458 Tire Options Size

Awesome, thanks for the suggestion!

 

Update: Randomly found someone locally selling a set of 20x9 ET44.7 and 20x11 ET48.4 forged aftermarket wheels that were the same model as my current 21/22s. Think these appear to be exactly Speciale spec sizes and offset. I'm hoping I can fit the 255/35/20 upfront without rubbing, given the less aggressive offset (by 5.7mm) vs. my current front wheel

 

Thanks for sharing the info with me really appreciate it I guess the tyre shop didn’t know too much technically and wanted to upsell me the tyres. I m now 1.5 months in and hardly drive it. Put no more than 300 kms on it. Should I change back to the 295 factory spec? And sell off the 305 at a loss?

 

I would personally do the other thing.

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I think you should. It's far from an optimum situation.

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Thanks for the input once again.
Would the situation be potentially dangerous only in wet situations or could something go wrong in dry conditions as well ?

or would driving in dry CT mode be safer than sport or race in order for it not to intervene the way it does ?

TIA

 

Once you depart from the factory recommended sizes, it’s hard to predict. The SSC (side slip control) has very complex parameters. Unless you have a “very sensitive butt” like Niki Lauda did, you may not find out until too late. I am tempted to try the slightly upsized fronts (the Lusso spec), but even then, not sure.


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Like N4S says, once you depart so much from the factory front to rear bias, it's a total unknown. You can easily upsize as long as you stay within some safe parameters regarding front to rear wheel speed.

The fact that your car is trying to apply brake force to your wheels, is a very clear indication that this is a bad situation.

You might get away with it in CT-Off, but what happens when you find yourself in a situation where you need Sport or Wet? You might find yourself in a situation where you have to drive on getting caught in the rain. Imagine driving along and one or both rear brakes suddenly being applied.

Doing the Lusso size is well within what the system can accommodate for. It is not a bigger difference than could be found because of wear. But your situation is FAR beyond what the system was ever designed to work with, and when you see what goes on in Sport that's a clear indicator of this. So in short, yes it is potentially dangerous.

 

Thanks so much for your inputs gents
Appreciate it a lot, I ll find time to get the tyres swapped out.

If in any case should I keep the 305 s for the odd track day ? Or just get rid of it?

 

I'd sell it? Seems like something of a hassle to mount/balance a different set of tires to wheels for a track day, and then unmount them afterwards

 

Sell them. 305/30-20 is OEM size for a number of Porsches.


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Just sell them.
Even in CT off on track they might be a problem. As was said, lots of cars running that size.

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I will be due for new tires this summer season, started to do some research. In 458 stock sizes, the Michelins are a no-brainer.

I did however look into a nominal upsize to 245/305 maintaining the same 35 aspect ratio. That opens up the option of the Conti Extreme Contact tire - these are ostensibly 'copies' of a Michelin Super Sport, and very good indeed. I have them on my 993 and they are great street tires.

In Fcar fitment, they are about $200 less a set than the Michelin. Assuming those prices hold in summer, I'll probably go that way.

Cheers

Matt

 

Question for Co-Pilota,
You give great information and advise.. So, is the below tire size’s ok to use? Will there be any issues with braking and speed? Safety?
I too, like others who own a 458 would like the wider rear tires.

Would like to use:
245/35/20 MPS4S
305/35/20 MPS4S

Currently, on the 458 Spider:
235/35/20 MPS4S
295/35/20 MPS4S

I appreciate your input.
Ray,

 

My '12 Italia is not lowered and I drive already for years with MPS 305's on the back: not ever a problem, also not on the track ! Image Unavailable, Please Login

 

Zero issues Ray. Will work well and look good doing it.

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He was asking about 305/35R20.

What are you running on the front?

If stock fronts or 245/35 and you don't have any issues with ABS or TC when in Sport or Wet. Then you are the only one I have ever heard of.
It is definitely not normal that the Speciale size combo works without issue on a 458. If your fronts are 245/30R20, then I can understand, but if 245/35R20 and zero issues in any mode, that's very unusual for a 458 with no ECU/ESC programming mods.

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I have stock 235/35 in front …

This setup works super with me …

305/35R20 seems wrong to me ...

 

305(35R20 is much closer to OE than 305/30R20. 305/35R20 is 28.4" in diameter, so 0.3" more than stock as 295/35R20 is 28.1". The 305/30R20 is 27.2" so almost a full inch smaller in diameter, hence why people usually also have all sorts of issues with the ABS, especially when using 245 fronts which offset the difference in the wrong direction even more. It also lowers the rear 0.45" compared to the front which has a significant effect on the overall balance of the car, and also reduces the diffusers effect. Lastly it opens up the rear arch gap another 12 mm which makes the already huge wheel arch gap on the 458 seem even more massive.

So from several standpoints, the 305/35R20 is definitely a more "natural" choice. It is so close with its 0.15" radius that you would probably need a 458 with OE tyres sitting next to it to tell the difference. What you gain by going to 245/35R20 and 305/35R20 is primarily width, and very little actual tyre wall height. We're talking about 3.5mm of tyre wall height difference compared to stock. With the 305/30R20 you lose 11.5 mm tyre wall which is added to the arch gap.

 

In that case you can use the full Lusso set.

MPS4S in:

245/35R20 K1
295/35R20 K1

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Thanks for all the info I am looking at the ps4s 305/35 and 245/35 set up as suggested.

The question is the 245 is available as K1 ferrari but the 305 is not.

What should I go for the K1 and what other or all 4 in which set up e.g porshe, mercedes generic as I would like to keep this size tyre in ps4s (has a ps4s and pss at the moment hence the change)

Hope this makes sense and appreciate any advice on this.

 

I think that is correct.

Is 245 instead 235 not giving issues ?

 

No issues.

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If using the 305/35R20 in the rear, I'd use a non-OE 245 front. The non-OE tyres are usually a bit more neutral, and that is something the 458 can take advantage of.

It is important to stress that the K marking does in no way mean better quality or "For all Ferrari modeks". They are model soecific, and there are no such thing as a Ferrari compound or the like. If you decide to use a K, then go K1. The K2 is the Porto tyre and have a very narrow tread, so completely wrong for what you are doing.

But in this case, I'd go non-OE on both axles.

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