ITRCA

Hi all,

What do roadracers use for their ITR's for wheel and tire sizing? I'm trying to decide between 15x7 or 16x7 and I assume 225/50 all around.

badkarma wrote:Hi all,

What do roadracers use for their ITR's for wheel and tire sizing? I'm trying to decide between 15x7 or 16x7 and I assume 225/50 all around.

That'll depend on the class I assume. Do you mean for road racing or driving schools?

I'd run 15x7. Cheaper wheels, cheaper tires. R compounds and full slciks have very hard sidewalls so the advantage of small sidewalls with street tires isn't as big and I'd rather have the wheel mass closer to the hub.

I'm running 15X7 205/50 15" Falken Azenis. The wheels are Stern Auguzze's which are discontinued...

You'll find dave is correct about 16" being VERY expensive in comparison.

I'd even run 15x6.5 or 15x6 before I'd spend the extra dough for 16"...that is unless you're VERY serious about getting some traction w/light weight wheels & have lots o'dough

Thanks for the posts guys. I'll be running some time trial events. I saw on Kosei Japan's website their K-1's are doublespoke... look much nicer than the single spoke ones at Tirerack... anyone know where you can get those?

Those are the new design K1's that have not yet hit the states.

I have to agree 15x7 would be my choice.

Trey wrote:Those are the new design K1's that have not yet hit the states.

I have to agree 15x7 would be my choice.

Yeah, I emailed tirerack, they said they'll be here in a couple of months to replace the old K1's.

225/50/15's are too tall. 225/45/15 (Hoosiers) are the only tire I'm aware of in a 225 that will fit on an R. Even then you'll have to roll the rear fenders. That said, a good 205 (street or competition) tire will be more than enough for an R especially with 7-8 wide wheels.

SSR Compeitions are good choice for the R. Look good and are 7.5 inches wide and are about 10lbs. They are more expensive that other options, but are lighter and wider than most 15 inch wheels

TypeR 801 wrote:225/50/15's are too tall. 225/45/15 (Hoosiers) are the only tire I'm aware of in a 225 that will fit on an R. Even then you'll have to roll the rear fenders. That said, a good 205 (street or competition) tire will be more than enough for an R especially with 7-8 wide wheels.

SSR Compeitions are good choice for the R. Look good and are 7.5 inches wide and are about 10lbs. They are more expensive that other options, but are lighter and wider than most 15 inch wheels

Oh damn, thought 225/50/15 would fit. 205's are enough for traction?

It's funny, you guys make 16s sound so expensive... my daily driver is a Supra, try 18s. Last year we ran my friend's supra in a trial, 315s in the rear... one tire cost me enough to buy an entire set of 15s.

Does enkei make the the RPF1 in 15x7 5x114.3?

I run UKDM Type R rims which are the same size as US stock, 15x6JJ, but lighter at 12 lbs. each; I wrap them with Falken Azenis 205/50/15 tires. I'd like 15x7 rims better but at $400 for a set of the Euro R rims, I couldn't pass 'em up

They'll fit in front, but not in back. They really slow the car down though. Gearing is much taller, you can really tell the tires are bigger.

Traction is fine with 205's especially if you go with 7-8 inch wide wheels. The wider the better.

The 215/45/16 Azenis also fits, but is still taller than stock and only .1 in wider than the 205/50/15 Azenis, hardly worth the gearing penalty.

badkarma wrote:Oh damn, thought 225/50/15 would fit. 205's are enough for traction?

What offset 15x7 TE37 would fit over Spoon calipers? I'm guessing +45?

I *think* 42 or 43mm is about the correct offset, but I could be wrong. It might even be 38mm. Stock is 50mm btw.

badkarma wrote:What offset 15x7 TE37 would fit over Spoon calipers? I'm guessing +45?

I have recently installed 15x7 wheels with 45 mm offset for the track. The wheels are made by Team Dynamics in England and distributed in US by TeamdynamicsUSA. They weigh 13.2 lbs (I checked them).
For tires, I use 225/50/15 Michelin Pilot Sport Cup R compound front and rear. I removed the plastic trim in the rear fender and the fender liner in the front fender. I rolled up the fender lips using a baseball bat. My car is lowered almost 2" front and back using threaded body coil-overs. I took it to the track for the first time with these tires and I had no rubbing in the back, but when braking and cornering simultaneously, I had rubbing in the front, which I need to resolve. There was no rubbing when cornering without braking or when braking in a straight line. The tires do not rub on the inner suspension parts with 45 mm offset. It might be possible to use 50 mm offset wheels, but I am not certain. (50 mm offset moves the tires closer to the middle of the car than 45 mm offset wheels).

