Tire Profile Question
- Thread starter cwing6
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There may be a slight gas mileage hit. Also, depending on the offset, the wider tire may rub on suspension components or parts of the wheel well during hard turns.
With independent suspension it can also lower your ride height ever so slightly. It might be worth getting an alignment after switching to wider tires. On a truck with straight axles it shouldn't matter. If the truck has Ford, excuse me, weak power steering, you may also find parking lots slightly less pleasant.
One way or the other it shouldn't have anywhere near the dramatic effect from wheels spaced further out from the vehicle centerline. That can be truly awful.
One way or the other it shouldn't have anywhere near the dramatic effect from wheels spaced further out from the vehicle centerline. That can be truly awful.
If you change from 235 to 255 and lower aspect ratio by 5, example from 235/60-17 to 255/55-17 then handling/performance may improve but you will suffer a little on MPG, and possible rubbing when doing maximum turn.
Discount Tire Has a Dimensional Calculator on their site to help figure out the differences from one size to the next IE:
Sidewall height, section width, overall Diameter, Circumference, and revs per mile, as well as how far off your speedo would be @ various speeds.
Tire Dimensions Made Simple - Discount Tire
Sidewall height, section width, overall Diameter, Circumference, and revs per mile, as well as how far off your speedo would be @ various speeds.
Tire Dimensions Made Simple - Discount Tire
Wider tires will decrease the car's poor weather performance. More likely to hydroplane, won't bite through snow as well, etc.
Switching to a lower profile is a bit complex. You have to consider the load carrying capacity, the rim width, the diameter, space in the fenders, etc.
There are a lot of things that can go wrong, so it is best to do your homework first.
But to answer the question you asked: Directionally, you are going towards worse ride, worse fuel economy, worse snow traction, worse wet traction, worse wear, better handling, and better dry traction. But careful selection of tires can change that picture.
There are a lot of things that can go wrong, so it is best to do your homework first.
But to answer the question you asked: Directionally, you are going towards worse ride, worse fuel economy, worse snow traction, worse wet traction, worse wear, better handling, and better dry traction. But careful selection of tires can change that picture.
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The "better dry traction" is not something you'll notice unless you are taking on-ramps at high speeds or generally driving too fast for public roads. The "decreased wet traction" IS something you'll notice in the mundane and slow driving around town.
Something to think about.
Something to think about.
Yeah, but who cares about safety in poor weather? What really matters is how an SUV looks....
Originally Posted By: cwing6
I like the look of tires with a slightly wider profile than most OEM tires. Is there any advantage or disadvantage to switching from a 235 to 255 profile on an SUV daily driver?
Let's fix up the naming conventions here a little. When talking about tires, 'profile' usually refers to sidewall height and is expressed in % of tread width. On the other hand, the 235, 255 numbers you are referring to is tread width in mm, not really profile.
With that said, if you want to go with wider tread width, it would make sense to reduce the sidewall profile (in %) so that the overall tire diameter would remain about the same as stock. If you don't adjust the profile %, you will end up with tires that are not only wider but also taller. Maybe you already knew that, but I thought I'd throw it out there just in case.
I like the look of tires with a slightly wider profile than most OEM tires. Is there any advantage or disadvantage to switching from a 235 to 255 profile on an SUV daily driver?
Let's fix up the naming conventions here a little. When talking about tires, 'profile' usually refers to sidewall height and is expressed in % of tread width. On the other hand, the 235, 255 numbers you are referring to is tread width in mm, not really profile.
With that said, if you want to go with wider tread width, it would make sense to reduce the sidewall profile (in %) so that the overall tire diameter would remain about the same as stock. If you don't adjust the profile %, you will end up with tires that are not only wider but also taller. Maybe you already knew that, but I thought I'd throw it out there just in case.
Those numbers are not for a wider profile.
They are the approximate height in MM from the rim to the tread.
Who knows what you want?
They are the approximate height in MM from the rim to the tread.
Who knows what you want?
Originally Posted By: mechtech2
Those numbers are not for a wider profile.
They are the approximate height in MM from the rim to the tread.
Who knows what you want?
He basically wants wider tires. The height of the tire (profile) from the rim to the tread is not expressed in MM.
Those numbers are not for a wider profile.
They are the approximate height in MM from the rim to the tread.
Who knows what you want?
He basically wants wider tires. The height of the tire (profile) from the rim to the tread is not expressed in MM.
Sorry for the confusion. I am referring to tread width (and yes, I know the "profile" actually refers to the space from rim to tread, so I did use the wrong description.)
As for safety, that would be my utmost concern which is one reason I asked the question. I'm not looking to do anything crazy, just maybe switch from a 235 to 255, which is just 20mm of tread width.
