Lower profile tyres = harsher ride?

[Clay1391]

35 rears ?

Should be 35 fronts and 30 rears given it appears you have the staggered rears (wider) with the 275 width.

The lower profile on the rear maintains the rolling diameter as close as possible given the extra width.

If you had the same width rims front & rear, you would have the same profile front & rear, i.e. mine are 245/35/20 all round coz I have 20x8" rims on all four corners.

If you are looking for 40 profile, you will need 19" rims with a 245/40/90 tyre.

18" rim will need a 245/45/18 tyre but as I mentioned above you will need to check fitment as they may not clear the Brembos.

Thanks, so the highest I would be able to go on 20inch rims would be 245/35/20
275/40/20?

 

[panhead]

Thanks, so the highest I would be able to go on 20inch rims would be 245/35/20
275/40/20?

I think that would look awful but that's just my opinion.





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[VS 5.0]

275/40/20?

Wrong size.

Use that tyre comparison link I posted and you'll see how much taller that is and the impact on your speedo (under reporting the actual speed.) Not sure I'd want that scenario, esp in the low tolerance state of Vic.

May also be clearance issues but you would have to measure that.

 

[Clay1391]

Saying my speedo is wrong under current setup of 245/30/20 - 275/35/20

 

[VS 5.0]

Saying my speedo is wrong under current setup of 245/30/20 - 275/35/20

Your still showing them around the wrong way.

 

[Clay1391]

Your still showing them around the wrong way.

AHH! I see. hahaha! Thanks, im a night shift worker and shockingly tired. Would you recommend getting the same brand of tyre on all 4? Is there certain brands that a suited for comfort rather than sport? I look at the tread on the tyres and they make no sense to me, how am I suppose to know whats good.

 

[MrBags]

If you have never heard of the brand before and they are cheap, very good chance they are rubbish.
My advice on tyres: Buy the best, most appropriate tyres you can afford. They are pretty important.

 

[Clay1391]

If you have never heard of the brand before and they are cheap, very good chance they are rubbish.
My advice on tyres: Buy the best, most appropriate tyres you can afford. They are pretty important.

Exactly my train of thought at the moment, thought id like Pirellis the brand and maybe go with the ones I can afford in that range.

 

[figjam]

I look at the tread on the tyres and they make no sense to me, how am I suppose to know whats good.

This is hard to explain and requires a bit of your imagination. Look at the tread, and its pattern, and imagine how it contacts the road.
If the sipes (cut-outs) are in a pattern that directs water to the outside of the tyre when travelling forward, that is a good starting point.

 

[Skylarking]

Does lower profile tyres mean a harsher ride?

Currently have on front 245/30/20
Rear 275/30/20

Im going for comfort now, so would I be better going for a higher profile tyres?
Wanted to go 40 profile.

Would flat runs be more comfortable?

The compressive behaviour of the bushes within the suspension, spring rate, shock compression and rebound settings all play a part in how a car feels and behaves. Such is defined at vehicle manufacture and can be different between the various model variants. In Holden speak i think it’s FE2, FE2.1? and FE3 which were available for the sports variants and likely other codes for non performance models. Luckily onstalling different rate bushes, springs and shocks seems not restrained by mod rules

Wheel sizes and tyre size are also defined within the compliance documents for each model variants with some variants having optional (bigger) wheel sizes available for fitment. Rules for installing different wheels exist while what is standard or optional for a model variant is clearly defined within the Road Vehicle Descriptor. All RVD for VF commodores are available here

At the end of the day it’s the combination of bushes/springs/shocks and wheel size that provides the feel you get behind the twirler. Calais bushes, springs, shocks, wheels & tyres would get you a Calais feel

Being that SSV’s were sold with 19’s or optional staggered 20’s, I’d say the feel would be much the same with either wheel choice as suspension tune is already on the harsher performance side

SS’s were sold with 18’s and were supposedly a little softer and a little quicker off the mark due to more tyre squat when the drivers foot dropped (but such may be more a jurno’s writing style than an absolute truth).

In any case, a higher sidewall will generally provide a slightly floater ride at the expense of turn in but the practical difference between 19’s and 20’s is probably marginal on your SSV. And Holden won’t recommend anything other than factory 19’s but if you want to go 18’s, your problem will be sourcing a strong wheel that will fit over the brembos. And finding staggered tyres for 18” rims is an unknown as I never got that far with my investigations.

The other problem you may have is that if staggered wheels were standard for your variant and you want to reduce rear wheel width to match the front, you can’t as it’s illegal.

In my experience, run flats would be much harsher (if BMW is anything to go by)