First impression of Formula Atlantic slicks

[thehelix112]

Guys,

 

Sorry to linger on this guys, would you say a 23 x 9.5 x 15 slick in correct speak (metric) would be a 250/590R15?

 

Also, does anyone have any experience with the Yokohama A005s? Many thanks.

 

Dave

[JMortensen]

I have run the A005's for years. I ran them on 8" wheels though, which was not the right thing to do. The 250/590/15 is the same application as the 23x9.5x15, although the Hoosier is the faster tire and the Yoko is just ever so slightly taller. I found the Yokos to be hard and they didn't seem to have the grip of my friends' Goodyear and Hoosier tires. I have probably gone through 5 or 6 sets on my car. They don't wear out; they get heat cycled and hard to the point where they need to be replaced. I ran one set for a full season and 3 track days and it still had probably 40% tread on it. It is nice when you have limited adjustability and can't get them really dialed in right. Run them about 28 or so hot, that can be down in the 22/23 range cold if you're doing track days.

 

Clifton also ran them for years, I think he still is running them in the front of his track car which I saw was unfortunately for sale the other day...

[thehelix112]

Thanks Jon, much appreciated.

 

Dave

[TheNick]

Got to see Cameron run on these today in Terre Haute - car looked very very good - put down power very well with the LS1 and Cameron seemed spot on with his patience - which was extremely important on this course.

 

Great looking car Cam - what did you end up getting down to? I went over and started changing tires after your second run so I didn't get a chance to see the other 3.

[heavy85]

Got to see Cameron run on these today in Terre Haute - car looked very very good - put down power very well with the LS1 and Cameron seemed spot on with his patience - which was extremely important on this course.

 

Great looking car Cam - what did you end up getting down to? I went over and started changing tires after your second run so I didn't get a chance to see the other 3.

 

That's a really nice surface and super well run event - I highly recommend the Indy region and WILL be back next year. Drivers meeting at 10:00, 137 cars, 5 runs, and trophies still over by 5:00 - this is something the local club couldn't even dream of. I forgot about the timezone change so got there late and didn't have time to walk the course. First two runs I was just trying to figure out the course and was in the mid to low 40's. Ended up with a 40.7 once I figured out the course which if I remember right is just a couple tenths behind you in your frigging stock S2000 (sigh). For reference to others I believe FTDI was wicked big aero BM at ~36.5 raw time and I finished second in EM to a purpose build mid engine supercharged Corvair who got a ~40.1. I was happy with my street car times and it was warm enough the tires worked really well. The EM Lotus clone in front of me was planning to swap from bias to radials midway through to get direct comparison but had an oil pouring out the valve cover after second run so never got to the radials. I was really looking forward to hearing the side-by-side comparison. Nice meeting you - maybe I'll have to make it down to St Louis sometime.

 

Cameron

[TheNick]

Those other EM cars were spewing crap everywhere - I guess that's pretty typical for them though right

 

The Corvair was supercharged too

 

The BM car was driven by a guy who's taken top 2 or 3 both of the past two years in Topeka and I think he ended up in the 35's raw time - he won PAX too - followed closely by a CM car and then myself and Geoff Chambers in a virtual tie for 3rd and 4th (he got me by .006 seconds!!!!!)

 

 

I was pretty happy with how things went - that Honda leaves me with huge grins every time I drive it

 

 

How come you run EM instead of XP? Too light for the 5.7liter?

 

Our courses are significantly faster than what we saw there - last one I designed had an average speed of 45+ and I was hovering right under the rev limit at 55 for most of the course - here's an incar from an STS CRX that took 4th on PAX - no video from my car yet - we don't have the MaxQ hooked up yet with the two cameras (thats the co-driver's - I have a DL1 already in the car)

 

[74_5.0L_Z]

Just thought I would add my impressions of the FA slicks at the end of their useful life.