I chose 225 width section tires because that is what Realtime Racing has used on their cars since 1997. They have used 225/50/15, 225/50/16 and now use the mandated size of 225/45/17 in Toyo T1-S. I have looked at their cars and the tires certainly fill the wheel wells. How they avoid rub I am not sure. I do know that this year they are running 900 lb front springs and that last year they won the championship with 800 lb front springs. I also checked 2 ITR's in a local race series and they were both using 225/50/15 Toyo RA-1's (the series tire) I had 450 lb front springs and rubbing. The front camber was at -1.2 degress since I had not had time to adjust it to -2 to -3 degrees which is optimum for these tires. I am not sure this will affect the rubbing I am getting. I can of course raise the car, but lower is better!I want to make the 225's work since others have done it. I am not racing, just tracking my car, but wider is better so why not!

descartesfool wrote:I have recently installed 15x7 wheels with 45 mm offset for the track. The wheels are made by Team Dynamics in England and distributed in US by TeamdynamicsUSA. They weigh 13.2 lbs (I checked them).
For tires, I use 225/50/15 Michelin Pilot Sport Cup R compound front and rear. I removed the plastic trim in the rear fender and the fender liner in the front fender. I rolled up the fender lips using a baseball bat. My car is lowered almost 2" front and back using threaded body coil-overs. I took it to the track for the first time with these tires and I had no rubbing in the back, but when braking and cornering simultaneously, I had rubbing in the front, which I need to resolve. There was no rubbing when cornering without braking or when braking in a straight line. The tires do not rub on the inner suspension parts with 45 mm offset. It might be possible to use 50 mm offset wheels, but I am not certain. (50 mm offset moves the tires closer to the middle of the car than 45 mm offset wheels). I chose 225 width section tires because that is what Realtime Racing has used on their cars since 1997. They have used 225/50/15, 225/50/16 and now use the mandated size of 225/45/17 in Toyo T1-S. I have looked at their cars and the tires certainly fill the wheel wells. How they avoid rub I am not sure. I do know that this year they are running 900 lb front springs and that last year they won the championship with 800 lb front springs. I also checked 2 ITR's in a local race series and they were both using 225/50/15 Toyo RA-1's (the series tire) I had 450 lb front springs and rubbing. The front camber was at -1.2 degress since I had not had time to adjust it to -2 to -3 degrees which is optimum for these tires. I am not sure this will affect the rubbing I am getting. I can of course raise the car, but lower is better!I want to make the 225's work since others have done it. I am not racing, just tracking my car, but wider is better so why not!

What calipers you have? I checked out those wheels on their website, looks like they come in quite a few offsets. How much did they cost/wheel?

I have stock calipers. There is a lot of clearance between the new wheels and the calipers, more than there is with the stock wheels. The wheels cost me $125 ea., but I had to wait a long time for them (they came from England and they had to wait to fill a container or part thereof) because I think I was the first person to order them for an ITR and they had none in stock. Distributor told me he was now going to keep some in stock. Tires cost $204 ea. I think from Tirerack, and they have fantastic grip. The tires weigh 20.4 lbs ea., making each wheel and tire combo weigh a total of 33.6 lbs, whereas the stock ITR wheel with an RE-010 195/55/15 weighs 35.0 lbs. So my set-up is wider and lighter.

A note with regards to the rub in the front: the Ground Control guys shipped me 7" springs and this lowered the car 2" with the spring perches turned all the way up. I suspect they sold me springs which are too short, and that 8 or 9" springs would have been more appropriate, since they would allow me to raise the car.

I'll probably order a set of those as well. I'll try running 225/45/50 Hankook Z211 R compounds. Cheap and supposedly decent. What colour did you get and do you have pics?

Thanks.

