Tyre recommendations - Auris T Spirit 5dr 1.8 VVT-i Hybrid

[Anthony Poli]

I stand corrected on the profile, so I would like to apologise to all.

I did find this on speedometer standards:-

International agreements
In many countries the legislated error in speedometer readings is ultimately governed by the United Nations Economic Commission for Europe (UNECE) Regulation 39[4] which covers those aspects of vehicle type approval which relate to speedometers. The main purpose of the UNECE regulations is to facilitate trade in motor vehicles by agreeing uniform type approval standards rather than requiring a vehicle model to undergo different approval processes in each country in which it is to be sold.

European Union member states must also grant type approval to vehicles meeting similar EU standards. The ones covering speedometers [5] [6][7] are similar to the UNECE regulation in that they specify that:

The indicated speed must never be less than the actual speed, i.e. it should not be possible to inadvertently speed because of an incorrect speedometer reading. 
The indicated speed must not be more than 110 percent of the true speed plus 4 km/h at specified test speeds. For example, at 80 km/h, the indicated speed must be no more than 92 km/h. 
The standards specify both the limits on accuracy and many of the details of how it should be measured during the approvals process, for example that the test measurements should be made (for most vehicles) at 40, 80 and 120 km/h, and at a particular ambient temperature. There are slight differences between the different standards, for example in the minimum accuracy of the equipment measuring the true speed of the vehicle.

The UNECE regulation relaxes the requirements for vehicles mass produced following type approval. The upper limit on indicated speed is increased to 110 percent plus 6 km/h for cars, buses, trucks and similar vehicles, and 110 percent plus 8 km/h for two or three wheeled vehicles which have a maximum speed above 50 km/h (or a cylinder capacity, if powered by a heat engine, of more than 50 cc). European Union Directive 2000/7/EC, which relates to two and three wheeled vehicles, provides similar slightly relaxed limits in production.

 

[Kojac]

Ok - so heard back from insurance company (Admiral) - All other things remaining equal - changing from 87W to 91W will not affect our insurance negatively in any way whatsoever.

This particular insurer has no problem with this particular load index increase.

So here's a new question - which has been addressed - but I want to 'flesh it out' a bit:

 

A)Say I now switch to the 91w from the previous 87w - what is the technically accurate way of establishing the new tyre pressure required (vs OE) - given the change of tire spec.

B)Clearly the tyres are made for a heavier weight to carry - but I am not increasing the weight of the vehicle - how will this affect braking distance and grip performance? Will we suffer for it?

[yossarian247]

There is no change of tyre pressure needed on an increase in load index. Nor is there likely to be any change in braking distance, or if there is it will be a very very slight reduction, as a higher load index tyre will deform less under severe stress such as emergency braking.

I have changed from standard load to extra load tyres, and back sometimes, on various cars over the past few years, and really, you can't tell any difference. The brand, composition and tread pattern make a huge difference to how a tyre handles, but the load index by itself in my experience does not make any noticeable difference at all on most cars.  I have always stuck to the vehicle manufacturer's recommended pressures in all cases by the way, regardless of whether using XL tyres or not, and not experienced uneven wear.

For example just last week I replaced the awful 91V Chinese budget tyres on my Auris with some 94V Michelin Crossclimates (of the same size). Despite the increase in load index the new tyres are noticeably softer and more compliant, with far better and safer handling!

I would get away from this idea of higher load index tyres being just for heavier cars. They are for 'up to and including' heavier cars, with no problem at all arising from using them on a slightly lighter vehicle.

An old tyre fitter once said to me that he would by choice always go for highest load index available in any given tyre size. The reason being that the higher index tyre is 'the same tyre, just more solidly built' so less likely to suffer structural damage if kerbed for example.

 

[Beekeeper D]

21 hours ago, FROSTYBALLS said:

Not relevant.

If the change in tyre size makes the speedo under-read, it is illegal.

Yes, IF it makes the speedo under-read the true speed, it would be illegal. 

The 215 to 225 change seems to give about a 1.5% reduction in the speedo reading at whatever speed. 

However, IF the speedo was previously over-reading by more than 1.5% (as unclepoo believes - and which can be checked by GPS on a smartphone), then changing to 225's would indeed just reduce the error, and, since the speedo would still be over (not under) reading the true speed, the tyre change would not be illegal - at least not on that specific ground.  

[FROSTYBALLS]

That is OK if one has a pretty realistic idea of how optimistic one's speedometer is.  In our second car, which has an analogue style speedometer and a digital speed readout, the digital readout, when compared to GPS, is approx 1.4% optimistic - reading 71mph compared to 70mph on GPS. So if we were to make a similar change in tyre size to that the OP is considering, the second car could either be borderline or illegal. That is assuming the degree of optimism of the digital readout remains the same over the speed range - which may not be the case.

GPS readings are an average taken over several positions, so although pretty accurate, are still subject to a percentage error.

[Beekeeper D]

Just to flog the horse once more to ensure it is properly dead, my 'new' 14 plate Auris TS Excel Hybrid has as original fit (as per page 501 of the manual) 225/45/17 tyres ... and is likely to get its noisy Dunlop SP Sport Fast Responses replaced with Michelin Cross Climates whenever an adequately tempting 'deal' appears!  

