I must be getting old, let me know if this makes sense, I drive a 03 sedan
with 18" wheels. When I put on my little fellas 16" winter tires I find
she is quicker. My summer tires are 245/45/18, and my winters are 215/60/16
If I went to a 225/45/18 would she feel quick and would I lose 1/2" in height
which I would like. Just want to be sure before I make the plunge..

Thanks

 

probably not, its feeling quicker mostly do to the extra weight of the wheels and not necessarily the tires, if you want to be "quicker" get new lighter wheels, they'll make more of a difference and stick with the 245s because they are acutally increasing your gripping potential

 

Smaller tires should translate into a higher numerical (i think) gear ratio. This would quite possibly make your car "quicker" from an acceleration standpoint but reduce top-end speed. As a side note I'd expect gas mileage to suffer, especiallt the highway driving side of MPG.
Yikes, I'mgonna get flamed if I'm 180 off and it's a BIGGER wheel that would cause above!!

 

You are correct shorter tires, would give you a effectively shorte final drive (higher numerically). Meaning quicker acceleration, but higher revs at highway speeds. That being said it would generally decrease mileage on the highway. But there are a lot variables here, it depends on where the car revs in regard to the torque peak, speeds etc. It is quite possible to see better mileage around town, due to the more stop and go friendly ratio.

 

I've found that low profile tires tend to have stiffer sidewalls, and they seem to weigh more than tires that retain the same dimensions, but are smaller diameter with a larger sidewall. It's also surprising to see the differences in weight between same size tires from different manufacturers or model lines...

 

smaller wheels, less weight, less rotational mass, better acceleration
i noticed this when i went from 18s to 19s

 

Thanks guys, so the upside is quicker take offs but gas milage suffers
but I imagine that would be minimal, and would another upside
be bettter handling because the car would be lower to the ground
by 1/2 inch..

 

your handling will likely be worse because of the narrower tires, you could always stagger and go 225 front 245 rear and get a good balance

 

I hear that staggering with the sedan might not be a good thing
plus there goes the rotation to get the most out of the tires..

 

If you want to be able to rotate, stick with 245s, but go down to a 40 series, a 225/45/18 is almost exactly the same diameter of a 245/40/18, so you get the shorter tire, and the better grip from the 245s

 

Bingo. The rotational mass moves outward, even if the wheel weigh the same. This needs more torque to accelerate the bigger wheel diameter as opposed to the smaller diameter, which needs less torque to accelerate equally.

Some people don't notice, others do. I would do what you think makes you happy.