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your car looks great. Do you have any rear quarter panal view, maybe showing a little of the front wheel as well. Just want to see how the tires fits under the fenders.
 

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I read through the whole thread and couldn't find a specific example of the tires i'm trying to run. I'm looking at picking up a set of 18x8.5s and 18x10s and pairing them with some RE71Rs.

My first choice is 245/40/18 and 275/35/18. Is that an issue because it's a 1.2% increase in front diameter and a 2.9% decrease in rear diameter?
I know I could do a 235/40/18 with 0% change or a 255/35/18 with have -1.5%. But I'm trying to keep handling balance as similar as possible by increasing wheel and tire width equally front and rear.

-Thanks
 

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I've done RE71R in 235/40/18 and 255/40/18. No issues on street or track. But I want to try wider, so next set will be 255/35/18 and 275/35/18. I think its important to keep that rear diameter bias.
 

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I have a very simular set up(to Credit) with the exception of Ohlins 70n/mm spring rate F and 80 n/mm spring rate rear. I am very satisfied with RE255/35/18 F and 275/35/18 R. This combo is very balanced and fit perfectly on my light weight Signature SV-104 monoblock forged wheels (F 9 in 47 offset and 10 in 35 offset). I am using Tarett Cup lower control arms with 10 mm LCA spacers front and rear. the chassis camber adjuster used to get the final -2.6 front and -2.5 rear camber. Using adjustable Tarett GT swaybars 2 hole from softest in front (5 holes) and second hole stiffest in rear (4 holes). I do change the compression/rebound and front to rear swaybars depending on the track, bumpy vs smooth, grip, surface type, etc. Use for autocross, DE's and PCA tours.
Past weekend PCA had first autocross of the season, 35 degrees and wet, but slowly drying track. The RE71R's worked perfectly. I sort of wished I would have gone Ryan Clarks way with 265/35/18 F and 285/30/18 R. Maybe next set in a couple of years. I want to try Hoosiers A7's next.
 

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Just bought a set of HRE FF15 for my 987.2 on stock suspension. 19x8.5 +50 front and 19x10 +40 rear. Looking for optimal tire sizes to get so I can get these mounted on the car. What tire size should I run? Thanks
 

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Well, not knowing what your ideas are for these tires uses are, but if they are Michelins, something like 255/35/19 f and 275/35/19. These will fill up your wheelwells. Your front offset of +50 on a 8.5 inch wheel says you can push the wheels out a little more to get away from your spring perch with a 5 mm spacer. The rear should be fine, but again you could use a 5 mm spacer to push your wheel out if needed. I would think your tires will fit fine with these offsets. Apex wheels are suggesting 48 offset front and 36 rear.
I use this combo with a 47 offset in front with a 9 inch wheel, 255/35/18 and 35 offset rear with a 10 inch wheel, 275/35/18 tire. They are RE71R's race tires for autocross. I will be doing a few DE's later this year as well as Porsche Club tour events. My daily driver wheels are also 18's OEM 8 inch in front 57 offset and 9 inch in the rear offset 43 with Michelin PSS 235/40/18f and 265/40/18r. Hope that helps.
 

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Well, not knowing what your ideas are for these tires uses are, but if they are Michelins, something like 255/35/19 f and 275/35/19. These will fill up your wheelwells. Your front offset of +50 on a 8.5 inch wheel says you can push the wheels out a little more to get away from your spring perch with a 5 mm spacer. The rear should be fine, but again you could use a 5 mm spacer to push your wheel out if needed. I would think your tires will fit fine with these offsets
I use this combo with a 47 offset in front with a 9 inch wheel, 255/35/18 and 35 offset rear with a 10 inch wheel, 275/35/18 tire. They are RE71R's race tires for autocross. I will be doing a few DE's later this year as well as Porsche Club tour events. My daily driver wheels are also 18's OEM 8 inch in front and 9 inch in the rear with Michelin PSS 235/40/18 and 265/40/18. Hope that helps.
Thanks for the reply. How about 245/40/19 and 275/35/19? I'm just mainly using it for street use and maybe going to try to go on a track in the near future.
 

