Aug 15, 2020 update to the Toyota MR2 Turbo project car

Project MR2 Turbo: How to Find the Correct Wheel and Tire Combo for an Odd Fitment

It feels awkward referring to our 1991 Toyota MR2 Turbo as an “older” car. After all, we still remember it winning our Editors’ Choice award as the best new car back when it came out. That we dove that first mid-engined turbo Toyota nearly 30 years ago seems fairly absurd, yet here we are.

And here we also are: Our car also required some new wheels and tires, which is where we ran into some issues. The second-generation MR2 is notoriously tricky to fit modern wheels and tires on. They were originally equipped with 14-inch wheels in 1991–adding 15-inch units a couple of years later to the OEM specs–but you can see the problem already when trying to find an appropriate setup. These days, even the cheap econoboxes come on 17s at a minimum. And while there are some 15-inch wheel options available that would fit our MR2, the availability of modern, sporty tires in those sizes is far from ideal.

So we almost had to work backward. First, we needed to identify some tires that we deemed appropriate, then find some wheels to fit them. For our tire choice, we knew we wanted something extremely sporty, but not a dedicated track tire. Basically most of the current crop of 200tw rubber in the Extreme Summer Performance category filled our needs nicely. This was not going to be an everyday commuter, or a “fighting for the last hundredth” track car, but it needed to be able to do mundane daily duty when the mood struck, or do an autocross or track day without changing tires. The 200tw scene is essentially built on that ethos.

For sizes, our most extreme limiting factor was the overall diameter in the front. Due to the proximity of the spring perch to the hub, you’re limited to around a 24.5 inches overall diameter in the front with the stock spring perches in place. Switching to coil-overs gives you more options, because the wheel wells are physically large enough to contain larger tires, but we weren’t ready to make that leap (yet). In the rear, we had a lot more options and leeway vertically. There’s all kinds of room vertically between the hub and the perch in the rear, so width becomes your limiting factor for a tire in the rear.

Taking all this data and cross-referencing what we could use with who had those sizes in a tire we liked led us to the Falken Azenis RT660. While our testing and the tests of other outlets have shown that there may be 200tw tires that can run an absolute faster lap time that the RT660, it’s regarded as one of the best tires in the category for all-around performance on both street and track. So while it may give up a couple of hundredths to other rubber, it makes up for the deficit by being extremely livable in a variety of conditions.

For sizing, the front dictated a 23.8-inch-tall 215/40R17. There were 15- and 16-inch options available, but wheel availability and the additional desired width in the rear weren’t always options in those diameters, so 17 was seen as the best all-around use of resources.

For the rear, we wanted to fill out the wheel wells and take advantage of the available space, but we didn’t want to have to get into modifying the sheet metal for clearance. Preliminary measurements showed we had a little over 10 inches of space between the strut and the fender lip, and the 10-inch-wide, 24.8-inch-tall 245/40R17 RT660 looked like it would be the perfect fit in the wheel well.

Now for wheels. Our current setup was a set of Derpmaster 3000 alloys, likely bought off of some Balkan eBay pirate clone site that stole everyone’s credit card number after it sent them crappy wheels. Sure the wheels were ugly, but at least they seemed to be of suspect quality as well.

So while anything would be an upgrade, we still wanted to choose a high-quality wheel that properly fit and also enhanced the MR2’s retro vibe since this car is now older than most of the NFL‘s starting lineup. And, much like our tire situation, we thought we’d also be limited in wheel choice by a tight set of available options.

Fortunately, technology has caught up with wheel demand in the last few years, and the current generation of flow-formed wheels offer an exceptional strength-to-weight ratio, and a wide variety of sizes at reasonable costs that just weren’t realistic only a few years ago.

The tooling for flow-forming can be quite expensive, and the learning curve for properly producing wheels can be steep, but the payoff is in increased versatility of the molds,” explains Konig’s Scott Weiss. "That gives us flexibility down the road that we don’t have with other manufacturing methods, and lets us produce wheels to meet more and more specific demands.” As Scott adds, all wheel production ultimately flows from customer demand, but the versatility of flow-forming allows Konig to react to and serve more niche audiences.

For us, that meant the availability of Konig’s flow-formed Hexaform model–a style that looks a bit like something from the ’90s JDM scene while invoking some of the OEM wheels Toyota offered on the SW20 MR2 back in the day–in a variety of sizes and offsets. A 17-inch model weighs about 17 to 19 pounds depending on offset, and figure about a grand street price for a set of four. 

