Tyres question

[R3N]

Thinking of getting a set of 18x7.5" or 18x8" for the Astra; standard is 195/60 R15 and 88Y rating (I think).

Which is the more common tyre size:

215/35 R18 or 225/35 R18?

I believe these 2 will fit either the 7.5" or 8" width, or am I wrong?

Anyone have rough ideas on prices? Will call up some local places here tomorrow.

[DirtyHarry]

mate the most important issue is getting a tyre that is rated at more than 88H,
which there isnt many, especially in 18's.

Mind you if you put a tyre that is less than 88H load rating than it would be illegal and you can get defected on it. Let alone if you have a accident and the insurance company decides not to pay out because you had incorrect load tyre on the car.

[R3N]

Well maybe I should rephrase that, which is the more common of the 2 with the correct load/speed rating?

[Poogene2001]

35 is a rediculously low profile tyre for a front drive astra.
You arent going to be gaining much traction, but will definitely reduce the life of your tyres to a noticable degree and add a significant expense to your annual car budget.
I would recommend something around the 40-45 profile.
Just judging from the bridgestone range, you get most options for compound and tread patters at the 40 profile level.
It seems very few offers a 215 width though, which means you would probably opt for the 225 which fits 7" wide wheels (i think).
If you are only interested in grip then Federal might be a good option for you to consider. They won the Wheels Tyre of the year handling contest earlier this year. http://www.federaltyres.com.au/car/ss595.htm
Good luck with the purchase!

[blueraven]

you will rub with 18's on a 40 profile.

trust me :( .... it willl only happen on the bigger bumps tho. mine only rubs now on the bigger bumps, and mine is lowered (and has the worng offset :( )

[R3N]

not to mention throwing the speedo out, which a 40 profile will do

[EL BURITO]

did they do optional 18's on the TS in Uk or Europe if so it will be an option on the ecu

[blueraven]

they fit 215 /35/r18 on that option :)

the new ah astra has 40 profiles on 18's on the sri, and they are clearly bigger than a std TS tyre.

the tyres i have are nearly 30mm bigger in circumference that the stock wheels and its very noticeable.

[EL BURITO]

was not sure as 17's were an option on the Corsa ECU

[Jai]

225/35r18 would be your best option, plus load index is easier to get in that size. the AH astra came with a higher load index from standard and they used a bigger OD tyre. standard AH is a 92 load.

check the tyre plaque on YOUR specific astra as it does change from models/years/cars. etc....

I have been in the tyre industry for 6 years and currently rep for a wholesale company in perth.

i would recommend the Federal SS595 as a great all round tyre and for pure bang for your buck... you WONT beat it. :)

[R3N]

225/35r18 would be your best option, plus load index is easier to get in that size. the AH astra came with a higher load index from standard and they used a bigger OD tyre. standard AH is a 92 load.

check the tyre plaque on YOUR specific astra as it does change from models/years/cars. etc....

I have been in the tyre industry for 6 years and currently rep for a wholesale company in perth.

i would recommend the Federal SS595 as a great all round tyre and for pure bang for your buck... you WONT beat it. :)

That's what I want to hear! The 225/35/R18 is spot on in terms of the rolling radius, the 215/35/R18 throws it out by 1.3% or something like that. Any idea on prices?

[Jai]

just checked the load index and unfort the federal is only an 83 load....

ways to get around this... go to holden... buya tyre plaque for a TS SRi Turbo. with standard 17's.... this model only needs an 83 load index. swap your tyre plaque sticker for this one... problem solved.... ;)

[Lt Ketch]

go here

http://www.chris-longhurst.com/carbibles/tyre_bible.html

and just over half way down is a calculator to see what tyre/rim size is closest to what you already have!

[windy]

I reckon you should go with 17's mate :)

Just IMO though

[entice]

IF it's an AH, then GM does provide a placard to add to the OEM placard to allow other lower rated (load) 18's. They have done this for ages. The sticker only costs like $8, and also u will need to speed limit your spare tyre (80km/h sticker, 2 odd bucks). you do NOT replace the current tyre placard, but rather add to it on the door jamb, not on the fuel flap. ask your local GM dealer that has half a clue and does a lot of GM by design accessories.

[DirtyHarry]

changing tyre placards isnt entirely legal you know.

didnt the 17's on the turbo have a load rating of 87v or more? not 83

[R3N]

IF it's an AH, then GM does provide a placard to add to the OEM placard to allow other lower rated (load) 18's. They have done this for ages. The sticker only costs like $8, and also u will need to speed limit your spare tyre (80km/h sticker, 2 odd bucks). you do NOT replace the current tyre placard, but rather add to it on the door jamb, not on the fuel flap. ask your local GM dealer that has half a clue and does a lot of GM by design accessories.


Its for the TS

[Jai]

who said it was legal?? haha.. not that i'd promote ilegal activities... but then if you want to be technical any car mods (wa more so....) are not 'legal' so really whats the difference

[entice]

the difference is in the ease of getting caught.

If I had to insure you blokes and you wiped out a 1/4 of a Mill ferrari doing something daft, then yes, I'd be going over the technical aspects of your car and picking on things that were distant to what we had agreed upon in your policy docs (duty of disclosure).

[Jai]

the difference is in the ease of getting caught.

If I had to insure you blokes and you wiped out a 1/4 of a Mill ferrari doing something daft, then yes, I'd be going over the technical aspects of your car and picking on things that were distant to what we had agreed upon in your policy docs (duty of disclosure).

i am pretty sure that load index only comes to affect when a tyre gives out while driving.

