Wheel Triumph, Tire Bummer
07-15-2016, 12:42 PM
#1
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Wheel Triumph, Tire Bummer
Hello:
I think I found the last silver finish Fuchsfelge wheels left on the planet at Rose Passion in France (they seem like a sharp outfit in my dealings with them). Got the wheels to the US today and delivered to the installer along with my 2004 C4S. Wheels are super cool, I'm stoked.
Here's the bummer: One of the main reasons I bought the wheels is that they are 18", as opposed to the 19" Champion RG5s on there currently, and I thought I would be able to smooth out the ride a bit. Well, the new rear wheels are 295/30, which I'm virtually certain is the same as what shipped on the 18" OEM Technosports that came with the car originally.
I looked at the wheels that are on the 19" Champions and what do I see? 295/30. This led me to the depressing conclusion that the amount of air underneath me is going to be exactly the same with my new 18"s as it was with the old 19"s.
Well, I'm a complete n00b at this stuff, so I'll chalk this one up to learning. At least I bought some relatively inexpensive tires. Does anyone know if/how I can achieve a softer ride using different tires? Talking quickly with the gent at the installer shop, he thought maybe 285/40 or something like that might do it (can't remember if I have that exactly right).
Finally, I'll be listing my RG5s along with the Pirellis on the them in the classifieds. They are in super cherry condition.
L8er,
Brad
I think I found the last silver finish Fuchsfelge wheels left on the planet at Rose Passion in France (they seem like a sharp outfit in my dealings with them). Got the wheels to the US today and delivered to the installer along with my 2004 C4S. Wheels are super cool, I'm stoked.
Here's the bummer: One of the main reasons I bought the wheels is that they are 18", as opposed to the 19" Champion RG5s on there currently, and I thought I would be able to smooth out the ride a bit. Well, the new rear wheels are 295/30, which I'm virtually certain is the same as what shipped on the 18" OEM Technosports that came with the car originally.
I looked at the wheels that are on the 19" Champions and what do I see? 295/30. This led me to the depressing conclusion that the amount of air underneath me is going to be exactly the same with my new 18"s as it was with the old 19"s.
Well, I'm a complete n00b at this stuff, so I'll chalk this one up to learning. At least I bought some relatively inexpensive tires. Does anyone know if/how I can achieve a softer ride using different tires? Talking quickly with the gent at the installer shop, he thought maybe 285/40 or something like that might do it (can't remember if I have that exactly right).
Finally, I'll be listing my RG5s along with the Pirellis on the them in the classifieds. They are in super cherry condition.
L8er,
Brad
07-15-2016, 06:04 PM
#2
Race Director
I'm not quite sure I understand what you're getting at.
yes, the size of the sidewall on a 295/30 is going to be the same regardless of the wheel diameter. However, given that you now have the same sidewall on a 1" smaller wheel, your car will actually be lower to the ground and the speedo will read higher than before. The overall diameter of your wheel/tire package is now smaller.
Generally when going -1 on wheel size, you would go up from a 295/30 to like a 295/40 or similar, giving you the same diameter but more sidewall.
yes, the size of the sidewall on a 295/30 is going to be the same regardless of the wheel diameter. However, given that you now have the same sidewall on a 1" smaller wheel, your car will actually be lower to the ground and the speedo will read higher than before. The overall diameter of your wheel/tire package is now smaller.
Generally when going -1 on wheel size, you would go up from a 295/30 to like a 295/40 or similar, giving you the same diameter but more sidewall.
07-15-2016, 11:25 PM
#4
With the same 295/30 tires, the car will ride 1/2" higher on 19" rims than 18" rims. This not fatal for most people. Tire Rack has 295/35-18s and 295/35-19s but not 295/40-19s. The 40 aspect ratio would make the car ride even higher but I don't see that size on Tire Rack. I would suggest that you use the 18" rims and maybe pick 295/35-18 tires. The ride will be softer but the difference will not be significant in my opinion.
Be sure to check the rim width and offset to be sure they are correct for the car. It should be 8 and 11" width and 50 and 45 mm offsets.
Be sure to check the rim width and offset to be sure they are correct for the car. It should be 8 and 11" width and 50 and 45 mm offsets.
07-15-2016, 11:50 PM
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With the same 295/30 tires, the car will ride 1/2" higher on 19" rims than 18" rims. This not fatal for most people. Tire Rack has 295/35-18s and 295/35-19s but not 295/40-19s. The 40 aspect ratio would make the car ride even higher but I don't see that size on Tire Rack. I would suggest that you use the 18" rims and maybe pick 295/35-18 tires. The ride will be softer but the difference will not be significant in my opinion.
Be sure to check the rim width and offset to be sure they are correct for the car. It should be 8 and 11" width and 50 and 45 mm offsets.
Be sure to check the rim width and offset to be sure they are correct for the car. It should be 8 and 11" width and 50 and 45 mm offsets.
What I am just now realizing: the previous owner may well have had the suspension lowered when he put the 19s on to avoid that half inch you mention, such means I'll need the Porsche dealer to reverse that as well when the 18s go on! This failed attempt at achieving a softer ride keeps going up in price.
Measure once, cut twice, as the saying goes. At least I think the wheels look sweet!