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That should work perfectly.
 

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Thanks for the reply. How about 245/40/19 and 275/35/19? I'm just mainly using it for street use and maybe going to try to go on a track in the near future.
If you are doing mostly street driving, then why not stick to OEM size? That would be optimal in my opinion. Keep in mind that 245/40/19 is close to 5% larger then stock 235/35/19. If you absolutely must go up a size, increase both front and rear to maintain the rear bias as Porsche intended.
 

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I read through the whole thread and couldn't find a specific example of the tires i'm trying to run. I'm looking at picking up a set of 18x8.5s and 18x10s and pairing them with some RE71Rs.

My first choice is 245/40/18 and 275/35/18. Is that an issue because it's a 1.2% increase in front diameter and a 2.9% decrease in rear diameter?
I know I could do a 235/40/18 with 0% change or a 255/35/18 with have -1.5%. But I'm trying to keep handling balance as similar as possible by increasing wheel and tire width equally front and rear.

-Thanks
After this past weekend autocrossing on a damp, cold track, I would like to change to 265/35/18 F and 285/30/18 R. Unfortunately Bridgestone does not make a RE71R in 285/35/18 or I would have bought those, instead, I went down one size to 255/35/18 F and 275/35/18 R to keep the sidewalls the same. The car can handle a bigger tire footprint as Ryan Clark showed late last year at the Solo National autocross by winning B/S with this combo. They fit the wheel wells without rubbing and fit on 8.5 and 10 inch wheels. Ryan's car did not have an adjustable rear swaybar, only a Tarett GT front bar. So for those of us with both adjustable bars, we certainly can dial in the balance as least a well as Ryan did.
My reason for not getting the bigger footprint was that it makes the car sort of a tail dragger, but I am getting a new LN/BILT 2 qt sump and skid protector plate. Again, it certainly did not have any negative effects on Ryans performance over the past year to qualify for the nationals, be invited, then win. So a lot of racing with this setup with the rake that is not within Porsche recommendations. He had no brake issues as well.
 

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I would doubt that you would rub. If the inside does rub, use a 5 mm spacer on both sides and push your wheels out. Apex 10 inch wheels use a 36 offset for 987/981's in the rear, so their wheels are setup closer to the fender lip as opposed to the spring perch.
 

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I would doubt that you would rub. If the inside does rub, use a 5 mm spacer on both sides and push your wheels out. Apex 10 inch wheels use a 36 offset for 987/981's in the rear, so their wheels are setup closer to the fender lip as opposed to the spring perch.
Got them installed today and no rubbing =) I got some new TPMS on the new set but when had issues resetting it. Now I have TPMS warning. I used new OEM set of TPMS.
 

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You may have to reset a few times, making sure the take off wheels are not even close, so the receiver in your car is only picking your the new TPMS senders. I had to drive around for 20 minutes while my computer was thinking about it. Summer tires for the HRE's, winter tires for the take off's, wheel size, etc. You will get it figured out. Glad they fit.

Take a picture and download it to your computer, then on Planet 9 hit the 3rd button from the right on top of the typing box. Make sure the cuser is down below by a couple of lines you wrote and let the picture rip. What size tire did you decide to install in front to go with the 285/35/19's in the rear? How are the wheel/tire fitment to the ach of the wheelwell? Too much space? May need H&R springs to lower your car 25 mm? I chose Ohlin coilovers, but that was because I knew I want to autocross/DE's and needed the adjustability of the compression/rebound. After you lower it, you can push the wheels and tires out to the edge of the fender lip with wheel spacers depending on your HRE wheel offsets. Let us know your progress.
 

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You may have to reset a few times, making sure the take off wheels are not even close, so the receiver in your car is only picking your the new TPMS senders. I had to drive around for 20 minutes while my computer was thinking about it. Summer tires for the HRE's, winter tires for the take off's, wheel size, etc. You will get it figured out. Glad they fit.

