I've just bought some poverty Pork…
Discussion
ferrisbueller said:
pete.g said:
ferrisbueller said:
ATM said:
I have flirted with the idea of fitting the 2.7 986 brakes to my 996 so I could use the 16 wheels but its doesn't sound simple.
You read like an accident waiting to happen.If you have a reason to doubt the wisdom of someone's course of action, then you can give your view, rather than post negative assertions framed in provocative language.
. . . consider me a spatterer.
I am therefore willing to consider you a spatterer of some volume.
Before you post, think WWFD - what would Ferris do?
Edited by pete.g on Thursday 12th December 20:51
pete.g said:
ferrisbueller said:
pete.g said:
ferrisbueller said:
ATM said:
I have flirted with the idea of fitting the 2.7 986 brakes to my 996 so I could use the 16 wheels but its doesn't sound simple.
You read like an accident waiting to happen.If you have a reason to doubt the wisdom of someone's course of action, then you can give your view, rather than post negative assertions framed in provocative language.
. . . consider me a spatterer.
I am therefore willing to consider you a spatterer of some volume.
Before you post, think WWFD - what would Ferris Bueller do?
Escy said:
My 986 will be 450+bhp which is why I need the widest tyres I can fit.
When talking to a well known figure in the US Porsche racing scene, his recommendation on tyre size for the front of a fast road car was as much tyre as I could get on the front. He runs race cars with a square setup but rather than go smaller at the rears, he goes bigger at the fronts to stop the understeer.
No you don't need the widest tyres you can fit.When talking to a well known figure in the US Porsche racing scene, his recommendation on tyre size for the front of a fast road car was as much tyre as I could get on the front. He runs race cars with a square setup but rather than go smaller at the rears, he goes bigger at the fronts to stop the understeer.
You may want the widest tyres you can fit but you don't need then.
If you want your car to transmit as much of the power available into forward acceleration then you need the most grip possible from the driven wheels. You have seen the massive tyres drag cars use. And to a lesser degree those drag type street cars too which run 15 inch rims and balloon Mickey Thompson tyres.
Those tyres are awful at going round bends.
Then you have the advice from the race car guy. He is trying to get his race cars to go as fast as possible round bends and brake as hard as possible. So he wants a large contact patch on the front wheels which do most of the turning and braking. He doesn't want too much on the rear because this will promote understeer and make the car worse at turning and therefore slower on a track with lots of turns.
These 2 approaches are totally different.
Drag racers dont care about bends and dont really want their cars turning at all.
Track racers understand you make up more time in the braking zone and then going round bends quicker.
This is why we have to compromise with a car's setup. We cant have everything so changes in one area will affect another.
I'm guessing now that you want more of everything from your modified car. As much forward acceleration as possible and as much braking force as possible and as much turning speed as possible. You may need to compromise in some areas but as a basic rule of thumb yes wider and wider tyres will give more grip and that might make the car quicker and quicker.
I'm less interested in going as fast as possible. I'm more interested in the way a car feels and what its telling me. I may have the wrong car but I like it and that's the car I have. When I switched from 18 to 17 wheels I really liked the change. I can't say I felt the car moving around because it's still pretty planted but there is a bit more feedback and chatter through the wheel to my hands which I like. I dont need to go to even smaller wheels or tyres I'm just intrigued to try it really. You enjoy modifying cars and I do to an extent but in practice I cant be bothered so I don't have the same level of enthusiasm as you do. Bolting some wheels on I can manage. Really I should probably get my dampers rebuilt but again that feels like hard work right.
Chris Stott said:
Unless you’re driving beyond the tyre grip limit, more grip at the rear does not reduce front end grip, therefore does not increase under steer.
I thought it was commonly accepted that wider rears increase under steer. Not because they reduce front end grip but because they increase rear end grip. This will move the balance of grip towards the rear.But I'm no expert.
If you're beyond the grip limit at the rear you can use this to help rotate the car... making the car turn faster.... in effect reducing understeer... but this isn't increasing the front tyres grip.
Assuming you're within the grip limits of the tyres, the width of the rear tyres have no effect on front end grip.
Assuming you're within the grip limits of the tyres, the width of the rear tyres have no effect on front end grip.
edc said:
If you're within the 'grip limits' of the tyre then to won't get understeer or oversteer no matter what the tyre size.
The tyre choice comes into play more in that transition phase.
I have a slight resentment when I change rear tyres. I quite enjoy the playfulness of the rear but am also mindful of wet stopping distance. The wet is typically the only time I have ever got any movement out of the back of my cars.The tyre choice comes into play more in that transition phase.
I personally subscribe to the smaller wheels / less grip ethos (but still sufficient for day to day driving obviously). I don't want the fastest car on the road as it's impossible to use without going to jail. If I did I wouldn't be starting with a 987 Boxster/Cayman anyway.
Doesn't this video demonstrate (to extremes) what we're talking about?
https://www.youtube.com/watch?v=HPh90yNX-mY
I wouldn't advocate that we all fit space savers to our cars and drift everywhere but the video perfectly demonstrates the concept of how much fun it can be with a more playful setup.
I run a 2.7 987 Boxster on 17's and standard tyre sizes and think it's got a nice balance but maybe still too much grip at the rear.
Cmoose .... I'm about ready for a new set of boots. Have you experimented with changing the standard tyre sizes? Any recommendations?
Doesn't this video demonstrate (to extremes) what we're talking about?
https://www.youtube.com/watch?v=HPh90yNX-mY
I wouldn't advocate that we all fit space savers to our cars and drift everywhere but the video perfectly demonstrates the concept of how much fun it can be with a more playful setup.
I run a 2.7 987 Boxster on 17's and standard tyre sizes and think it's got a nice balance but maybe still too much grip at the rear.
Cmoose .... I'm about ready for a new set of boots. Have you experimented with changing the standard tyre sizes? Any recommendations?
Edited by John Laverick on Tuesday 17th December 09:28
I currently have 225 50 17 winter tyres on my big BMW. Heavy car, all the weight up front [sort of], 5 litre engine with 370 bhp and an open diff. It gets the power down ok. You will get wheel spin if you floor it off the line. Otherwise you'd hardly know the tyres were a bit skinny accelerating in a straight line. So my view is the 2.7 would cope fine with 205 all round in terms of getting the power down.
I ran my 944 track wheels - 225x45 17's on my Boxster S - it was very nicely balanced on circuits. I think a square setup is quite normal on Boxster race cars. Don't see any reason why it wouldn't be fine on the road (mine was). 255 might look more pleasing to the eye.
IIRC the contact patch shape changes with tyre width increase, but the contact patch size stays the same.
IIRC the contact patch shape changes with tyre width increase, but the contact patch size stays the same.
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