I bought a set of wheels that are 15 x 8in that came with tires but they are too low profile to run on my Sunfire. The wheels fit and rotate just fine with no rubbing but I need to find a tire size that will keep me at the right ride height and not mess with my speedometer. Anyone have any suggestions on what would be a good tire size for them? I have two sets of tires in stock 195/65-15 size. One of the sets are winters and the other set is All-Season, but the stock size tires don't fit on the new wheels.
________________________________________________________________
"For some reason it is a very American thing to do to take highly unlikely vehicles and stick insane engines in them at huge cost for no reason." Oh hell yeah!!
The Hellserpent
How do you calculate exactly how wide the tire would be in inches? I want to make sure not to go any wider than what the tires on the wheels are now. The ones that are on them are 195/50-15's.
________________________________________________________________
"For some reason it is a very American thing to do to take highly unlikely vehicles and stick insane engines in them at huge cost for no reason." Oh hell yeah!!
The Hellserpent
tire width is given in mm in the size
ie....... the 195/65/15 , is 195mm wide , 245/50/15 would be 245mm wide
1" = 25.4mm
i would probably go with a 225/60R15 or a 225/50R15.
both are going to be out a bit, probably under 3% or so, which is in acceptable limits. my boss had a set of 225/50R15 on his sunfire, he said they were good on there.
[quote=97cavie24ls(JDM&00s/c sedans)]tire width is given in mm in the size
ie....... the 195/65/15 , is 195mm wide , 245/50/15 would be 245mm wide
1" = 25.4mm
close, but obviously know one listens to me, which i dont blame anyone for that. i wouldnt either.
yes, one inch is equal to 25.4 mm. but, rubber is rated really weired.
lets take a look at the BFG G-Force Sport tires, which is what i always recomend to people.
the BFG in the 225/50R15 is able to be mounted on a 6.0 - 8.0" wide rim. so far so good. that tire meaures 9.2" ( approx. a 235mm wide tire) on a 7.0" wide rim. you are mounting it on an 8.0" wide rim. for every .5" wider rim you mount a tire on, the tires footprint increases .2", so when you actually get that tire mounted on a rim, it will equal 9.6" wide ( or approx. a 245mm tire).
the 225/60R15 will work out about the same as the 225/50R15, approx. a 245mm tire once mounted on your 8.0" wide rim.
not to say that every tire will turn out this way, but it is something to keep inmind that almost everyone forgets. that is alot of rubber to squeze under that car...
i had a set of 205/60R15 Michelin Energy MXV4+ that once even mounted on the factory 15x6" steelies measured out to be almost 225mm wide.
Injection is nice but id rather be BLOWN!
that is only true for the side wall
the tread will still be narrower on the 225 than a 245
your missing my point....
you take a tire like the ones i mentioned above. the 225/50R15 is 9.2" wide when mounted on a 7.0" wide rim. if you stretch that rubber out and mount it on a 8.0" wide rim, should the amount of rubber not stretch out from the 9.2" that was hitting the road before?
it is an approximate 0.2" inches of extra rubber contacting the road when you mount it on a 0.5" wider rim than the tire dimensions are given on. i did not mention the side wall at all...
this is not a really well known fact. i went over 2 and a half years installing tires without knowing that. its hard to explain, but trust me, the wider the rim you install the tire on, the more rubber you will lay down.
Injection is nice but id rather be BLOWN!
section width and tread width are 2 different measurements
you can only go so wide on a rim before the tire cups in the middle
and the tread is only so wide , and will only flatten out so far before it cups , causing wear problems
putting a wider tire on a narrow rim will make the tire more narrow and taller , because the side walls roll , and give you less contact with the road
and the oppistie goes for the wider rim , but you cant get it wider than its max width
you go from (_) to I_I to \_/
whitegoose wrote:your missing my point....
you take a tire like the ones i mentioned above. the 225/50R15 is 9.2" wide when mounted on a 7.0" wide rim. if you stretch that rubber out and mount it on a 8.0" wide rim, should the amount of rubber not stretch out from the 9.2" that was hitting the road before?
