How to Handle Handling?

[projectrracing]

From taking that information, is the only advantage of having a wide tyre, having more "off the line" grip because of the larger contact patch? I see it that way, especially with how powerful these cars are, the first few gears will spin the tyres way too much if there isn't enough tyre on the ground to put the power down.
Would keeping the same width tyres for acceleration, but having higher tyre pressures to reduce side wall flex be a good combination?

common misconception is that tyre width increases grip. its not always the case. you may just be changing the shape of the contact patch. and this is when you get increased wheel spin.

the contact patch is an oval shape pointing headlights to taillights. when you get wider tyres, the contact patch is more door to door oval. great for latteral grip, not so great for accelleration or braking. when the rolling diameter increases, you increase the oval shape more head to taillight. it's a balancing act between the 2.

increasing rolling diameter normally nets better larger contact patch results than wider tyres does. without trying to type a whole essay on the subjuct. if you ever get wider tyres, make sure the tyre has the same or larger rolling diameter. if not, you'll loose some/most of the gains from the width increase.

larger rolling diameter also always a tyre to run tyres at a lower temp due to the contact patch spending less time touch the ground per km to say. so that allows you to run softer compounds for longer. and softer compound equal more grip.

[GibbA]

Just looked and they're actually still for sale, but it's ony two. $160 to my door. Should I do it @ledfootrob?

[projectrracing]

In what way are they radical @projectrracing? What kind of values for toe, caster and camber are generic?

http://www.ozmpsclub.com/forum/handl...tml#post212982

Flick through that thread. You'll get the drift pretty quick.

[GibbA]

common misconception is that tyre width increases grip. its not always the case. you may just be changing the shape of the contact patch. and this is when you get increased wheel spin.

the contact patch is an oval shape pointing headlights to taillights. when you get wider tyres, the contact patch is more door to door oval. great for latteral grip, not so great for accelleration or braking. when the rolling diameter increases, you increase the oval shape more head to taillight. it's a balancing act between the 2.

increasing rolling diameter normally nets better larger contact patch results than wider tyres does. without trying to type a whole essay on the subjuct. if you ever get wider tyres, make sure the tyre has the same or larger rolling diameter. if not, you'll loose some/most of the gains from the width increase.

larger rolling diameter also always a tyre to run tyres at a lower temp due to the contact patch spending less time touch the ground per km to say. so that allows you to run softer compounds for longer. and softer compound equal more grip.

I'm not sure on the rolling diameter in comparison to stock with my rims, as I haven't been able to physically compare.

So you're saying that the only advantage of a wider tyre is lateral grip, not acceleration/deceleration grip? It wouldn't mean WORSE acceleration grip though would it?

[ledfootrob]

Just looked and they're actually still for sale, but it's ony two. $160 to my door. Should I do it @ledfootrob?

I payed $300 for 4 wheels painted them and then $1200 for Toyo R888 tyres. Its up to you. $160 to your door is a decent price but then you have to find another 2. There are 2 sets for sale on Ebay in NSW.

[GibbA]

I think the only thing holding me back on these is I may be changing to the CS BBK and not entirely sure if these being 16's will fit over those brakes :/

[GibbA]

I payed $300 for 4 wheels painted them and then $1200 for Toyo R888 tyres. Its up to you. $160 to your door is a decent price but then you have to find another 2. There are 2 sets for sale on Ebay in NSW.

What size tyres did you put on your rx7's?
There aren't any rx7's on my eBay! Maybe i'm not typing in the right thing, "RX7 FD" and the looking under the wheels/tyres category?

[ledfootrob]

What size tyres did you put on your rx7's?
There aren't any rx7's on my eBay! Maybe i'm not typing in the right thing, "RX7 FD" and the looking under the wheels/tyres category?

I've got 225/50/16 tyres


Mazda RX7 Series 6 Wheels 16X 8 in Sydney, NSW | eBay

Mazda RX7 Series 6 Wheels AND Tyres 16 X8 | eBay

[GibbA]

Beauty, the second set are 15 mins from my place.
Thanks

[ledfootrob]

I like the look of the Wilwood brakes that Edge have got now and they are cheaper too.

[GibbA]

I like the look of the Wilwood brakes that Edge have got now and they are cheaper too.

Yes I noticed them too. Is it me, or do both the wilwood and corksport brakes appear smaller than the OEM ones?
I read on MSF that the CS ones have approx 2x the surface area of piston compared to OEM, but haven't read anything about the Wilwood ones? I'm guessing you would need a spacer to run the rx7's with the wilwood brakes...

[ledfootrob]

Try and get the templates from Corksport and see if they have one for Wilwood and i can measure my wheels for you.

[GibbA]

Is it the same brakes for gen1 and gen2 though? (ie if you measure yours, will it be the same measurements for on my car?)

[ledfootrob]

Is it the same brakes for gen1 and gen2 though? (ie if you measure yours, will it be the same measurements for on my car?)

Probably not but with the RX7 wheel specs and the template you should be able to work it out

[RedDjinn]

http://www.ozmpsclub.com/forum/handl...-template.html Search function boys!

[GibbA]

http://www.ozmpsclub.com/forum/handl...-template.html Search function boys!

CS template not on there

---edit---

Actually isn't that new wilwood bbk edge posted up about a redesigned kit? Hence meaning that template may not be correct for it?

[RedDjinn]

If you look at the date of thread was a while ago

[GibbA]

Yeah, so it wasn't entirely relevant. But I guess they could be added now?
I clicked the link on CS's website for the template but for some reason It doens't load.
I did use that wilwood template and there is no way the old brakes are fitting under my wheels, interested to get a template for the new ones though.

[projectrracing]

I'm not sure on the rolling diameter in comparison to stock with my rims, as I haven't been able to physically compare.

So you're saying that the only advantage of a wider tyre is lateral grip, not acceleration/deceleration grip? It wouldn't mean WORSE acceleration grip though would it?

its more relivent to larger changes. mazda have jammed pretty big tyres into a small space already on a 3 MPS, so any larger changes will be minimal. so effects will be minimal. the tyre compounds in this situation becomes the bigger factor as this is the biggest change you can make in this situation.

[GibbA]

So it's been a little while, and I finally got around to checking tyre pressures tonight to start and set different ones and feel the differences.

Funny thing is, these were the pressures in the tyres already!!!

Front L&R: 38psi
Rear L&R: 48psi!!!! :O

So I set the front at 35psi and the rear at 40 and seems ok so far.
Car seems to rotate well in the corners, but i'll have to drive on these settings for a while to get the feel of it, then change and see if it makes things worse or better.

I can say though, even on the stiff setting on the rear sway bar, I really haven't been getting any oversteer to speak of, still just understeer if there's too much speed in the corner.
This goes for too fast of an entry speed, turning the wheels too sharp too fast (Expect understeer here anyway though), as well as accelerating too much during the corner.
It has reduced the understeer somewhat, but definitely not "induced" oversteer like i've heard some people say.