Question about 225 width compared to 235

[1WICKED6]

Hey guys/Gals
I'm in the market for some new tires and as of now I'm running 215/35 and I know Venom And Sgt. Okinawa ran 225/35 on there 19's but how much wider is 235/35 compared to a 225/35. I remember getting the 215/35 because I was scared of tire rub in the fender but I got plenty of clearance for at least 225....just wondering how much wider I'm looking at with the 235(P2K suggested earlier that I go with 235's but havent seen anyone run this tire on their 19's )...The wheels are 19x8.5 with 48mm offset...Any insight on this would be great.
The reason I want new tires is because the 215/35 have a smaller rolling diameter than the stock ones and ever since I started putting different wheels on the 5 (RX-8 with 215/35, and these 19's with 215/35) I've gone from getting 24mpg to 16-17 and I'm banking on that the tires have something to do with it ( if the speedometer says 60 and I'm only going 57....this has to play something in the MPG's i would think)

 

[VenomDesign]

235 is a bit large, but if you roll your fender it will pass without any big issues. But you really need to roll them before trying it. I'd go with 225 since they are the right size to put on.

 

[thaxman]

If the speedo says 60, but actual speed is only 57, you are about 5% off, so if you were to go 220 miles (accd to the odo) but used 13 gal, then you would need to add 5% to the 220 (231) and you would get the true mpgs: about 1 mpg more. That's not much, so I don't think tire diameter is the sole problem. The lower the sidewall percentage (i.e. 35 series) the wider the 215 seems, since on 215/75/15 tires, the 215 is measured @ the widest point (1/2way btw the rim & the tread) but w/35 series, the tread typically is almost as wide as the widest point. how this matters is that there is more rubber touching the ground. Rubber causes lots of friction, of course, or else tires would be made of something else. So your mpgs will be going down just based on that. I'm sure you remember how much more resistance you felt in the steering when you put the 19s on. There is also the added weight of the 19 inch tire/wheel combo as well. Each of these most likely is combining with winter suck (bad gas + A/C compressor used when defrosting + running REALLY cold until the engine warms up) is probably dropping your mpgs. We go from 24 mpg winter (no A/C drain) to 19 or so in the summer, when the car idles more to cool down and the A/C is on 99.99 percent of the time.

 

[red headz]

If the speedo says 60, but actual speed is only 57, you are about 5% off, so if you were to go 220 miles (accd to the odo) but used 13 gal, then you would need to add 5% to the 220 (231) and you would get the true mpgs: about 1 mpg more. That's not much, so I don't think tire diameter is the sole problem. The lower the sidewall percentage (i.e. 35 series) the wider the 215 seems, since on 215/75/15 tires, the 215 is measured @ the widest point (1/2way btw the rim & the tread) but w/35 series, the tread typically is almost as wide as the widest point. how this matters is that there is more rubber touching the ground. Rubber causes lots of friction, of course, or else tires would be made of something else. So your mpgs will be going down just based on that. I'm sure you remember how much more resistance you felt in the steering when you put the 19s on. There is also the added weight of the 19 inch tire/wheel combo as well. Each of these most likely is combining with winter suck (bad gas + A/C compressor used when defrosting + running REALLY cold until the engine warms up) is probably dropping your mpgs. We go from 24 mpg winter (no A/C drain) to 19 or so in the summer, when the car idles more to cool down and the A/C is on 99.99 percent of the time.

Well said/written.
I love the calculations and justifications.
michael.

 

[dfskinner]

I've just put 225/50/17's on my car, replaced the 205/50/17's....... really looks a lot nicer and the ride is a little bit better......... not as much road noise as I had from the 205's...... I'm going to get the car cleaned up and I'll take some pic's to compare....

 

[red headz]

I'm going to get the car cleaned up and I'll take some pic's to compare....

(thumb)

 

[SGT_OKINAWA]

I roll 225/35 R19's no problem, venom is right, put one on and see how it looks/feels/fits. If you have no familiarly with rolling a fender, do lots of research, RUST is a Mother$%# ! to deal with, so head the warning and roll with caution.

Peace!(rei)