it is an approximate 0.2" inches of extra rubber contacting the road when you mount it on a 0.5" wider rim than the tire dimensions are given on. i did not mention the side wall at all...
this is not a really well known fact. i went over 2 and a half years installing tires without knowing that. its hard to explain, but trust me, the wider the rim you install the tire on, the more rubber you will lay down.
if im ever in canada, remind me never to have tiresmounted by you
i understand section width and tread width are 2 different things, but both are very important.
tire width DOES increase / decrease as you increase / decrease the width of the rim. and YES there are limits to how wide and narrow of a rim you can mount a certain tire on. the applicable rim widths are indicated by the manufacturer.
the manufacturer also indicates what the recomended rim width is, and how wide in inches the tire will measure when mounted on that wide of a rim.
now, you even got on that type of trail when you said that the tire will buldge out when mounted on a wider rim because it will "stretch out". as you stretch a tire out on to a wider rim (still keeping within its allowable limits), would the amount of tire hitting the road (contact patch) increase aswell?
yes, the contact patch will increase. and, your kind of right about the cupping. the pressures need to be adjusted properly for that tire to hold the cars weight. lets say for the hell of it, the tire will maintain the cars weight at 30 psi. now we stick that tire on a rim that is a full inch wider than what the tire is recomended for. with the tire mounted on a wider rim and now bulging out like it will, the center of the tire will wear down faster than the shoulders. this needs to be corected.
we correct the center of the tire wearing out prematurly by adjusting the pressure. for every inch wider we increase the tire over its recomended rim, we decrease the presure by 5psi. same as if you go an inch under (smaller rim) than what is recomended, except you add 5psi. this is another rule of thunb and is not ment to be carved in stone, but the tire pressure will need to be adjusted so the tire wears properly and you get maximum contact patch, comfort while driving.
ever see those old hot rods with the big fat tires on them? most of them are worn right down the center because they stick a tire on a huge rim and dont adjust the pressure.
if you dont want to believe me, thats fine, i dont care that much. i know what im doing when it comes to installing tires, but im still always learning new things, which is why i love the job. if you dont want to get your tires installed by me, even better. thats one less dickhead i have to deal with in the coarse of my day that thinks he knows more than me, and still thinks the maximum pressure stamped on the side of the tire is what he is supposed to run his tires at.
thats just my piece....
Injection is nice but id rather be BLOWN!
So.... um..... What tire size do you guys recommend for my 15x8 wheels? lol
________________________________________________________________
"For some reason it is a very American thing to do to take highly unlikely vehicles and stick insane engines in them at huge cost for no reason." Oh hell yeah!!
The Hellserpent
id go with the widest possible that keeps the height in the right range
it also depends on the offset of the wheels
id go with the 245/50 or 255/50 if they are avaliable at a decent price
Forgive me for thread jacking, but will a 245 or 255 tire even fit on a Cavalier? That's a lot of rubber. I'm only asking because I'm planning on doing the same thing, 15"x7 or 8" wheels. And what offset are these 8" wide rims anyway?
ln2johnny wrote:Forgive me for thread jacking, but will a 245 or 255 tire even fit on a Cavalier? That's a lot of rubber. I'm only asking because I'm planning on doing the same thing, 15"x7 or 8" wheels. And what offset are these 8" wide rims anyway?
