Tire sizes
01-10-2002, 04:00 AM
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Tire sizes
Hi,
what is the better tire size combinations for handling and comfort on a '99 C2 Cab?
a) 225fr & 265re
or
b) 225fr & 285re
or
c) 235fr & 285re
or
d) 245fr & 285re
wheel sizes are 8"x18"fr & 10"x18"re
H & R sports springs
what is the better tire size combinations for handling and comfort on a '99 C2 Cab?
a) 225fr & 265re
or
b) 225fr & 285re
or
c) 235fr & 285re
or
d) 245fr & 285re
wheel sizes are 8"x18"fr & 10"x18"re
H & R sports springs
01-10-2002, 10:37 AM
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You'd think wider would be better on the front, but who knows. The fact Porsche is using 225/285 on all new 18" equipped 996s is a good place to start. BTW, you have added some negative camber to the front of yours now that it's lowered, right? That'll probably make a huge diff.
And, Porsche uses the 225/285 on the stock GT3 which is a much more performance oriented car than the base 996:
GT3 specs from Porsche: http://193.175.6.197/news/archive/990616.htm
GT3 specs from Porsche
And, Porsche uses the 225/285 on the stock GT3 which is a much more performance oriented car than the base 996:
GT3 specs from Porsche: http://193.175.6.197/news/archive/990616.htm
GT3 specs from Porsche
01-10-2002, 12:11 PM
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Ben,
just to comment on your thoughts, I think we all agree that we can improve on the products Porsche put out. They are restricted by budget constraints per each car sold hence the equipment level are kept to particular specs.
I have changed to 235fr & 285re SO3 from 225fr & 265re Contis. I found the car tracks far better (atleast 50% better).
I read somewhere that 245 will fit fronts so I was hoping to get a bit of an incentive to go wider at front. The thinking behind that was wider gives better traction.
Somehow I feel I can do better with the handling - close to neutral as possible. However I am reluctant to add coilovers & sway bars as I am still not convinced it would improve my current setup by a significant margin.
Any more thoughts, anyone?
just to comment on your thoughts, I think we all agree that we can improve on the products Porsche put out. They are restricted by budget constraints per each car sold hence the equipment level are kept to particular specs.
I have changed to 235fr & 285re SO3 from 225fr & 265re Contis. I found the car tracks far better (atleast 50% better).
I read somewhere that 245 will fit fronts so I was hoping to get a bit of an incentive to go wider at front. The thinking behind that was wider gives better traction.
Somehow I feel I can do better with the handling - close to neutral as possible. However I am reluctant to add coilovers & sway bars as I am still not convinced it would improve my current setup by a significant margin.
Any more thoughts, anyone?
01-10-2002, 12:58 PM
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"just to comment on your thoughts, I think we all agree that we can improve on the products Porsche put out. They are restricted by budget constraints per each car sold hence the equipment level are kept to particular specs."
I would agree with you if this (225/285) wasn't standard equipment on the high performance Euro GT3. Still you might just be right about the wider track up front (it sure makes sense!). Who knows what the other issues were that prompted Porsche to use the 225s on the GT3. BTW, check out the times:
http://home3.swipnet.se/~w-32546/nbr...ent%20cars.htm
"Somehow I feel I can do better with the handling - close to neutral as possible. However I am reluctant to add coilovers & sway bars as I am still not convinced it would improve my current setup by a significant margin."
I went the coilover/adj sway route and my car is almost exactly neutral (225/285..-1 deg frt camber/-1 1/2 deg rear camber), and I still have two settings in the rear to likely change it from fractional (almost not worth mentioning) understeer to oversteer.
Turn in is "supposed" to be better with smaller tires up front (225s), so I'd think the adj sways (think they require coilovers) are the best way to go.
Besides, I kinda doubt that you're going to neutralize a 40 ft/60 rr wieghted car by uping the size of the tires in the front. You'd think that even if you could get the same contact patches up front as the rear (285) - which you can't - that the weight would still cause understeer absent suspension changes, no?
What have you noticed as far as up AND downsides to running 235s on the front? Any ride or tramlining problems on the street? Any less precise turn in?
