Very surprised by new Bridgestone tread pattern

Hi Guys

My F355 rears were Bridgestone Expedia S.01 'ZR' as recommended by the handbook. It was time to replace them so I looked for the same but was unable to find them so I went for the nearest I could find which is Bridgestone Potenza S001 'R'. I could have gone budget, but I wanted to remain as original as possible. Have a look at this photo and see the huge difference in the tread pattern;

Image Unavailable, Please Login

The old tyre has a total of 35mm rotational groove. The new tyres have a total of 65mm of groove. This may well give it a huge potential water dispersal up to monsoon conditions, but the car is never driven in the rain! This must be at the expense of dry grip. The tyres are 260mm wide so this is a 14.3% reduction of rubber on the road. What do you think?

 

The original tyres are twenty years old

Why do you expect them still to be available ? The 355 and its technology have been superceded and funnily enough the same applies to the tyres

 

Tire engineering is quite a science. You can't really make any assumptions about wet or dry handling by looking at the tread blocks.

 

I'm not sure its as much science as it is marketing. Generally speaking the wide deep grooves are for rain as you surmised. At least that's what all the tire marketing I've read indicates. The rest of the tread pattern is hit or miss if its better or not. If it had lots of shallow sipes that would be for snow or slick surfaces indicating all weather. Looks like those are for summer and rain. The biggest advance in tires is in the compound and the ability to shed heat especially during braking. Any new tire will feel great but you'll need to put lots of miles on to really know. Don't like that they are more narrow though.

 

I read an article by a Michelin engineer that said most treads are designed to look cool. Rain and off road type tires are the exceptions.

 

Wow, and I've been accused of overthinking things

 

The evolution of the tire carcass and tire tread compound formula is probably so much better and stickier than the original tires that even with the different tread pattern, the tires have much more grip in both the wet and dry. If you are exceeding the grip levels of these tires on the street, then you are hauling ass.

 

What's the difference in grip numbers (seen on the sidewall)?

 

Your new tires need to have more cuts for rain because the newer compounds allow fo so much more grip you need to get rid of the water or you will hydroplane at the increased speeds. This is especially true in the corners

 

Sorry, the old tyres have now gone so I can't check.

I didn't expect to find the same tyres as I had before, but I thought I'd find the nearest thing available now.

Reasons have been given for the difference which I appreciate, but I'm not sure if these are opinion or science based fact? I've contacted to Bridgestone to see what they say.

All I know is when during F1 commentary they talk about rain tyres after the rain has stopped and the track is drying they have said many times that the tyres will overheat because the tread blocks move about more. Also, as a consumer shopping around you can choose what kind of performance you want in a tyre, better in the dry, or wet, or quiet or better mpg, longer life etc. So what I'm wondering is; given the case that I do not drive in the rain (or if I were caught out in the rain I would not drive fast) have I chosen a tyre with higher rain performance (and possibly a shorter life given there is less rubber on the road) instead of a tyre with higher dry performance, or are all new tyres of this width now profiled with grooves of this size?

 

Although the tread pattern used on wet weather race tires is designed to pump away as much water as possible, they actually degrade rapidly in dry conditions because of the compound of rubber they are constructed of. It is considerably softer and less durable than dry compound race rubber and quickly overheat, break down and become useless without the needed moisture to keep them cool and in their optimal temperature range.

I would choose a tire based on what kind of performance characteristics I expect or prefer to drive in.

 

Well, if - as mentioned above, the tread pattern is to look cool, then based on the pictures, Bridgestone really missed the point. IMO the new tires design appears to belong on a Corolla.

Since the Bridgestone Expedias aren't available anymore, why not change for Pzeros or MPSS - if they make them on the needed sizes, of course. Those are great tires and with beautiful tread design for a Ferrari.

 

Interesting questions! It's worthy to note that the Modena handbook spec'd the Potenza tire as an OEM choice so I don't think you have done wrong to put them on your car. Especially since the Modena is newer and would potentially place a higher demand on the rubber. This is from the Model Year 2000 handbook. It's also interesting to note that the snow tire reference only appears in this model year chart. Newer years do not show the Pirelli winter tire.

