overall tire diameter subject to stretch over wider rim?
#1
Pro
Thread Starter
overall tire diameter subject to stretch over wider rim?
I guess this is more of a question for one of the sponsors, more of a technical question I can't just find googling.
Does anyone know how the overall tire diameter is affected when putting a narrow tire over a wider rim?
Example. Tire diameter of a 255/35/19 is around 26" inch.
One is to assume that is only true if the tire side wall is square with the wheel, ie. Installed on a 8.5" wheel.
If I were to put a 255/35/19 over a 19X10 wheel, that according to most sites is the smallest recommended tire width for a 10" wide rim.
So one would think since the tire's side walls will stretch outwards, this would decrease the overall diameter of the tire since its mounting surface was stretched outwards .75" on each side.
How much does that affect the overall diameter, is it safe to say I would see atleast a .25" overall diameter decrease?
Thanks!
Does anyone know how the overall tire diameter is affected when putting a narrow tire over a wider rim?
Example. Tire diameter of a 255/35/19 is around 26" inch.
One is to assume that is only true if the tire side wall is square with the wheel, ie. Installed on a 8.5" wheel.
If I were to put a 255/35/19 over a 19X10 wheel, that according to most sites is the smallest recommended tire width for a 10" wide rim.
So one would think since the tire's side walls will stretch outwards, this would decrease the overall diameter of the tire since its mounting surface was stretched outwards .75" on each side.
How much does that affect the overall diameter, is it safe to say I would see atleast a .25" overall diameter decrease?
Thanks!
#2
Pro
Thread Starter
Ok so found a thread on some VW forum, stated that the rolling diameter does not change when stretching a tire over a wide wheel, reason being because the tire is made of re-enforced steel belts, which cannot compress, the cross sectional width of the tread however does, which makes sense.
Hope wheel / tire expert can confirm. Techincally my 255/35/19 tire being 26.02" or so, will be 26.02" whether its on a 8.5 or 10" rim! Please confirm, if so I'm a happy man.
Hope wheel / tire expert can confirm. Techincally my 255/35/19 tire being 26.02" or so, will be 26.02" whether its on a 8.5 or 10" rim! Please confirm, if so I'm a happy man.
#3
Race Director
Ok so found a thread on some VW forum, stated that the rolling diameter does not change when stretching a tire over a wide wheel, reason being because the tire is made of re-enforced steel belts, which cannot compress, the cross sectional width of the tread however does, which makes sense.
Hope wheel / tire expert can confirm. Techincally my 255/35/19 tire being 26.02" or so, will be 26.02" whether its on a 8.5 or 10" rim! Please confirm, if so I'm a happy man.
Hope wheel / tire expert can confirm. Techincally my 255/35/19 tire being 26.02" or so, will be 26.02" whether its on a 8.5 or 10" rim! Please confirm, if so I'm a happy man.
Since it's a calculated diameter where wheel width isn't in the calculation then the calculated diameter would remain the same.
Since the calculation depends on the aspect ratio and the aspect ratio % WILL change with wheel width then actual tire diameter would change with wheel width.
The only way to prove it would be to mount the tire on a 8.5" wheel, measure the diameter, then mount the tire on a 10.0" wheel and measure the diameter again and compare the difference.
#4
Pro
Thread Starter
After thinking it about, the tire shouldn't be able to shrink, the steel belts inside will keep it same, the side walls would just come up slightly as they stretch, the tire itself would remain. otherwise you would need to compress the treat as well which is not going to happen.
#6
Not an expert but;
Since it's a calculated diameter where wheel width isn't in the calculation then the calculated diameter would remain the same.
Since the calculation depends on the aspect ratio and the aspect ratio % WILL change with wheel width then actual tire diameter would change with wheel width.
The only way to prove it would be to mount the tire on a 8.5" wheel, measure the diameter, then mount the tire on a 10.0" wheel and measure the diameter again and compare the difference.
Since it's a calculated diameter where wheel width isn't in the calculation then the calculated diameter would remain the same.
Since the calculation depends on the aspect ratio and the aspect ratio % WILL change with wheel width then actual tire diameter would change with wheel width.
The only way to prove it would be to mount the tire on a 8.5" wheel, measure the diameter, then mount the tire on a 10.0" wheel and measure the diameter again and compare the difference.
#7
Pro
Thread Starter
Found best info right here:
http://www.yokohamatire.com/tires_10...io_calculator/
Because the overall diameter of a radial is determined by its belts, this tire's overall diameter should remain virtually unchanged.
Aspect ratio changes, on that site tells you how to calculate.
http://www.yokohamatire.com/tires_10...io_calculator/
Because the overall diameter of a radial is determined by its belts, this tire's overall diameter should remain virtually unchanged.
Aspect ratio changes, on that site tells you how to calculate.
#9
Pro
Thread Starter
255's on a 10" wheel is what I'm looking to do. Reading up on what brand tire to use, some stretch better than others. I have 19X10 in the front ZR1's, I want to run 255/35/19. First, its 26.02" so it will raise the car a bit. I can't run 285's cuz will touch fenders I dont have widebody up front. and running 265/30/19s the diameter is only 25.25 so its low to the ground. Going to 255/35/19 will go up to 26.02 raising the car and filling in the wheel gap.
Also 255's should steer much nicer and not follow the grooves on our Vancouver broken roads. Also 255's so long as they stretch nicely and I don't think i'm asking for a lot putting 255's on a 10" rim, it will let me lower the car slightly and not worry about fender clearance.
Also 255's should steer much nicer and not follow the grooves on our Vancouver broken roads. Also 255's so long as they stretch nicely and I don't think i'm asking for a lot putting 255's on a 10" rim, it will let me lower the car slightly and not worry about fender clearance.
#10
Race Director
Raising the car and filling in the wheel gap?
26.02" Diameter
-25.71" Diameter
= 0.31" Diameter difference
That means raising the car 0.155" and filling the wheel gap by the same amount. Hardly measureable, let alone noticeable.
26.02" Diameter
-25.71" Diameter
= 0.31" Diameter difference
That means raising the car 0.155" and filling the wheel gap by the same amount. Hardly measureable, let alone noticeable.
#11
Pro
Thread Starter
No right now I have 265/30/19s in the front, thats only 25.25", I bought my wheels with these mounted on them so 0.385 will be raised by. Thats noticeable. Plus i'm putting a small spacer on the wheels to fit z06 front brakes on so I need to tuck the tires in some.