[Nem]

I think this (http://www.1010tires.com/TireSizeCalculator.asp) tyre calculator offers the best options for your car. It will even list who makes the tyres in the size you want.
I found with 18's that my performance off the mark wasnt as nimble but I got better top end running as I was able to sit on 170km much more easily for extended periods of time. (It's legal up here :D) But they look dead sexy and fill out the rims so much nicer.
Basically, the most affordable tyre is the 225/35/18 when you consider that you need a 215/35/18 that meets the load requirements. There's a thread (http://www.opelaus.com/forum/showthread.php?t=7977) in the turbo section about this issue and its been discussed many times before.

i am pretty sure that load index only comes to affect when a tyre gives out while driving.
Pfft yeah and I wanna be covered by insurance when that happens! If you consider that they could tell you you couldnt brake effectively enough or that your tyre blowing was due to load rating I'd wanna have it legal. Not meeting load requirements makes the vehicle unroadworthy and therefore uninsured. I bet the RTA (http://www.opelaus.com/forum/showpost.php?p=123832&postcount=65)would have something to say about that comment. :p

[entice]

spot on.
sub-sufficient load index = unroadworthy.

Unroadworthy = void insurance.

[Jai]

Pfft yeah and I wanna be covered by insurance when that happens! If you consider that they could tell you you couldnt brake effectively enough or that your tyre blowing was due to load rating I'd wanna have it legal. Not meeting load requirements makes the vehicle unroadworthy and therefore uninsured. I bet the RTA (http://www.opelaus.com/forum/showpost.php?p=123832&postcount=65)would have something to say about that comment. :p

if you want to get technical with this issue... and this is the words from the techincal director from roads in WA. if the tyre load is correct for the exact weight of the car then it is covered. IE TS Astra 4 door about 1300kg's plus load fuel etc say 1600KG's there for tyre needs to be able to carry at least 1700 kg's (425kg's per corner) load index of 78

soooo.. a tyre with a load index of 83 can carry 487kg per corner

this is the long way of getting around it.

much easier to change the tyre plaque. hahahaha

[entice]

yep.. but you forgot it has a 5 passenger carry capacity, 5 x 75Kg and that's also a bit of load...

[Nem]

if you want to get technical with this issue... and this is the words from the techincal director from roads in WA. if the tyre load is correct for the exact weight of the car then it is covered. IE TS Astra 4 door about 1300kg's plus load fuel etc say 1600KG's there for tyre needs to be able to carry at least 1700 kg's (425kg's per corner) load index of 78
soooo.. a tyre with a load index of 83 can carry 487kg per corner
this is the long way of getting around it.
much easier to change the tyre plaque. hahahaha
The car was approved for legal road use within Australia with whats printed on the sticker - regardless of how stupid the load requirements may or may not appear to be. I think I'd rather just stick to the requirement because then you dont have to argue that "my mate the technical director said" with your insurance company.

[Jai]

and back to my original arguement... change the sticker... hahah ;)

or just find an appropriate brand tyre with correct load...

[entice]

Jai, Misinformation can be a very damaging thing... especially to those who will take it as gospel. adding or ammending to the placard with a legal, approved placard is what to do if you choose to detract from the OEM load rating. All you need to do is call spare parts or technical assistance and you may well find that the motor company acknowledges that the oem load rating (perhaps chosen cos they got a better deal on volume for that tyre) is a tough one to stick to, especially if they also offer different alloys as accessories (ie, HBD). The company (in this case Holden) may then undergo testing and ADR approval for a different load rated tyre. As stated previously, I know for a fact that they have done this for teh AH series, as even for the standard 15" model you can option/accessorise with the 18" wheel. Holden engineers used the Bridgestone G3 tyre as the test bed, and have adr appproval for that load index for that size...

They even have a page available telling you where to place the additional (not replace) tyre placard.

When there is no room for arguement, you will have no hassles with insurance or authorities. For teh sake of $8, i'd suggest all AH owners with rims over 16" standards go out and buy one, and also buy the 80Km/h ($2) speed limiting sticker (as the spare will be a dirrerent diam rim).

[nicecar]

WA's car modifications regs are very strict.

The Astra Turbo convertible is the same as the standard Astra convertible (apart from the rims and engine).
My standard Astra convertible has the 17x7.5 Astra turbo rims on it now but it doesn't comply to the regs as I've upgraded, the rim width can only be 7.0 max (and then the weight raiting would not comply!)

Suppose it is a case how obvious your upgrade is. When I had an accident (my car was hit while parked), the first thing the insurance company repair place done was took photos of the engine, engine number, back of the car, side of the car and front of the car. This got sent to the insurance company (and if it was my fault, repairs probably would not have been carried out till they approved it) - NOt sure what they would do, compair to a library photo of the car or check any modifications are allowed by the policy and the state regulations?

[Jai]

its funny how such a simple question can promote sooo much response, i am well aware of misinformation being damaging, and was never my intention. Just as someone who has worked in the wheel/tyre/susp industry for 7 yrs i thought i would give a few different options as to what a tyre store might do in this situation.

as for max rim width you can go above standard but only by 2 inches and you are only allowed to change the vehicle track width by no more than 25mm total. ( i think from memory ) you are also legally allowed to change the rolling diameter by 14 mm ( again think... )

most panel shops are generally hand in pocket with insurance assesors and i have personally fix cars when they have bald tyres... so i dont think they might nec. nail you unless your wheels are hanging out your guards for example.

[EL BURITO]

from wat i hsve been told Rolling diamater is not allowed to be more than 10% more than factory mines at by 1% or somethin