 

When I first installed these I was impressed with their overall grip, but thought the slip angle would take some getting used to. Well, as the tires aged, the slip angles kept growing and the traction kept diminishing. This can be expected with any race tire as it ages. However, these tires go away quickly. All totalled, I got about 20 good runs, 20 mediocre runs, and about 10 runs that were scary as hell because I had no traction.

 

For the price that I paid, I guess they worked well enough (I only paid $100.00 for a set of four). Next season, I will fork out the money for a new set of Hoosier A6 275/35/15 tires. The FA slicks are not in the same league as the Hoosier A6 tires for autocross.

[heavy85]

Another follow-up for those running or thinking of running Hoosier FA slicks. I agree that in general these are not the best for autox because it takes too long to get heat into them. I'll also add they dont need or like much camber. I am now trying a set of Avon slicks based on recommendation from my used tire supplier (Jon Berget). FA tires were made for ~1300 lb cars where the Avons were designed for full size much heavier cars. I've not run low speed autox with them yet but yesterday I ran a high-speed autox at Blackhawk Farms and took over 2 seconds off my best lap times. I ended up 2nd out of 12 in the 'A Race' class which is a more or less anything goes class just 0.045 seconds ahead of an '06 Z06 w/ 600 hp, suspension, and R6's. Needless to say I'm very happy with their performance and they seem to need even less camber than the Hoosiers. I'm guessing they still aren't quit up to A6's but I've never run them for side-by-side comparison. For reference there was a new ZR1 on stock tires ... well stock for a ZR1 ... with a good driver who although was in a different class was about 1 second ahead of me. I'm interested to see how they perform in a low speed autox but that might be a while.

 

Cameron

[74_5.0L_Z]

Ok, I've gone through several sets of the used Hoosier 23x9.5-15 FA slicks. I typically get 3 to 4 events before they die. I get them cheap, but not that cheap. I am tired of buying used tires, so I plan to order some new tires this week.

 

Here are the tires I am considering:

 

Hoosier 275/35-15 A6

Goodyear 23.0x10.5-15 Bias Ply slick (250 compound)

 

The initial cost for each is the same. Does anyone have any experience with the Goodyear? How is the longevity? I would really like a set of tires that wil last for a whole season.

 

If anyone else has a good suggestion for a tire that fits the 15x10 wheels, I'm all ears.

[JMortensen]

It's not on your list Dan, but those Yokohama FA tires lasted FOREVER on my car. Granted, my car wasn't really set up right for them, but I would think my way too soft springing would make the tire wear worse. I ran one set for a season of autox and a couple track days, and then replaced them just because they were losing grip and were worn unevenly (much more wear on the outside edge due to camber loss as a result of body roll). I never ran one to the belts, never had a puncture, or any other issue with them. I gather from Cary that they don't grip as well as the Hoosiers, but if you're looking for longevity, that's an option. There is a cool factor to be had with the Yokos too. They have a kevlar belt in the middle of the tread that keeps the tires from expanding at high speed.

 

Cameron, the FA tires are designed for a light car, but one with aero. I think FA min weight is 1250 lbs or so. BUT, those light cars can pull 3-4 g's under braking. so your 1250 lbs is effectively 5000 lbs at the tire. Your 2550 lb Z (guessing weight with you in it) at 1.5 g would give significantly less force, 3825 lbs, and that's assuming you can get a full 1.5 g in there.

 

I think the problem with the Hoosiers is that they're like the other Hoosier race tires. Built to be light and fast on raceday, and who cares about longevity because racers are made of money. I expect A6's would be much the same story.

Edited December 1, 2010 by JMortensen

[heavy85]

This is an old thread - my last post three up was over a year ago but while I'm here I'll add. I tried the FA Hoosier Radials again this year after upping springs to 375 / 300 and they lasted 2.5 20 minute sessions before they were trashed with a LOT of cord showing on the outer ~20%. I'm not convinced it's camber control because I had zero issues with bias ply, either Hoosier or Avon, and my RE-01 street tires don't roll over at all. Not sure what it takes to make the Radials work but I haven't figured it out and am giving up trying.

