245/45/16s on the rear?

I doubt it. You might get a little more understeer. Actually, I should say you would have less oversteer since you're not changing the front grip at all, rather increasing rear grip.

 

Joe, you'll probably gain a few more revs on the freeway as the 245/45 has a smaller overall diameter than 225/50 (by about 2%). Personally, I went with 225/55 series on the rear to lose a few revs on the freeway - it's more comfortable cruising at 3,400 rpm rather than 3,800-4,000rpm.

Not sure about the understeer/oversteer thing, I try to not to do a lot of drifting on the street as a matter of personal safety (for myself, and others!).

 

Joe,what make of 245/45/16 tyres are you looking at?

 

If the wheel diameter changes (by about 2% according to your post) does it not also change your speedo reading? So your speedo would read 2% faster in this case. That is, unless of course you are using a GPS system in your car or some other speed indicating device.


PDG

 

I have looked real hard but it doesn't appear that the Avid V4s is available in a 245/45/16.... I only saw 245/50/16

 

Patrick, yes, you are exactly correct, it affects the speedo reading accordingly.

Not always is this bad - many speedos run a little fast from the factory (not sure why that is), so, increasing the rolling radius can sometime make the speedo more accurate. That's not always the case obviously, depends on the car, the magnitude of the change in rolling radius, etc. With 225/55/16s on my 308 the speedo actually reads within a couple percent of my hand held GPS, so I'm pretty happy with that.

 

You have nothing to worry about except the fact that you can not get the tire in that size.
The tires fit fine and the difference in handling front to rear would be minimal. The stance will be fine and you will get to make it even better when you do change the fronts. Getting the size is the biggest problem.

 

The only problem with the 245/45 is that it is visually smaller than the front 205/55. I know people say you can't see it, but that combination always looked wrong to me.

I know a 245/50 fits (at least on mine) and looks better, IMHO

 

To each his own, but raising the back end of a 308 (by fitting taller tires) gives it a hot rod look, and the sidewalls get that early 70's balloon look, to me.

Either will fit, so go with the look you like.

 

Here is an image of my car with the 245/45's. You can see how the stance of the car is level and the sidewalls front and rear have a similar look. (My fronts are 225/50's, which are virtually identical to stock diameter (.5mm taller))
225/45's are 4.5mm shorter then stock, 225/50's are 20mm taller then stock. That is a big difference.
But again, what looks good to you is the key.
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See http://ferrarichat.com/forum/showpost.php?p=135427879&postcount=54 for mine on 225/45-16 and 245/50-16 with stock ride height.

See http://ferrarichat.com/forum/showpost.php?p=137447396&postcount=5 for FourCam's car with the same sizes and a better ride height.

 

One other consideration, especially since you may use a different brand of tire, is that different companies tires are different dimensions even with the same tire size. Even from the same manufacturer you may see some differences. The actual dimensions are generally available from the manufacturers so you could look for a tire that runs a little tall (245/45) or short (245/50) to get as close to stock as possible.

 

I know you said you wanted to keep the fronts but have you considered putting a set of Toyo T1Rs or RA1s on? They are at least as good, an by the number of people I've known with them on, possibly better than the Yokohamas. As a reference I currently have a set of ES100s on my car but they no longer make them and the S-Drive replacement tires are only available in stock sizes. Toyo is what i'm going for in the next month or so... probably the T1R. To each his own as far as putting 245/50 series tires back there. I don't care for all that aspect ratio on the back of the car. I agree with QVB, 45 series tires just look right.

 

+1

I'm actually running 215/50 in front and 245/50 in rear. I believe that the slight rake in the vehicle stance provides better aerodynamic stability and a better look. The slight increase in rear wheel diameter does improve the speedometer accuracy, as well as brings the revs down a bit when cruising. Keep in mind also, that the wheel opening in the rear is slightly larger than in the front and the 245/50 fills it in better (take a look at the wheel gap in the front and rear of the above black car). The 215 in front is a good compromise - slightly wider better grip & not too wide to make steering too heavy.

And, yes not all tires of the same size are the same. Remember, these are nominal sizes. The actual sizes can vary between manufacturers and even between models. Also, you don't have a lot of choices in either size (245/45 or 245/50). Take a look at www.tirerack.com

Do whatever you want, it's your car. Here's what mine looks like:
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