Edited April 29, 2020 by M. Schneider