THE Wheel & Tire Thread

[Tamra]

I used one of the wheel/tire calculators online, and according to it your setup in the rear will be 3mm closer to the suspension than ours (17x8, et 45 Enkei PFO1's with 255/40/17 Direzza Z2 tires, OEM trailing arms). We don't have much clearance, but it does fit as is. I imagine with a small spacer you would be fine on the inside suspension. However, it does say it will stick out 17mm further, so I'm not sure about fender clearance. We don't have the body on yet, so can't comment on our fitment.

We also have 17x8, et 45 Enkei PFO1's with 235/40/17 Z2's on the front, with the aluminum control arms with the castor mod (4mm spacer). We rub slightly at full lock, but we have not limited the steering yet.

[Pearldrummer7]

Scargo- we all know you like saying "I told you so"


The fronts fit great (17x8 +35)



The rears... (18x9.5 +38) aren't even remotely close. I measured quickly and need at least an ~8mm spacer to comfortably clear I think. Which is too much I think. I'm sure Wayne's mod (which I intend to do either way) will help with that, but not that much I think.




According to Rev F of the manual, I can run this size -_- That's what I get for listening to the manual!

[Scargo]

Nice looking wheels. I had it in my head that you were getting NT03s, which have the ring I don't care for.
You need ARP studs anyway. Get them and buy the adapter or send the rear wheels back if you can. I'm not familiar with the Wayne fix for the trailing arm unless it is to move the front trailing arm mount as far inboard as you can.

[Pearldrummer7]

Nice looking wheels. I had it in my head that you were getting NT03s, which have the ring I don't care for.
You need ARP studs anyway. Get them and buy the adapter or send the rear wheels back if you can. I'm not familiar with the Wayne fix for the trailing arm unless it is to move the front trailing arm mount as far inboard as you can.

I like the wheels a lot. And at 15.6 and 18.6 lbs, they're pretty light. Wayne cuts and welds the trailing at the end that attaches to the spindle.

I'll be trying to send them back for 17x9 +35mm RPF1's. Cheaper tires, and lighter overall (wheel + tire). Might even fit

Scargo- is it possible to install ARP studs in the rear without removing the wheel bearing? Maybe through the ABS slot or something?

[Wayne Presley]

Nice looking wheels. I had it in my head that you were getting NT03s, which have the ring I don't care for.
You need ARP studs anyway. Get them and buy the adapter or send the rear wheels back if you can. I'm not familiar with the Wayne fix for the trailing arm unless it is to move the front trailing arm mount as far inboard as you can.

He's talking about my wide wheel trailing arms.
http://www.verycoolparts.com/home-copy-3.shtml

[wleehendrick]

I'll be trying to send them back for 17x9 +35mm RPF1's. Cheaper tires, and lighter overall (wheel + tire). Might even fit

Those will definitely fit. My rears are XXR 18x8.75" +35 (255/35 Kumhos mounted) and I have at least 15mm of clearance with OEM trailing arms.

[Wayne Presley]

The rears... (18x9.5 +38) aren't even remotely close. I measured quickly and need at least an ~8mm spacer to comfortably clear I think. Which is too much I think. I'm sure Wayne's mod (which I intend to do either way) will help with that, but not that much I think.

Pearldrummer, I'm running 18x9.5 Enkei Kojins with +40 offset and clear my arms so your +38 RPF01 will have 2mm more clearance with my arms

[Scargo]

Sounds like Wayne may have the solution!
I have only done late-model (GR) and it can be challenging, but doable without pulling the hub out. In one case I just ground a small spot on the flange of the upright and was able to wiggle them past. Might have ben the front... You can use the ABS hole in the backing plate, too. Here's a how-to. Now, I AM NOT advocating grinding down the heads, but assuming you are not using ABS then just open up that hole. It can still be used but alignment of the sensor is trickier.
Studs don't have to be for a Subaru, either. In fact, if you haven't spent $500 for Ti lug-nuts then switch to 1.5 thread pitch studs. The 12x1.5 nuts are far more common, plentiful and a little cheaper. Just get studs with the .565" knurl. Look on Summit's site. You want a Mitsubishi Evo stud. Amazon may be cheapest.

[Pearldrummer7]

Pearldrummer, I'm running 18x9.5 Enkei Kojins with +40 offset and clear my arms so your +38 RPF01 will have 2mm more clearance with my arms

Wayne, what size tires are on the 9.5?

