Wheel size

[Ian2470]

Hi just bought a rav 4 with 18 inc wheels are they more practical or would I be best with 17 inc but saying that they do look nice . 
thanks 

[philip42h]

An odd question to ask in the C-HR section ... 😉

It looks like a 4.2 3-dr; the wheels look as though they came from a 4.3 so I'd guess 235/55 R18s? And, if so, they are exactly the same rolling diameter as the 17" wheels fitted to the 4.3. I don't have the specs for the 4.2 to hand but I suspect that they are the same.

That being the case, there'd be no particular benefit nor drawback switching back to the 17" wheels and the ones you have do look nice.

[Stivino]

6 minutes ago, philip42h said:

rolling diameter

Do you mean circumference?

[philip42h]

Just now, Stivino said:

Do you mean circumference?

No, I mean diameter ... but I could have said radius or circumference instead 'cos they all boil down to the same thing. 😉 

[Stivino]

Rolling diameter is meaningless.

Radius, diameter and circumference are all completely different things and cannot be interchanged.

[philip42h]

10 minutes ago, Stivino said:

Rolling diameter is meaningless.

Radius, diameter and circumference are all completely different things and cannot be interchanged.

For a definition see below:

Quote

 

In order to properly understand plus sizing it is important to understand some of the terminology used:

• Wheel or Rim Diameter: This is the diameter of the wheel or rim, not including the tyre. Usually measured in inches, modern vehicles usually have rims ranging from 16” to 20”. Although some high performance or modified vehicles can have rim diameters in excess of 20”. For a detailed description of how to identify your rim size please click here.
• Overall Rolling Diameter: This is the outside diameter of the tyre, while it is fitted to the chosen rim. This measurement is usually given in millimetres and can be calculated by adding the diameter of the rim to the sidewall height of the tyre. Sidewall height is also known as sidewall aspect ratio, profile or series. For a detailed description of how to calculate this value please click here.

 

[Stivino]

ooo

[philip42h]

29 minutes ago, philip42h said:

I don't have the specs for the 4.2 to hand but I suspect that they are the same.

... and they are not! 🙂

If the Internet is to be believed the 4.2 came shod with either 215/70 R16s or 225/55 R17s so a properly fitting 18" wheel would need to have rather low profile tyres fitted. What is the size of the wheel and tyre that you currently have.

[philip42h]

4 minutes ago, Stivino said:

Obviously written by someone with no mathematical qualifications.

The only thing that matters is the circumference.

Last try ... the circumference = pi x diameter = 2 x pi x radius of the whole wheel (rim + tyre wall).

[Stivino]

Thanks for the maths lesson, which I don't need.  Apart from having a maths qualification, I'm sitting here with a maths teacher and we are both of the persuasion that while radius, diameter and circumference are all related, they are also completely different things and the cannot be interchanged randomly.

I won't reply further. 

 

[Cyker]

Depends what you mean by 'practical' - Certainly you wouldn't want low-profile tyres for any serious off-road use, as the first big rock crawl you hit and bye-bye alloys.

If like 99% of RAV4s it's just going to be used on roads and the occasional field then either is fine. You'll get slightly better feedback and the ability to fit larger brakes with the 18's, but slightly better fuel economy, acceleration, braking and cheaper tyres with the 17's.

 

[Ian2470]

Hi thanks for the reply and advice sorry I put on wrong page .  

[TonyHSD]

3 hours ago, Ian2470 said:

Hi just bought a rav 4 with 18 inc wheels are they more practical or would I be best with 17 inc but saying that they do look nice . 
thanks 

These tyres although 18” does not look to be very low profile therefore no need to worry about changing them. Set the correct pressure at cold and you won’t have any issues. The car looks very good 👍 

[Cyker]

don't worry, frosty is pretty on the ball for moving things to the right forums  

[philip42h]

1 hour ago, Ian2470 said:

Hi thanks for the reply and advice sorry I put on wrong page .  

I've struggled to find the original specification for the wheels on the 4.2, but I think they were 215/70R16 as per this article on the Toyota media site. If this thread gets moved to the RAV4 there's a good chance that a 4.2 owner will be able to confirm / correct this.

But that then defines the correct size of wheel for your car - i.e. the size that the speedometer and odometer are calibrated for. You are the reasonably free to swap to any rim / tyre size combination that retains the same size wheel.

If I've got the size correct in the first place, then a 225/60 R17 (0.6% smaller), a 225/55 R18 (0.1% smaller) or a 235/55 R18 (1.3% larger) would be suitable replacements.

Do let us know what is actually on the car today.

[TonyHSD]

Here some useful information: 

https://www.wheel-size.com/size/toyota/rav4/2005/