Need some input: tallest 20" tire size on stock suspension
04-19-2011, 05:06 PM
#1
Thread Starter
Join Date: Feb 2011
Location: Michigan
Posts: 20
Need some input: tallest 20" tire size on stock suspension
Hello everyone:
I'm the new owner of an '07 Whipple-charged Tungsten GT, and couldn't be happier. Let the modding begin. For my first official post, I have a tire question I hope you all can help with.
Yes, I know - not another 20" tire question! But honestly I've searched a lot and just can't find an answer for my situation.
I just bought four used 8.5 X 20" (38mm offset) chrome wheels for a great price from a former Mustang owner. I need some tires for the rims. My car is not lowered, and i don't plan on it. So I'd like to fill up the fender wells with a taller 20" tire to keep the ride nice. Since the rims are all 8.5" wide I'm going with 4 tires the same size to be able to rotate. Not much room for staggering on an 8.5" wheel unless somebody convinces me otherwise.
Does anyone have experience on what is the tallest 20" tire that can be run on the stock suspension height? I know the stock 18" tires/wheels (235/50/18) measure 27.3" tall. People always suggest a 255/35/20 to keep the ratio the same and not have to adjust the speedometer. But I want to fill the fenders up and keep a larger sidewall height (around 4.5") for ride. I will get the speedo adjusted with my next tune.
So, anybody running a 255/45/20 tire in front on stock suspension? This setup is 29" tall, so I don't know if it will work without rubbing or anything. Keep in mind my car will not be lowered? Other sizes like 245/45/20? 255/40/20? I suppose tire cost and availability will affect this also. I don't want to spend a ton on some special order exotic tire size.
If you are running taller tires on you 20s with stock suspension, chime in and set me straight. Thanks!
Jeff
I'm the new owner of an '07 Whipple-charged Tungsten GT, and couldn't be happier. Let the modding begin. For my first official post, I have a tire question I hope you all can help with.
Yes, I know - not another 20" tire question! But honestly I've searched a lot and just can't find an answer for my situation.
I just bought four used 8.5 X 20" (38mm offset) chrome wheels for a great price from a former Mustang owner. I need some tires for the rims. My car is not lowered, and i don't plan on it. So I'd like to fill up the fender wells with a taller 20" tire to keep the ride nice. Since the rims are all 8.5" wide I'm going with 4 tires the same size to be able to rotate. Not much room for staggering on an 8.5" wheel unless somebody convinces me otherwise.
Does anyone have experience on what is the tallest 20" tire that can be run on the stock suspension height? I know the stock 18" tires/wheels (235/50/18) measure 27.3" tall. People always suggest a 255/35/20 to keep the ratio the same and not have to adjust the speedometer. But I want to fill the fenders up and keep a larger sidewall height (around 4.5") for ride. I will get the speedo adjusted with my next tune.
So, anybody running a 255/45/20 tire in front on stock suspension? This setup is 29" tall, so I don't know if it will work without rubbing or anything. Keep in mind my car will not be lowered? Other sizes like 245/45/20? 255/40/20? I suppose tire cost and availability will affect this also. I don't want to spend a ton on some special order exotic tire size.
If you are running taller tires on you 20s with stock suspension, chime in and set me straight. Thanks!
Jeff
04-19-2011, 07:25 PM
#2
6th Gear Member
A taller tire than the OE which is about 27" might be a bit much. For every 1" of extra tire diameter you gain only 1/2" of additional fill. Normally, I'd say just 20's alone will hinder performance and then going with a taller tire would zap your power even more but with the Whipple it shouldn't be much problem except around town.
With those 8.5" wide wheels, you'll be very limited in width which will also limit you in height. I'm seeing no wider than 255's on an 8.5" wheel. 255's for a 20" wheel and all I'm seeing when I sample different brands are tires close to the OE 27". Your width for those wheels is a hinderance to your goal.
EDIT: I take some of that back. A 20" truck tire will fit your 8.5 rims with a 31" diameter but it'll probably ride like a truck.