 

Cameron

[74_5.0L_Z]

I'm past the point where I'm trying to make them work. I plan to buy some NEW tires. I have 15 x 10 wheels and want the best tires I can get in terms of traction and longevity.

 

The ones that I have found that will fit are the following:

 

Hoosier 275/35-15 A6

Goodyear 23.0x10.5-15 Bias Ply slick (250 compound)

 

I have never run the Goodyears and was hoping to get impressions from someone that had.

 

Cameron, have you found a favorite tire?

I think you tried the Avon slicks. Did they work and last better than the Hoosiers?

[tube80z]

The ones that I have found that will fit are the following:

Hoosier 275/35-15 A6

Goodyear 23.0x10.5-15 Bias Ply slick (250 compound)

 

I've had more experience with Kumho than Hoosier street radials. In watching a few local guys it seems like the Kumhos may not be as quick but they last much longer, often to the cords. For the GY slicks the new radials are light years faster than the older bias plies. I would not even consider bias slicks if you have the new option. In back to back tests the radials were three quarters of a second faster on a 46 second course. We only changed camber for the radials (similar to what a Kumho/Hoosier would run). The only downside is they are heavy and a ***** to mount. Compared to Hoosier/Avons the GYs are currently the quicker tire.

 

Cary

[74_5.0L_Z]

I looked at the Goodyear radials, and they look like a good option with one minor problem: They cost nearly twice as much as the Bias-Ply. I can't afford $400.00 per tire.

[heavy85]

Interesting to hear about the GY being faster. Just to be clear to other readers ... if there are any ... bias ply FA Hoosiers work quite well and last a good long time. They may not be the fastest but do work well, it's just the radial version that I cant get to work. The Avon's were somewhat quicker than the Hoosiers but they were fast last race of '09 then first race of '10 they were utterly worthlessly slow. Just sitting in the garage for 6 months and they went to hell. The Avons are kind of odd tires as the center bulges out - like a balloon - since there's little structure in the center of the tread plus they feel gummy to the touch. Not sticky but more like a pencil eraser. Neither of these causes any issues they just are MUCH different than your typical tire. The 'fast' guys around here all pretty much run A6 both on the racetrack and in the parking lots. I've never tried and A6 so have no direct comparison to the slicks. I was impressed though with how sticky the A6's are as a guy had four tires mounted on rims strapped to his trailer. These were Miata size tires/wheels stacked four high sidewall to sidewall. When he picked up the top tire, the whole stack lifted off the ground. Nothing but the stickiness of the tires was holding them together. We actually had to pry them apart. Now that's sticky! I have noticed that the A6 heat cycle out and loose ~2 seconds on a 1:20 racetrack as they age.

 

I'll have to call Jon Berget in the spring to see if he has any A6 or GY that fit 15x10 rims and give them a shot ... assuming I dont just run street tire class all year again. 140 street tires are fun IMHO if you've never run on them but a heavily modified car has no home for them in most club's rules.

 

Cameron

[74_5.0L_Z]

Ok, I am digging up this old thread because it is that time again:  I am trying a different tire set-up.

 

For the last couple of years I have been running Hoosier 275/35-15 A6 tires on 15x10 wheels.  They have worked well (when the tires are fresh), but the A6s fall off a cliff after about 30- 40 runs.  Additionally, Hoosier is no longer making the A6 as they are switching to the A7.  The 275/35-15 in the A6 was 23.0 tall x 10.3 wide, and the 275/35-15 in the A7 is 22.8 tall x 10.1 wide.  If anything, I needed a slightly taller and wider tire than the old A6.  So, the reduced dimensions of the A7 and the Hoosier low life expectancy are pushing me to try something different.

 

I am staying with the 15x10 wheels, so my options are limited.  I will be trying out some Avon 23.0 x 10.5 x 15 bias ply slicks (A11 Compound).  I am mainly trying these because they are the right size (23.5 tall x 10.3 wide), and because they supposedly last longer than the Hoosiers. 

