Track tire advice/suggestions

WC13

WC13

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As the track season wraps up here in the Midwest it is time to start planning for next year....

Up to this point I have just been going out with what I've got, working more on my line and driving than my equipment. I am now at the point that I want to start getting better equipment.

First up for change is my tires. I have some 17" turbo twists that have some Hankooks on them. They were fine for my street use (not great track tires) but they still had some life so I figured I would wear them out on the track and get better tires next year.

I want to keep the cost of tires down since it is all a part of the same budget (more $$ on tires = less $$ for track events). Knowing I was going to be looking for tires for next year I began asking around at events. I had several suggestions for Michelin, Pirelli or Bridgestone, but they tended to be on the higher end of the $$ scale. The ones that got good recommendations and were on the less expensive side were the Falken Azenis & Kumhos Ecsta XS.

The problem..... they do not come in 205/50-17.... Is there a different size tire I could use up front? Someone suggested 225/45-17 as that would not change the speedo reading. But wouldn't putting that much more rubber up front significantly change the handling (more oversteer)? The Azenis come in 205/40-17. What will lowering the sidewall ratio do? Any other suggestions for tires?

I know there are a lot of track & AX guys on this site and was hoping for some suggestions.

Many thanks!!
 
check out Bridgestone RE11s

as far as sizes you should be running 225x45x17s up front on the 7" wheels:D
 
I don't think that 225 up front induces oversteer, but it actually reduces understeer :D
I like the Dunlop Direzza Star Spec Z1 very much as a street/track hybrid tire (they seem to last much longer than the Nitto NT-05 I had before which didn't stick any better), the only problem I had that I took them to the track brand new and the front right started chunking, but I'd guess that this would happen with any brand new tire with lots of thread (as opposed to shaved). The Dunlops have an initial thread of 10/32 as opposed to the new thread of 6/32 for the Nittos (that would also explain why they don't last that long)

If you want to know how you car feels with 225 in front:
I switched to 18" wheels and still have 2 225/45/17 Bridgestone RE050PP (with about 5~6/32 thread left) which I am selling for $25 / piece + shipping
 
Two years ago I switched to 225/45-17 since the Falken Azenis RT-615 tires I put on did not come in the 50 series. I like the feel of the car much better and it definitely takes out some of the low speed understeer these cars are built with. The plus side is that you also have move rubber on the road for braking!
 
Docdanracy said:
as far as sizes you should be running 225x45x17s up front on the 7" wheels:D
Click to expand...

Did not know that. I always just stayed with the same size that came on the car. On that same note, should I keep the rears at 255x40x17 or should those be adjusted too?

Thanks!
 
Leave the rears at 255. To move up in rear 17" size, you have to go to a 275 and they are quite tall in comparison with the 255s. Changes your gearing and the idea of the 225 up front is to get a little more tire patch so you can negate some of the factory built in Understeer.;)
If you go wider front and rear, you have only went up in size but not changed the front rear dynamic.
Also get a good alignment, and try to maximize your front negative camber..with a stock suspension you will only be able to get about -.7 or -.8 maximum....not great but better than from the factory at almost 0.:eek:
the more negative front camber, the better your tires will wear (not killing the outside edge) and you will get better turn in.
 
ChrisZang said:
I don't think that 225 up front induces oversteer, but it actually reduces understeer :D

I switched to 18" wheels and still have 2 225/45/17 Bridgestone RE050PP (with about 5~6/32 thread left) which I am selling for $25 / piece + shipping
Click to expand...

Chris: Couple questions... 1) What difference do you feel running the 18s compared to the 17s and 2) What size tires are you running on your 18s.

Since I am getting a 2nd set of dedicated track wheels I am trying to decide which size I should go with.

Thanks!
Colin
 
I had 18s on my 2.5 and sold them after 6 months. They where heavy and I did not feel they worked any better overall than the exact same tires on 17s.
17s are much cheaper for wheels and tires. :)
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I'm trying to decide between these sets of tires: Dunlop Direzza Star Spec Z1 or Kumhos Ecsta XS? I'll use them mainly for AXs.

Any recommendations?
 
Switching from 205/50/17 to 225/45/17 will be one of your best decisions made to the Boxster :) Your car will be much more neutral (still a little under-steer) than before (crazily under-steer). Keep the rear the same, 255/40/17 is good.

I love my track tires. My Thunderhill track time was improved by 13 seconds, (yes you heard it right, 13 seconds), simply by swapping street Michelin PS2 to track Toyo R888. One other benefit of R888 is that you can still drive (it's road legal and safe) to the track without towing a trailer with tires.

Have fun~
 
Duster said:
I'm trying to decide between these sets of tires: Dunlop Direzza Star Spec Z1 or Kumhos Ecsta XS? I'll use them mainly for AXs.

Any recommendations?
Click to expand...

If it's mainly for A/X, then all I read about these two tires they seem to be about equal. If you also want to go on the track I'd go with the Dunlop
 
I just read and compared the Dunlops to other "Z" rated tire on Tire Rack and I'm convinced as well. I'll need new rubber about mid year and will put four of the Direzza Sports on. I'm still a little in the dark though about going from a 205/50-17 in the front to a 225/45-17. Will both fit on the same stock front rim and is the 225/45 lower profile and wider?
 
225s will fit on the stock front wheels with no rubbing or other issues. 225x45 has almost exactly the same overall diameter as the stock 205x50s.
Posted via Mobile Device
 
Docdanracy said:
225s will fit on the stock front wheels with no rubbing or other issues. 225x45 has almost exactly the same overall diameter as the stock 205x50s.
Posted via Mobile Device
Click to expand...
Then why change from OEM recommended size?:confused:
 
offshore said:
Then why change from OEM recommended size?:confused:
Click to expand...

Simple: When Porsche designed the Boxster it was targeted for the mass market, not for driving enthusiasts which were familiar with how to deal with oversteer.
Therefore the OEM tire/suspension/alignment combo was dialed into understeer (which is deemed safer than oversteer). This might be a safe thing for a commuter car. But as soon as you go to the track or do A/X you are probably more interested in a more neutral handling. Before you start playing with alignment the easiest method to dial out some of that understeer is to put on wider tires in the front.

Definition of understeer vs. oversteer by (my hero) Walter Roehrl:
Understeer means that you see the tree that you are about to hit
Oversteer means that you only hear (and feel) the impact
 
no, the rolling diameter is about the same for the two tire sizes, but the 225 is 20mm wider....bigger foot print gives you a better turn in, and less push (understeer). With the rolling diameter being nearly equal, the larger size will not upset the computer for the ABS or traction control. If the tire diameters are too far off % wise front to rear it will cause the computer to believe there is a braking discrepancy or traction problem. The sensors are in the hubs of each corner of the suspension.
The wider tire patch helps eliminate the heavy understeer the factory built into the suspension. This gives you a better balanced handling.
 
Thank you Chris and Doc I get it now. So here's my next question. My Boxster has a tendency for the rear end to swing out in high speed turns and I turn into the "swing" and keep on the gas to straighten it out. Isn't that oversteer? My suspension has been aligned for track use and I first started noticing this after I installed the Pedro Technobrace. I have to add that as I'm getting more used to the handling characteristics of the car I'm driving more aggressively but my car seems to be handling in the opposite of what the factory intended or do I need another glass of wine?
 
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