I would agree with you if this (225/285) wasn't standard equipment on the high performance Euro GT3. Still you might just be right about the wider track up front (it sure makes sense!). Who knows what the other issues were that prompted Porsche to use the 225s on the GT3. BTW, check out the times:
http://home3.swipnet.se/~w-32546/nbr...ent%20cars.htm
"Somehow I feel I can do better with the handling - close to neutral as possible. However I am reluctant to add coilovers & sway bars as I am still not convinced it would improve my current setup by a significant margin."
I went the coilover/adj sway route and my car is almost exactly neutral (225/285..-1 deg frt camber/-1 1/2 deg rear camber), and I still have two settings in the rear to likely change it from fractional (almost not worth mentioning) understeer to oversteer.
Turn in is "supposed" to be better with smaller tires up front (225s), so I'd think the adj sways (think they require coilovers) are the best way to go.
Besides, I kinda doubt that you're going to neutralize a 40 ft/60 rr wieghted car by uping the size of the tires in the front. You'd think that even if you could get the same contact patches up front as the rear (285) - which you can't - that the weight would still cause understeer absent suspension changes, no?
What have you noticed as far as up AND downsides to running 235s on the front? Any ride or tramlining problems on the street? Any less precise turn in?
01-10-2002, 04:56 PM
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Hi Ben,
Well, compared to the 225 Contis, instant change with SO3 - just sticks to the road. I have also added GT3 front spoiler only (no sides or rears) to aid high-speed stability and it really does make a difference in crosswinds. Car felt and still feels well planted to road like M3 Evo. Steering is so precise, turn-in or tracking is so true and I am able to 'throw' the car into bends with high degree of confidence. All this made me feel that I had nailed the handling as I did on my previous car, a 2.5lt Boxster - handled like it was on rails! Specs were Sports pack, 18" with 225 & 265 SO2 & lowered tire PSI.
I agree with you about the 40/60 weight distribution.
What I am reluctant to do is to try making a GT, which essentially is what the 996 Cabriolets are, handle like a nailed Coupe - expense and rigidity consideration means I might be better off buying a 964RS lightweight or a 993RS Club Sport for that real go-kart race feel.
However when I upped tire size from 225 to 235, I felt I was heading the right way. That is my reason for pursuing this very avenue. I just need the opinion of anyone out there who has tried the 245fr & 285re combination. I may not get the 50/50 weight but I surely can get the fronts to be just as unstickable as the rears are currently. It is really fine tuning at present.
Maybe the coilover & sway bars are the answer to my prayers but as I said earlier, I am not that sure now. It is just the front I need nailed to the road. My car did not have the traction control (TC) option by the way – would that have made a difference?
Well, compared to the 225 Contis, instant change with SO3 - just sticks to the road. I have also added GT3 front spoiler only (no sides or rears) to aid high-speed stability and it really does make a difference in crosswinds. Car felt and still feels well planted to road like M3 Evo. Steering is so precise, turn-in or tracking is so true and I am able to 'throw' the car into bends with high degree of confidence. All this made me feel that I had nailed the handling as I did on my previous car, a 2.5lt Boxster - handled like it was on rails! Specs were Sports pack, 18" with 225 & 265 SO2 & lowered tire PSI.
I agree with you about the 40/60 weight distribution.
What I am reluctant to do is to try making a GT, which essentially is what the 996 Cabriolets are, handle like a nailed Coupe - expense and rigidity consideration means I might be better off buying a 964RS lightweight or a 993RS Club Sport for that real go-kart race feel.
However when I upped tire size from 225 to 235, I felt I was heading the right way. That is my reason for pursuing this very avenue. I just need the opinion of anyone out there who has tried the 245fr & 285re combination. I may not get the 50/50 weight but I surely can get the fronts to be just as unstickable as the rears are currently. It is really fine tuning at present.
Maybe the coilover & sway bars are the answer to my prayers but as I said earlier, I am not that sure now. It is just the front I need nailed to the road. My car did not have the traction control (TC) option by the way – would that have made a difference?
01-10-2002, 05:05 PM
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"Well, compared to the 225 Contis, instant change with SO3 - just sticks to the road."
I'd think you notice a large diff between the Contis and the S03s with even the same tire size. That said, I had the S02s on 17"s on my old 993 cab. Upon switching to Contis on 18"s (they came on the wheels), the car was night and day improved. So, who knows.
"What I am reluctant to do is to try making a GT, which essentially is what the 996 Cabriolets are, handle like a nailed Coupe - expense and rigidity consideration means I might be better off buying a 964RS lightweight or a 993RS Club Sport for that real go-kart race feel."