Sounds like Wayne may have the solution!
I have only done late-model (GR) and it can be challenging, but doable without pulling the hub out. In one case I just ground a small spot on the flange of the upright and was able to wiggle them past. Might have ben the front... You can use the ABS hole in the backing plate, too. Here's a how-to. Now, I AM NOT advocating grinding down the heads, but assuming you are not using ABS then just open up that hole. It can still be used but alignment of the sensor is trickier.
Studs don't have to be for a Subaru, either. In fact, if you haven't spent $500 for Ti lug-nuts then switch to 1.5 thread pitch studs. The 12x1.5 nuts are far more common, plentiful and a little cheaper. Just get studs with the .565" knurl. Look on Summit's site. You want a Mitsubishi Evo stud. Amazon may be cheapest.

My fear is not that they'll fit or not, it's much more that there's no reason for the size, cost, and weight if I'm only running 255 tires, which should fit nicely on a 9" wheel (perhaps even nicer than on a 9 than a 9.5).

[Scargo]

I understand. I did not say this before but the stock studs are prone to failing when highly stressed, as during track days+. They are not reliable. They snap off in an unpredictable fashion and they get chewed up. Sometimes, at the track, I am changing wheels three~four times a day. Constant re-torquing. Weight of longer studs in the center of the hub is insignificant. It does, incrementally increase un-sprung weight but it's still insignificant. Just do them...

[Wayne Presley]

Wayne, what size tires are on the 9.5?.

I'm running 265/35/18's

[Pearldrummer7]

I'm running 265/35/18's

Excellent. Food for thought. Probably sending you my arms to hack up

I understand. I did not say this before but the stock studs are prone to failing when highly stressed, as during track days+. They are not reliable. They snap off in an unpredictable fashion and they get chewed up. Sometimes, at the track, I am changing wheels three~four times a day. Constant re-torquing. Weight of longer studs in the center of the hub is insignificant. It does, incrementally increase un-sprung weight but it's still insignificant. Just do them...

I meant weight of 18x9.5's vs. 18 or 17x9's. The stronger studs make perfect sense.

3-4 times a day is a lot!!

[Scargo]

I thought you might have.
Not a lot of changing if you arrive with rain/street tires (in my case Michelin Pilot Super Sports) on your trailered car then change to dry tires and then to wet and then back to dry (repeat as necessary) and/or need to rotate them based on wear. You get used to it. I have a small trace of anti-seize on my studs and make a small torque allowance for it.
Since race tires don't tend to hold air that well I usually go back to the Michelins when I'm done...

[Pearldrummer7]

So, how does the FFR world like 235/40/R17's on the fronts? My 17x8 +35mm wheels would probably rather have 235 wide tires than 215, but the 235/40/17 is too tall, is it not(24.4")? I don't want to have to run a 215/40, but if it's my only option for a non-slick tire I will.

Tamra, you said you only rub slightly at full lock. Any photos of clearances?

[Silvertop]

The size tire you plan on running on the rear has a LOT to do with what size will work on the front. FFR and others who have completed cars and driven them at speed on race tracks have already determined that the car handles best with front tires that are at least 30 mm or so narrower than the rears. For example, since I'm using stock Subie wheels, and because my car will be an NA pure streeter, I'm planning on running 225's on the rear (widest tire that will fit the rim), and 205's on the front. I'm actually debating going down to 195's on the front to get a little more range between the fronts and the rears, to get a better grip balance. I'm not remotely suggesting you do that -- but the point is that if you want to run big tires on the front, you will want to run REALLY big tires on the back. Unless you are planning on doing that, my thought would be not to go bigger than the recommended 215's on the front. Unless maybe you like the idea of having the rear be a little "loose".......... I'm no expert, just sayin'

[Pearldrummer7]

The size tire you plan on running on the rear has a LOT to do with what size will work on the front. FFR and others who have completed cars and driven them at speed on race tracks have already determined that the car handles best with front tires that are at least 30 mm or so narrower than the rears. For example, since I'm using stock Subie wheels, and because my car will be an NA pure streeter, I'm planning on running 225's on the rear (widest tire that will fit the rim), and 205's on the front. I'm actually debating going down to 195's on the front to get a little more range between the fronts and the rears, to get a better grip balance. I'm not remotely suggesting you do that -- but the point is that if you want to run big tires on the front, you will want to run REALLY big tires on the back. Unless you are planning on doing that, my thought would be not to go bigger than the recommended 215's on the front. Unless maybe you like the idea of having the rear be a little "loose".......... I'm no expert, just sayin'

this agrees with the two FFR guys I talked to today about this. I guess 215 is what I'm going for! Cheaper, anyway My real concern is that it is too narrow for a 8" wheel, but seeing stance guys fit the tires they do.... I'll probably be okay.

