305/30/19 or 315/25/19?
05-24-2006, 06:47 PM
#1
Cruisin'
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305/30/19 or 315/25/19?
1 have a 2001 996TT lowered with Techart springs. I am interested in purchasing 19" wheels in sizes of 19x8.5 and 19x11.
Dealer tells me that 305/30/19 will be a acceptable fitment. However, when checking specs on the Michelin's site, the 2 sizes vary significantally (26.3 vs 25.2). Front size will be 235/35/19. It appears 315/25/19 is a better fitment. Any info or comment will be appreciated.
Dealer tells me that 305/30/19 will be a acceptable fitment. However, when checking specs on the Michelin's site, the 2 sizes vary significantally (26.3 vs 25.2). Front size will be 235/35/19. It appears 315/25/19 is a better fitment. Any info or comment will be appreciated.
05-24-2006, 07:11 PM
#2
Drifting
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I have the 315/25/ZR19's and work perfect,do not rub.
fronts are 235/35/ZR19's and work perfect, do not rub.
I am using Conti SportContact2 On Champion RG19 Monolite wheels
Love em!
Marty
fronts are 235/35/ZR19's and work perfect, do not rub.
I am using Conti SportContact2 On Champion RG19 Monolite wheels
Love em!
Marty
05-24-2006, 07:13 PM
#3
Nordschleife Master
You are correct to be concerned that the front and rear diameters should be fairly close (but there is little data that decsribes the optimum difference). On my car, shod with Pirelli Assemetricos, I use 255x30x19 with 305x25x19, These two match up nicely, and have a similar overall diameter to the stock 18" tires.
05-24-2006, 09:46 PM
#4
Rennlist Member
You can put 315's on the 11 inch wheel for street use only!! Believe me I ruined a set of tires on the track like that. The michelin co replaced them but the wheel guys (champion) said they should not have been on an 11 and need a 11.5 at least.
235 is best for this car in the front, 255 would cause to much understeer and certainly more road "huntin" due to the width.
so yes, 235, 315 but rear wheel should be at least 11.5 to be correct. I have the GT2 rear wheels which are 12 inches wide. I also have the set up you asked about.
235 is best for this car in the front, 255 would cause to much understeer and certainly more road "huntin" due to the width.
so yes, 235, 315 but rear wheel should be at least 11.5 to be correct. I have the GT2 rear wheels which are 12 inches wide. I also have the set up you asked about.
05-24-2006, 11:00 PM
#5
Cruisin'
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I apologize, let me clarify.......
The wheels are Champions RG5B: 19x8.5 and 19x11.5.
My main concern is the overall rolling diameter between the 2 rear tires. Michelin specs:
235/35/19 (F) diameter25.5 rev/min 817
305/30/19 (R) 26.3 788
315/25/19 (R) 25.2 824
Strictly comparing number wise, the 315 is a closer match. The dealer claim the 305/30/19 would be a more ideal fitment because it would give the car a more favorable rake/stance as the 315/25/19 is actually a shorter tire. I am concern that the discrepancy would upset the AWD computer readings and cause additional wear and tear.
What do you guys think? Has anyone used 305/30/19 in the rear?
The wheels are Champions RG5B: 19x8.5 and 19x11.5.
My main concern is the overall rolling diameter between the 2 rear tires. Michelin specs:
235/35/19 (F) diameter25.5 rev/min 817
305/30/19 (R) 26.3 788
315/25/19 (R) 25.2 824
Strictly comparing number wise, the 315 is a closer match. The dealer claim the 305/30/19 would be a more ideal fitment because it would give the car a more favorable rake/stance as the 315/25/19 is actually a shorter tire. I am concern that the discrepancy would upset the AWD computer readings and cause additional wear and tear.
What do you guys think? Has anyone used 305/30/19 in the rear?
05-24-2006, 11:47 PM
#6
Nordschleife Master
"... 235 is best for this car in the front, 255 would cause to much understeer... "
I'm not a 996 guy, but its hard for me to understand how a wider tire (on the appropriate wheel) will cause more understeer. That is certainly not true on my car. And while I've never tried the well respected Michlein PS 2 tires, I'm very, very pleasantly surprised by the Pirellis. No "hunting" either.
"...the discrepancy would upset the AWD computer..."
I believe the 996 AWD system is the same as the 993... a purely mechanical viscous coupler... no computer, no electronics involved. Again... I could be wrong, but I don't think so. In any event, the viscous coupler can easily overheat if the diameters are too different. I "believe" the ideal setup is to have them closely matched, but the rears a tiny bit smaller to keep the fluid warm, but not too hot.
My humble opinion, of course.
I'm not a 996 guy, but its hard for me to understand how a wider tire (on the appropriate wheel) will cause more understeer. That is certainly not true on my car. And while I've never tried the well respected Michlein PS 2 tires, I'm very, very pleasantly surprised by the Pirellis. No "hunting" either.
"...the discrepancy would upset the AWD computer..."
I believe the 996 AWD system is the same as the 993... a purely mechanical viscous coupler... no computer, no electronics involved. Again... I could be wrong, but I don't think so. In any event, the viscous coupler can easily overheat if the diameters are too different. I "believe" the ideal setup is to have them closely matched, but the rears a tiny bit smaller to keep the fluid warm, but not too hot.
My humble opinion, of course.
05-25-2006, 10:32 AM
#7
Rennlist Member
ca you may be right, not sure either, as for the poster the wheel tire combo should be fine as that is what alot on this forum run, question answered.
ca I had a set of 245's on the front and it just felt as if it wasnt as crisp in the corners, I may have chosen my words incorrectly.
ca I had a set of 245's on the front and it just felt as if it wasnt as crisp in the corners, I may have chosen my words incorrectly.