Mine feels like a Kart now! I've driven coupes with the sport package and my coupe is easily as flat and responsive now (probably much more so even). It really is incredibly faster in faster turns with much more balanced throttle steer. Before about all I could do was throttle steer around the understeer, now I can easily move both ends of the car with throttle. Also, I know it sounds funny but the GT3 seats actually make me feel faster. I think they actually make you faster as you stay planted in the seats instead of sloshing side to side in both the stock and sport seats. The lower to the ground affect of the GT3 seats also adds to the kart feeling.
"However when I upped tire size from 225 to 235, I felt I was heading the right way. That is my reason for pursuing this very avenue."
Hey, I'm certainly more than open to moving up to 235s upon wearing out the new Contis, but I'd really like to know if tramlining is increased. Is your experience that there is no noticable diff in ride quality or turn in with the 235s?
"Maybe the coilover & sway bars are the answer to my prayers but as I said earlier, I am not that sure now. It is just the front I need nailed to the road."
The nice thing about the coilovers and bars is that you increase grip on both sides (IMO) while also dialing out understeer.
"My car did not have the traction control (TC) option by the way ? would that have made a difference?"
How so, slightly lighter? Where's the weight for the PSM?
BTW, have you had your car corner balanced and what camber settings are you using?
Also, did you change the shocks when you changed to the more aggressive springs?
I'd think you notice a large diff between the Contis and the S03s with even the same tire size. That said, I had the S02s on 17"s on my old 993 cab. Upon switching to Contis on 18"s (they came on the wheels), the car was night and day improved. So, who knows.
"What I am reluctant to do is to try making a GT, which essentially is what the 996 Cabriolets are, handle like a nailed Coupe - expense and rigidity consideration means I might be better off buying a 964RS lightweight or a 993RS Club Sport for that real go-kart race feel."
Mine feels like a Kart now! I've driven coupes with the sport package and my coupe is easily as flat and responsive now (probably much more so even). It really is incredibly faster in faster turns with much more balanced throttle steer. Before about all I could do was throttle steer around the understeer, now I can easily move both ends of the car with throttle. Also, I know it sounds funny but the GT3 seats actually make me feel faster. I think they actually make you faster as you stay planted in the seats instead of sloshing side to side in both the stock and sport seats. The lower to the ground affect of the GT3 seats also adds to the kart feeling.
"However when I upped tire size from 225 to 235, I felt I was heading the right way. That is my reason for pursuing this very avenue."
Hey, I'm certainly more than open to moving up to 235s upon wearing out the new Contis, but I'd really like to know if tramlining is increased. Is your experience that there is no noticable diff in ride quality or turn in with the 235s?
"Maybe the coilover & sway bars are the answer to my prayers but as I said earlier, I am not that sure now. It is just the front I need nailed to the road."
The nice thing about the coilovers and bars is that you increase grip on both sides (IMO) while also dialing out understeer.
"My car did not have the traction control (TC) option by the way ? would that have made a difference?"
How so, slightly lighter? Where's the weight for the PSM?
BTW, have you had your car corner balanced and what camber settings are you using?
Also, did you change the shocks when you changed to the more aggressive springs?
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01-10-2002, 05:22 PM
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Hi Ben,
there is no tramlines with the 235.
Incidentally, check this http://www.miata.net/garage/tirecalc.html.
see what happens when you select 245/35fr and 295/30r (not 285). The speedo reading is calculated as closer to orginal 205/50 & 255/40.
I opted out of TC not to save weight, at time of purchasing, all articles on TC on 996 said it was hardly worth having so I opted it out. Just one of those things - if not needed, get rid of it!
there is no tramlines with the 235.
Incidentally, check this http://www.miata.net/garage/tirecalc.html.
see what happens when you select 245/35fr and 295/30r (not 285). The speedo reading is calculated as closer to orginal 205/50 & 255/40.
I opted out of TC not to save weight, at time of purchasing, all articles on TC on 996 said it was hardly worth having so I opted it out. Just one of those things - if not needed, get rid of it!
01-10-2002, 07:30 PM
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Porsche over the years has been trying to take out the "Tail Happy" qualities of the car we all love to drive (911).
Far too many of it new customers got in way over their heads and lifted in turns with a very well known result.