Image Unavailable, Please Login

 

It's also very weird that the background image on the Potenza info page shows this tire. This looks very different to what you are showing.

Image Unavailable, Please Login

 

I have now received an answer from Bridgestone and they said the following;

Hello and thank you for your email.

Tyre tread patterns are subject to change even on the same tyre pattern. One of the likely reasons may be to upgrade/better the EU labelling grade. Please be rest assured that although the new spec tyre may have a lesser tread to groove ratio, this is not compromising on the required performance abilities. The Bridgestone Expedia S01 was and still is solely manufactured and tuned for the DNA requirements of the Ferrari 355.

I trust this answers your question.

Regards,

Salik A Ali

Field Engineering Technician

What I find strange is Salik saying "One of the likely reasons" inferring that even a Field Engineering Technician doesn't know the reason for the new tread pattern and can only speculate. Anyway it is too late now, perhaps I should have chosen a more 'dry focused' tyre, but the Bridgestones are fitted now.

Now that they have been fitted that brings me to a different but sort of related question. Yesterday I picked up the wheels from the paint shop and took them directly to the tyre fitters without giving a thought to the original valves. When I picked up the fitted tyres I saw the valves they put on and now I am wondering if it makes no practical difference and the difference is cosmetic, or if I need to get the tyres off again and get the metal valves re-fitted?

Image Unavailable, Please Login

 

Or wear potential. Structural design and rubber compounds are constantly changing

 

I do like to keep Ferrari OE stems but in reality it is 90% cosmetic.

 

Also looks like the new tire tread design is directional (one-way rotation), and the old one is not ?? ---- that would account for a big difference in tread design right there.

I also highly doubt the "PR spiel" response you received from Bridgestone is genuine or accurate technically ---- no way any main-stream, high-volume, tire manufacturer is paying any attention to the tire design requirements of a 20 year old car..... even if it's a Ferrari.

If they are designing at all to Ferrari performance optimization, it is to the 458 / 488 ---- not any of the previous models.

Plus, Pirelli is Ferrari's commercial tire partner, not Bridgestone, so it's a safe bet they are much more "in the loop" with what Ferrari wants out of a tire on their road cars --- past and present.

Whereas Ferrari represents such a minor portion of Bridgestone's market (OE and after), that I'll bet they don't give two ****s about how their tires perform on any Ferrari !

 

I much (actually, absolutely) prefer metal stems to plastic / rubber ones on all my performance cars. They are infinitely more robust, which is very important on a car that you gauge check and adjust tire pressures on often. They are also less prone to becoming leaky.

If I were the OP, I would definitely put the OE (metal) stems back on ---- or maybe even spend some good $$ and get new metal ones (or if you want to save a bit, you can just have the original ones cleaned up and re-valved & new seals put on).

I also much prefer metal stem caps ---- if a valve fails / leaks, only a properly tightened down metal cap (with a quality rubber seal insert) is capable of maintaining an air seal for the tire.

 

The metal valves are common for truck wheels. Mos tire auto tire shops won"t stock them, and they won"t really know what to do with them. They should have asked if you wanted them changed, if not leaking just leave them be. New ones are available from Ricambi, etc. not that big a big price to stay original.

 

More groove = less rubber to be used. Imagen millions of tires with more grooves ...

Guido

 

I've never given a damn about the cosmetic attributes of tread patterns.

 

Some tire treads do look better on classic cars than the modern treads, its the sidewall design as much as the tread pattern. This tire would look good on our cars, and appears to be available in the relevant sizes, which is not always the case with modern tire options. This firm did do a designer tire some years ago with the tread and sidewall designed by Guigiaro, but I presume it did not sell well, so most people probably don't put much value on the cosmetics of the tire or at the least won't pay more for it. I confess I put Pirelli P7 AS Plus on my Mondial 3.2 in part for the Italian connection, and the tread pattern.

https://www.vredestein.com/car-suv-van/tyre-finder/tyres/product/3/summer/904-ultrac-satin
Image Unavailable, Please Login