tyres chewed up on outter edge (post-trackday)
Discussion
I'm not sure quite sure where to place this, so mods, feel free to move if somewhere better suited.
after a hot trackday on friday at Abingdon (ambient around 23c), the outer edge of the loaded tyre is all chewed up. Tyres are Dunlop RT2's on a 2015 Civic typeR. I ran around 40-42PSI hot in the front as i seemed to be rolling over a bit too far onto the sidewall with lower pressures.
based on this, what do you think i should do to stop the chewed up tyres at these events? personally, i'm in two minds if it's just down to a hot day, with softer sidewalled tyres than the usual track-focused tyres, or if i need to look into additional camber. If so, how much camber would i roughly need?
tegiwa/honda dealer sells an extra 0.5deg camber ball joints. i believe the car runs around 1deg negative from factory, but there is a kit that can give upto 2.1 degrees but far more expensive.
i did get some tuition on the day, but no suggestions were made that could be attributed to the chewing of tyres so i assume things were ok in that department.
after a hot trackday on friday at Abingdon (ambient around 23c), the outer edge of the loaded tyre is all chewed up. Tyres are Dunlop RT2's on a 2015 Civic typeR. I ran around 40-42PSI hot in the front as i seemed to be rolling over a bit too far onto the sidewall with lower pressures.
based on this, what do you think i should do to stop the chewed up tyres at these events? personally, i'm in two minds if it's just down to a hot day, with softer sidewalled tyres than the usual track-focused tyres, or if i need to look into additional camber. If so, how much camber would i roughly need?
tegiwa/honda dealer sells an extra 0.5deg camber ball joints. i believe the car runs around 1deg negative from factory, but there is a kit that can give upto 2.1 degrees but far more expensive.
i did get some tuition on the day, but no suggestions were made that could be attributed to the chewing of tyres so i assume things were ok in that department.
From the sound of it you've overheated the outer edge of the tyre and/or been getting too much slip.
I don't know what the normal tyre pressures are on that car, but the numbers you're quoting seem very high to me. Raising the pressure is not always the right answer and could have made things worse.
The interaction between the road and the tyre is quite complex and it is hard to predict the effects of raising the tyre pressure based on limited information. For example, depending on the tyre/rim dimensions, tyre roll in cornering could increase or reduce the effective camber. Raising the pressure will also increase the stress and deflection within the tread (while reducing it in the rest of the carcass) so there are counteracting effects which could vary with all sorts of factors.
If you want to get serious about it, you would need to monitor the inner, center and outer tyre temperatures to see where the heat is going - this tells you where the most weight is on average so that you can play with camber and tyre pressures to even this out. The optimum will vary hugely depending on the track, driving style, weather conditions and so on so don't think of this as finding the one right answer, but just telling you where you have room for improvement on a given day.
If you're starting with a mass produced road car on standard suspension, you will probably find you have got a lot of body roll so increasing roll stiffness will reduce the amount of camber change around the circuit and which will make it easier to keep the tyres flat - but there will always be a compromise, and you should be able to get a good compromise with the original suspension if you set it up methodically.
PS
Using high performance track tyres will likely make this problem worse, since you'll get higher cornering forces and more suspension/tyre deflection.
I don't know what the normal tyre pressures are on that car, but the numbers you're quoting seem very high to me. Raising the pressure is not always the right answer and could have made things worse.
The interaction between the road and the tyre is quite complex and it is hard to predict the effects of raising the tyre pressure based on limited information. For example, depending on the tyre/rim dimensions, tyre roll in cornering could increase or reduce the effective camber. Raising the pressure will also increase the stress and deflection within the tread (while reducing it in the rest of the carcass) so there are counteracting effects which could vary with all sorts of factors.
If you want to get serious about it, you would need to monitor the inner, center and outer tyre temperatures to see where the heat is going - this tells you where the most weight is on average so that you can play with camber and tyre pressures to even this out. The optimum will vary hugely depending on the track, driving style, weather conditions and so on so don't think of this as finding the one right answer, but just telling you where you have room for improvement on a given day.
