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SentraSE-R · 04-30-2011, 03:14 AM

My xB is shod with P185/60-R15 tires, standard. The OEM tires are 23.74" tall, and turn 876.1 revolutions/mile.

I'm thinking of buying 17" wheels with P205/45-R17 or P215/45-R17 tires. The former are 2.15% larger. 24.26" tall, and turn 857.3 revolutions/mile. The latter are 3.45% larger. 24.61" tall, and turn 843.1 revolutions/mile.

I am hoping the taller tires and taller effective gearing will result in better fuel economy, but the Internet is rife with claims that larger tires result in worse fuel economy for users.

Adverse factors are potential increased wheel/tire weight with the larger wheels and tires, and worse aerodynamics from the new alloy wheels v. the stock steel wheel/hubcap combo.

Is this wheel/tire swap likely to be a win, or a big fail? I didn't find any good ABA testing. If anyone can point me to testing that's been done, let me know.

Unfortunately, there are no LRR tires small enough in 17" size to fit my car. I could possibly go with 205/50-17 tires, but they're >5% taller, and may start rubbing.

04-30-2011, 03:14 AM	#1 (permalink)
SentraSE-R Pishtaco Join Date: Jun 2009 Location: Bay Area, California Posts: 1,485 Mean Green Toaster Machine - '06 Scion xB Team Toyota 90 day: 48.92 mpg (US) Thanks: 56 Thanked 286 Times in 181 Posts	Tire size expectations? My xB is shod with P185/60-R15 tires, standard. The OEM tires are 23.74" tall, and turn 876.1 revolutions/mile. I'm thinking of buying 17" wheels with P205/45-R17 or P215/45-R17 tires. The former are 2.15% larger. 24.26" tall, and turn 857.3 revolutions/mile. The latter are 3.45% larger. 24.61" tall, and turn 843.1 revolutions/mile. I am hoping the taller tires and taller effective gearing will result in better fuel economy, but the Internet is rife with claims that larger tires result in worse fuel economy for users. Adverse factors are potential increased wheel/tire weight with the larger wheels and tires, and worse aerodynamics from the new alloy wheels v. the stock steel wheel/hubcap combo. Is this wheel/tire swap likely to be a win, or a big fail? I didn't find any good ABA testing. If anyone can point me to testing that's been done, let me know. Unfortunately, there are no LRR tires small enough in 17" size to fit my car. I could possibly go with 205/50-17 tires, but they're >5% taller, and may start rubbing. __________________ Darrell Boycotting Exxon since 1989, BP since 2010 Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac? George Carlin Mean Green Toaster Machine 49.5 mpg avg over 53,000 miles. 176% of '08 EPA Best flat drive 94.5 mpg for 10.1 mi Longest tank 1033 km (642 mi) on 10.56 gal = 60.8 mpg Last edited by SentraSE-R; 04-30-2011 at 03:23 AM..