Upsizing tires
#1
Le Mans Master
Thread Starter
Upsizing tires
Let's say a person wanted to keep the factory size wheels (17s front, 18s rear), but wanted to go slightly larger diameter with the tire size to take up some of the space in wheel well. Can I just jump up the aspect ratio from a 45 to a 50 on the front, and from a 40 to a 45 on the rear, or would I have to play around with the width as well to get them to look right? Have any of you done this, and if so, could you post some pics so I can see what it looks like?
Another thing I'm wondering about is having such sizes installed by tire places. I have noticed these places are getting very picky about the size tires that are going on a particular vehicle, and some refuse to install tires that are not exactly the same size that originally came on the vehicle. Have you guys run into this problem, and if so, how do you get around it? Thanks.
Another thing I'm wondering about is having such sizes installed by tire places. I have noticed these places are getting very picky about the size tires that are going on a particular vehicle, and some refuse to install tires that are not exactly the same size that originally came on the vehicle. Have you guys run into this problem, and if so, how do you get around it? Thanks.
Last edited by grampi50; 11-18-2016 at 04:09 PM.
#2
Instructor
You can, but I personally think it'll look terrible. These cars simply don't look right with a high profile tire; they're sports cars, not trucks.
If you want less gap, lower your car. The factory bolts do a fine job and will leave you with reasonable clearance.
If you want less gap, lower your car. The factory bolts do a fine job and will leave you with reasonable clearance.
#3
Le Mans Master
You can, and I doubt most tire shops would refuse mounting (although it is possible, they questioned my tire choice for my wife's Tucson at only one size bump).
Going up one aspect ratio would increase each tire diameter by an inch. That's a lot IMO. Circumference of the rear tire would thus increase from 83.75 to 87.15, effectively changing your rear gear ratio from (unsure what you have):
2.73 to 2.62
3.15 to 3.03
3.42 to 3.29
You'd have to get your speedo adjusted accordingly.
How many miles on the existing tires?
Have you considered instead lowering the car a bit?
Going up one aspect ratio would increase each tire diameter by an inch. That's a lot IMO. Circumference of the rear tire would thus increase from 83.75 to 87.15, effectively changing your rear gear ratio from (unsure what you have):
2.73 to 2.62
3.15 to 3.03
3.42 to 3.29
You'd have to get your speedo adjusted accordingly.
How many miles on the existing tires?
Have you considered instead lowering the car a bit?
Last edited by grantv; 11-18-2016 at 05:27 PM.
#5
Melting Slicks
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Location: Fort Myers Beach Florida
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Great idea! Now your speedometer will be wrong and the computer will go crazy with active handling and traction control. My car has worked great for 15 years with the proper size tires (just replaced in September) Just another great improvement idea (mod). What could go wrong? (tire rub, alignment, active handling, speedometer, there must be more)
Last edited by DDaaryl; 11-18-2016 at 09:54 PM.
#6
Le Mans Master
Thread Starter
Great idea! Now your speedometer will be wrong and the computer will go crazy with active handling and traction control. My car has worked great for 15 years with the proper size tires (just replaced in September) Just another great improvement idea (mod). What could go wrong? (tire rub, alignment, active handling, speedometer, there must be more)
I can't take credit for the idea...there are plenty of guys in this site who have gone with different size tires and/or wheels...
#7
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Not hard to do and less expensive than buying new tires.
#9
Le Mans Master
There are a lot of choices.
For the Active handling and traction control to work normally the rear tires need to be 0.5" to 1.5" bigger diameter than the front tires.
As others have said, a different tire diameter will change the speed relative to the speedometer reading.
You can use a calculator to compare tires sizes front to rear and also how the speedometer will be effected. See the link below or search for tire calculators online.
https://www.rimsntires.com/specspro.jsp
As to the look of the tires/gap/height/ etc. that is only your opinion as to what you want it to look like.
Good luck.
For the Active handling and traction control to work normally the rear tires need to be 0.5" to 1.5" bigger diameter than the front tires.
As others have said, a different tire diameter will change the speed relative to the speedometer reading.
You can use a calculator to compare tires sizes front to rear and also how the speedometer will be effected. See the link below or search for tire calculators online.
https://www.rimsntires.com/specspro.jsp
As to the look of the tires/gap/height/ etc. that is only your opinion as to what you want it to look like.
Good luck.
#10
Melting Slicks
Two good reasons for higher sidewalls, has nothing to do with looks!
A better way IMO to lessen wheel gap is larger wheels and lower car. The speedo and can be reprogrammed. These cars look great with 18"/19" and still have room for good rubber
A better way IMO to lessen wheel gap is larger wheels and lower car. The speedo and can be reprogrammed. These cars look great with 18"/19" and still have room for good rubber
Last edited by Forcedvert; 11-19-2016 at 03:39 PM.