Would buying 19" tyres save fuel?

[kevinswan007]

If for example, someone has 13" mags/tyres and decides to put on 19" mags/tyres, wouldnt that same car save on fuel because it now does the same distance in less revolutions?

Whats the circumference of a 13" compared to a 19"? Surely the car does less to travel the same km?

 

[CaTcH21]

If for example, someone has 13" mags/tyres and decides to put on 19" mags/tyres, wouldnt that same car save on fuel because it now does the same distance in less revolutions?

Whats the circumference of a 13" compared to a 19"? Surely the car does less to travel the same km?

ROFL ...

 

[LCBXX]

No it will not. The 19" contact patch is bigger than the 13", hence more rolling resistance. You will mainly notice the increase in fuel consumption on roads with rough tarmac. Then there is wind resistance etc

 

[The_Unbeliever]

19" tyres surely do cost a lot more than 13" tyres?

So I'd rather stick to 13", save a lot of money which can be used for fuel, instead of sticking on 19", have a huge overdraft which I'll have to pay off, and still buy fuel afterwards...

plus the fact that fancy tyres do get stolen more often than standard tyres....

 

[VanZan]

It is likely that the vehicle (designed for 13" tyres) would be much heavier on fuel with 19" tyres. The reason being that the total amount of energy needed to accelerate/move a vehicle depends much more on the weight, air resistance etc than on the rolling resistance of the tyres, but that the tyre size does not affect these factors. However - the engine now runs at a less than optimum speed - often below it's best torque profile. This means that you need to give it more fuel to accelerate or maintain speed - hence higher fuel consumption.

 

[Waaib]

Also. 19" tyres will probably cost more to inflate so you'd loose money there.

Why does spell check not recognize the word tyre.

 

[Moederloos]

Also. 19" tyres will probably cost more to inflate so you'd loose money there.

Why does spell check not recognize the word tyre.

Except air is free.

US spelling. Notice some signboards at car fitment centres "Come here to get tired".....

 

[Waaib]

But it takes longer to fill 19'' so more time so more money.

 

[Claymore]

Whats the circumference of a 13" compared to a 19"? Surely the car does less to travel the same km?

Should be the same, within a small margin. When you change sizes on a car, you need to change the tyre profile too, in order to maintain the same rolling circumference. If you don't, your speedo and odometer will be out.

Thus, if you wanted to swap your 13" rims for 19" rims with wide (say 215) tyres, you have to swap your 155/85R13 tyres for 215/25R19 tyres to be only 0.6% out.

http://www.miata.net/garage/tirecalc.html

 

[jab2]

Your car is geared to run with tires of a specific circumference. If you want to go from 13" to 19" you have to go to a very low profile, something like 25 as Claymore suggested. Having the same circumference will leave you at the same fuel situation.

I think you want to increase circumference to reduce rpm at a specific speed, thus reducing fuel consumption. This is however not really possible as the torque curve of an engine is a parabola and the engine is geared, and wheel circumference is part of this gearing, to give normal road speed at the top of this curve. By increase circumference you will lower the rpm and loose a lot of torque, and the car will be a bitch at slow city speeds.