I bought black Team Dynamics rims with white lettering. I exagerated a little about the lowering of the car. It is lowered 1.5" all around and not 2". I too was going to buy Kosei rims but I thought these because they looked a lot nicer, and they had a lot more choice in offsets. There was one small negative, and that is the plastic hub-centric rings that came with them stuck to the front hubs due to brake heat from the track. I had to pry them off the hubs with a screwdriver.

I will re-install wheels as I came home from the track on my stock wheels and take a few pictures and check the actual clearance between stock caliper and my track wheels.

By the way, with regards R compounds, the latest issue of GRM magazine has a new tire test worth checking out.

How does one post pics for this site? If someone lets me know, I will post a couple.

descartesfool wrote:I bought black Team Dynamics rims with white lettering. I exagerated a little about the lowering of the car. It is lowered 1.5" all around and not 2". I too was going to buy Kosei rims but I thought these because they looked a lot nicer, and they had a lot more choice in offsets. There was one small negative, and that is the plastic hub-centric rings that came with them stuck to the front hubs due to brake heat from the track. I had to pry them off the hubs with a screwdriver.

I will re-install wheels as I came home from the track on my stock wheels and take a few pictures and check the actual clearance between stock caliper and my track wheels.

By the way, with regards R compounds, the latest issue of GRM magazine has a new tire test worth checking out.

How does one post pics for this site? If someone lets me know, I will post a couple.

Yeah, plastic rings are not good for use on track cars. If you don't mind please let me know how much more clearance these rims clear your calipers than the stock rims. I can host the pictures if you want, just email me.

badkarma wrote:Hi all,

What do roadracers use for their ITR's for wheel and tire sizing? I'm trying to decide between 15x7 or 16x7

I'd stick w/15x7 if I were you. I'm not sure what sanctioning body you're looking at, but you might be limited to 7" wide, which eliminates the SSR Comps from consideration.

I have a set of 16x7 Spoon wheels w/Azenis 215-45-16, and a set of 15x7 Kosei w/Kumho V700 205-50-15.

and I assume 225/50 all around.

You'll probably want to pick between 205-50 and 225-45, not 225-50.

Moreover, the difference in price and clearance problems introduced by the 225-45 size might make it too much trouble for you to deal with.

With the Kosei 15x7 wheels at +35 offset, most ITR can take the 225-45-15 size with no rubbing. However, it's not guaranteed in every case. Kumho V700 and Hoosiers are both available in that size.

An R compound tyre that's really very popular and has a lot of advantages over the other two brands is the Toyo RA-1. However, it's only available in the 205-50-15 size. It lasts longer than the other choices, and doesn't need to be heat cycled or shaved to work correctly. It won't chunk, either.

George...are you sure on the +38mm Kosei K-1 rims? I know of several local autocrossers that are running 205-50/15 V700's and have had to roll the fenders to prevent rubbing issues.

I'm also aware that Mario on Honda-Tech is selling his +38mm with 205-50/15 Falken Azenis due mainly to a rubbing issue. This is the main reason that I've been searching all over for a pair of the +45mm offset rims, I had purchased a set off of a totaled itr, turns out that 2 of them were bent...since I was unable to purchase replacement rims as they discontinued them 2 months before I bought the rims, I paid a local wheel repair company $240 to fix the rims. My steal of a deal at $150 for 4 15x7, +45mm offset K-1's, have not turned into a decent deal at $390 for the rims.

Austin

If you want 15x7 rims with 45 mm offset, get the Team Dynamics Prorace rims like I did. They're cheap. I got tired of trying to find Kosei rims with other than 38 mm offset. The Team Dynamics rims are available in a wide range of offsets. Only downside is you may have to wait 4 months to get them. The lower the offset, the more your tires are being pushed out to the fender. Thus I want the highest offset that allows the wheel and tire to clear the inner suspension, plus it keeps the scrub radius closer to the stock value, since the stock ITR rims have a 50 mm offset. I was even thinking of getting some 48-50 mm offset rims for the front with the 225 section tires. It is just a little hard to get in there and check the clearance on the inside.

Austin wrote:George...are you sure on the +38mm Kosei K-1 rims? I know of several local autocrossers that are running 205-50/15 V700's and have had to roll the fenders to prevent rubbing issues.

I'm running 205-50-15 V700 w/+38 Kosei and have absolutely no problem; however....

