Tyre Sizes Rav 4 Nrg

[jimmiley]

New member today, so please be kind....... not sure of forum etiquette :D

I need to replace my current 235/60 R16 tyres and wondered if I could replace them with 215/70 R16's. I don't use my Rav 4 'off road' as such and I did hear that I might get better on road performance and slightly reduced noise with the 215/70's.

Also any advice as to a decent price 'fitted' would be appreciated.

Thanks loads,

Jim.

[anchorman]

Hi Jim, welcome to the club.

A quick calculation suggests the 215s have a 9mm bigger radius but this doesn't always follow true. Ask the supplier if they are the same rolling radius. 9mm is a bit too much I would suggest as it will effect the speedo (read slow) and may reduce the design brake force.

I don't know about prices.

Cheers

[jimmiley]

Hi Jim, welcome to the club.

A quick calculation suggests the 215s have a 9mm bigger radius but this doesn't always follow true. Ask the supplier if they are the same rolling radius. 9mm is a bit too much I would suggest as it will effect the speedo (read slow) and may reduce the design brake force.

I don't know about prices.

Cheers

[jimmiley]

Thanks loads for that - on reflection maybe I should just stick with original sizes then. Thought I might save a bit of money/ get better perfomance - but safety is my main priority.

Thanks again !

Jim.

[bothwell_buyer]

The 215/70/16 tyre is widely available, and indeed was the tyre (Dunlop) of choice fitted to the RAV when it was launched in 1994.

I've moved up to 18" wheels since; and will be picking up more 18" rims with lower profile tyres for sprint purpose this week.

Main consideration is amount of tyre on road, and the speedo calibration. As I've moved to wider tyres, the cornering ability has greatly improved, although I have noticed some degradation in high speed through water - depends on tread pattern.

I use a guy called Ian at AutoImage in Glasgow for all my tyres and wheels - its his trade and his business, and I rely on him to share his wide knowledge when it comes to me choosing wheels and tyres for a job/vehicle. He specialises in selling alloys. I'd imagine any such dealer would give you the benefit of their knowledge.

They will also be able to tell the rolling radius/diameter, and whether a wheel/tyre combination will affect things - eg on full lock. To be honest, the speedos are not the most accurate by any means - remember they have to deal with new tyres through to worn tyres which is a few mm difference!! My current wheel/tyre set up gives me a slightly optimistic speed reading. Once I use the lower profile tyre, the speedo will be 10% out/optimistic, but then I'll be using these for off road.

My 2nd RAV has 235/60 tyres fitted. You do need to make sure that whatever tyre you go for - all 5 need to be the same size.

[Robert6920]

Hi and welcome. Rav4.2s like my better half's were originally supplied with one of two tyre size options, the ones you mention. Hers has the 215/70 R16s. I can't imagine that the brakes etc would have been any different but I wouldn't be an expert on that. There are numerous tyre (and even tire) size calculators that, amongst other things, work out the effect on the speedo, try here

[bothwell_buyer]

Thats a helpful tool !!

In the daylight, I can see my RAV is running 245/45 x 18. The wider tyre has aided stability both on straight and on cornering substantially. However, it is marginally smaller and has an effect of optimism on the speedo - ie the speedo reads faster than actual. However, as I wanted acceleration rather than top speed, I'm not bothered. An unwanted effect is the wider tyre and tread pattern has a tendency to tramline - follow white lines. A change of tread pattern would probably cure this. I went for lighter alloys with the MAK Mirrors and so the end result is the wheel is lighter, making no untoward impact on the braking/suspension system. The wheel arch clearance is excellent, and the wheels clear the calipers - the reason for going to 18".

[anchorman]

Bothy

Is that why your speedo said 68 and the polis radar said 112? :D :D :D

[bothwell_buyer]

Bothy

Is that why your speedo said 68 and the polis radar said 112? :D :D :D

Other way roon ma man! Thats why I've asked for the photo proof. If ma RAVmometer reads 100mph, its actually doing 92 or less.