As a result they have all but removed any oversteer the car would have by making it understeer when you go into a turn "too" fast.
Put the wider tires on the front and the car sticks to the road like nothing you could imagine. (For those of you still on the 225's your giving up a LOT of performance).
I run the 245x35 and the 285x30 and love'm.
However, if you don't drive the car hard on the street and don't go to the track for D.E's and never really want to feel what the car can really do...(SELL the CAR to someone who will, you don't deserve a machine like this!!!)
Going to the 245 & 285 is the most cost effective change you can make to your 996 if you want better lap times (other than investing in more seat time at the track!) I would guess it would save you 4-6 sec on a 2+ mile track with at least one good high speed sweeper!
The sad part is that it seems only Hoosier seems to be making the 245's.
If you don't go wider at least go in and have your camber dialed in at something more Neg than zero (0 seems to be the stock setting, try -1.5) It will feel like you have wider tires.
Only draw back is a little more tire noise, nothing you can't fix with the volume ****
Far too many of it new customers got in way over their heads and lifted in turns with a very well known result.
As a result they have all but removed any oversteer the car would have by making it understeer when you go into a turn "too" fast.
Put the wider tires on the front and the car sticks to the road like nothing you could imagine. (For those of you still on the 225's your giving up a LOT of performance).
I run the 245x35 and the 285x30 and love'm.
However, if you don't drive the car hard on the street and don't go to the track for D.E's and never really want to feel what the car can really do...(SELL the CAR to someone who will, you don't deserve a machine like this!!!)
Going to the 245 & 285 is the most cost effective change you can make to your 996 if you want better lap times (other than investing in more seat time at the track!) I would guess it would save you 4-6 sec on a 2+ mile track with at least one good high speed sweeper!
The sad part is that it seems only Hoosier seems to be making the 245's.
If you don't go wider at least go in and have your camber dialed in at something more Neg than zero (0 seems to be the stock setting, try -1.5) It will feel like you have wider tires.
Only draw back is a little more tire noise, nothing you can't fix with the volume ****
01-10-2002, 10:34 PM
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Hi Armando.
Remember me? Used to be ben, fla. We met at Hooters to demo Fabs, remember? It only took me a year, but I was inspired to get the GT3 seats after riding in yours and finding out how comfy they are. I didn't want to give up my heated seats, but found the more I "drove" the car, the worse the lack of lateral support became more important to fix than heat :-)
ANY drawbacks to the 245s on the STREET? I bought an extra set of rims just for DE/tracking, etc, but wonder if I want to go 235 or 245 for the STREET as well.
Hope all is going great for you.
TIA
Remember me? Used to be ben, fla. We met at Hooters to demo Fabs, remember? It only took me a year, but I was inspired to get the GT3 seats after riding in yours and finding out how comfy they are. I didn't want to give up my heated seats, but found the more I "drove" the car, the worse the lack of lateral support became more important to fix than heat :-)
ANY drawbacks to the 245s on the STREET? I bought an extra set of rims just for DE/tracking, etc, but wonder if I want to go 235 or 245 for the STREET as well.
Hope all is going great for you.
TIA
01-11-2002, 05:20 AM
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Hi Armando & Ben,
Good of you two for keeping this thread going.
Armando, thanks! for echoing precisely what I believed was just the thing to do first and foremost, sorry Ben!
I think the current '911' range, or 996 for those who want to be specific, are more Grand Tourers (GT) than racers. The GT3, GT2, and maybe TT are racers but not comparative to say a 2.7RS or 964RS in terms of ***** out driving IMHO.
Therefore spending time, effort and bucks to try achieveing close to a racer with a stock 996 seems pointless IF the whole excercise does not tackle basics like tires PSI & wheel sizes first and foremost.
Tinkering with our pride & joy, and I mean our cars and nothing else!, is OK but hearing some mebers spending more money on a stock 996 than a GT3 or 99RS cost new just to 'get close' to a GT3 or 993RS towering abilites seems pointless to me! If you want a faster car, buy a fast one in the first place!. If you want a track car, buy one in the first place! If you want a multi-function FRED, well you are beyound saving. Just give your money to charity!
I am close to what I am looking for interms of a racer that performs just as well on the streets at reasonable cost. Before I start fitting sway bars etc, I would just by an RS (964) or GT3 Clubsport.
Just my penny worth.
Good of you two for keeping this thread going.
