Wheels 15" Or 16", Primarily Track Use, Thoughts?

[GregTas]

Hi,

 

I'm about to order the wheels for my 240 and have decided on some Rota RBs in either a 15x8 +4 or RB-Rs in a 16x8 +4, but I don't know whether 15" or 16" would be the way to go.

 

I believe this width and offset will fit under standard guards ok. The car will be primarily used for track, but will get some limited road use.

 

I intend to run 225 tyres, so thinking they they'll be either 225x60x15 or 225x50(45)x16. I think I can get decent tyres in both 15" or 16".

 

So are there pros and cons between 15" and 16" or is it just looks? The tyre sidewall will be a bit less on the 16" tyre which might be better on track, but don't know if the difference over a 60 series tyre would be noticeable.

 

Has anyone got track experience with 15" and 16" wheels, or just general experience?

 

Thanks, Greg 

 

 

[RLY240]

I've run both 15 and 16 in 205 on a 7 inch rim, moved to the 16's mainly for brake clearance. No real performance difference but the tyres are more expensive in 16in.

[GregTas]

Thanks for info. Is the tyre range comparable in both?

 

I was going to run R33 GTS front rotors which I believe are 296mm. I think these will just fit under 15" wheels. What size rotors are you running?

[KatoKid]

I've got R33 GTS-T brakes and they clear 15" no problem.

[260DET]

Don't go any bigger in diameter than you have to, just check the availability of tyre sizes. For some reason I think that 15" are available in a larger range than 16".

[24 Dat]

If you are ever planning the AZC 6 pot wilwood brake upgrade http://www.arizonazcar.com/brake.html go the 16's i have this set up on my car and the brakes are awesome, some 15's will fit over the 6 pots but there is a bee d#$k clearance and the smallest stone will get caught up.

 

I run 225/50/16 Hankooks Z214's

[GregTas]

24 Dat those brakes do look nice and not that expensive either. I have just gone with R31 brakes on the rear and so prob not much point going bigger than R33 on the front.

 

With Kato Kid and Rcihard's comments I'm now thinking  perhaps 15".

 

Richard why is it best to keep the diameter as small as possible?

[RLY240]

Thanks for info. Is the tyre range comparable in both?

  What size rotors are you running?

310mm.

I run Advans and the same size / compound is available in both.

[RLY240]

If you are ever planning the AZC 6 pot wilwood brake upgrade http://www.arizonazcar.com/brake.html go the 16's i have this set up on my car and the brakes are awesome, some 15's will fit over the 6 pots but there is a bee d#$k clearance and the smallest stone will get caught up.

 

I run 225/50/16 Hankooks Z214's

What pads are you running Dave?

[Cozza]

Recently I have been running 225/45/15 Nittos. Thanks Geoff ?

And find they are slightly too small in diameter for my current motor, i'm redlining on the main straight at EC, about 200k's.

I think I will move up to 225/50/15 but there aren't many brands to choose from in this size.

Not sure, but from memory, there are more options in 16's for a similar diameter??

Cheers

Mick

[GregTas]

Thanks for comments all. Well still not sure. Sounds like both could work ok. I might spend some more time looking at tyres.

 

I haven't yet bought the stuff for the front brakes and so perhaps before ordering wheels I get them sorted and if I do decide to go bigger than the R33 rotors I can.

[dat2kman]

I have fitted 15"x8" Wata/Rota RB style rims over the larger AZC 2 piece rotor and brake setup

They do clear

The Simmons 16" that the owner wanted to fit, did not, simply due to the inner spoke shaping.

 

There is a wider range of track use road legal semi slicks available in 15"

The Prod Sports and Touring racers, all seem to like the Yoko A050 in 225/50x15

There are cheaper tyres about, that some think are a "semi slick" but, better you check for yourself what the fast track cars are using at one of the tracks down your way.

[GregTas]

Thanks dat2 that's been very helpful. If there's a better choice of tyres then that's a good enough reason for me to go with the 15s.

