Any benefit to running the same tire on a 1" wider wheel?
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From: Pittsburgh, PA
Any benefit to running the same tire on a 1" wider wheel? Let's say that due to wheel well constraints, the biggest tire I can run is a 225/55-16 tire, front and rear. I have two options for wheels - one is 16x7" and one is 16x8". Will there be an noticeable difference in performance between the 7" wheel and 8" wheel? Factors I am considering are ride quality, high speed stability (anything over 75mph), traction, responsiveness, cornering, etc.
Also, the manufacturer's recommended wheel width for that particular tire is 6" to 8".
My best guess is that the wider wheel will hurt acceleration and stopping because it is heavier, but will benefit high speed stability and responsiveness because the sidewalls will be a little more taught. I know that in the 80's, the Corvettes with the handling package (Z- something, can't remember) ran the same model/size tires are the regular Corvette, but with a 1" wider wheel. That also leads me to believe that there's something to be gained on the performance end.
I have no proof or explanation to backup any of this!
Any thoughts/discussion?
Also, the manufacturer's recommended wheel width for that particular tire is 6" to 8".
My best guess is that the wider wheel will hurt acceleration and stopping because it is heavier, but will benefit high speed stability and responsiveness because the sidewalls will be a little more taught. I know that in the 80's, the Corvettes with the handling package (Z- something, can't remember) ran the same model/size tires are the regular Corvette, but with a 1" wider wheel. That also leads me to believe that there's something to be gained on the performance end.
I have no proof or explanation to backup any of this!
Any thoughts/discussion?
modern tires are highly designed with a lot of R&D I would assume if a manufacturer gives a range of appropriate wheel width it indicates that change occurs in how the tire behaves within this range but it still meets the manufacturers standards.
the change in behavior can be a number of things the first that would come to mind are contact patch and lateral loading.
if we try to figure this out (because I dont know)we can imagine a strip of paper bent into a "U" shape held at the ends, representing a section cut of a tire, bringing the ends closer together creates a rounder shape which would indicate to me the contact patch will want to ride more aggressively on the center of the tread. if we move the ends farther away it appears like the tire would distribute the weight more evenly.
as far as lateral loading take the same strip of paper put a weight in the middle and drag it side to side across a table. by doing this we can see that when the ends are held further apart the paper resists the lateral load better than when they are closer together.
the change in behavior can be a number of things the first that would come to mind are contact patch and lateral loading.
if we try to figure this out (because I dont know)we can imagine a strip of paper bent into a "U" shape held at the ends, representing a section cut of a tire, bringing the ends closer together creates a rounder shape which would indicate to me the contact patch will want to ride more aggressively on the center of the tread. if we move the ends farther away it appears like the tire would distribute the weight more evenly.
as far as lateral loading take the same strip of paper put a weight in the middle and drag it side to side across a table. by doing this we can see that when the ends are held further apart the paper resists the lateral load better than when they are closer together.
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From: Norn Iron
Let's say that due to wheel well constraints, the biggest tire I can run is a 225/55-16 tire, front and rear. I have two options for wheels - one is 16x7" and one is 16x8". Will there be an noticeable difference in performance between the 7" wheel and 8" wheel? Factors I am considering are ride quality, high speed stability (anything over 75mph), traction, responsiveness, cornering, etc.
But I'd think a 225/55x16 would be a very wobbly handling tyre anyway. That's a pretty huge sidewall. Certainly not something that would ever be considered responsive as far as cornering or handling goes.
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I think almost all your answers are going depend on the type/brand of tire you are using... even though there are stated sizes not all manufacturers follow them to a T. I would say there always a safety margin figured into the specs but why take a chance if you have both options?
The basic size you mention will probably be fine on larger rim, my c3 came stock with 205/70's on an 8 inch rim but they were bias ply with a big sidewall and probably befited from it... I think the side wall size, stiffness and even tread pattern (wear pattern is a product of tire shape which will change) is going to dictate what to use for a rim. There have been plenty of times I have gone outside the recomendations but you have to think about the consequesnces. Too small of a tire on a rim at high speed will pull off the bead as it grows, this is the safety aspect of drag racers using screws or bead locks....but again the type of tire affects this... I have used 275/60 dr's on an 8 inch rim with success but def a little wobbley at the top end slowing down....
The basic size you mention will probably be fine on larger rim, my c3 came stock with 205/70's on an 8 inch rim but they were bias ply with a big sidewall and probably befited from it... I think the side wall size, stiffness and even tread pattern (wear pattern is a product of tire shape which will change) is going to dictate what to use for a rim. There have been plenty of times I have gone outside the recomendations but you have to think about the consequesnces. Too small of a tire on a rim at high speed will pull off the bead as it grows, this is the safety aspect of drag racers using screws or bead locks....but again the type of tire affects this... I have used 275/60 dr's on an 8 inch rim with success but def a little wobbley at the top end slowing down....
When you go wider on a wheel, the amount if sidewall and bead holding force is increased. This is because of the tires natural resting state. Try putting a VW 165 on a 7 inch wheel. Not likely to happen without a tube and bead glue, and the sidewalls would fail from the side load and lack of contact patch.
Best bet would be to use a 7 inch wheel on that size of a tire. If you are going for the DEEP DISH look, order one with a lower rear backspacing. The rim width of 7 inches will remain unaffected, but where the tire rides in the wheel well will be moved outwards. Just remember, the closer to half the width the back spacing is, the closer to the middle it will run. small backspacing means deep dish, big backspacing means shallow running like a front wheel drive car.
For my own opinion, stick with the 7. If you want a better ride, go for a lower speed rating, if you want firm ride and better handling, go with the higher speed rating because they are made stiffer.
Best of luck..
Best bet would be to use a 7 inch wheel on that size of a tire. If you are going for the DEEP DISH look, order one with a lower rear backspacing. The rim width of 7 inches will remain unaffected, but where the tire rides in the wheel well will be moved outwards. Just remember, the closer to half the width the back spacing is, the closer to the middle it will run. small backspacing means deep dish, big backspacing means shallow running like a front wheel drive car.
For my own opinion, stick with the 7. If you want a better ride, go for a lower speed rating, if you want firm ride and better handling, go with the higher speed rating because they are made stiffer.
Best of luck..