To figure out exactly what fits under our wheel wells and inside our Falkens, we took some measurements, but we also consulted some testimonials. The “gallery” section of the Fitment Industries website is an exceptional resource when it comes to finding workable wheel specs for many models of cars. In their gallery, you’ll find posts from actual users listing wheels specs, tire sizes, car setup (lowered, stock height, etc.) and any modifications required to fit the combo together (cutting, flaring, fender rolling, etc). We found it to be an excellent resource to back up our own measurements and to get an idea of what to expect in regards to potential complications in fitting together our combo.

Ultimately, our setup:

Front wheels: 17x8 inches with 38mm offset

Rear wheels: 17x9.5 inches with 38mm offset

Our measurements showed that we might be a little close to the strut housing on the inside of the rear fender, but it would ultimately come down to the shape of the tire once mounted, and it could be easily solved with a thin spacer in any case.

When our wheels arrived, we first mounted them on the car without tires to confirm fit. (Konig will not accept returns once the wheels have been mounted.) This gave us a chance to confirm that our measurements were correct, and check that our tire should fit fine within a certain margin of error. As we suspected, the inside edge of the rear wheel was pretty close to the strut housing, but tire shape would ultimately dictate our path.

With the Falkens mounted up, there was a very slight bit of “stretch” to the rear tires–enough to create plenty of clearance between the spinning assembly and the strut housing and preclude any need for a spacer. The fronts–as we suspected–fit fine.

We did put an ever so slight roll on the rear fender lips–mostly to take a sharp edge out of the equation, although we don’t think at our current ride height that lip would ever be in play unless something extremely bad happened. Still, we considered a small fender massage to be a little insurance policy against a disaster, no matter how unlikely that disaster was in the first place.

Our final product fits great, looks appropriate and provides performance beyond even what Toyota ever intended for these cars. Modern, high-performance rubber is a real transformation for older cars, giving them grip you’ve barely ever dreamed of while retaining uncanny road manners.

As soon as our new Konig Hexaform wheels arrived, we test-fit them to make sure our measurements checked out. Once they bolted up smoothly, we felt safe having our Falken tires mounted.

The front wheels had good clearance from the strut housings, but the distance from the wheel to the spring perch on SW20-chassis Toyota MR2 is restrictive. A short tire is a must for cars with stock spring perches.

The rears have plenty of vertical room, but our 9.5-inch-wide wheels were pretty cozy with the strut housings. A favorable sidewall profile makes rear fitment much tidier.

The 245/40R17 Falken RT660s in the rear have just a very slight amount of stretch, creating a little extra clearance to the strut housings. Once mounted, it looked like our rear fitments would be fine without any spacers needed.

The rear tires filled out the wheel wells nicely, without any hint of interference on the inside edges. Under full compression, though, we worried that there could be some fender interference so we decided to put a bit of a roll on the rear fenders–just to be safe.

We didn’t massage the rear fenders much, just enough to take the sharp horizontal edge out of play.

Our final product uses modern wheel and tire technology to create a pleasing, retro look.

Quick Tips for Using a Fender Roller

Most metal cars have a fairly aggressive lip inside the fender opening that stiffens the fender and provides support to the arch. It can also be a dangerous point of contact for tire sidewalls on a lowered car with wide tires. So rolling that sharp edge over is an easy way to get a potential hazard out of harm’s way.

Fender rollers are fairly affordable these days. Tire Rack will sell you one for $139 with free shipping, but rental units are still available from a variety of vendors for around $40/week plus shipping. But their ubiquity doesn’t mean you still can’t screw things up real bad and real fast. So here are a few tips when working with a fender roller:

  1. Things can go very wrong in a hurry, so work in very small increments. When rolling fender lips, we’ll turn the main adjustment screw about a quarter turn for each “bite." It’s much better to take too many small bites than too few large ones and risk creasing some sheet metal.
  2. Not all fender openings are circular. In fact, hardly any are. But the fender roller–being anchored by the hub–will sweep in a circular arc. This means it could put more tension on a certain part of the fender than another during a sweep. So when you make that first contact and get ready to start rolling, be sure to check the tension through the entire range of motion before you lean into it.
  3. Heat is your friend. Rolling the fender lip can sometimes crack the paint in that area. Heating the lip with a heat gun softens the paint and softens the metal to make for less risk of collateral damage. Don’t use too much heat or you can blister the paint, but raising the temperature of your work area can make your job easier and less risky.
  4. Tension works both ways. Remember, while you’re pushing up on the fender lip, the fender is pushing down on your suspension. This articulation can actually aid in negotiating non-circular fenders as we mentioned before, but understand as your suspension droops to the point where it runs out of travel, the tension on the roller could change dramatically from one adjustment to another.

