Dynamics difference between 16inch 205s and 17inch 215s tyres

[nikitopo]

Originally Posted by BentAnat

On the edge, the wider tyre with less side wall (i.e. the 17") will almost definitely offer better grip.

Originally Posted by sav

17" is comfortable enough for me, I didn't buy the car expecting Merc levels of comfort.

Originally Posted by BentAnat

Dynamically, a 17" 215 section will provide a bigger contact patch and smaller sidewall (i.e. less deformation) when compared to a 205R16, and as such WILL be superior on a track.

Gazoo racing GT86/BRZ cars are equiped with 16x6.5 wheels and 205/55 performance tires. This is the best combination. By using wider and low profile tires you'll get some more grip, but you'll lose a lot of acceleration. This means worst track times! The specific engine is not very powerful for bigger wheels and tires which add a lot of unsprung weight. Sometimes people confuse this with other cars that have more power.

So, if you have already 16'' wheels just upgrade the tires. If you don't have and care about it then go down to 16''. Standard 16'' wheels are pretty good as OEM equipment. They are manufactured by ENKEI and weight 7.2 kg each. You'll find lighter wheels only if you go to very expensive racing specific equipment.

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[nikitopo]

Here is a nice video of a Gazoo racing car. It has 205/55/R16 Dunlop Direzza ZII tires:

[ame="https://www.youtube.com/watch?v=_VZUWBl6P-A"]SUBARU BRZ "RA Racing"(DBA-ZC6) No.61 - YouTube[/ame]

[CWP68]

Originally Posted by nikitopo

Gazoo racing GT86/BRZ cars are equiped with 16x6.5 wheels and 205/55 performance tires. This is the best combination. By using wider and low profile tires you'll get some more grip, but you'll lose a lot of acceleration. This means worst track times! The specific engine is not very powerful for bigger wheels and tires which add a lot of unsprung weight. Sometimes people confuse this with other cars that have more power.

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Couldn't agree more. Our cars are 2.0l, unsprung weight is a big factor.

I saw that RGM ran their car at Kyalami on Sunday on OEM 17" with 215 Bridgestone semi's and apparently did pretty well.

[BentAnat]

That's actually very true (the weight diff and acceleration factors). Thanks for that.
I am still on stock everything for now.

[Fish Eagle]

Originally Posted by CWP68

I saw that RGM ran their car at Kyalami on Sunday on OEM 17" with 215 Bridgestone semi's and apparently did pretty well.

Yep, sub 2 mins which is great.

Quoting RGMotorsport Facebook page...

"We are stoked that we achieved a time of 1:59.77 with our Supercharged Toyota 86, with full interior (Air-con, standard seats, radio, spare wheel etc), our Öhlins Racing AB Street to Track suspension and 215/45/17 Bridgestone semi slicks on the standard wheels. Our Class T Champion Graeme Nathan did a time of 1:56 in his fully gutted race prepared VW Golf 6 GTI on the same day to compare what this little monster is capable of! Well done Team RGMotorsport!"

[Vic_RSA]

I still have 3mm give or take on my stock 16" Yoko dB E70's and they have proven to be quite hardy in daily abuse. Got a brand new set of Yoko AVS dB v550's waiting at home for when E70's have had enough.

[FT_86_SM_GP]

From my experience lately:

- I have been driving with the Standard 16inch Yoko's from March 2014 to Sept 2014 (7 months)

- I recently changed my wheels to the High Spec 17 inch Michelin Primacy from Sept 2014 till current(Octover 2014) (1 month)

Traveling the same routes, at same speeds under similar conditions, similar tyre conditions(both have around 10,000km wear and tear) the following was noted:

1) Yoko's gripped better - this difference is noticable.

2) The Michelin's make noise - It screeches louder when taking bends/drifting and at instances screeches when breaking on uneven surface.(Yoko's did not screetch on the same surface).

3) Ride is smoother with the Yoko's - This is obvious. But had to mention it for the sake of it.

4) High spec 17inch wheels - Look better with standard suspension. I guess you can get the 16inch Standard rim to look nice, but you will need to lower your 86, and then the "Ricer" inside of you takes over.

5) In terms of speed /acceleration - I cannot notice much as I am at a terrible altitude (JHB), Audi a1's kills me on a straight line ...so cannot comment on that.

My two cents of thoughts - not sure if I have a bad batch(production) of tyres on the high spec rims(Michelins), but I will be trying to get 225/45/17 tyres to replace them when they are done, and in the mean time.. rotate usage with my 16inch Yoko's

[Fish Eagle]

Originally Posted by FT_86_SM_GP

From my experience lately:

- I have been driving with the Standard 16inch Yoko's from March 2014 to Sept 2014 (7 months)

- I recently changed my wheels to the High Spec 17 inch Michelin Primacy from Sept 2014 till current(Octover 2014) (1 month)

Traveling the same routes, at same speeds under similar conditions, similar tyre conditions(both have around 10,000km wear and tear) the following was noted:

1) Yoko's gripped better - this difference is noticable.

2) The Michelin's make noise - It screeches louder when taking bends/drifting and at instances screeches when breaking on uneven surface.(Yoko's did not screetch on the same surface).

3) Ride is smoother with the Yoko's - This is obvious. But had to mention it for the sake of it.

4) High spec 17inch wheels - Look better with standard suspension. I guess you can get the 16inch Standard rim to look nice, but you will need to lower your 86, and then the "Ricer" inside of you takes over.

5) In terms of speed /acceleration - I cannot notice much as I am at a terrible altitude (JHB), Audi a1's kills me on a straight line ...so cannot comment on that.

My two cents of thoughts - not sure if I have a bad batch(production) of tyres on the high spec rims(Michelins), but I will be trying to get 225/45/17 tyres to replace them when they are done, and in the mean time.. rotate usage with my 16inch Yoko's

If you'd like another set of 16 Yokos which are almost brand new, I've got a set which you can have cheap.
They're in Nelspruit tho... (so you'll have to come down for the Imperial run Which you definately won't regret)