[FROSTYBALLS]

3 minutes ago, Beekeeper D said:

Just to flog the horse once more to ensure it is properly dead, my 'new' 14 plate Auris TS Excel Hybrid has as original fit (as per page 501 of the manual) 225/45/17 tyres .

Which is fine. If those were OE, the speedometer would be calibrated to suit that fitment.

[TomdeGuerre]

43 minutes ago, Beekeeper D said:

Just to flog the horse once more to ensure it is properly dead,

Dead Horse Theory

The tribal wisdom of the Dakota Indians, passed on from generation to generation, says that "When you discover that you are riding a dead horse, the best strategy is to dismount." However, in government, education, and in corporate America, more advanced strategies are often employed, such as:

1. Buying a stronger whip.

2. Changing riders.

3. Appointing a committee to study the horse. Better yet, bring in an army of consultants to over study the horse.

4. Arranging to visit other countries to see how other cultures ride dead horses.

5. Lowering the standards so that dead horses can be included.

6. Reclassifying the dead horse as living-impaired.

7. Hiring outside contractors to ride the dead horse.

8. Harnessing several dead horses together to increase speed.

9. Providing additional funding and/or training to increase dead horse's performance.

10. Doing a productivity study to see if lighter riders would improve the dead horse's performance.

11. Declaring that as the dead horse does not have to be fed, it is less costly, carries lower overhead and therefore contributes substantially more to the bottom line of the economy than do some other horses.

12. Rewriting the expected performance requirements for all horses.

And of course:

13. Promoting the dead horse to a supervisory position.

[Heidfirst]

TdG, might have to steal that ... 

[FROSTYBALLS]

45 minutes ago, Beekeeper D said:

Just to flog the horse once more to ensure it is properly dead ...

One likes sadism, bestiality and necrophilia.

Is one flogging a dead horse?

[eygo]

3 hours ago, Beekeeper D said:

Just to flog the horse once more to ensure it is properly dead, my 'new' 14 plate Auris TS Excel Hybrid has as original fit (as per page 501 of the manual) 225/45/17 tyres ... and is likely to get its noisy Dunlop SP Sport Fast Responses replaced with Michelin Cross Climates whenever an adequately tempting 'deal' appears!  

have a look and see if your local KwikFit has had a refurbishment and they have a relaunch event

at the event if you arrived between

7am- 8am = 50% off

8am - 9am = 40% off

9am - close = 30% off

so i purchased 4 x 225/45/17 cross climates & 2 years of 4 wheel geometry check and adjust up to 8 times for £289.90

 

[Kojac]

14 hours ago, eygo said:

have a look and see if your local KwikFit has had a refurbishment and they have a relaunch event

at the event if you arrived between

7am- 8am = 50% off

8am - 9am = 40% off

9am - close = 30% off

so i purchased 4 x 225/45/17 cross climates & 2 years of 4 wheel geometry check and adjust up to 8 times for £289.90

 

Which branch did you visit?

Is there a way to check a large number of kwik fits for relaunch events?

[eygo]

the quick fit i used is in ellesmere port

i only needed 2 tyres but i bought four because of the price

[Beekeeper D]

On 12 July 2016 at 7:24 AM, Anthony Poli said:

Hi Kojac,

One option that has been chosen on here, is to go for 225 45 R17 tyre size. Which should give you more to chose from. I fancied the cross climate ones but they are not in the original size, but if i choose the 225 45 R17 instead of 215 45 R17, then I can get the tyres.

If only budgeting for them was as easy

Happened to spot the other day that the Crossclimates ARE now available in 215/45/R17. But they are distinctly more expensive than the 225's (for my estate) that I was pricechecking at the time. 

[Anthony Poli]

1 hour ago, Beekeeper D said:

Happened to spot the other day that the Crossclimates ARE now available in 215/45/R17. But they are distinctly more expensive than the 225's (for my estate) that I was pricechecking at the time. 

At long last, luckily i still have time/tread to save up for them

[Kojac]

Just to update the thread:

 

I went for Avon ZV7's, all round - had Halfords fit them.

 

A rated - grip

C rated - fuel efficiency (as it's a hybrid the offset is small).

 

Manufacturer is a know entity here in europe.

 

For the intended user profile - great balance of cost vs function.

 

Kojac

[Anthony Poli]

Just to update the thread:

 

I went for Avon ZV7's, all round - had Halfords fit them.

 

A rated - grip

C rated - fuel efficiency (as it's a hybrid the offset is small).

 

Manufacturer is a know entity here in europe.

 

For the intended user profile - great balance of cost vs function.

 

Kojac

What size is your tyres?

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[Kojac]

On 19/09/2016 at 6:24 PM, Anthony Poli said:

What size is your tyres?

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Avon ZV7 XL 215/45 R17 91Y 

Went for XL Load rating/91Y speed rating - informed insurance company of the upgraded ratings from stock - they said no issue/no problem as long as you've told us.

Kojac.

 

[Anthony Poli]

Thanks.

How do you find them?

 

[Kojac]

17 minutes ago, Anthony Poli said:

Thanks.

How do you find them?

 

The ol' lady likes them.

There used to be an issue with this brand that the tyres would wear a little quickly. I had to guess that they've been sorted out by this stage.

The grip is very good - and the wet performance is especially good. 

For the price/performance balance - I would be happy to recommend them.

Just make sure you look at a few other opinions about these tyres online too.

 

Kojac