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What are the pros and cons to putting the 17" front 18" rear combo on C4s? Do you have to flash the prom to recalibrate the speedo for the size change in rear? Thanks
It depends on the installed height of your wheel tire combo - I lost 2/10th of an inch going to 18" wheels (275/40-17 vs. 275/35-18) - so for me, it wasn't that big of a deal. The Tire Rack at http://www.tirerack.com has all of the specs on the various brands of tires in terms of height, recommended rim width, etc.
I went with 275/35-18, but 285 or 295 18’s might be a closer fit depending on which size 17’s you’re running.
Not all tyres of identical size are actually the same dia. (or tread width for that matter) - actual size does and tread width does vary somewhat from manufacturer to manufacturer. Point being, check the manufacturers specs closely for the most accurate info when comparing tyres.
What are the pros and cons to putting the 17" front 18" rear combo on C4s? Do you have to flash the prom to recalibrate the speedo for the size change in rear? Thanks
Pro's.....Look's good, con's....speed-o will read about 5 miles off with stock size tires that comes on the 18 inch C-5 rear rim's. :thumbs:
con's....speed-o will read about 5 miles off with stock size tires that comes on the 18 inch C-5 rear rim's. :thumbs:
which is why you should get 35 series tires on the rear instead of 40 series, then you won't be off but maybe 1 mph, which is practically neglegible :D
If you get 285/35-18’s, they are a ‘perfect’ match (for 275/40-17's)- I bought 275's 'cause the tires I wanted weren't available in 285's at the time from my dealer - plus I saved some money.
I gave up only 2/10ths of an inch in height (i.e., Dia.) - which means my car sits lower by only 1/10th inch (1/10th of an inch less rubber appearing in the wheel well).
Kumho Specs
275/40-17: 25.7” dia
285/35-18: 25.7” dia.
con's....speed-o will read about 5 miles off with stock size tires that comes on the 18 inch C-5 rear rim's. :thumbs:which is why you should get 35 series tires on the rear instead of 40 series, then you won't be off but maybe 1 mph, which is practically neglegible :D
Which is what I wanted to do, the only problem that I would of had was that I would have had to lower the rear even more in order for me to obtain the look I wanted, and doing this would put me into the "ruff riding" limits that I wanted to avoid.
When the car is lowerd, you dont get much of a change in the ride, untill it reaches a curtain point, which is the point that I'm presently at right now.
You are 100% right though about the speed being only a mile or 2 off. Mahalo and Aloha. :thumbs:
Maybe I'm just silly but when you talk about tires and fractions of an inch I just can't see a giant difference. Wouldn't a new tire and a well worn tire be different in diameter as well as the difference between a properly inflated tire and an underinflated tire. :confused:
...also, if your tires are of a smaller diameter, as are mine, it takes you longer to get where you are going - so you are always having to leave a little earlier than you normally would, which is what I have to do now - after awhile it gets to be a real pain.
I think it has something to do with that space-time continuum thing, but I’m not sure.