bigger mags, lesser gas mileage

**isa1023** · January 19th, 2010 12:17 PM

Just installed 17s lightweight mags on 215/40R17 Advan Neovas on my Sentra n16. Fits well, no offset adjustments needed.

Someone told me to expect poorer gas consumption...

Makes sense since wheels now need slightly more torque to move.

But is the difference that substantial and the FC increase that noticeable?
Should I be worried?

**ghosthunter** · January 19th, 2010 05:29 PM

Originally Posted by isa1023

Just installed 17s lightweight mags on 215/40R17 Advan Neovas on my Sentra n16. Fits well, no offset adjustments needed.

Someone told me to expect poorer gas consumption...

Makes sense since wheels now need slightly more torque to move.

But is the difference that substantial and the FC increase that noticeable?
Should I be worried?

It will have to do with the diameter of the original and new wheels and the weight as well.

Bigger wheels would act like there was a longer pole at one end of a seesaw. So it would take more power to move the same mass. This means if you are in a stop-go type of traffic, you will need more energy to move and accelerate the car everytime.

Weight is another consideration. In general, bigger wheels also have more weight. Or if they weigh the same, the mass is more concentrated at the outside diameter. This results in the car needing more power to accelerate the wheel itself.

Also wider tires than stock will have more friction. This is good and bad. Good because you can steer better and stop earlier. Bad because wider tires will have more friction to slow you down as well. This is why cars designed for better fuel economy have narrow tires to minimize the friction of the tires on the road.

**Type 100** · January 19th, 2010 06:26 PM

Fuel consumption will still depend on how you drive, although it should get a little worse. To a certain extent, it also depends on how variable the fuel consumption is for your car.

Going lightweight is the right way to go though. You want to reduce unsprung weight (brakes, wheels, tires, suspension etc), which is the worst kind for the car. The funny thing with lightweight wheels, however, is that they cannot account for the weight of the tires. If the tires are heavy, they can cancel out any benefit to unsprung weight brought by the lightweight wheels.

**isa1023** · January 20th, 2010 02:27 PM

Thanks for the replies.

Since now Ive got 0.25 inches more in wheel diameter, wider rubber and more metal to torque up and roll, guess it's a fact that I now have to drive more prudently. So far hindi naman po noticeable yung FC increase, I hope a little bit of overinflation (2 psi than normal) could help. Matagtag na eh

**ghosthunter** · January 20th, 2010 02:38 PM

Originally Posted by isa1023

Thanks for the replies.

Since now Ive got 0.25 inches more in wheel diameter, wider rubber and more metal to torque up and roll, guess it's a fact that I now have to drive more prudently. So far hindi naman po noticeable yung FC increase, I hope a little bit of overinflation (2 psi than normal) could help. Matagtag na eh

Careful with overinflation. That can result in less than optimum tire grip when trying to brake quickly.

**isa1023** · January 21st, 2010 06:10 AM

Originally Posted by ghosthunter

Careful with overinflation. That can result in less than optimum tire grip when trying to brake quickly.

Noted sir.

The tires had very minimum grip at all since they're overused, I think.
Almost "kalbo" na.

Treads are really worn out and Im working to replace them with cheaper comfort tires (if ever those have sizes in 17s)...

**redorange** · January 21st, 2010 07:25 AM

Also keep in mind that the bigger rims and tires will alter the odometer and speedometer reading unless you calibrate it. Both will read lower than what you are actually doing.

**meledson** · January 21st, 2010 08:30 AM

I have upgraded from 14" to 16" but the outside diameter of the new tires are the same as stock. error is less than 1%.

**ghosthunter** · January 21st, 2010 10:19 AM

Originally Posted by isa1023

Noted sir.

The tires had very minimum grip at all since they're overused, I think.
Almost "kalbo" na.

Treads are really worn out and Im working to replace them with cheaper comfort tires (if ever those have sizes in 17s)...

Good luck in looking for "cheaper" 17 inch tires.

Anyway, Neova tires aren't really known for comfort because they are more performance oriented.

You might want to be careful in picking/choosing your next tires. It's because more comfortable tires would probably mean softer sidewalls and that might end up causing some damage to your 17 inch wheels if you encounter a pothole.

Taller sidewalls would help add some cushion effect and also distance between the wheel and the road (for extra protection).