You're right.

I checked w/Warren and although he does run his +38 Kosei with 225-45-15 tyres, his rear fenders are rolled.

Sorry.

It's looks like there's a slight variability of several mm in the rear fenders from car to car.

I have a few pictures showing the clearance between the stock brake caliper and stock ITR wheel, as well as the wheel to upright clearance. I also have some pictures of the Team Dynamics Prorace 1 wheel in 15x7 with 45 mm offset, on which are mounted Michelin Sport Cup 225/50/15 R compound tires. The brake caliper clearance is much larger than with the stock ITR wheels. Plus there is even room for more negative offset. The camber was set at -1.5 degrees for the pictures, and the car was lowered 1.75 inches. Camber was later set to -2.3 deg.

1. My ITR with Team Dynamics Prorace 1 wheels 15x7 45mm offset
http://www.imagestation.com/picture/sra ... 627a9e.jpg

2. Team Dynamics Prorace 1 wheel with Michelin Pilot Sport Cup 225/50/15
http://www.imagestation.com/picture/sra ... 627b83.jpg

3. Guaging Stock ITR caliper to stock ITR wheel clearance
http://www.imagestation.com/picture/sra ... 6285fa.jpg

4. Measuring Stock ITR caliper to stock ITR wheel clearance at 0.185"
http://www.imagestation.com/picture/sra ... 6284d8.jpg

5. Guaging Stock ITR front wheel to stock ITR upright clearance
http://www.imagestation.com/picture/sra ... 6283d2.jpg

6. Measuring Stock ITR front wheel to stock ITR upright clearance at 0.740"
http://www.imagestation.com/picture/sra ... 6282fc.jpg

7. Team Dynamics increased wheel clearance to caliper
http://www.imagestation.com/picture/sra ... 628215.jpg

8. Guaging Stock ITR caliper to Team Dynamics wheel clearance
http://www.imagestation.com/picture/sra ... 628141.jpg

9. Measuring Stock ITR caliper to Team Dynamics wheel clearance at 0.498"
http://www.imagestation.com/picture/sra ... 628027.jpg

10. Guaging 225/50/15 tire to upright clearance on Team Dynamics wheel with 45mm offset
http://www.imagestation.com/picture/sra ... 627f04.jpg

11. Measuring 225/50/15 tire to upright clearance on Team Dynamics wheel 45mm offset at 0.710" (more room here!)
http://www.imagestation.com/picture/sra ... 627df6.jpg

12. Guaging Team Dynamics front wheel to stock ITR upright clearance
http://www.imagestation.com/picture/sra ... 627d1e.jpg

13. Measuring Team Dynamics front wheel to stock ITR upright clearance at 0.557" (more room here too!)
http://www.imagestation.com/picture/sra ... 627c3e.jpg

In the end I should have ordered 48 or 50 mm offset wheels as there seems to be lots of clearance. Even at 50 mm offset, which is 5 mm (0.2 in.) closer to the upright than what I am using at 45 mm offset, there would still be .357" clearance between wheel to upright, and 0.510" clearance between my 225/50/15 Sport Cups. The extra offset would have helped in reducing fender to tire clearance problems. While I am certain the fender liner would still have to be partially removed, the fenders might not need quite as much rolling. You can see evidence on the second picture of the rolling by the red paint from the baseball bat I used on the top of the tire. Only trial and error will tell for sure.

I hope you find these pictures and measurements useful, as I sure could have used them before I took the jump and bought all my stuff. All I could seem to get from the forums was a ton of inconsistent and mostly incorrect information from a lot of people who obviously didn't know what they were talking about. I wanted to fit 225 wide tires on my 1.75" lowered ITR, and I did and they fit, with a little massaging. They should fit yours too if you really want maximum grip for corner carving. Good luck!

Wow thanks! I haven't checked the forum in quite awhile. I just got back from PRW, car runs pretty good except it's WAY too stiff. It's got Mugen N1 coilovers but I don't know what springrates the previous owner picked. I was hitting my helmet on the roof with the stock seats. After eating and driving home, suspension was so harsh I got cramps as if I went for a run! Sounds like a bronze Team Dynamics with a +47 offset would be the best bet for me! Thanks again descartesfool.

PS. What camber kit are you using?