Now, having learnt that the thing still has the 112mph limiter on, than the maximum speed is more like 100mph until I get the ecu altered. So the claimed 96mph is a bit unlikely.

I await the photos.......

[bitman]

@Robert6920, thanks for that link, very useful! B)

[Hoovie]

The Bridgestone Duellers are configured for 80% On-Road 20% Off-Road I think? If you went for a normal road tyre from one of the leading makers which was 100% road orientated, then that should give you a quieter ride and probably better economy as well due to the tread pattern

Question: If the car was fitted with a wheel/tyre combo that increased the rolling radius by 10%, the speedo would under-read and the odometer would under-read as well by 10% (I presume), acceleration would be worse BUT .... economy would improve presumably? as when you are doing a true 70mph on the bigger wheel/tyre set in top gear, instead of 20 mph/1000 RPM (so 3,500 rpm) , it would actually be working at 22mph/1000rpm (so 3,200 rpm)

I'm using 20mpg/1000mph as example - don't know what it really is

[anchorman]

The Bridgestone Duellers are configured for 80% On-Road 20% Off-Road I think? If you went for a normal road tyre from one of the leading makers which was 100% road orientated, then that should give you a quieter ride and probably better economy as well due to the tread pattern

Question: If the car was fitted with a wheel/tyre combo that increased the rolling radius by 10%, the speedo would under-read and the odometer would under-read as well by 10% (I presume), acceleration would be worse BUT .... economy would improve presumably? as when you are doing a true 70mph on the bigger wheel/tyre set in top gear, instead of 20 mph/1000 RPM (so 3,500 rpm) , it would actually be working at 22mph/1000rpm (so 3,200 rpm)

I'm using 20mpg/1000mph as example - don't know what it really is

Hoovie.

9mm would be nearer 3% but that is 28mm more circumference. The 3% has similar effect on the speedo so i guess your sums work out OK.

As to whether it makes a difference to the brakes, well I can rember some cases where wheel size determined if the vehicle would meet brake approvals or not and in the end, smaller wheels were chosen to get them through Type Approval. The wheel diameter is the lever that works against the brake (always smaller as it has to fit inside the wheel). The approval tests were made up of many different tests at different speeds and if something was borderline (say for instance higher speed test with the vehicle fully loaded and one half of the split system failed) then the next size of wheel could make a difference. For it to be important in practical terms would depend on circumstances. Imagine a situation where a vehicle failed to stop and caused an accident where there was a fatality. The DOT (or whatever they are called these days) would impound all the vehicles involved and examine them. If one was found to have different wheels they would then trawl back through all the approvals and see if it was within limits by calculation. If not then you could find yourself with manslaughter charges and no insurance. An extreme example but if you put yourself in the shoes of somebody that had just lost a partner or child you would want blood.

Its a risky business!

[bothwell_buyer]

The MOT test carries out a brake efficiency check, and so should throw up a warning if limits were unacceptable.

[anchorman]

The MOT test carries out a brake efficiency check, and so should throw up a warning if limits were unacceptable.

No I don't think so bothy. It would show if the minimum static brake force was met but not necessarily if it failed to meet one of the many other dynamic tests where wheel size is factored in.

[bothwell_buyer]

" Car Model:2006 RAV 4.3 2.2 D4D XT4"

Weel ah can see yer an expert oan the MOTs then - me wi a fleet o auld bangers and you wi yer posh shiny new motor.......

If the brakes were not up to it, then the garage would pick it up. Thats why I changed up to 6 pot calipers at the front to stop "the millstones" from turning. The garage words - not mine.

Then again, British rail and its subsequent companies get away wi trains that cannae stop with hundreds of yards - not even feet or metres!!! :P

[anchorman]

Stopping a train in a hurry is a strange sensation and the quicker you want it to stop the more it seems to amble along like nothing in the world matters. The biggest problem is uncurling your toes after!

[bothwell_buyer]

Stopping a train in a hurry is a strange sensation and the quicker you want it to stop the more it seems to amble along like nothing in the world matters. The biggest problem is uncurling your toes after!

Gosh - I never thought that they were like fred Flinstones Fleet!!