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Comments
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z31maniac
z31maniac MegaDork
8/12/20 8:47 a.m.

Always loved these, pain about the staggered setup and restrictions in fitting wheels/tires, but quick question:

"When our wheels arrived, we first mounted them on the car without tires to confirm fit. (Konig will not accept returns once the wheels have been mounted.)"

Did you mean once the tires have been mounted on the wheels Konig will no longer accept returns?

Tyler H (Forum Supporter)
Tyler H (Forum Supporter) UberDork
8/12/20 9:14 a.m.

Looks good!

JG Pasterjak
JG Pasterjak Production/Art Director
8/12/20 9:17 a.m.
z31maniac said:

Always loved these, pain about the staggered setup and restrictions in fitting wheels/tires, but quick question:

"When our wheels arrived, we first mounted them on the car without tires to confirm fit. (Konig will not accept returns once the wheels have been mounted.)"

Did you mean once the tires have been mounted on the wheels Konig will no longer accept returns?

Yeah, to clarify, once they've had tires mounted on them they're yours.

mr2s2000elise
mr2s2000elise SuperDork
8/12/20 9:28 a.m.

Due to tire problems, I have been running 195/50/15 and 225/45/15 Hankook RS-4 in place of OEM 195/55/15  - 225/50/15 . I refuse to put 17s on my MR2 .To each their own.

 

 

However, finally there is a perfect OEM size tire, and I ordered 2 sets for both my MR2. Advan a052, in OEM 15inch sizes. Cost me $800 for a set. 200 TW, which is way more than the 80/100 TW I DD on my Elise with.

JG Pasterjak
JG Pasterjak Production/Art Director
8/12/20 9:51 a.m.
mr2s2000elise said:

. I refuse to put 17s on my MR2 .To each their own.

Totally defensible position. I REALLY wanted 15s, but just couldn't make all the moving parts of the equation work together between widths and styles and tire classes and whatnot. A set of the most period-appropriate 17s seemed to be a reasonable compromise, and will likely be pretty future-proof.

Benswen
Benswen New Reader
8/12/20 2:33 p.m.

I'm on the hunt for some new wheels for my '91 MR2.  I like your new setup, I just prefer the look of smaller diameter wheels with a bit more meat on the tires.  Currently running 15x7's all around with 195/55 front and 205/55 rear Kuhmo's.

Love the style of these Konig wheels, I just with you could get them in 16x7 and 17x8.

hybridmomentspass
hybridmomentspass New Reader
8/15/20 8:31 a.m.

Have a 91 turbo as well

Came from PO with 14" stockers

I picked up a set of the 15" 93+ wheels off CL, and love them (I had a 93 turbo years ago)

But there is such a limited amount of tires for these cars, and I find that many cost more than a 17" of similar variety, that IM looking for a set of wheels in 17 for the car. Something simple, timeless. Something that looks, almost, factory. A set of SSR integrals would fit the bill perfectly, as they are similar to the 98-99 wheels on the SW20

slantsix
slantsix Reader
8/15/20 2:05 p.m.

Good information there. Especially on the fender roller considerations.

 

Thanks.

 

Greg

BryanH
BryanH
8/17/20 9:43 p.m.

A worthwhile upgrade from the Derpmeisters!  

I'd love to see an SW20 on wide 15" wheels with the A052s.  I put the 205/50-15, 225/50-15 Yokohamas on my '93 Turbo's stock sized wheels (15x6, 15x7) and they're balloons.  I think this tire combo might look pretty amazing on something more similar in width to the new hotness pictured in this article.  

JohnFBZ
JohnFBZ None
8/18/20 2:41 p.m.

Sadly, 15 inch tire sizes appear to be going away, especially in the more normal tire types (not 200 TW or track tires). I do think they look the best on the SW20 MR2.

These are 15x7.5 +37 Rota Slipstreams I had kicking around. The fronts have a 12 mm spacer, the rears have no spacer. I'm thinking that coilovers up front with camber plates instead of bolts would allow me to get rid of the wheel spacer. In the rear, there's plenty of room to the strut that adding another half an inch of wheel inboard would be really easy.

Another long-term risky wheel size would be the 16 inch wheel. I recall at last year's Nats the yellow STS SW20 was running Volks or SSRs in 16 inch on Yokos, but even then, the tires look like drag radials. I was eyeballing getting the Spoon SW388 (the original design which "inspired" the Rota Slipstreams) in 16x7.5 (STS size). However, I'm not particularly keen on buying 4K worth of wheels from Japan... 

David S. Wallens
David S. Wallens Editorial Director
8/18/20 2:49 p.m.

To see an SW20 on 16s, check out this Instagram account. 

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