Changing wheels for mpg

[Jeffyjazz]

I do 80miles a day to and from work on motorway with about 1mile of non motorway

Would larger wheels and possibly skinnier wheels help reduce the revs I'm doing at 70 and thus help mpg

Or would the engine just have to work harder to turn the larger wheels essentially wiping out any gains.


I know it would screw with the speedo but I go by the sat nav speed anyway as the speedo seems to read about 10mph to fast now

I would obviously be sacrificing some acceleration low down. i just noticed the other day that the BMW i3's have huge wheels that are really skinny but then they have the torque to turn them.

Anyone got skinny 17's on their jazz?

[VicW]

If you change your wheels and tyres such that the speedometer is inaccurate you may have broken the law and such a change probably requires that you inform your insurance company.
How much are larger wheels and tyres to fit going to cost you, possibly £400 for the tyres alone. How much petrol can you buy for that ?

Vic.

[Jeffyjazz]

Well it's not a problem telling the insurance company and I doubt it's breaking the law As it inaccurate from factory anyway. Unless it goes widely different

Was just after info if anyone has done it and seen if it makes a difference with the lower revs

Might also be quieter rather than doing 4000rpm @ 70mph all the way to work if I could lose about 500rpm just unsure on the rolling circumferences of them all

[Jeffyjazz]

looking into it more the width of the tire is probably going to have more effect on resistance but isn't going to reduce revs

I guess that jazz is just geared for city driving.  My type r is so much quieter on motor ways as it doesn't rev it's brains out at 60 and 70

[culzean]

The only legal tyre sizes you can fit are on the tyre information plate on drivers door pillar.  175/65 R15 and 185/55 R16 I think,  anything else and insurance may be compromised.

[John Ratsey]

I guess that jazz is just geared for city driving.  My type r is so much quieter on motor ways as it doesn't rev it's brains out at 60 and 70

This is one advantage of the Jazz with the CVT gearbox (which Honda says is 7 logical gears). It will cruise at 70 mph using no more than 2500 rpm unless you come to a hill.

[guest1372]

The original SE Sport alloys were wider than the standard steel wheels originally fitted to the S & SE, and the official mpg figures were worse, although many dealers sold cars with the wider alloy anyway.  Narrower tyres will always help reduce rolling resistance, as will tread pattern and composition; wheel diameter won't although a BMW i3 wears 155/60 R20 on the front and 175/55 R20 on the high torque rear driven wheels.

[ColinS]

Buy four space savers.  It would look silly if nothing else.

[Jeffyjazz]

Buy four space savers.  It would look silly if nothing else.

Now that's a plan  . Pizza cutters

Will keep the revs down as I can only go 50mph lol

[Jeffyjazz]

That's what I need skinny wheels

I have the wide 15" alloys and they are pretty wide for such a small car. Maybe some 14" steels would be better 145 or 155

The original SE Sport alloys were wider than the standard steel wheels originally fitted to the S & SE, and the official mpg figures were worse, although many dealers sold cars with the wider alloy anyway.  Narrower tyres will always help reduce rolling resistance, as will tread pattern and composition; wheel diameter won't although a BMW i3 wears 155/60 R20 on the front and 175/55 R20 on the high torque rear driven wheels.

[JohnAlways]

I'm a bit surprised JeffyJazz about you 4000 rpm at 70.  Mine does 3200 rpm at 70 on a 2013 1.2 s manual.
What is your Jazz?

[Garyman]

i would advice against putting 17s as that would impact on your mpg.

I tried putting some "lightweight" 17s wheels (Oz Superleggeras) but saw my mpg went from 46mpg to 38mpg so switched it back to my (then) lightweight 15" wheels (Enkei NT03).

I'm currently running on 16" Wedsport TC005 which for me is a good compromise between the "look" and mpg

[olduser1]

Thinner tyres & larger wheels for economy? not really you could use narrow studded tyres in in Finalnd Norway but that's another story.
Maybe replace current tyres when worn with premium brand [after inspection for mechanical issues.
Let forum know how you get on.

[Jeffyjazz]

I run bridgestones on it at the moment

And ref the rpm it's probably about 3800 at 70 (well gps 70 which is about 76 on my speedo)

[VicW]

The manual gearbox Jazz's that I have driven have all been geared at about 23mph/1000rpm in top gear so at 70mph that's about 3000rpm.
Of five Jazz's that I have owned their speedometers have all read 2mph high at speeds above 30mph when compared to a satnav.
The rev counter and speedometer are both driven electronically not by cables, does your car have a problem?

Vic.