I have a 2013 honda jazz sport , i have changed the original 185 55 16 wheel to a 185 60 15 . with 2010 honda jazz wheels (i paid $200 for the mags and tyres). the reason for this is that , the original tyres are pricey and they also weigh 18 kilos (39.6 pounds).The 15 inch wheels weigh 16.5 kilos (36.3) . I recently drove a 600 km trip (highway) and noticed that the car had better acceleration and the fuel consumption was better than with the heavier 16 inch wheels. i got a fuel consumption of 40 mpg to about 47 mpg when i did the dividing the miles driven by litres it took to refill .The meter in the dash was showing around 5.8 to 6.2 litres per 100 km . i achieved this by driving at 100 kmph in some places and 120 kmph. At 100 kmph is the sweet spot for me (5.8 l per 100 km)BTW the car had 4 adults plus a lot of other stuff in the back which weighed more than 50 kilos. I love my honda jazz.

 

i would like to change my tyres from 14 inches to 15 inches. do you think it is worthwhile?

 

I responded because I saw the ' wheels' when you really meant tire weights. Yes, lighter tires of the same overall diameter will make a difference in mpg - and acceleration. The original 185/55x16 tires are 24.01 inches (61 cm) and the 1855/60x15's are 23.74 inches (60.3 cm) which are for practical reasons the same size and have no real change in mph. odometer miles, or acceleration times. And yes much cheaper.
The reason for concern is too many think lighter wheels wikll make a big difference which they won't. In racing yes, but on the street no effect.
cheers.

 

That depends on why you want to change. If you want shorter sidewalls for better handling or to fit higher performance tires, tires more easily available, or last longer, then yes. Otherwise, it really doesn't make much difference. If you put bigger tires especially ones that weigh more then you will be costing you in mpg and acceleration.

 

i weighed the alloy mag wheel including the tyre filled with air and i got 18 kilos for the 16 inch.

 

you can change it , but make sure you do some research , the rolling diameter should be very close to the stock wheels or else you will find an inaccurate speedo, gearing rpm change etc . try google for tyre size calculator.