Mk2 wheel question

[mike.rodriguez]

This year will be my first year road racing my '85 GTi. Currently I've got a couple sets of 14x6 wheels that I might mount up some race rubber on.

My questions are:

1) What tire size is best for a stock GTi in a 14" diameter?
2) If I go up to a 15" wheel, what's the best tire size?
3) Should I go up to a 15" wheel? What are the benefits?


Sorry for the noob questions.

[Ralf]

Since you say you are just starting out, I would suggest sticking with the 14" wheels you already have and use Hankooks. Right now they are about $80+ cheaper then Hoosiers and you'll benefit with more tracktime then trying to get a few more tenths from the more expensive tire.
As far as size, I use a 225/50-14 Hankook on my car with 3/4" spacers. You can also use 205/55-14's. Hoosiers tend to be wider then other manufacturers, so not sure how well a 225/50-14 Hoosier would fit.
The advantage to going with 15" wheels would be more availability from different manufacturers. BFG and Goodyear don't offer 14" sizes.

[Chip42]

Mike, I'm not a VW aficionado so I won't claim to know what size is best for you, but some things to know:

many tire manufacturers don't make a 14" "DOT R" tire. those that do often have less available supply. You can get Hankook, Hoosier, Kumho, Nitto, and Toyo in 14". the kooks in particular are REALLY hard to get your hands on.

changing up to 15" opens the doors to a few other brands, like BF Goodrich and Goodyear, and better availability of most other brands. also worth noting: there's a reduced cost Hoosier 205/50R15 "SM6" at $166 vs. $234 for the "normal" R6 though they are the same tire. 205/55R14 and 205/50R15 are effectively the same diameter, as are 225/50R14 and 225/45R15, so "moving up" from 14" does not effect your gearing when staying with the same width tire. it will also not affect your ride height, roll center, etc.. and IT rules mean you can run your air dam/splitter whatever 1/2" lower with 15" vs 14" wheels. 15s do tend to be a little bit heavier than 14s, and have a little more rotating inertia, so there is a very small hp drag and reduction in braking capability, but I do mean VERY small with otherwise equal wheels.

15x6" aftermarket wheels for that will fit your car (or many others in ITB/C) are not readily available, though some OEM fitments are pretty good depending on your needs. We have a good, affordable 15x6 wheel in the works, stay tuned for more info.

[shwah]

Stick with the 14s as you get started. The Toyo RA1 in a 205/55-14 is a great tire for you right now. It will last a long time, and will get faster as it wears. Downside is needing to get them shaved, but Vilven Tire can take care of that for you.

If you go with a Hoosier, yes their 205 is a lot wider than Toyos. A 225 will fit on the 6" wheel too.

I don't recommend going to 15" wheels. No benefit, other than compatibility with take-off Spec Miata tires. If you change wheel size go down to 13 and use a 225/45 tire. The shorter diameter helps in a lot of ways - none of which are really relevant when you are just getting started though.

I did a few years on 14" Toyos, and once the car and driver were starting to work well, rebuilt the car/motor to win, moved to Hoosiers, and then moved to 13" Hoosiers.

Good luck - have fun!

[mike.rodriguez]

Thanks for the replies. !4's it is. my wallet thanks you. :023

Between the Toyo's and the Hankooks, what would be a better choice?

[Ralf]

Some say Hankooks are hard to get, but I haven't had any problems. I ordered 8 in the beginning of the season and two tires two other times last year.
As Chris mentioned, the Toyo's will last longer.

[shwah]

Can't speak to the Hankooks, but a set of Toyos will last a season or two (20-30 cycles) if cared for properly. Definitely the TOP choice for budget use, but at the expense of outright speed. I did end up using some unorthodox setup with them, but found them consistent and long lived.

[Knestis]

It's a MkIII but the same basics apply. These are 205 Toyos that started life with full tread:



They had about 9 hours of track time on them and they just got faster as I used the asphalt to "shave" them. Heat cycles didn't seem to matter.

K

EDIT - "Cared for properly" means not flat spotted, and rotated regularly as wear indicates...

[shwah]

I guess I should have mentioned that I never actually used my set up. I sold them cheap to another guy getting started. Way back in the early 90s, we learned on Chuck's car that the fastest laps on these tires were right about when they finally chorded.

[Flyinglizard]

14s to start. That car is legal on 13s also.
The 13 are the fastest for the VW and most small power IT cars.
About 1.2 sec faster @ Sebring over 205/50/15s.. But they are smaller and cost more. Hoosiers. Kumho, both have good 13 choices.

Just changing tire OD size to a smaller OD will tighten up the car a bit and some guys use a smaller rear tire. . Along with my DRS( dynamic rear steer) rear axle system.
MM

[mike.rodriguez]

I'll most likely get Hankooks since it's easiest for me to get them from Tire Rack.

thanks for all the advice...i'm sure I'll have more as the car gets built and I start racing.

[StephenB]

What is a DRS?

[shwah]

DRS = dynamic rear steering.

The rear beam design on VWs can provide some passive rear steer effect. If you use softer than stock bushings the effect can be amplified. Some folks do this to get the car to turn better. Others increase roll stiffness and spring rate at the back. They both seem to result in fastness... Mike is the first person I learned about the DRS idea from. It is a good one.

[StephenB]

So basically getting the car loose rather than tight... I was thinking it was something more. Sorry to get of topic!

Stephen

[Flyinglizard]

Thanks Chris. \
MM

[GTIspirit]

Way back in the early 90s, we learned on Chuck's car that the fastest laps on these tires were right about when they finally chorded.

I've heard the same thing from my friends who raced Spec Miata.

[S2_ITBVW]

13" wheels give you 1.2 secs!!

How? Why? That's a big difference. I will absolutely be testing 13" wheels this year.

WOW.

[shwah]

It looks like that was stated vs. one of the heaviest, largest diameter tires that we can use. If gearing was not changed between the two, I totally agree that this is possible. If the final drive is adjusted with the tire diameter I don't see that type of difference.

I had the gearing right when I ran 14s, and did change it for the 13s, but I do think they are marginally faster.