Thanks, Silver!

[Bob_n_Cincy]

The size tire you plan on running on the rear has a LOT to do with what size will work on the front. FFR and others who have completed cars and driven them at speed on race tracks have already determined that the car handles best with front tires that are at least 30 mm or so narrower than the rears. For example, since I'm using stock Subie wheels, and because my car will be an NA pure streeter, I'm planning on running 225's on the rear (widest tire that will fit the rim), and 205's on the front. I'm actually debating going down to 195's on the front to get a little more range between the fronts and the rears, to get a better grip balance. I'm not remotely suggesting you do that -- but the point is that if you want to run big tires on the front, you will want to run REALLY big tires on the back. Unless you are planning on doing that, my thought would be not to go bigger than the recommended 215's on the front. Unless maybe you like the idea of having the rear be a little "loose".......... I'm no expert, just sayin'

Hey Silvertop.
I was running 205 front and 225 rear at my walesburo autocross test. The car was pretty loose.
I was in go kart mode.

http://youtu.be/sZ7PRMYRqRw

Bob

[Silvertop]

Well, that was entertaining!! And thanks for that input. It kinda confirms my concerns. For me, that means I will probably need to either go a little bigger at the rear (which means buying different $wheels$) or dropping down smaller on the front. Or be prepared to be a little "loose"

[Tamra]

So, how does the FFR world like 235/40/R17's on the fronts? My 17x8 +35mm wheels would probably rather have 235 wide tires than 215, but the 235/40/17 is too tall, is it not(24.4")? I don't want to have to run a 215/40, but if it's my only option for a non-slick tire I will.

Tamra, you said you only rub slightly at full lock. Any photos of clearances?

Here's the front. I don't have a photo of them at full lock, but we have a bit of clearance turning toward the passenger side, and just hit at full lock turning toward the driver. These are 235/40/17 Direzza Z2's on 17x8's et 45 PFO1's. Note we have aluminum control arms and the caster mod with a 4mm spacer.


The rear, 255/40/17 on 17x8 et 45 PFO1's.

[Scargo]

This is an interesting discussion. I feel like a leper with my setup...
I would ask: What is full lock? Do you really need to worry about that as a high priority? I was told that 20+ degrees of turn was enough (for me). Rubbing can and should be addressed with stops (in the front) wheel spacers, rim diameters, rim offsets, widths and tire sizes. Options are almost unlimited.
Some issues can be addressed with juggling spacers in the suspension mounts and using the available space between the brackets to your advantage. This is without the consideration that you could (heaven forbid) move suspension mounting points. The body can be flexed, stretched and cut.
This doesn't even get into the looks issue. If you want stance or just big then I will bow out.

[Pearldrummer7]

This is an interesting discussion. I feel like a leper with my setup...
I would ask: What is full lock? Do you really need to worry about that as a high priority? I was told that 20+ degrees of turn was enough (for me). Rubbing can and should be addressed with stops (in the front) wheel spacers, rim diameters, rim offsets, widths and tire sizes. Options are almost unlimited.
Some issues can be addressed with juggling spacers in the suspension mounts and using the available space between the brackets to your advantage. This is without the consideration that you could (heaven forbid) move suspension mounting points. The body can be flexed, stretched and cut.
This doesn't even get into the looks issue. If you want stance or just big then I will bow out.

You're right. There are so many variables; it's very intimidating to me at least!

I think it's safe to say the vast majority of the people on here want performance over looks. I for one couldn't care less about looks, and can't stand the idea of "stance". I only mentioned it before because I'm concerned with not having bloated tires for once haha but many people do far more stretching than a 215 on an 8" wide wheel without issue, I think.

[Scargo]

For a tire like a Michelin Pilot Sport A/S 3 215x45x18, all-season performance tire 8 inches is not stretching it, though it is at the high end of the recommended width. It's important to stay within the recommended ranges.
If racing, sidewall flex is an important component of suspension performance and good handling. It's part of a tire's job to have some compliance and flex and make up for the imperfections in the suspension's geometry withing a reasonable range.
When you stretch a tire beyond it's designed range it doesn't do as good a job. Similarly, cramming it on a small rim does the same kind of negative things and affects the footprint.

