I want to get about 275R and 245F tires with my rims, but will these bigger tires make my car slower?

 

assuming you mean that you are keeping the stock 18" rims, the answer is yes, but not enough to really make a difference.

 

I got 295/275 tires with new wheels. The wheels are slightly less wt than the OEM and Toyo's I have are suppose to be a light tire but I still feel a loss of power compared to stock. Another friend of mine with larger tires told me the same. I think part of it must be larger surface area = resistance because if the toal wt of tire/wheel is not greater, what else could it be?

 

you must be talking not stock rims, even 8.5 a 275 on that would hurt you in every performance area possible.

but with other rims... depends on the rims, but I would doubt it. using light weight rims and tires, you will still be a good bit lighter.

I didnt notice a decrease in power with mine.

 

Your loss of power is attributed to the larger moment of inertia that the wheels possess. Even though they may weigh less overall, the weight is concentrated further away from the rotational center of the wheel. This leads to greater inertia and therefore more resistance to rotate.

 

Thanks for the physics explanation. Interesting others did not notice it. Could the 295 vs 275 tire size be the diffference? Seems to me, they are both much larger than stock 235 or 245 rears....

Jeff

 

I'm sure the 275/295 tires are compounding the problem of power loss. the larger tires will place even more weight on the outside wheel edges on top of the weight that is from the rims. I know this sounds unaesthetically pleasing, but if you want your car to go faster...then go to smaller rims...noticeable difference going from 18's to 17's.

 

Actually, one of my reasons for going 18's instead of 19's was to cut wt a little + trying to keep just a little more tire side wall thus preventing wheel damage.

My solution is to put either a SC or TT later. The power loss i noticed when changing tires/wheels was there but not a dramatic change. Now, with 2800 miles, the car seems to be getting a little quicker each time I drive it. Seems like breaking in the motor is making it quicker.

 

Tell me how it goes with the TT or SC.

Yeah, my car was noticeably quicker after my break in. I religiously kept my car below 4k rpm/shift and 65mph (usually 60). My car dynoed 233 RWHP at 1600 mi. My car then got a little quicker when I changed to MOBIL 1 Syntec and place a K&N drop in filter.

Good luck with your engine mods!

 

[QUOTE]Originally posted by zland


I noticed in your sig that you may want a brake upgrade. I got my stoptech 13" cross drilled rotors with 4 pot Red calipers about three months ago and it stops on a dime...squeals a lot though....BUT the best and worst thing about them is that everyone who sees my car looks at the brakes first and so the car goes unnoticed a bit.

I definitely would get brakes...but that is just my opinion.

 

I got 235 fr and 275 rear I didn't really notice a difference..