225/60/15 tyres?

[gogoboygareth]

Hi all...

I've got a stock standard VX Series II Exec - with the standard rims sporting Bridgestone RE92's (205/65/15).

I've driven the same (original) set for 60,000km's now - and I'm estimating another 5 - 10,000km's as they're no where near the wear indicator yet!. They handle like crap in wet weather though - the tail can't help but slide out around round-abouts (usually because I drive too fast).

My uncle just dumped 4 mags off on my front door (free!) off his old commodore - he traded the car in for a VX Series II Exec, but with 17" alloys (he swapped the original tyres back to his old car).

The mags are fitted with "Federal" 225/60/15's. So although I'll be swapping my 15" rims for 15" mags - the tyres are being reduced from 65 to 60 (even though the tyres are now wider). Is this a problem? I'm guessing there'll be a slight reduction in rolling diameter... is this legal/safe/okay to do?

- Gareth

[mixin]

It's not illegal, but please don't fit 225s to the standard 6" rim - it will handle worse.

Why?

A 6" rim is too narrow for 225s, and the sidewalls flex & "walk" around - making it handle worse & lessening grip around corners.

The ideal wheel width for a 225 is 7"

If you want wider tyres, fit wider wheels to suit them. There are a number of GMH 15 x 7 wheels available in commodore pattern, or you could go aftermarket.

On the 6" rim, a 215 is the maximum width you can run before the handling becomes worse.
If you have the time & patience to try it, you'll find a quality set of 205s will handle better than 225s on the same rim.

You will probably find that the 'federal' tyres will handle like crap, even compared to RE92s, which are really only a family hack/repmobile tyre.

Get yourself some good tyres to suit your spirited driving, and you'll be surprised at how well 205s can actually handle.

[gogoboygareth]

The "mags" attached to the Federal tyres are GMH 15x7 alloys. I've no intention of sticking the tyres onto my own rims.... I'll keep my RE92's (and rims) as spares in the shed.

The federal tyres have significantly more tread left on them than my RE92's, hence my wanting to change (plus I'd rather have the alloys on my car rather than hubcaps!).

- Gareth

[PIMPIN]

I guess the only thing is it may not give you the right kms travelled, coz of the sidewall...dunno about the legalities of it though...you may have to get your odometer recalibrated..?

[gogoboygareth]

Hmmmm good point.

Anyone out there running 60's instead of the standard 65's in the VT/VX/VY cars?

- Gareth

[TheLucksta]

I'm running G-Grid 225/60R 15's on mine.
I dont think i've ever seen 15" 225's that are larger than 60 anywhere?!
I've got a feeling that V6 Vengeance has 225/65 15's on it though.

[mixin]

Go for it: 225/60/15 are so close in rolling diameter it's not funny : 651mm vs 647.5mm

Allowing for 8mm of tread depth in a tyre, that overall diameter can change by as much as 16mm as the tyre wears out!

So in real terms, the difference in your speedo is 0.6% slower than what you are going (ie if your speedo is dead accurate you would be doing 100.6km/h when it shows 100).

A 205/65/15 tyre on it's own from new to worn out will show a 2.5% variation in rolling diameter (& therefore speedo error).


And I didn't pick up that you had 15x7 mags to put them on - 7" are perfect for 225 so go whack 'em on!

[DavidPartay]

Don't forget that the 60 is the percentage of the width of the tyre:

225 * .6 = 135mm sidewall
205 * .65 = 133.25mm sidewall

You would see a bigger difference if the 225 had a sidewall ratio of 65%, which would be:

225 * .65 = 146.25mm

So yeah - go for it!! Absolutely no worries there.

Someone posted a link to a Yokohama rolling diameter calculator, I'll try and find it. It's a very useful tool - you enter in the relevant details, it will tell you speed differences, rolling radius/diameter (I think both?) and you can compare the two tyres to find out exactly how much difference there is

[gogoboygareth]

So how's it look?





- Gareth

[dumpd6]

id say they wer legal because cop cars have 225/60/15 bridgestone turanza so i think your safe therre. i dont think the cops would be too worried about the profile of your tread unless you had some thing like 40 series on 15" rims on a commodore ore some thinks stupid like that..

[DavidPartay]

Looks pretty schmick to me!

[cvwagon]

Not bad, much better than stockers anyway. Maybe time for FE2 springs to get it a bit lower down. Recommend a camber kit for the rear though, if going that way and you will need 2 kits for lowered springs.

[gogoboygareth]

Hehe thanks everyone.

I actually plan to pick up a set of FE2 springs (probably off Ebay) sometime in the near future... I was under the impression the VX Series II didn't near the rear camber kit though?

I find the inner tread of the fronts wear out for me.... either I need a wheel alignment, or I just push it too hard (in the old skyline, it was the outer tread of the fronts that always wore out first though).

- Gareth

[cvwagon]

Sorry Chief, didn't realise it was a series 2. Have fun with your car!!

[gogoboygareth]

Cool! I guess that means the VX II has all that sorted out.

BUT... I forgot about insurance. Am I up sh*t creek without a paddle? I'm currently with NRMA for full compo - rating one, max no claim bonus (I'm 25, and it costs me about $550 to insure it). I hope they don't say "nup, can't cover you anymore"...

I don't plan to insure the wheels or anything (since they were free), but I still need the car itself to be insured.