I'm not sure of the exact offset of the wheels. I bought them off a friend who bought them off of someone else, lol. I'd buy some 18's but I'm getting married next year in May and me and my fiance are trying to save as much as we can because we both have huge families... plus I'm going to buy either the "fiberglass ram air hood" or the Dual Catback exhaust" off of RKsport sometime this summer. Expensive new wheels and tires are last on my prioirty list at the moment. But when my friend offered these wheels to me for only $175 and saw that they fit I bought them of him. I just need to find a set of tires to fit them that will keep my speedometer the same as close as possible. So far though I'm having a hard time choosing what size to buy. I've driven around on
225/50-15's before and they road really nice but the downpoint to them was that my speedo thought I was driving noticebly faster than I actually was, and I drive 440 miles every weekend to NYC for work at a cancer center in Manhattan and I really didn't want all those added miles on my car that didn't really exist. They add up pretty fast with my commute. So far I've been looking online at
225/55-15's, 225/60-15's, 235/50-15's, 235/55-15's. Anything wider than the
235's I think would be a bit much would prob look retarded by sticking out too far. Either way though, I haven't been able to find any
235/50-15's or
235/55-15's at all so I've pretty much ruled them out of the book. So now I'm leaning towards
225/60-15's. They are just about half an inch bigger in diameter than the stock
195/65-15's that I'm on now, but are supposedly as wide as the
225/50's that I had on before which is what I would be satisfied with, but my friend says that the
225/60-15 tire wound't be as wide as the
225/50-15 tires. Is this true? The guy at the tire shop says that they should be identical widths. I'm not sure who to believe, lol. It's hard to tell without actually seeing them side by side. Also the
225/50-15 tires that I was riding on before were mounted on a 6 inch wheel, so the being that my new wheels are much wider the
225/60-15's mounted on a wider wheel should still be wider or at least about the same width as the
225/50's were on the 6 inch wheels, right? Or am I mistaken?
----------------------------------------------------------------------------------------------------------------------
________________________________________________________________
"For some reason it is a very American thing to do to take highly unlikely vehicles and stick insane engines in them at huge cost for no reason." Oh hell yeah!!
The Hellserpent
personally, i would go with the 225/60R15. that is your best bet, the 225/55R15 are a good choice aswell. going with something like that, the car will still be very streetable, meaning its not going to ride like crap.
my boss ran 225/50R15 tires when he had his sunfire, but the price was something he couldnt pass up (FREE!), so i would have run them too.
anything over the 225's may give you some clearance issues, then again they may not be a problem at all. if it was me, and i was still using this thing for comuting, the 225's woud be as big as i would go. thats a FAT tire when you compare what was on there OEM, and is going to make your fuel economy suffer enough without going to something like a 235, but if the price was right i would consider the 235's too.
this is a decision YOU have to make. now that you have some opinions, go hit up some tire shops and other sources, and get some prices and some model names.
Injection is nice but id rather be BLOWN!
Below is the tire size, sidewall height, speedometer reading, odometer reading, and percentage difference, in that order. The reference speed is 60mph, and reference odometer reading is 10000 miles. I used 195/65/15 as the reference since that's stock size. All I did was increase tread width by 10mm and decrease the aspect ratio by 5% to show more common tire sizes. 205/60/15 and 225/55/15 are the closest tire sizes to match the stock size, with 225/55/15 being less than 1% off.
195/65/15 - 5.0" - 60MPH - 10000mi - N/A
205/60/15 - 4.8" - 61MPH - 10120mi - (-1.2
215/55/15 - 4.7" - 62MPH - 10275mi - (-2.7
225/50/15 - 4.4" - 63MPH - 10470mi - (-4.5
225/55/15 - 4.9" - 61MPH - 10095mi - (-0.9
225/60/15 - 5.3" - 58MPH - 9747mi - (+2.6
taken from the link for the tire calculator
95/60/15 615 mm 117 mm 307.5 mm
Other Sizes
215/50/15 596 mm 107.5 mm 298 mm 1.03% 63 mph -2 mph
225/50/15 606 mm 112.5 mm 303 mm 1.01% 64 mph -1 mph
235/45/15 592.5 mm 105.75 mm 296.25 mm 1.04% 62.6 mph -2.4 mph
235/50/15 616 mm 117.5 mm 308 mm 1% 65.1 mph 0.1 mph
245/45/15 601.5 mm 110.25 mm 300.75 mm 1.02% 63.6 mph -1.4 mph
245/50/15 626 mm 122.5 mm 313 mm 1.02% 66.2 mph 1.2 mph
255/45/15 610.5 mm 114.75 mm 305.25 mm 1.01% 64.5 mph -0.5 mph
255/50/15 636 mm 127.5 mm 318 mm 1.03% 67.2 mph 2.2 mph
I got my measurements from Powerdog.com. That's where I get all my measurements when changing tire size and so far it's been accurate.