07-16-2016, 06:49 AM
#6
Rennlist Member
I wouldn't jump the gun and change suspension just yet. I "think" what people are trying to say to you is to change to a higher aspect ratio tires (middle number, in this case 30). You can use this link as a calculator or height to determine the correct aspect ratio for an 18" rim to match your 30 aspect ratio 19", which appears to be a 295/35-18. This should give you more sidewall, but the same (or very close) overall diameter. Make sense?
https://rennlist.com/forums/tire_rim_calculator.php
https://rennlist.com/forums/tire_rim_calculator.php
07-16-2016, 11:39 AM
#7
Oh, man. So, I'm going to 18" wheels with the OEM tire spec (rear 295/30 etc.). Established: The ride will not be any softer v. my 19" inch runs running that same tire spec, at least not on account of the tires.
What I am just now realizing: the previous owner may well have had the suspension lowered when he put the 19s on to avoid that half inch you mention, such means I'll need the Porsche dealer to reverse that as well when the 18s go on! This failed attempt at achieving a softer ride keeps going up in price. Measure once, cut twice, as the saying goes. At least I think the wheels look sweet!
What I am just now realizing: the previous owner may well have had the suspension lowered when he put the 19s on to avoid that half inch you mention, such means I'll need the Porsche dealer to reverse that as well when the 18s go on! This failed attempt at achieving a softer ride keeps going up in price.
Measure once, cut twice, as the saying goes. At least I think the wheels look sweet!
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07-16-2016, 12:03 PM
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Yeah, I'm virtually certain the car came to me lowered from stock to accommodate the 19" wheels it has. Is it a big operation to raise it back up when they put the 18" wheels on? Do I need to buy me parts, etc?
07-16-2016, 12:11 PM
#9
It will depend on whether or not they installed an adjustable suspension (aka coilovers). If they did the height adjustment is trivial and would only take a few minutes for each wheel. You can easily tell if you have coilovers by looking at the shock body. If it is threaded and has large nuts to adjust than you are in luck. If you google "How A Coilover Works" you should find a few good pictures.
If they aren't coilovers then you'd have to reverse the hardware the previous owner installed. That would likely be just replacing the springs with the original taller ones, but might also include replacing the shocks. Labour is pretty significant though.
Installing coilovers if you don't have them already is also an option, but the coilovers usually cost more than ~$2K new. H&R coilovers are the likely the cheapest option and are still reasonably good (which is what I have). PSS10s are noticeably more expensive but allow more adjust-ability. Note that the coilovers do not offer the full range of adjust-ability that you might expect though. I'm running my H&R at the tallest setting and wish they had a few more threads at the tall end to raise my car a little higher.
In both cases you should check/fix the alignment afterwards especially if you plan on keeping the car at the new height for a long time.
If they aren't coilovers then you'd have to reverse the hardware the previous owner installed. That would likely be just replacing the springs with the original taller ones, but might also include replacing the shocks. Labour is pretty significant though.
Installing coilovers if you don't have them already is also an option, but the coilovers usually cost more than ~$2K new. H&R coilovers are the likely the cheapest option and are still reasonably good (which is what I have). PSS10s are noticeably more expensive but allow more adjust-ability. Note that the coilovers do not offer the full range of adjust-ability that you might expect though. I'm running my H&R at the tallest setting and wish they had a few more threads at the tall end to raise my car a little higher.
In both cases you should check/fix the alignment afterwards especially if you plan on keeping the car at the new height for a long time.
07-16-2016, 01:30 PM
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It will depend on whether or not they installed an adjustable suspension (aka coilovers). If they did the height adjustment is trivial and would only take a few minutes for each wheel. You can easily tell if you have coilovers by looking at the shock body. If it is threaded and has large nuts to adjust than you are in luck. If you google "How A Coilover Works" you should find a few good pictures.
If they aren't coilovers then you'd have to reverse the hardware the previous owner installed. That would likely be just replacing the springs with the original taller ones, but might also include replacing the shocks. Labour is pretty significant though.
Installing coilovers if you don't have them already is also an option, but the coilovers usually cost more than ~$2K new. H&R coilovers are the likely the cheapest option and are still reasonably good (which is what I have). PSS10s are noticeably more expensive but allow more adjust-ability. Note that the coilovers do not offer the full range of adjust-ability that you might expect though. I'm running my H&R at the tallest setting and wish they had a few more threads at the tall end to raise my car a little higher.
In both cases you should check/fix the alignment afterwards especially if you plan on keeping the car at the new height for a long time.
If they aren't coilovers then you'd have to reverse the hardware the previous owner installed. That would likely be just replacing the springs with the original taller ones, but might also include replacing the shocks. Labour is pretty significant though.
Installing coilovers if you don't have them already is also an option, but the coilovers usually cost more than ~$2K new. H&R coilovers are the likely the cheapest option and are still reasonably good (which is what I have). PSS10s are noticeably more expensive but allow more adjust-ability. Note that the coilovers do not offer the full range of adjust-ability that you might expect though. I'm running my H&R at the tallest setting and wish they had a few more threads at the tall end to raise my car a little higher.
In both cases you should check/fix the alignment afterwards especially if you plan on keeping the car at the new height for a long time.
Rear
Front
07-17-2016, 01:06 AM
#11
If the car is lowered, it doesn't seem crazy to use the 18" wheels with 225/45-18 and 295/35-18 tires. Michelin Pilot Super Sport are the option I would choose. They will be close in diameter so the AWD is ok and they will be a little smoother. Talk to Damon at Tire Rack to get his input.
07-17-2016, 11:44 AM
#12
07-17-2016, 11:54 AM
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