17x8 - 40mm Offset - 225 Tires

[polyol]

So 17x8 w/ a 44mm offset with 225 Hoosiers.

Has anyone tried fitment on a stock rig with this setup, does not have to be exact I a just trying to get an idea of what I am up against before I go drop a couple grand? I am not afraid to run spacers and or rolling fenders. That said this is a brand new rig and would like plug and play if that is possible.

This would be for AutoX with Hoosier A7's and not a street setup. I understand that every tire is different etc, I have a lot of experience making tires fit on cars that never should fit. I just need a little input where the rub would be or if this iseven possible.

I could always go to a 16' rim and run 205's, but as is Hoosier does not make a 205 in a 17" size.

Thanks, Paul

 

[KuanR]

I'm running 17x8 37mm offset 215/40 tires lowered on springs and I get only get the slightest bit of rubbing with the fender liner on hard corners.

I'm debating on getting 235/40 tires once I get my KW V3 coilovers installed. I don't mind a tiny bit of rubbing on hard corners or rolling my fenders either.

Please update if you do go with the A7 because they are slightly bigger than regular street tires like the Dunlop ZII I'm running now

Sent from my SM-N9200 using Tapatalk

 

[BlueBullet]

I am running Michelin Pilot Supersports on FF10 tirerack wheels that are 17x7. The tires are 215/45/17 and with a little carpet adjustment I only rub on really bad bumps or tight turns. I would not go larger and kind of wish I had gone with the 215/40 because gearing was changed a fair bit. I really notice it above 5.5k rpm in anything over 2nd gear and my gauge is about 4 mph off at 65 mph. I thought it would help with fuel mileage but also found that to be a wash. Below 2.5k rpm the mileage is the same or better but once i go over 80 mph I drop lower than stock. For handling and rain these tires are great.

 

[polyol]

Thank you for the replies. I may have to do some measurements and see what I come up with. Maybe I will get a 16" rim and run 205's, they are cheaper for sure...just want something more significant in width for the track.

 

[Butterybunz]

You should be fine, especially if you roll your front fenders. I have been autoxing on 16x7 et40 225/45/16 tires lowered on coil overs.

 

[polyol]

Exactly what I wanted ^^^

 

[RAAMaudio]

This needs to be in a sticky as I have posted it dozens of times.

You need to look at the real specs when picking tires, 225/40, etc, is not an actual spec and far off on many tires, especially Hoosiers.

Diameter, section width, tread width and weight are what you need to look at.

Stuffing the widest tire you can under the fenders is not always the way to make the car faster, you need sidewall support, camber, lower weight when possible...

This car is not setup well for 17" wheels, far better off to go with 15 or 16" wheels in most cases and for many reasons.

(Hoosier example, 225/45/15 R6 has a tread wide enough it could be considered a 245, would not fit the rear of my car with camber change, rolled and pulled fenders, 15x9 +35 wheels. The 225 Rival S and 225 RA1 fit.)

 

[polyol]

I am a regional autox champ, so I get a lot of what you are saying. That said I do not claim to know everything, certainly not with this car.

I just needed to know what can or cannot fit ballpark. I have no intention of being nationally relevant with this car, just having fun with it.

I do agree with you, I am moving away from a 17" to a 16" for this setup for a lot of reasons. I plan to get 225/50/16 Hoosier on a 16x8" rim, just need to work out the offset measurements and if I need to roll fenders. If that doesn't work I will go 205/45.

 

[RAAMaudio]

Autocrossing can work with a bit overly wide tire better than road courses likely due to not staying in one direction for very long and the pace is so quick you have less time for the sidewalls to move, load up the suspension, etc like on long higher speed corners on a race track.

I just looked up the specs, the 225/50/16 is very tall at 24.7" but sometimes taller is better to keep you in second gear and off the rev limiter. If you are in a class where you can tune the car then it can be raised significantly and safely so you can run the shorter tire and save weight, rotational mass to stop and start moving, etc....

225/50/16, 24.7" tall, 8.8" tread width which is a very wide 225 and would be best on a 9" wide wheel for road racing and perhaps autocross.
9.4" section width, this is a very wide 225 and going to be a bit "pinched" on an 8" wheel, 9's if allowed require a rear camber change.
21 lbs with much of the weight far out from the center of rotation.

205/45/16, 23.0" tall, much easier clearance, a bit shorter than stock, would require more shifting unless you can raise the rev limiter in your class.
8" tread width is great on an 8" wheel, 8.5" section width, this is a very good fit on an 8" wheel, outside to outside the bead measures 9" on an 8" wheel. Just a tad bit of stretch which will provide much crisper turn in, feedback, quicker lateral transition.
17lbs, 4 lbs per corner less weight is a huge performance enhancement.

