Recs for R-comp tires on '06 987-S

[acadian_dad]

I'm hoping some Boxster drivers will respond with what wheel / tires sizes they are using on their 987 Boxster-S's ... in particular for street legal r-compound tires (Michelin PS Cups, etc.).

My use is only for DE's - no auto-x or racing. I have the stock 18" 40 profile wheels / tires front and back right now (and plan to keep those for the street / wet track days) but plan to get rims for use with the R-compound tires for dry days. Tire-Rack recommended 19" wheels / 35 profile tires but I would have thought that 18" (or even 17" if they would fit) would have been a better choice in terms of keeping costs down and minimizing un-sprung weight.

I did try searching the forums but either I'm not very good at it or I couldn't find many specific recommendations. :(

I'm also kind of wondering if it would be better to invest in lowering springs / camber adjustment rather than r-comps as a first mod to get around the tracks a little faster ... so if any opinions on that, appreciated as well.

:thankyou:

[ericinboca]

One of your Qs was about lowering and camber adjustment - merits of that prior to R compound. There are probably a lot of opinions on this - here is mine. :D

I drive a track dedicated '04 986S - I do about 30 DEs a year at several different tracks. If this is your first foray into road course driving, I would recommend you stay completely stock for your first couple of trips (although be sure your brake fluid is clear and at proper level).

Once you start getting some speed around the track, your first upgrades will probably need to be race brake pads that can handle the heat (I use pagid yellow for longevity, but also really like pagid orange; for me, black was too much brake even with r compounds).

Watch your tire wear (or even get a temp gun) - that will signal the time to get some camber adjustment. How much depends on how much wear, the track, the stiffness of the tire sidewall, and if your car is used on the street. I don't know about the 987s, but with the 986, I couldn't get the camber I needed in the front without lowering, or using camber plates or adjustable lower control arms -- so a camber adjustment in the front may drive you to a need to lower.

I would not rush to get out of street tires. I have set I use for rain tires, and often (especially at a new track or at a track I have not been to lately) I will run several sessions with the street tires. Their sqealing helps me get a feeling for corner speeds. Plus, it is a real hoot to drive a 986 or a 987 with street tires at the limit - you will slide, but the balance is incredible - makes you really appreciate what you have.

You also asked about tire and wheel size - since I drive a 986 not a 987, not sure this is helpful, but I use my stock wheels (front 7.5 x 18 ET 50 225/40/18; rear 9 x 18 ET 48 265/35/18) with BFG gForce R1. I love 'em. They have no tread, though, and are unsuitable for the street.

[acadian_dad]

... If this is your first foray into road course driving, I would recommend you stay completely stock for your first couple of trips ...

I've been doing PCA DE's and lapping days at the local track for 2 years (though not 30 / yr - I am envious ! :notworthy: ) - I'm in the PCA white run group now and I suspect I'll move up to blue sometime next year if I keep up the work ...

Once you start getting some speed around the track, your first upgrades will probably need to be race brake pads that can handle the heat (I use pagid yellow for longevity, but also really like pagid orange; for me, black was too much brake even with r compounds)

I just replaced the front pads for first time this spring and stuck with OEM but I expect to replace the backs next spring - will likely go with upgraded pads then (front and back) - Pagid yellow was what I was thinking about. Tho' I'm not looking forward to the noise / poor cold braking with street use.

... I have set I use for rain tires, and often (especially at a new track or at a track I have not been to lately) I will run several sessions with the street tires. Their sqealing helps me get a feeling for corner speeds. Plus, it is a real hoot to drive a 986 or a 987 with street tires at the limit - you will slide, but the balance is incredible - makes you really appreciate what you have ...

I completely agree re. new tracks / rain - no issues there. Mostly I'm at one local track that I am getting fairly comfortable / smooth / fast on. Still lots to learn but a little more grip would be nice ... Also, no arguments with the balance these 987's have and how forgiving they are with street tires once they are broken in ... I do love this car. :jump:

Wear on the tires is primarily outside edge which is why I'm thinking of camber adjustment. The car gets more miles on the road vs. the track but the track driving has a much more significant impact on my tire wear.

[ericinboca]

I'm sorry. I didn't realize you where expereinced and knew what you were doing. :o My advice probably wasn't too helpful. I'll lamely try to redeem myself by sharing my experience with R-compounds.

Depending on your wheel size, including offset, I think you will find more choice in 18 and 17 inch than 19.

In the 18 inch size, I've used the Yoko ADVAN before. They were pretty good. They are a medium compound, not nearly as soft as the Hoosiers or BFGs, which are essentially slicks, but once they got hot, they offered much more grip that street tires. They also have some tread, and I've seen some Carrera guys and Lotus guys use these in the rain and drive them to the track. Same for the Pirellis, but I've never used them.

I've also seen people drive the Pilot Sport Cups to the track and in the rain. I found them to be softer, and grippier than the Yokos, bit not as soft as the BFGs.

On the camber, I remember when I first got started, I saw lots of outside tire wear, I went to get a camber change, and the Porsche speed shop told me that they find alignment settings from the factory to be inconsistent. With an '06, you may not have had an alignment, and you may not have any adequate negative camber dialed in. If that is your case, you probably would benefit from some additional negaitve camber in the front - better tire wear and more contact patch.

I'm not sure what setting would be good as a combination street and track. As reference, I have -2.0 in the front right now, but will probably go to -1.8 soon as I plan to go with a stiffer spring set up. But it is strictly a track car - rides on a trialer to the track.

An finally, I found the pagid orange to have a lot more grip at lower temps than the yellow. The yellow lasts much longer though.

Hope that helps.