With those 8.5" wide wheels, you'll be very limited in width which will also limit you in height. I'm seeing no wider than 255's on an 8.5" wheel. 255's for a 20" wheel and all I'm seeing when I sample different brands are tires close to the OE 27". Your width for those wheels is a hinderance to your goal.
EDIT: I take some of that back. A 20" truck tire will fit your 8.5 rims with a 31" diameter but it'll probably ride like a truck.
Last edited by Nuke; 04-19-2011 at 07:30 PM.
04-20-2011, 09:55 AM
#3
Thread Starter
Join Date: Feb 2011
Location: Michigan
Posts: 20
Yes, I know the extra weight is a factor with taller tires. But I think the Whipple does help offset that. I didn't realize that getting taller 20" tires in a somewhat normal profile (touring tire or performance) would be so tough. I certainly don't want any type of truck tire. 
I do know that many other performance cars have 20s as an option now with slightly taller tires to keep the ride better. I think the Chargers have optional 20s with 245/45 tires. And the Camaro SS has optional 20s with 245/45 fronts and 275/40 rears (staggered). So performance tires are available in taller versions, but not as readily available and definitely more expensive. In fact there's a set of take-off Camaro SS tires with those sizes available locally for a good price.
Is a 275 tire too wide for an 8.5" rim?
Still just trying to figure out how tall I can go with 20s on the stock suspension.
I do know that many other performance cars have 20s as an option now with slightly taller tires to keep the ride better. I think the Chargers have optional 20s with 245/45 tires. And the Camaro SS has optional 20s with 245/45 fronts and 275/40 rears (staggered). So performance tires are available in taller versions, but not as readily available and definitely more expensive. In fact there's a set of take-off Camaro SS tires with those sizes available locally for a good price.
Is a 275 tire too wide for an 8.5" rim?
Still just trying to figure out how tall I can go with 20s on the stock suspension.
04-20-2011, 11:53 AM
#6
6th Gear Member
I often refer to the tire specs on sites such as tirerack.com. From what I've seen for the 20" tires that I sampled, 255 is as wide a tire that is recommended by those tire manufacturers, with the exception of the truck tires which come in a taller tire (and changes the ratios).
04-20-2011, 12:58 PM
#8
I often refer to the tire specs on sites such as tirerack.com. From what I've seen for the 20" tires that I sampled, 255 is as wide a tire that is recommended by those tire manufacturers, with the exception of the truck tires which come in a taller tire (and changes the ratios).
04-20-2011, 04:25 PM
#10
6th Gear Member
Not to offend or take this thread off-topic, but I find that larger wheels on our S197's detract from the overall retro look such that the wheels take your eyes directly to them instead of the car (although there are a few folks here who have pulled it off but ONLY because of other visual mods to their cars). Wheels should enhance the vehicle; not the other way around.
I understand personal preferences and all I'm stating is a personal opinion. For quite a few forum members, the S197's appeal is the retro look, especially to those of us growing up in the 60's, at a time when ALL you saw was big sidewalls on the meanest, fastest cars on the road. Large sidewalls was equated to brute V8 power. 30 series and even the 40 series tires on our cars just don't seem to capture that aura. My g/f's '06 with her stock 235/55/17's on the OE bullitt wheels almost have more "attitude" than my 275/40/18's on takeoff GT500 wheels.
I can't help but shudder when I hear someone say they're putting 19's or 20's on there ride. But that's just me. Sorry for the discertation but that's where my head is.
I understand personal preferences and all I'm stating is a personal opinion. For quite a few forum members, the S197's appeal is the retro look, especially to those of us growing up in the 60's, at a time when ALL you saw was big sidewalls on the meanest, fastest cars on the road. Large sidewalls was equated to brute V8 power. 30 series and even the 40 series tires on our cars just don't seem to capture that aura. My g/f's '06 with her stock 235/55/17's on the OE bullitt wheels almost have more "attitude" than my 275/40/18's on takeoff GT500 wheels.
I can't help but shudder when I hear someone say they're putting 19's or 20's on there ride. But that's just me. Sorry for the discertation but that's where my head is.