I know what tire I would pick, not the 225.

As an example of side wall specs not meaning much when picking tires, the 225/50/16 Bridgestone RE71R, one of the top max perf summer tires.
7.6 tread width, 9.2 section width, 24.9 diameter, 24lbs.

The only consistent spec is rim diameter, the rest can be about anything they want to put on the sidewall and dramatically different in reality.

--------------

I have not won a title in Autocross since the 70s's, we had our own regional organization, SCCA was not in the area. Since then I have built several fast cars the way I wanted them then ran the class they fell into, taking 2nds and 3rds in the wrong car for the class has been more rewarding to me than building the best car and winning easily, which I did in the 70's. First FWD was the first 1zz turbo Matrix ever done, not as good a car as this one for sure, far fewer mods than my ST, less power, still was second fastest SM class car in SoCal which means it was very quick as ran against RWD and AWD. Just saying these things to show I have a bit of experience in FWD and autocross and decades of researching tires.

---------------

All that said, the taller wider tire could still end up being a bit faster with the right driver, setup, etc...but likely it will be much more difficult to extract any benefit on a wheel not of optimal width for the real specs of the tire.

Hope this helps, that is the intention as always
Rick

 

[polyol]

No no...it is helpful. Ill take the criticism along with any help for sure. I actually like people to ask me "what the heck are you thinking dude".

My competitive rig is a stripped 2004 STi, street legal but hardly street-able. I do drive it to the events though. I run 285/30/18 A6's under her on 10.5" wide rims, at least I did but it looks like the A6 may be on its way out :/

I tend to go as wide as "practical". If I could fit a 275 under the rig in a practical sense, I would probably do it. Obviously that is unpractical, really I just want something fun for my 17 year old and I to blast on at the track while I drive it to work during the day. I will probably push the limits of tire width on an otherwise stock rig. At least that is what I always try to tell myself.

 

[KuanR]

I will probably push the limits of tire width on an otherwise stock rig. At least that is what I always try to tell myself.

This.

Please keep us updated on your progress, my tires are on their way out so it's time to think about what size to go with next.

I might even go with wider tires on the front for a reverse stagger setup.


Sent from my SM-N9200 using Tapatalk

 

[RAAMaudio]

Cool car, I got a chance to drive one of the first in the country and do some work on it as well

I had 18" V710 285's on 10.5 rims on my Forester XT, stock fenders, did not poke out, during a Pro Solo practice event, dusty parking lot, 1.6 second 60ft time I took second place in SM, full interior, roof racks, sunroof, looked rather stock except Cobb exhaust, wheels, Stoptech brakes, STI hood scoop, the only thing stock under the car was the block and heads. It still rode great, 28MPG on the road, was very quick on a road race course but I had to much money into it and wanted to go faster but power in a Subaru is very expensive and a bit of a grenade if you go very high and then the car is no longer a daily driver, a $90k Forester did not make much sense, parted and sold it off.

I tracked at MMP a few times, the last time the head instructor came down from the tower to check it out saying "I cannot believe the lap times you are running in what is it, a mini SUV?"

I asked if he had seen me get it sideways at 90 MPH and he said "we teach to not try to save it that far gone but you did a great job", I said I grew up in dirt and snow so was on automatic mode, just did it without thinking.

--------------

I have not studied a stock ST but they have rubber suspension bushings, rather stiff ones which helps a great deal in how it handles and feels but once past a certain point the stiffen up a lot and thus become none linear, why I have changed all the bushings to urethane with sleeves so they are far more free to travel and not stiffen at twisted.

That said, even as well setup as this car is stock it might be possible to get suspension bind from to much grip and not enough compliance in the suspension. When that happens it is a bit like hitting off the bump stops but there is rebound and compression going on, not good.

Couple that with less than ideally supported sidewalls allowing the chassis to move more than the tire patch, less feedback, etc....as mentioned in autocross the normal way to setup a car can be a bit different but the car can be much more difficult to control. I would think a bit more feedback would help improve a new driver more than ultimate grip with less overall feel and control.

--------------------

I am leaving AZ in 6 days or so, just started tuning the new turbo, if you want to see, go for a ride, etc, in a very modded FiST let me know, will see if we can work it out

 

[polyol]

Autox'ed this rig for the first time. I did ok in PAX but I must say that this car on stock tires is completely underwhelming. I would not even bother on these wheels next time...needs some serious work.