[Pearldrummer7]

For a tire like a Michelin Pilot Sport A/S 3 215x45x18, all-season performance tire 8 inches is not stretching it, though it is at the high end of the recommended width. It's important to stay within the recommended ranges.
If racing, sidewall flex is an important component of suspension performance and good handling. It's part of a tire's job to have some compliance and flex and make up for the imperfections in the suspension's geometry withing a reasonable range.
When you stretch a tire beyond it's designed range it doesn't do as good a job. Similarly, cramming it on a small rim does the same kind of negative things and affects the footprint.

Yup, which is where my concern comes in. I've only had 235+mm tires on my 8" wheels, but I think the Direzza ZII runs fairly wide, and I hope this will work. If not, I'll be rethinking front wheels, of course.

[wleehendrick]

If you look at the detailed specs, available at TireRack for ones they sell, and usually at the manufacturer's website, it will detail the nominal rim width and acceptable range for each model's size.

[iblackwe]

I have a question regarding wheel fitment. I have used the google spreadsheet at the beginning of this thread and found that for the front I have -24mm protrusion and in the rear its -65mm Protrusion, is this correct? The donor car I bought came with "street gear" aftermarket tires and rims which are 205/40/17 with a 7" width. If this is correct I am assuming I need to buy wheel spacers, any suggestions on where to get a good deal on these, It would be roughly 1" in the front and 2.5" in the back. Also, if I were to replace the wheel studs with ARP which length of stud should I be looking for?

Thanks!

[Scargo]

I've been accused of over-thinking. You might be doing that or trying to save money foolishly. I believe (especially if you pay someone to do some of the work required) that you could buy new rims for what studs and spacers would cost. There's some decent new $125 wheels out there and lots in the 150-200 range. Or, look for used ones. I would not discourage you from installing studs if you're going to do any track time, otherwise I would save my money in that area.

[C.Plavan]

I posted this originally in the wrong thread-

FYI- Data Point on the new Hoosier R7's

225/40 R17 in front are the same width as the 235/40 R17 Toyo RR's. Just a tad shorter in height
245/40 R17 in rear are a tad wider as the Toyo RR 255/40. A tad shorter also.

[Scargo]

Related: Santiago said, "According [sic] the early R&T article, FFR's blue 818R mule had a front track of 59.5" and 59.0" rear track."
Is it relevant that the front track was wider than the rear? Was it just happenstance and they ran with what they had?
Why wouldn't you want a wider stance in the rear? Isn't it more common than not with mid-engined cars?

[Hobby Racer]

I posted this originally in the wrong thread-

FYI- Data Point on the new Hoosier R7's

225/40 R17 in front are the same width as the 235/40 R17 Toyo RR's. Just a tad shorter in height
245/40 R17 in rear are a tad wider as the Toyo RR 255/40. A tad shorter also.

Chad, given that the R7's are the same width up front, do you think you will have the same rubbing issues, or will the shorter height be just enough to let them clear in the long sweepers?

[C.Plavan]

Chad, given that the R7's are the same width up front, do you think you will have the same rubbing issues, or will the shorter height be just enough to let them clear in the long sweepers?

It's still going to rub, but not when racing. It will rub just trying to maneuver tight turns (paddock). I got 1 full steering wheel turn with the Toyo's, and about 1 1/4 with the Hoosiers until it hits the frame. I raised the front up 1.5 turns on the coilovers to increase the ride height a bit. The Toyos were rubbing the upper fender inside the lip, so I think I fixed that also.

Even with the Toyo's on the track, there was never an issue with the tires rubbing on the frame while on the race track. (Hairpins etc) The Toyo's are fine for racing. I'm just use to and prefer the Hoosiers. They offer a better contingency and tires sizes for me. I'll know more in two weeks after my first race. I'm going to be practicing all day Friday, so I hope everything holds together.

[Scargo]

Hoosier A7/R7 225x40x17=23.8 OD and 9.6 section width.
245x40x17= 24.3 and 10.3
Chad, what are your track widths?