 

Greg

[Howdy]

Greg, make sure you plan out any suspension & brake changes before settling on the size, especially if you are going to 8" width because there is not much clearance on the front with standard guards. For example, I can't run 8" x 15" on the front due to camber take on blocks under the strut and modified tie rod ends to get rid of bump steer. The outer steering rod end sits too low and fouls the inner rim.

 

Consider camber, camber take on, ride height, caster (which will cause the wheel to hit the front of the guard) and position of the disc (over or under the hub).  Also make a firm decision about which tires you are going to use, or at least narrow the choice right down. Then look at the size range and recommended camber settings. Smaller diameter tires are getting less common with several brands starting at 17" now and some just having narrow sizes in the 15". The A050 is a very good track tire, as is the Z214.

[chris240]

Hmmm Jeez your pushing it with 8" rim and a +4.

It's frustrating that rota stoped making the 16x8 zero offset a few years ago.

[GregTas]

Greg, make sure you plan out any suspension & brake changes before settling on the size, especially if you are going to 8" width because there is not much clearance on the front with standard guards. For example, I can't run 8" x 15" on the front due to camber take on blocks under the strut and modified tie rod ends to get rid of bump steer. The outer steering rod end sits too low and fouls the inner rim.

 

Consider camber, camber take on, ride height, caster (which will cause the wheel to hit the front of the guard) and position of the disc (over or under the hub).  Also make a firm decision about which tires you are going to use, or at least narrow the choice right down. Then look at the size range and recommended camber settings. Smaller diameter tires are getting less common with several brands starting at 17" now and some just having narrow sizes in the 15". The A050 is a very good track tire, as is the Z214.

 

All very good information thanks.

 

I have threaded tubes to go on the struts. They have been slide on but I have decided not to weld them on until I get the ride height sorted. I'm just going to slide a bit of pipe on the strut for now which the threaded section will sit on. This will hold the car up and I can lengthen or shorten the pips until I'm happy the platform will be in the middle of the thread at the ride height I'm starting with.

 

No heavy engine in car yet so could be a while until I can set it up.

 

I'm keen to order my wheels but know I need to sort the suspension first

 

Hmmm Jeez your pushing it with 8" rim and a +4.

It's frustrating that rota stoped making the 16x8 zero offset a few years ago.

 

Chris, I thought the +4 would be better than the zero as it would sit in further. I like the Rota Wantabe knockoffs but they are 0 offset I thought they would scrape the guards.

[PZG302]

Performance wheels have now set up in Brisbane and are doing some of the old period wheels in good offsets for Zeds.

 

Hotwires, Challengers and formula all in 15x7 or 15x8 with offsets around 0 or up to -13, plus the ubiquitous superheavies.

 

http://www.performancewheels.com.au/wheels/ 

[260DET]

The procedure I've used for deciding on wheel sizes is to follow the following factors in this order. 1. brake requirements, 2. general clearances, 3. proposed alignment figures, 4. ride height, 5. wheel width, 6. wheel diameter, 7. tyre availability. Tyre availability is last because it changes over time so some estimation is required eg what is the trend as far as 15 and 16" tyre variety availability?

 

It's not easy which is why with a build wheels should only be decided on when all the above factors are known or decided. With the Z31 project 18x10's were chosen to allow for big brakes that will fill 18's and good tyre availability at a reasonable cost, 10" wide because race car.

Edited September 19, 2017 by 260DET

[GregTas]

I have checked the performance website. My current second choice behind the Rota Rbs is the Formula Black. Available in 15", but not 16".

 

My wheel choice will probably be a month or so off. My only concerns is how things sit with the lower arm and tie rod end. This will influence the offset.

 

 

[24 Dat]

What pads are you running Dave?

Hi RLY240 im running QFM Comp 2 on the rear and i think Comp 9 on the fronts, when i first put on the 4 pots on the rear i was locking up the rears as the compound that they came with was far to efficient, and i had the bias wound all the way back, now with the Comp 2 i have 1 1/2 turns i can play with. 

 

I got them from GSL Rally sport

 

I hope that helps.