tyre sizes and warranty

Submitted: Sunday, Oct 21, 2007 at 11:58

ThreadID: 50741 Views:2582 Replies:8 FollowUps:7

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diesel82

Gday Guys
Im waiting to pick up my new diesel prado and am looking at switching the 265/65/r17 tyres over to 265/70/r17. However i have heard that doing this can void your warranty and insurance claims if you have an accident.
Has anybody had any experience with this.
Looking forward to any feedback
Have a good one

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Reply By: 3.0turbob - Sunday, Oct 21, 2007 at 12:56

Sunday, Oct 21, 2007 at 12:56

I rang my insurance company (NRMA) and they said The tyre can't be wider than standard but can be larger in diameter as long as it is within the RTA (NSW) standards. So as long as it's legal it shouldn't affect any warranty issues. There may be some information in the vehicle hand book about tyres and warranties.

Rob

AnswerID: 267645

Reply By: Member - George (WA) - Sunday, Oct 21, 2007 at 13:08

Sunday, Oct 21, 2007 at 13:08

What is the actual difference between 265/65/r17 and 265/70/r17

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AnswerID: 267646

Follow Up By: diesel82 - Sunday, Oct 21, 2007 at 13:27

Sunday, Oct 21, 2007 at 13:27

Gday George

265/70 is 26mm taller in diameter. I think overall the rolling diameter is about 4% greater with the 70 than the 65.

FollowupID: 530019

Follow Up By: DIO - Sunday, Oct 21, 2007 at 13:33

Sunday, Oct 21, 2007 at 13:33

265 indicates size (diameter) of tyre
70 indicates the aspect ratio in percentage(%) i.e. 70% of the width of the tyre i.e. the distance from the ground to the rim (the 'bulge')
r17 indicates the tyre will fit 17" rims

Therefore an aspect ratio of 65% means that the 'bulge' area is slightly smaller resulting in marginal difference in handling characteristics. Most drivers wouldn't notice the difference. Have a look at an RTM you'll see that the tyre has a high aspect ratio meaning a higher/taller bulge area - less likely to stake (in theory).

FollowupID: 530022

Follow Up By: Member - George (WA) - Sunday, Oct 21, 2007 at 13:45

Sunday, Oct 21, 2007 at 13:45

Thanks guys, makes me wonder if it is worth the trouble of changing new tyres
Cheers

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FollowupID: 530023

Follow Up By: Gramps (NSW) - Monday, Oct 22, 2007 at 06:30

Monday, Oct 22, 2007 at 06:30

George,

Use this link to calculate differences in tyre sizes

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Follow Up By: Steve L - Monday, Oct 22, 2007 at 13:43

Monday, Oct 22, 2007 at 13:43

Dio,

265 does not refer to 'the size (diameter) of the tyre' - it refers to the section width which is basically the width of the tread part of the tyre that is in contact with the road. The diameter can be calculated by adding together the rim size and two times the sidewall height - but see below; simply adding 2 time 70% of 265 (using the tyre size being queried here) will not necessarily give you an accurate figure for a specific tyre!

Gramps,

These sites will give you the figure of what the tyres are supposed to measure - in real life very few are even close. A 285/75R16 is supposed to have a diameter of 833.9mm using the 'calculation' of 2 x (75% of 285mm) + 16 x 25.4mm - in reality there are very few that meet this, with most being around 842mm, and at least one being 851mm!! (And the same goes for other tyre sizes).

To be accurate, take the dimensions off the tyre manufacturers websites, or call them and ask for the figures. You can increase a tyres diameter (in most states) by only 15mm before requiring an engineers certificate, and the RTA does not calculate this 15mm by using the section, aspect, etc. figures for the tyre. Basically you are allowed to identify the largest diameter tyre manufactured in the size on your tyre placard and add 15mm to that - any tyre that fits within that diameter figure is then legal, so long as it doesn't exceed other requirements such as width restrictions, etc.

FollowupID: 530188

Reply By: PeteS - Sunday, Oct 21, 2007 at 13:52

Sunday, Oct 21, 2007 at 13:52

Hi diesel82

Can't answer your question directly however i'm sure (if you haven't already) it would also be worth posting this question on Pradopoint. Link is pradopoint tyres/wheels 120 series.

Reckon its worthwhile joining (it's free) and i found it a great source of info.

Cheers
PeteS

AnswerID: 267648

Reply By: PradOz - Sunday, Oct 21, 2007 at 16:14

Sunday, Oct 21, 2007 at 16:14

Not sure if this is of any help or not.

I changed my standard Grand Treks over to Coopers ATs and unfortunately had a tyre fault that caused us to have an accident. The insurance company didnt pursue Coopers for it and approved the claim which involved a new tyre, full respray, all the bumpers guards etc and side steps, windscreen, back window, rear left window and interior detail as well as replacing part of the dash. I think they could of made it hard on me now that I know a bit more about tyres etc. I even got a new tyre from Coopers to replace the faulty one so all up 2 new tyres.

I think it would depend on the assessor at the time and what he/she is like. Good Luck

AnswerID: 267663

Follow Up By: Shaker - Sunday, Oct 21, 2007 at 16:46

Sunday, Oct 21, 2007 at 16:46

Another Cooper failure!

FollowupID: 530050

Follow Up By: 96 GXL 80 series - Sunday, Oct 21, 2007 at 22:27

Sunday, Oct 21, 2007 at 22:27

Are these made in the coopers Brewery after hrs?

FollowupID: 530118

Reply By: 96 GXL 80 series - Sunday, Oct 21, 2007 at 22:24

Sunday, Oct 21, 2007 at 22:24

Going bigger also:
Puts extra strain on drive train components, such as axels / gearing / uni joints etc:

Making radical changes will cause problems in those areas.

Just because you change tyre sizes it can mean a difference in fuel economy, as you can use more just because the engine is labouring more and that also means more gear changes.

Another problem this ca cause is over heating because the engine and if a belt driven fan they are labouring.

AnswerID: 267735

Reply By: Member - Bucky (VIC) - Monday, Oct 22, 2007 at 06:23

Monday, Oct 22, 2007 at 06:23

Tyre size " rolling diameter " specs are usually posted on their web pages ( someshere )

Do not go too big, or too much different in the rolling specs, and have your speedo checked, with a GPS, or it could get rather expensive, as some specs will put your speedo oout by as much as 10-12 km/hr.. And that will give the coppers reason to pull you over
Cheers
Bucky

AnswerID: 267749

Reply By: Member - Norm C (QLD) - Monday, Oct 22, 2007 at 08:03

Monday, Oct 22, 2007 at 08:03

Diesel, My tyres are just over 4% larger than standard. Speed is now accurate (used to read slow befor the change). I've had vehicle in for a number of minor warranty issues, including clutch. Never been an issue raised over tyres.

Of course, this does not mean you will have the same experience, but that is mine.

With the small change you propose, I doubt you would have a problem. I believe it is those who go for radical change (35 inch or more) who draw the crabs and have problems.

AnswerID: 267759