 

I just received them from John Berget Racing tires and plan to have them mounted next week.  At the same time I get the tires mounted, I am getting the car aligned and corner balanced.

 

My questions are these:

 

1. What is a good starting air pressure for these tires.  From what I have read on-line, these require much less pressure than the Hoosier A6 radials.

2. What is a good starting camber for these tires.  From what I have read on-line, these don't require (or like) much camber.

 

Cameron, I know that you have run the Avons in the past.  What are some good starting points?

 

I am also interested in hearing what Cary, JohnC, Jon, and the other smart people have to say on the subject of the Avon Slicks.

Edited March 20, 2015 by 74_5.0L_Z

[JMortensen]

I talked to a local DP Miata hotshoe about Avons. Pretty sure he said he was running 20 psi on I think that same size. Can't speak to how long they last or how long it takes to heat cycle them to death. Another local guy, Ron Bauer, won the DP class last year with Hoosiers.

[tube80z]

For the bias ply tires I'd probably start in the 18 to 20 range.  You may need to run lower.  They are more squirmy than the A6 you had and take more slip angle to work.  When you turn you're going to need to do it quickly and a little more lock to compensate.  Camber will be in the 1 to 1.5 range unless you have a lot of roll.  If you're running front droop limiters you may need 1 degree or less.  My old car settled on 0.5 to 0.75 degrees depending on the course.  Even used these should amaze you.  

 

If you decide on new tires or Berget can get GY 15 inch atlantic fronts try them.  Only in R160 compound.  10x23x15.  Reports of them doing 160 runs still fairly well.  Tighter than Avons but overall grip may be just a little lower.  May seem expensive but should be cheaper than the A6s.  Similar size but will last much longer.  R160 compound requires a little heat but you should be golden in Florida.  These are generally considered a good match for the Avons.  GY used to make a slightly softer compound that was even faster but we can't get them anymore.  

 

We have a 240Z and an RX-7 (2nd gen) running those tires.  They work well on both cars but since they are soft you can kill them easily of you don't stay on top of pressure and wear patterns (if you're not measuring tread temp).

[z-ya]

I haven't run the Avons, but I now am running some Hankook radial road race slicks that I got used. I run them on my Datsun 1200 which weighs about 1500lbs. The tires are 8" wide, and about 22" high 13" rims. I can get the exact compound information if you want (sorry, don't know it off the top of my head). They were inexpensive (~$60 per tire), and I really like the compound. Once they heat up, the grip is amazing. This is a road race application BTW.

 

[74_5.0L_Z]

At this point, I have the Avon 23.0 x 10.5 x 15 cross ply slicks in hand and ready to install.   They are getting mounted on my wheels monday.  Then I will spend the early part of next week doing preliminary adjustment to the car (reduce camber, set ride height). I plan to install the new wheel and tire combo, remove the springs, and verify clearances for the anticipated range of suspension motion. The clearances found during this testing will determine the minimum camber that I will be able to run.  Once I have found the preliminary settings, I am taking the car to a friend's shop where we will perform final alignment, corner balancing, and bump steer adjustment.  This is scheduled for next Friday.

 

One problem I may encounter is the inability to reduce camber sufficiently to make the tires happy.  The Avons appear to be a little wider that the Hoosiers (at least while not mounted), so I may encounter clearance issues between the tires and fenders if I take out too much camber.  With the Hoosiers, I was running -2.5 camber at the front and -2.0 at the rear.  I am shooting for less than -1.5 at the front and less than -1.0 at the rear.  Unfortunately, reducing camber on these cars reduces clearance between the fender and tire.  We'll see how it goes.

 

The car has a very stiff suspension (500 lb/in front springs and 425 lb/in rear springs) and I will be running between 6.5 to 7.0 degrees of caster at the front. 

 

The attached pictures shows how close the Hoosiers were (especially in the rear):

 

 

Edited March 26, 2015 by 74_5.0L_Z