hi, first topic.
anyways, im replacing my tires and i need opinions. my rims are 17"x7.5" and the stock tires are 215/45R17. I plan on replacing them with 245/40R17.
The numbers pan out like this.
215/45 Overall Diameter: 24.61 [625.09]
245/40 Overall Diameter: 24.71 [627.63]
215/45 Section Width: 8.46 
245/40 Section Width: 9.64 
+2 lbs. per tire.
My reasons to do it.
-moar contact patch
-can get the tires for the same price as 215/45.
My reasons not to do it.
hi, first topic.
Worse gas mileage, easier hydroplaning. worse in snow and possible fender or other interference. ( The wider the tire in snow the more you get a driving with blocks in front of the wheels effect and the quicker you climb up on top of the snow and lose all traction. )
oh i live in south florida.
If they fit, you pretty much covered it. What is the total weight of the tires and the tire-wheel combo? I am thinking that 2# is not very significant.
The extra over 1" width is the spec I’d be most concerned about. Will the tires clear the wheel wells? Not just standing still but as the car is put into a hard corner as well. The extra width on the rims with less height may put the tire beads at a odd angle on the rims. Not sure if this is a safe size tire to mount on these rims. You’d have to consult with more tire experts on that issue.
I’d be sure to do more research before putting out the money and finding out it doesn’t work.
I would also be concerned about the wheel bearings if these tires are mounted.
Other than clearing the shocks/struts/etc. the one thing that would concern me would be the tires being too wide for the rims.
It would not be fun to be in the middle of a hard cornering maneuver and have a pair of tire beads break loose, leading to instant loss of tire pressure and a possible rollover.
A 10 MM overwidth is one thing but 30 MM gets a bit iffy.
Probably should have added that many or most tire stores may not even want to mount these due to a liability issue.
I had 245/50R16’s on an 86 Camaro. The car tended to wander because the tires were so wide. Several front end alignments did not help. Driving was very tiring due to the constant need to correct the steering. Dry traction was great, wet traction was non-existent.
Rough ride and tires and wheels easily damaged by pot-holes…Tires will be “crowned” because rims are not wide enough…
According to the Tire and Rim Association, P245/40R17’s don’t fit on 7.5" rims. The minimum is 8"
Using a rim that is too narrow causes the tread face to arch. This makes the tire want to follow all the ruts and grooves in the road. The car will feel (and be) unstable.
In short, you lose all the larger footprint advantage, and replace it with instability.
I can add one more possible problem. If you are in a snow area, you will be reducing snow traction and handling.
As others have stated, the tires are too wide for the rims, the wheel wells, and the heavy rain.
225x45 will fit on 7.5 inch rims however and improve the looks without serious compromise.
i guesstimate around 35-40 lbs. im trying to find out the exact weight for the wheel.
i bought the tires this morning, the tires did clear the well. even at full-lock condition, there is still clear space leftover. now regarding tire flex at high speeds, we will see. the mechanic installed the tires at 45psi.
so your concern is that the wheel bearing will wear out prematurely.
what is your estimate (mileage-wise) of when OEM wheel bearings will start to fail.
i bought the tires this morning, the store installed them no problem. But you are correct, there is the possibility of having a bead pop loose. that would suck.
the 245/40 increases width by 30mm and reduces height by .100"
the 225/45 increases width by 10mm and increases height by .300"
this car will never see snow. but yes good arguments about the snow.
Can you provide a specific citation to the TRA data.
yeah the tires will be crowned at one point, when do you think this would be around 2-3K miles?