Please educate me more on the wet traction. How does wider tread reduce wet traction?
As for safety, that would be my utmost concern which is one reason I asked the question. I'm not looking to do anything crazy, just maybe switch from a 235 to 255, which is just 20mm of tread width.
Please educate me more on the wet traction. How does wider tread reduce wet traction?
Bigger rafts float better. More surface area means better chance to hydroplane when you hit a puddle.
simple physics.
A tire with a width of "X" at, say, 88 FPS (which is 60 MPH) has to displace 88X square feet of water from the road every second.
A tire with a width of "1.2X" has to displace 88x1.2X, or aobut 106X square feet of water from the road every second.
Since you've got the tires on the same vehicle, the weight is the same...but the wider tire has to displace more water from the road over the same distance traveled...it simply contacts more area and for a given water depth, you will hydroplane at a lower speed...ask yourself this: do narrower water skis work just as well as wider ones?
Incidentally, this is why wider tires suck in snow...more area covered with the same weight means that they float on top, instead of sinking in and grabbing...
A tire with a width of "X" at, say, 88 FPS (which is 60 MPH) has to displace 88X square feet of water from the road every second.
A tire with a width of "1.2X" has to displace 88x1.2X, or aobut 106X square feet of water from the road every second.
Since you've got the tires on the same vehicle, the weight is the same...but the wider tire has to displace more water from the road over the same distance traveled...it simply contacts more area and for a given water depth, you will hydroplane at a lower speed...ask yourself this: do narrower water skis work just as well as wider ones?
Incidentally, this is why wider tires suck in snow...more area covered with the same weight means that they float on top, instead of sinking in and grabbing...
Originally Posted By: oiltard
Bigger rafts float better. More surface area means better chance to hydroplane when you hit a puddle.
Given the same exact tread pattern and compounding, of course.
BUT, if the wider, lower profile tire has better/much more; siping/rain cuts/bigger center grooves, etc. and a softer compound, wet performance (but NOT frozen precip) could actually be better than the narrower/higher profile donuts.
Bigger rafts float better. More surface area means better chance to hydroplane when you hit a puddle.
Given the same exact tread pattern and compounding, of course.
BUT, if the wider, lower profile tire has better/much more; siping/rain cuts/bigger center grooves, etc. and a softer compound, wet performance (but NOT frozen precip) could actually be better than the narrower/higher profile donuts.
It would certainly behave as everyone has said. It is also, however, an issue of "how much". Plenty of vehicles come with wider tires. I doubt there's going to be much real-world difference between the two tires, personally.
Originally Posted By: cwing6
Sorry for the confusion. I am referring to tread width (and yes, I know the "profile" actually refers to the space from rim to tread, so I did use the wrong description.)
As for safety, that would be my utmost concern which is one reason I asked the question. I'm not looking to do anything crazy, just maybe switch from a 235 to 255, which is just 20mm of tread width.
Is this for your Pilot? OEM rims? If I'm not mistaken, the OEM 16" rims are only 6.5" wide. To mount 255/65 tires (to keep the proper overall diameter same as the stock 235/70) the minimum recommended rim width is 7". Tire selection in that size isn't the greatest either, but not terrible...
Sorry for the confusion. I am referring to tread width (and yes, I know the "profile" actually refers to the space from rim to tread, so I did use the wrong description.)
As for safety, that would be my utmost concern which is one reason I asked the question. I'm not looking to do anything crazy, just maybe switch from a 235 to 255, which is just 20mm of tread width.
Is this for your Pilot? OEM rims? If I'm not mistaken, the OEM 16" rims are only 6.5" wide. To mount 255/65 tires (to keep the proper overall diameter same as the stock 235/70) the minimum recommended rim width is 7". Tire selection in that size isn't the greatest either, but not terrible...
I guess it matters how big of a jump it is...235 to 255 could be a significant difference...
on the other hand, on my Tbird I went from 225/60/16 to 235/60/16 (using same OEM wheels and keeping everything same except for the width) and didn't really notice any of the negatives - did notice better stability a bit...esp. on cornering. As the wider tire was a better tire model in wet weather to start with, it actually does better in wet weather than the 225s, and not worse.
Some things to consider. Like Pete said, which tire brand and model you select to be the wider can perhaps eliminate some of the negative aspects, or come near to eliminating them.
on the other hand, on my Tbird I went from 225/60/16 to 235/60/16 (using same OEM wheels and keeping everything same except for the width) and didn't really notice any of the negatives - did notice better stability a bit...esp. on cornering. As the wider tire was a better tire model in wet weather to start with, it actually does better in wet weather than the 225s, and not worse.
Some things to consider. Like Pete said, which tire brand and model you select to be the wider can perhaps eliminate some of the negative aspects, or come near to eliminating them.
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