Tire Size Conundrum

Context: 16" wheels on a GT4 vintage race car

"Everyone" seems to use the 245/45/16 rear ad 225/50/16 front.

On my car, (with old Khumos), I can notice –*pretty obviously –*that the front tire is bigger.

I know the Toyo R888 (a tire I was planning to buy) for example has a small diameter difference, but the front IS taller.

245/45: 24.4"
225/50: 24.7"

And what about the 225/45 (a size I've never heard mentioned here)
225/45: 23.8"

 

We had another tire discussion thread, Pen.

I have 205/55/ZR16 front
with 225/50ZR16 rear

1977 308GTB

The problem is that even 16" is getting left behind on "Z" rating tires.
That's the reason you may not find a full size range....

 

The BBS RS1 16" wheels I have came off of a GT4 track/race car. It has Michlin PS2 Cup 225/245. That was the setup of the day.

 

Yep. I went with BF Goodrich Comp 2s from Tire Rack and am very pleased. ZR rated 16 in for less than $100 delivered each. No brainer in my book. Aggressive tread, great tire overall.

 

It will probably not make any noticeable difference in handling, it may have a tiny bit less front grip, but if you prefer the look with the shorter front tire then go for it. You can always try the 50 series next time to see if you notice anything. Visually, it is a small difference front to rear so I wouldn't be too concerned about it, particularly as you are using it on the track.

 

https://www.hoosiertire.com/rrtire.htm

I think the 0.3" taller front is not an issue. Since you have zero testing I would buy Hoosier A7 tires. Trust me this is the fastest current tire. Call me for the secrets to running them. Do not use Hoosier running specs unless you want to go slow. The R888 is a lame tire as far as DOT-R is concerned. It is an OK street occasional track tire but not for a race car. New rubber is important for you so that you can test and adjust the suspension as needed. If you adjust on old rubber you are fooling yourself. Also see if Toyo Ra1 or nitto nt01 come in your sizes. If you need rubber yesterday and can't get race rubber you may have to go with one of the new 200 tread wear rated street tires that are all the rage for the dual use guys who drive to the track or are locked in a stock race class. Also see if Hoosier is supporting the race you will be at in NorCal. You can call them a order and they will have tries on the truck. You just pay for them when you get there and they mount and balance trackside. You might call hoosier west and ask
https://www.hoosiertirewest.com/

If you get tires I can mount and balance them for you this week.

 

He can't run the Hoosiers. I was going to recommend the NT01's but there are no sizes (only one 16" size). I am kind of surprised that the 888 is legal, I would check before you buy as it is not listed on the list in the other thread.

 

Unfortunately, the A7 is not a vintage legal tire. The R888 is legal – what the club is trying to do is eliminate the so-called "street-slick" tires.

And I went with the seemingly tried and true 245/45 and 225/50 combo

And, I had to pull the trigger on a tire brand due to schedule issues, so I went with the R888. I've used R888's both a Europa and 914 race cars. Those are both mid-engined race cars, too (but about 1000 pounds lighter than the 308) –*but they always worked well.

I would have preferred to use something with more of a traditional tread pattern, because the R888's will look a little Civic Si on the 308 in my opinion. Hell, I almost got Hoosier TD's!

FYI, I tested yesterday. It was a very low key, "pre-test", because there was still work that needed to be done – and I had 15 year old tires! I thought I'd be sliding around like crazy, but the tires gripped astonishingly well. I was amazed! (Khumo Ecsta's.) The rings have not even set!

So…I'm kind of stuck (non intentional pun). I'm sure the Toyos will be fine for the FCA event. We can debate further when it comes to race time.

I loved the fact that that I was on the oval track! The only time a Ferrari will ever be on that track, I'm guessing….
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Big Tex - Strange, I wrote a response to your post but it's not here. Anyway...I opened up a new thread (I always feel like I need official permission) because the question I was asking was so specific (mixing the difference aspect ratios). Coincidentally your use of the 205/55/ZR16 front with 225/50ZR16 rear also mixes aspect ratios! And that's a combo I've never seen before. Why the difference from the 245 rear / 225 front with the higher aspect ratio? I've seen people run the 225/205 combo, but still with the lower aspect ratio. (And yes, if you want to forward me to the other thread, be my guest)

By the way, for race spec tires, there are actually a decent amount of choices for 16" tires.

 

The 205/55 and 225/50 is the original equipment size for the 16 inch wheels on 308's in general. The mixed ratios keep the overall heights close to the same. The 225/50 and 245/45 sizes you are using are what I am using and they are the correct wider option. Good luck with the racing.

 

This is the exact answer...mine personally would have been: "I dunno!"
That's directly off a Ferrari windshield sticker for an '80s model with 16" rims.
Note: 7.5" wide fronts, 8.5" wide rear rims.

I have just replaced the sizes that were on the car, with these wheels, when I bought it.

I sold a set of BBS 16"s that had MONSTER rubber on them!
I never used them on a car, but they also came with one of my 308s...

Thanks for the input, John!