18" Alloy Wheel Without Modication?

[BarryIQ]

As title. Previously I thought the limit to fit in an alloywheel without modification was 17"x7.5"

However... a Toyota dealer has fitted a 18" into one of their IQ and the sales claimed that they did not modify anything to fit that in...

Here is the link of that car

http://www.trademe.co.nz/Trade-Me-Motors/Cars/Toyota/auction-261942362.htm

Can anyone please confirm if thats true?

[Zulley]

There never 18's.

[BarryIQ]

Did you even check the link that I've posted?

[S2Sosmart]

BarryIQ

I can see what they're saying though. They may list them as 18's but in the image the rims just don't 'seem' to fill the arches which is what you'd expect with a rim that size.

I stand by to be fully corrected though,

Si

[macabeus]

No 18's on that foto I'm sure.

[SallyIQ]

I do believe they are 18s!

The car obviously hasnt been lowered and they have put a low profile tyre on, looks to be about 35-40. When i put my 17s on, it was before the car had been lowered and the arch gap was huge still. 18s wouldnt automatically go into the wheel arch with standard suspension!!

[BarryIQ]

I've pretended to be a buyer and txt the Toyota agent who is selling that car.

He told me they are 18x7.5 ANZ alloy wheel and there is no other modification done to the IQ. I've explicitly asked if he has done any adjustment to the suspection to fit the wheel in and his reply is no.

If he has replaced it with a sport suspension, meaning he has put more value to the car and in concept there is no point for him to hide this information from a potential customer :)

How reliable is a Toyota agent? I have no clue... But he will be in deep trouble if he is doing any false advertisment tho...

[lil.smartie]

They look like 18's to me too :) Mine has 16" rims and as Sally says you lower the profile with larger rims so as to keep the rolling radius the same so as not to knock the speedo out (any more than it already is!) and the trip.

Kate

[macabeus]

215/35R18 would be possible on 18 by 7,5..............not my choice but its possible

[BarryIQ]

Just wondering if there is any bad effect on the car engine or the fuel efficiency if I use a 18"?

[lil.smartie]

Nope as long as the tyres are right! Very harsh ride though with such low profile tyres, I don't think I'll switch from 16" rims, will go wider though and some progressive lowering springs :) Just need to get Ozzy back from the garage now :(

Kate

[macabeus]

Yes it will use (a lot) more fuel of course because more rubber (wider) contact on the road.

[BarryIQ]

Yea, I am also concering about the increased weight of the 17". And the increased road resistance due to wider tyre.

Anyone got a figure for the weight of the original wheel of IQ?

[lil.smartie]

If the tyre pressure and the weight of the car remain the same then so will the contact patch! Simple physics! will be wider but not as long!

Kate

[macabeus]

Which school did you go?

please get a refund if possible for your Simple physics (ask your teacher for Circels of KAM)

[BarryIQ]

Which school did you go?

please get a refund if possible for your Simple physics (ask your teacher for Circels of KAM)

I am confused... and lost... Here I got a summary of what I think is correct, please correct me if I am wrong. I've just passed my highschool Physics... ;)

Disadvantage:

Bigger Alloy = Wider tyre = more road resistance = more fuel

Bigger Alloy = Possibly heavier overall wheel weight = more fuel

Bigger Alloy = thinner tyre = more bumpy ride = reduce in traction = loss of power = more fuel

Advantage:

Bigger Alloy = better handling... (I dont really know why but I think thats the basic rule)

Bigger Alloy = more tyre contacting the road = more grip

And of course... Bigger Alloy = badass look on a small IQ

Basically, I think its just a matter of if I want to trade off fuel efficiency for handling and comfortable ride.

[SallyIQ]

Bigger wheels dont mean better handling.

[BarryIQ]

Bigger wheels dont mean better handling.

Ah... Someone told me about it and I never get to understand why. Thanks for point that out for me :)

[lil.smartie]

http://www.carbibles.com/tyre_bible_pg3.html read part about contact patches.....

Kate

[BarryIQ]

http://www.carbibles.com/tyre_bible_pg3.html read part about contact patches.....

Kate

Great site! So wider tyre does not mean more grip and use more fuel.

Thanks for giving the direction to the right knowledge, now I got something to show off in front of my engineer friend who told me wider tyre use more fuel.

[macabeus]

So that's why formula 1 cars have very small and tiny tires because then there is more rubber on the road so the grip is improved?

I learn things from "experts" every day

ROTFL

[BarryIQ]

So that's why formula 1 cars have very small and tiny tires because then there is more rubber on the road so the grip is improved?

I learn things from "experts" every day

ROTFL

I guess it is due to the increase in acceleration? Smaller wheel radius give more acceleration? Their tyre is not small at all compare to the size and weight of the car.