[R.Spec]

Thinking about running rso5rr wheels 18x9.5" inset 43 in the rear and 18x8.5" inset 42 in the front. Will I run into issue with the 8.5" in the. I have huge brakes that I need to clear. But I am worried about lock to lock and the tire hitting the firewall.

http://enkei.com/wp-content/uploads/2015/01/rs05rr.pdf

[Scargo]

R.Spec: Dude! You don't even mention tires. Have you read any of this thread? Lock to lock in the front is manageable. That has been discussed too.
The Stoptechs won't work with hardly any, if any, 17" wheels, so that is a significant issue right there. You need to be below 24"diameter in the front, I believe to keep from rubbing the frame/front bulkhead. I don't know what kind of 18 inch tire would work...
That's just a start.

[Hindsight]

I really wanted those RS05RR wheels but just don't feel going with an 18 in front is going to be very doable. I'm pretty sure it's been done before but but the front is going to be ultra low profile and it might be tough or impossible to find a top-tier tire that fits and also has a matching version for the size you need in the rear. I put extremely good tires at the top of my list. Wheel selection is then limited to the available sizes of tire I like. Maybe someone will prove me wrong? I still haven't bought wheels or tires yet.......

[metros]

Just got my Mach V Motorsports 'Awesome' and 'wicked awesome' wheels. The 'awesome' wheels are 17x9, +42 offset and 17.8 lbs. The 'wicked awesome' wheels are 18x9.5, +42, and 19 lbs. Obviously I'll be using the wider wheels in the rear. I'll be using Yoko AD08R tires 235/40/17 and 265/35/18.

I was testing a 10mm spacer in the front. At full lock, the driver side cleared by the width of a credit card, while using a 10mm spacer. At full lock, the passenger side cleared by 1/8". Neither side has any additional caster mods right now.

The rear wheels will require a 15mm spacer. I tested them with a 10mm and they were just barely touching the shock.

Pictures!
Here's what they look like in the sun after all that love.


Room light:


Installed!




Rear wheels look meaty


Front wheels installed:

[Tamra]

So want to ask everyone for a fitment opinion. We are wanting to go DOWN in wheel diameter, for autocross. 15" fronts, 16" rears. The reasoning behind this is an easy drop in height without affecting bump steer or other suspension geometry. Our current "daily driver" tires are 24.4" diameter in the front, the new ones would be 22.7" diameter. We are sitting at a 4" ride height right now, so the tire reduction would give us a nearly 1" drop in the front. The rear would be about a 3/4" drop, so we would have a little rake as well.

We will be running Hoosier A6/A7's in 245/40 square to start (mostly because we got the rears on closeout for $90/each!! Thank you Hoosier). Later the rears will likely go to a wider tire size. The tires are decided, we just need the wheels now.

Wheel options we are looking at:

15x8.25, et 25 (front)
16x9, et 28 (rear)

The fronts, we are mostly concerned about not hitting the suspension. We will flare the the fenders if necessary. Do you think the 15x8.25 et 25 would meet this requirement?

The rears, we do not want to flare the fenders - we want to stay inside the wheel wells - and do not want to hit the suspension. Do you think 16x9, et 28 would fit?

We know we will likely have to change the front brakes in order to fit the 15" wheels, and we are fine with that.

[Bob_n_Cincy]

Do you think 16x9, et 28 would fit?

My 16x6.5 et55 OEM wheel just clear the rear suspension by 1/4".
You are 2.5" (63.5mm) wider / 2 = 1.25" (31.75mm)
offset 55mm-28 mm = 27mm

So 31.75mm - 27mm = 4.75mm closer than me.

I think you will clear by a credit card, but will rub trailing arms during acceleration because of suspension twist.
Bob

[Tamra]

Thanks Bob, that is very helpful.

[Tamra]

Based on your recommendation, we went with 16x9, et 20 in the rear. Hopefully it won't poke out of the fenders. Also went 15x8, et 20 on the front.

Looking at our suspension, we would be mostly concerned about the upper link, not the lower link. However, we can modify the spacers and shift it inward if necessary. We'll let you know in a week or two.

[Tamra]

Unfortunately we were not able to get those sizes... tried twice through two manufacturers and they were all out of stock/discontinued sizes, despite still being listed. The next step up would have been fully custom and cost an arm and a leg (Volk/SSR level), so we opted to find something more readily available and less harsh on the pocketbook, since these are just going to be autox wheels.

Ended up with 15x8 et 25 and 16x8 et 25. Will report back in a week or two when everything is here.