18" tires for street/track use? .. OR stick w/17"

[TSY]

Originally Posted by BlaineWasHere

I disagree, wider is better. Have you driven the car on wide tires? I have (and a WAY stickier compound) and I think it's more precise.

Wider is not necessarily better. Road and Track ran an FR-S with stock tires around the track, then changed them out for stickier tires of the same size (Star Specs) and then wider 18" tires (235s). The wider tires were faster than stock but slower than the stickier stock width tires.

On an Auto-X course though I'm sure the wider tires are faster.

[BlaineWasHere]

Originally Posted by TSY

Wider is not necessarily better. Road and Track ran an FR-S with stock tires around the track, then changed them out for stickier tires of the same size (Star Specs) and then wider 18" tires (235s). The wider tires were faster than stock but slower than the stickier stock width tires.

On an Auto-X course though I'm sure the wider tires are faster.

I guess you didn't notice they changed the diameter of the tire also which ruins the gearing and made the car go slower. If you know what you are doing you can avoid that.

I have a much wider set-up that is identical to stock tire diameter. I get more grip and no loss of power due to taller tire. In the viedo they mention they use a taller tire, but don't talk AT ALL about how that effects the result. It's put a ton of misinformation on the boards.

[TSY]

Originally Posted by BlaineWasHere

I guess you didn't notice they changed the diameter of the tire also which ruins the gearing and made the car go slower. If you know what you are doing you can avoid that.

I have a much wider set-up that is identical to stock tire diameter. I get more grip and no loss of power due to taller tire. In the viedo they mention they use a taller tire, but don't talk AT ALL about how that effects the result. It's put a ton of misinformation on the boards.

It's true it would have been a better apples to apples comparison if they had mounted 17" wheels/tires of the same diameter, but the difference was still small (less than 2mph at 60) and sometimes taller gearing can help depending on the track (and the car)

But I think this still helps to show that for lower powered cars a wider wheel/tire is not necessarily going to be faster around a track. In this case the mild extra grip simply couldn't overcome the lack of power this car has for this track. (you would think with extra grip you would gain speed through a corner and actually be faster out of a turn despite the taller gearing but this wasn't the case)

Also wider tires can diminish your road feel, alter the cars balance and willingness to rotate, and affect turn in so for most people who have these cars and will never see a track, wider may not be the best decision and in fact may diminish the 'feel' and 'fun' of driving. One of my previous track cars was a miata and putting huge tires on it really reduced the fun of driving it. It could carry a ton of sped through the corners though.

BTW, in the article they do talk about how the taller diameter and 18" wheels/tires affected acceleration. They may not have addressed this in the video.

[TSY]

To the OP

I guess it really depends on what you want and how much you're willing to spend.

Ideally, a different set for street and track- one for show and one for go. And if you are doing a lot of track time the extra wear and tear you save driving around town and to and from the track might pay off over time (especially if you move up to R-comps)

If you're just driving on track for fun and no one is timing you, then spending thousands of dollars on tires to save you 4/10 per lap probably isn't really cost effective.

And as poor as these OEM Prius tires are, it certainly is fun to be on the edge of grip and slide the back end a little. So maximizing your lap times and grip may not be the most fun you can have with this car.

[zhupanov]

Originally Posted by BlaineWasHere

I wound up going with 17x9 et42 and 245/40/17 R-S3s btw...

Which 17x9 wheels did you get, please? The lightest 17x9 I see on tirerack.com are Enkei Racing RPF1 (15.9 lbs), but they are 45mm offset, not 42mm. Thanks much!

[gmookher]

17

[Gearhd79]

I agree with TSY. I had a miata with stock size wheels and tried a much bigger wheel and it totaly ruined the feel of the car. I wanted to go 18" with the FRS but do not want to ruin the way this car feels. looks like im going with a lighter 17x7 wheel with a stock size star spec or RS3. and I will be running CS RTR in 2013 at least for now.

[Z-PDX]

Let me tag my questions on to this thread rather than starting a new one.

I am begining to order parts for primarily a track / weekend toy. No Auto-X, just not my thing. But lots of respect for the guys who make it happen.

Just a dizzying array of options for tires / wheels and very little concensus or hard data for what works well.

Local track is PIR. Pretty fast track.

My thoughts are to go as light as possible as the motor will remain stock. I am settled on 17" wheels, which seem to make the most sense.

I am absolutely struggling over wheel width and offsets as well as tire width.

Car is going down 20mm, which I understand will bring the wheels inboard a bit???

My inital thought is to stick with 225/45. I know a lot of guys are running 245/40, but I skeptical that this is leading to better lap times. Any input here?

Tire options in 235/40 is limited and 235 / 45 is getting a bit tall. So I am liking either 225 or 245.

Wheel options are many as well, but I have narrowed it to these. I am going to run Enkeis and have it narrowed to these.

Will some of you experts please comment on my thoughts? Especially concerns of offset.

17 x 7.5 +48 - 15.25 lbs.
-lightweight. offset may be a bit high. limited to 225 tires.