Take a picture and download it to your computer, then on Planet 9 hit the 3rd button from the right on top of the typing box. Make sure the cuser is down below by a couple of lines you wrote and let the picture rip. What size tire did you decide to install in front to go with the 285/35/19's in the rear? How are the wheel/tire fitment to the ach of the wheelwell? Too much space? May need H&R springs to lower your car 25 mm? I chose Ohlin coilovers, but that was because I knew I want to autocross/DE's and needed the adjustability of the compression/rebound. After you lower it, you can push the wheels and tires out to the edge of the fender lip with wheel spacers depending on your HRE wheel offsets. Let us know your progress.
I messed around it some more today. Finally got it to say process complete. BUT....I still have TPMS light and red "!" on. I just checked the TPMS I bought were OEM 911 ones that has 315mHz it says. Did I get the wrong one? =(
 

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433 mHz is what I ordered from TireRack and they work perfectly. The 315 mHz maybe for the 718 or 911's.
 

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UPDATE:
i had a full weekend of auto-x with both cars and had no problem with the tires.

the 2014 981 cayman s with PASM has just over 1 deg of neg camber all around and 19X8.5 STARKE DESIGN 52mm offset and 19x9.5 43mm offset. with bridgestone re71r 255/35/19 26" dia and 285/35/19 26.8" dia. they did good and no rubbing at all. it was a cold day in Marina and i was running 32 psi front and 34 rear once up to temp. started out the afternoon with lower pressure cold and didnt notice much difference.

2006 987 cayman s has gt3 arms in the front with just over 2 deg of neg camber and just under 2 deg in the rear. i got a set of 18" wheels from and early 981 that are 8" front with 245-40-18 re71r and 9" rear with 275-35-18 re71r. no rubbing at all. the wheel well gap in the rear is big but i am happy with the set up so far. i was using 32 psi front and 34 psi rear when hot.

i will update again if i end up putting the 19" wheels on the 987. i doubt there will be a problem. i had them on the car for a short time on the street without an issue.


 

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Thanks for your tire pressures. I started this Sat, first PCA autocross with my RE71R's pressure set a little low at 31 due to fog and slight dampness on the track and let it build to 35 in both the front and back. When I got home, I noticed the outsides were scuffed, while the insides were smooth on both front and rear tires. This tells me that with that lower pressure first run, some tire roll, but the other 3 runs at higher pressure, I need more camber to scuff the entire tread face. Currently Camber at -1.6 in front and -2.1 in the rear. In a couple of weeks, the car will go into the shop for Tarett Cup lower control arms to push the wheels out and add camber -2.6 in front and-2.5 in the rear. That should solve the scuffing on the outside of the tires. The suspension balance was great, almost no understeer, and the rear was sticking with no wheel spin on the inside rear tire as well. I use 255/35/18 F and 275/35/18 R.

Have you thought about putting spacers on your cars, seems both are running close to oem offsets. Your front track is pushed out at least 10 mm with the GT3 LCA camber spacer on each wheel, while the back is at the OEM track? Just a thought.

With my 18 inch OEM rims and Michelin PSS's, I use 18mm spacer in the front offset of 57 on 8 inch wheels and 23mm spacer in the rear with an offset of 43 on 9 inch wheels. My race wheels 9 in F and 10 in R, I am using 47 offset in front with no spacer and 35 offset in the rear with a 10 mm spacer. However, when the Cup LCA's go on the track will be increase 11 mm on each side front and back with a 10 mm Tarett spacer and a 1 mm litronic bracket on each control arm.
The LCA's also lowered the ride height about 5 mm more than now to about 35 mm lower than OEM.

The new Tarett Cup lower control arms front and rear made a dynamic difference in the suspension as far as driving impression goes. My car is very responsive to steering input, braking, trail braking all due to the stiffer monballs and the solid thrust puck. After the installation, I had to back off the Ohlin damping/rebound rate as the new control arms somehow affected the wheel rate making the Ohlins spring rate much more sensititive. I now am using 18 clicks from full stiff with the Ohlins for my daily travels. Autocross will be 12 clicks from stiff f&r. This combo of coilovers,spring rates and lightweight LCA's with stiffer bearings, solid thrust puck, is working well enough to put a smile on my face.

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