Armando, thanks! for echoing precisely what I believed was just the thing to do first and foremost, sorry Ben!
I think the current '911' range, or 996 for those who want to be specific, are more Grand Tourers (GT) than racers. The GT3, GT2, and maybe TT are racers but not comparative to say a 2.7RS or 964RS in terms of ***** out driving IMHO.
Therefore spending time, effort and bucks to try achieveing close to a racer with a stock 996 seems pointless IF the whole excercise does not tackle basics like tires PSI & wheel sizes first and foremost.
Tinkering with our pride & joy, and I mean our cars and nothing else!, is OK but hearing some mebers spending more money on a stock 996 than a GT3 or 99RS cost new just to 'get close' to a GT3 or 993RS towering abilites seems pointless to me! If you want a faster car, buy a fast one in the first place!. If you want a track car, buy one in the first place! If you want a multi-function FRED, well you are beyound saving. Just give your money to charity!
I am close to what I am looking for interms of a racer that performs just as well on the streets at reasonable cost. Before I start fitting sway bars etc, I would just by an RS (964) or GT3 Clubsport.
Just my penny worth.
01-11-2002, 12:25 PM
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"If you want a faster car, buy a fast one in the first place!."
As soon as they make one in a cab that doesn't weight nearly 2 tons, count me in. Until then, this is our only choice to get that kind of performance from a Porsche cab.
As soon as they make one in a cab that doesn't weight nearly 2 tons, count me in. Until then, this is our only choice to get that kind of performance from a Porsche cab.
02-22-2002, 05:15 PM
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I have gotten a bubble on my sidewall also and now have the Pirelli Assimetricos 225/265(Factory). Will changing to the SO-3 235/40 and 285/30 effect my speedometer? From what is said in this post, I believe this is a good combo. You guys have stock in Bridgestone or something?
Thanks,
John
Thanks,
John
02-22-2002, 06:02 PM
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F.Y.I
On the PSI-Motorsport website the put 255/285 configuration.
<a href="http://www.psi-motorsport.com/pages/eng/fs-2-porsche.html" target="_blank">http://www.psi-motorsport.com/pages/eng/fs-2-porsche.html</a>
Bel996
On the PSI-Motorsport website the put 255/285 configuration.
<a href="http://www.psi-motorsport.com/pages/eng/fs-2-porsche.html" target="_blank">http://www.psi-motorsport.com/pages/eng/fs-2-porsche.html</a>
Bel996
02-23-2002, 08:07 AM
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Sicaone,
I have 235/285 combo and I must say the fronts grip very well however I do not believe the 285 rears are right for me so when my rears need replacing, has 10k mileage at present and looks good for another 3k to 4k, I am trying out 295/30 SO3s!.
I believe I need more grip on rears and as the 996TT has 295 rears, I am giving that a go. My main quibble is a hint of body rolls on the rears at high speed cornering.
I also believe the SO3s seem to loose their grip, wet & dry, after about 60% wear. Anyway I will post results on 295\30 rears after some trials.
If you want a good tire size calculator, try this here <a href="http://www.miata.net/garage/tirecalc.html" target="_blank">www.miata.net/garage/tirecalc.html</a> .
996 C2 Cab
H & R Sports Springs
8”x18” fr 3-pce light alloys
10”x18” fr 3-pce light alloys
SO3 235fr (30PSI) / 285re (32.5PSI)
GT3 front spoiler (has helped with high speed nose stability)
I have 235/285 combo and I must say the fronts grip very well however I do not believe the 285 rears are right for me so when my rears need replacing, has 10k mileage at present and looks good for another 3k to 4k, I am trying out 295/30 SO3s!.
I believe I need more grip on rears and as the 996TT has 295 rears, I am giving that a go. My main quibble is a hint of body rolls on the rears at high speed cornering.
I also believe the SO3s seem to loose their grip, wet & dry, after about 60% wear. Anyway I will post results on 295\30 rears after some trials.
If you want a good tire size calculator, try this here <a href="http://www.miata.net/garage/tirecalc.html" target="_blank">www.miata.net/garage/tirecalc.html</a> .
996 C2 Cab
H & R Sports Springs
8”x18” fr 3-pce light alloys
10”x18” fr 3-pce light alloys
SO3 235fr (30PSI) / 285re (32.5PSI)
GT3 front spoiler (has helped with high speed nose stability)