17 x 7.5 +38 - 17.15 lbs.
- this was the setup on the yokohama / enkei demo car. safe / conservative if a bit heavy. limited to 225 tires.

17 x 8.0 +35 - 16 lbs.
- can run tires from 225 to 245 no problem. concerned may stick out too far.

17 x 8.0 +45 - 16 lbs.
- can run tires from 225 to 245 no problem. Is this too much inset?

Finally, does going +35 or +45 affect scrub radius enough to make a difference on these vehicles? I would think not, but wanted to get your thoughts.

Thanks in advance and stay safe out there!

[gmookher]

Originally Posted by CSG Mike

my BRZ currently runs out of front grip far earlier than rear grip. I'll be doing some testing this weekend with 225 RS3 up front and 215 Star Specs in the rear.

FRS may be a bit different, but it seems we both have the BRZ.

@ BlainWasHere: How do your stickier/wider times compare with stock size stickier tires?

sway setup? front camber?
your saying you need more than r comps at 225 width?
I am looking at going to a 235 or 245 as well next, but unsure if its worth the weight penalty vs potential extra entry/exit speeds

[Ro_Ja]

I'm curious; there's a lot of talk about diameter and width, but what about offset? I've heard bits and pieces about keeping the offset close to stock, but it was never concrete information. At what point does a wider stance (that offers more stability) outweigh the drawbacks of the scrub radius change? What about track widths? Basically, when it comes to offset, how low is too low? Are the effects of a low offset wheel weakening wheel bearings or knuckles something to take into consideration with this car? Apologies for the semi-vague question, but I hope someone understands what I'm getting at.

[CSG Mike]

Originally Posted by Ro_Ja

I'm curious; there's a lot of talk about diameter and width, but what about offset? I've heard bits and pieces about keeping the offset close to stock, but it was never concrete information. At what point does a wider stance (that offers more stability) outweigh the drawbacks of the scrub radius change? What about track widths? Basically, when it comes to offset, how low is too low? Are the effects of a low offset wheel weakening wheel bearings or knuckles something to take into consideration with this car? Apologies for the semi-vague question, but I hope someone understands what I'm getting at.

More than scrub radius, I'm more concerned about the aero penalty at high speeds. The car is extremely aerodynamic from the factory, so we're worried about hurting that slipperyness/stability at speed.

We have a few different wheel setups, so we'll keep you posted as we get more development done.

Long term reliability effects are... unknown as of yet. We'll need years of data before we have anything conclusive to say there.

Originally Posted by gmookher

sway setup? front camber?
your saying you need more than r comps at 225 width?
I am looking at going to a 235 or 245 as well next, but unsure if its worth the weight penalty vs potential extra entry/exit speeds

That's quite an old post you quoted... see this thread:

http://www.ft86club.com/forums/showp...37&postcount=4

[mission2toilet]

Originally Posted by random hero

Aesthetically, I like the 18" wheel over the 17", but it's pure aesthetics... I'd like to purchase a single set of wheels for the BRZ, it's driven on the weekend, and will see the track often, also see commutes of 2-4 hours to the local tracks. Because of that, the idea of a good sticky tire, but something that will last a bit intrigues me... Looking at an 18x8.75" wheel, what would be a good size tire for the BRZ? I'd like to run the Hankook RS3's, but not sure how they'd hold up on highway commutes, etc. I want a car that works well for my purpose, rather than "hella flush" or whatever the new crazy is with stretched tires, etc. I want some sidewall on the tire, the cars look great w/a 225 tire, but the lack of sidewall scares me for track duty.

OR

Do is it better to stick with a 17" wheel?? The car sees limited mileage, but maybe 2 sets of wheels would be the best way to go, 18's for street, 17's for track. ... any thoughts

I hope this helps
[ame]http://youtu.be/r_IWa_qlt3g[/ame]

[pepe]

Good question ..... that preparers will a 18 "?
another question. the car is approved for 215 ... if we put more tire width .... that would be the equivalent?

[dradernh]

Reviving from the semi-dead...

Originally Posted by Roberkent

Quick question on the subject from someone not too knowledgable on the matter. I get a universal yes from reading the comments on the forums that a 17 inch wheel is better then a 18 when it comes to performance in mind, so is there a specific reason why the griffon trd 86 uses 18 inch wheels without much upgrades under the hood? Or the crawford brz? Couldn't they have just opted for a sticky tire setup on 17's? Is it the needed cearance for upgraded brakes? Thanks to any future replies. One of the first upgrades I plan on doing will be wheel and tire.

If you look at the availability of racing slicks in 17" vs. 18", there is much more selection in 18s; 17s are almost orphans:

http://www.tracksideperformance.com/...13-product.pdf
http://www.michelinman.com/mediabin/...orts_Final.pdf
http://www.hoosiertire.com/pdfs/speccat.pdf

Terminology Note: Race slicks are not DOT-R compound tires. DOT-R compound tires are, by definition, not slicks. DOT-Rs have grooves, slicks do not, and when seen in person it's very easy to visually confirm what you're looking at.