[bdill1]

I am kind of going through same thing lately. My 05 Boxster S has 19 inch stock currently. I used up my Mich PS2s a couple of months ago and have used Pirelli PZeros in 3 events since. No edge wear but heavy wear on the center smaller treads. I keep trying to decide between track tires and streets. Originally I intended to use the streets only, but the wear keeps me rethinking...

Have spend a lot of time looking at rims and tires both 18 and 19. The big favorite around here with NASA runners are the Toyos particularly the RA 1s which are being replaced this year with the R888. The R888s are listed as available in a 235/40/18 and a 275/40 and a 265/35/18. If I can find an appropriate 18 inch set wheels I may move down to have more to have more track tire options. With 19s I am sure the Sport Cups would be fine and could be driven to track. Costs don't seem to me to vary much in the 18/19 sizes and unsprung weight seems to be more a function of what wheel, not what size. Anyway thought I would comment even though I'm not currently using track tires. There are about 3 here that are but most seem to transport the car and use slicks.

PCA has a tech article about cambers adjustments on newer Boxsters that stay on the street. Basically says don't make the change which requires lowering and adjustable control arms. In the tech section.

Good luck.

[ericinboca]

I continue to be a big fan of the BFG R compunds in the 18" size. Yes, I trailer my 986S - it is dedicated to the track.

I have had an interesting and new experience with street tires on it at the track lately.

I use a set of Bridestone Pole Position as a rain tire. Recently, while visting the Sebring Club course, I corded my rear BFGs after a long and fruitful relationship, and put the Bridestones on to finish out the day even though it was dry. These street tires have very little wear on them - full tread. They chunked a little. With the course being pretty rough, the heat, and me really flogging it, I broke out some of the tread.

If they were shaved a little or had more natural street wear on them, they probably would not have chunked. But then again, they wouldn't be as effective as a rain tire for me.

[Topless]

I too have been doing performance driving and track days for two years on street tires. I will share my experiences. The first three or four days I saw plenty of outside edge tire wear even with a max negative camber alignment. As I progressed and drove faster/smoother the outside edge wear disappeared. Tire wear is now very even across the tread both street and track.

We have a bunch of fast drivers in our area running R888s and I have considered changing to these tires next time. In talking with other drivers it seems that the R888 needs 2-3 degrees neg. camber to get the most out of the tire and avoid excessive outside edge wear. This means the car must be lowered. I currently run 17" wheels and plan to go with 245s all around next time to reduce under steer and allow for tire rotation. I consider this an intermediate step to running full racing compounds like the BFG, R6, or V710.

Edited December 24, 2008 by Topless

[renzop]

I'm hoping some Boxster drivers will respond with what wheel / tires sizes they are using on their 987 Boxster-S's ... in particular for street legal r-compound tires (Michelin PS Cups, etc.).

My use is only for DE's - no auto-x or racing. I have the stock 18" 40 profile wheels / tires front and back right now (and plan to keep those for the street / wet track days) but plan to get rims for use with the R-compound tires for dry days. Tire-Rack recommended 19" wheels / 35 profile tires but I would have thought that 18" (or even 17" if they would fit) would have been a better choice in terms of keeping costs down and minimizing un-sprung weight.

I did try searching the forums but either I'm not very good at it or I couldn't find many specific recommendations. :(

I'm also kind of wondering if it would be better to invest in lowering springs / camber adjustment rather than r-comps as a first mod to get around the tracks a little faster ... so if any opinions on that, appreciated as well.

:thankyou:

Here is a question that you need to answer before anyone can really recommend track tires - are you planning on driving on the street on your track tires? If you have a way to transport the wheels and tires to the track and then change them at the track there are some really grippy tires but they are dead awful on the street. But if not then you need to compromise on grip and tread so that you can safely ge to the track and back.

If you need a dual purpose tire then I think you are right on with the Pilot Sport Cup. It's an expensive tire but its supposed to last pretty long on track and cna be driven in the rain to and from events yet is a very very good dry tire.

For a single purpose track only tire I would look at a Hoosier R6. Still expensive but not quite as high a price.

For wheels, you are right on about 18" instead of 19". The 19" is always going to be heavier and more expensive and so are the tires that go on them. The only performance reason for large diameter wheels is if you have large diameter brakes. Since you are not racing and don't have to stay to stock wheel sizes I recommend going to a wider than stock 18" wheel. Tire Rack has a great deal a a relatively light wheel Enkei Racing NT03-M. For the front the 18x8.5 costs $325 and weighs 19.2lbs which is almost 1lb lighter than the stock 18x8 lobster fork. The rear is an 18x10 for $440 and weighs 1lb lighter than the stock 18x9.

If you go with those size wheels there is a large variety of tires that will work (I am not 100% sure about the larger sizes and clearance issues)

Hoosier front - 245/35/18 or 255/40/18 (this might be a little tall)

Hoosier rear - 275/35/18 or 285/30/18 or 295/30/18

Michelin front - 235/40/18

Michelin rear - 265/35/18 or 285/30/18 or 295/30/18

As far as lowering the car goes - given the right setup a lower car should handle better. But it will usually ride rougher on the street. With a true coil-over setup and good shocks you cna have your cake and eat it too but that's costly both in purchase price and finding someone who knows what they are doing to setup your suspension. You can't just slap a set of shorter springs on the car and expect to do a better job than those high-paid Porsche engineers did with the factory suspension.

And camber adjustability is probably not as important in a DE environment than at an autox. Stock the car can get about 1 degree negative in the front and more than you want in the back. A good alignment is all you need. Get as much negative camber as possible in the front, as little neg camber in the back, 0 toe in the front and maybe a tiny bit of toe in in the back.

Tires will be your biggest performance improvement. Good luck and be careful out there!