Skinny Tires

[anandsihra]

As noted in my sale thread, my commuting distance has doubled. I really don't want to sell the princess, but its just doesn't make economic sense at 24 MPG. I was thinking of putting narrower tires on it to try and improve fuel efficiency. Does anyone know the narrowest tire size I can use on a 17 inch rim while maintaining stock tire height? Thanks in advance.

[tigger]

215/60-17 is the "skinny" alternative listed at most tire websites. I think a 205/65-17 may work but anything narrower would need a narrower rim as well. The 215 is almost exactly stock height, the 205 is .33" taller.

[bignick]

Jan 10, 2014 13:15:55 GMT -6 anandsihra said:

As noted in my sale thread, my commuting distance has doubled. I really don't want to sell the princess, but its just doesn't make economic sense at 24 MPG. I was thinking of putting narrower tires on it to try and improve fuel efficiency. Does anyone know the narrowest tire size I can use on a 17 inch rim while maintaining stock tire height? Thanks in advance.

If you do opt for narrow tires, make sure their load index meets the minimum required for the weight of your car. And also keep in mind that a tire that can run at a higher pressure (some tires have sidewalls that indicate a max pressure of 50+ PSI) will provide lower rolling resistance (and slightly better mileage as a result) but with a harsher ride quality. Narrower tires will increase resistance to aquaplaning as they have less of a tendency to "float" on standing water, but due to a smaller contact patch cornering traction will be reduced.

Use the cruise control as much as possible during your commute. It will help. My car (not an Aurora, sadly) exceeds its 30 MPG highway sticker mileage when I have the cruise set on the legal limit (indicated 32 MPG at 65 and 35 MPG at 55 on a "pure" highway run: pulling out of the gas station directly onto the highway and checking the DIC mileage listed after stopping at the first traffic light at the end of the off-ramp). Your Aurora should be able to hit 26 to 28 MPG highway if the engine is in good condition.

Also if it is an option where you are, try to find fuel with less ethanol in it. 0% to 5% ethanol will give you better mileage than 10% to 15%. I don't believe GM recommends anything higher than 10% except in Flex Fuel vehicles.

Also this may be helpful: tire-size-conversion.com/tire-size-calculator/

[emarkay]

Tire size and related resistance is not a great factor, but pressures are(as high as you can stand it, below max PSI) and of course, alignment is, also regarding rolling resistance; brake drag, excess weight, excess speed... Then consider inertia; quick starts, quick stops, varying speed - use your "Instant MPG" display as a pseudo vacuum gauge. Maintenance; air filter, and air intake optimizing, plugs, fuel quality, HO2 sensors, check fuel trims, alternator load, AC use, as well as failing items like TCC and transmissison, restricted exhaust... Also look at some "hypermiler" sites for more extreme ideas on maximising MPG.

[plato442]

My 2G doesn't get very good gas mileage either. I've done a lot to maximize the MPGs and HP/TQ, but when I had my ECM tuned my MAXTUNERS, I opted for power instead, so I can't be too upset. You could look at some narrower wheels with the proper off-set coupled with narrower tires.