If you're starting with a mass produced road car on standard suspension, you will probably find you have got a lot of body roll so increasing roll stiffness will reduce the amount of camber change around the circuit and which will make it easier to keep the tyres flat - but there will always be a compromise, and you should be able to get a good compromise with the original suspension if you set it up methodically.
PS
Using high performance track tyres will likely make this problem worse, since you'll get higher cornering forces and more suspension/tyre deflection.
> Using high performance track tyres will likely make this problem worse, since you'll get higher cornering forces and more suspension/tyre deflection.
that did go through my mind as a potential concern.more grip then it could just make things worse.
the car is stock in terms of suspension, but i ran in +R mode all day so very firm and very little roll in the car. I've no idea how the geometry changes when the car is pushed, being a fairly rare car there isn't that much info on these types of details.
like i say in the original post, i believe the car is factory setup with around -1deg camber from factory. seems low to me, but thats what stock is. stock pressures are 33f/30r, but found these RT2's are noticably softer than the factory CSC6's so i'm running 35f/30r on the road.
the car is also a daily driver with trackdays thrown in a few times a year (or at least that's the plan) so while i don't mind a bit more camber, or running more track focused tyres, it will be a bit of a compromise.
i'll look into the real cost of camber changes and how it affects these exotic torque-steer reducing hub designs ('Dual Axis Strut' as honda call it).
that did go through my mind as a potential concern.more grip then it could just make things worse.
the car is stock in terms of suspension, but i ran in +R mode all day so very firm and very little roll in the car. I've no idea how the geometry changes when the car is pushed, being a fairly rare car there isn't that much info on these types of details.
like i say in the original post, i believe the car is factory setup with around -1deg camber from factory. seems low to me, but thats what stock is. stock pressures are 33f/30r, but found these RT2's are noticably softer than the factory CSC6's so i'm running 35f/30r on the road.
the car is also a daily driver with trackdays thrown in a few times a year (or at least that's the plan) so while i don't mind a bit more camber, or running more track focused tyres, it will be a bit of a compromise.
i'll look into the real cost of camber changes and how it affects these exotic torque-steer reducing hub designs ('Dual Axis Strut' as honda call it).
entry line is something i need to work on for/at the next event and get another tuition session in to see how i'm improving.
I've finally found out some prices for front camber adjustment; £200 for honda +0.5deg (adjustable upto 1.5deg) ball joints, £300 for modified balljoints that go up to 3deg, plus whatever price CenterGravity charge for geometry setup.
factory camber is 1deg negative but i don't know enough about the car to know if i should be looking at 1.5deg, or closer to 2. i typically getting around 12months/9k road miles out of my summer tyres and with a few trackdays thrown in each year, i doubt i'd see tyre replacements because of 2deg camber.
my heart is set on adding more camber and going for a more corner focused geo setup anyway. Done it in the past on my s2000 and the car was a hoot over standard setup.
I've finally found out some prices for front camber adjustment; £200 for honda +0.5deg (adjustable upto 1.5deg) ball joints, £300 for modified balljoints that go up to 3deg, plus whatever price CenterGravity charge for geometry setup.
factory camber is 1deg negative but i don't know enough about the car to know if i should be looking at 1.5deg, or closer to 2. i typically getting around 12months/9k road miles out of my summer tyres and with a few trackdays thrown in each year, i doubt i'd see tyre replacements because of 2deg camber.
my heart is set on adding more camber and going for a more corner focused geo setup anyway. Done it in the past on my s2000 and the car was a hoot over standard setup.
veehexx said:
i don't know enough about the car to know if i should be looking at 1.5deg, or closer to 2.
Tyre temp distribution would tell you where the weight is averaging out on a given day. Tyre wear will tell you the long term trends. You will need to choose how you're going to compromise between maximum performance on the track, and day to day tyre wear. Neither of the figures above seem excessive for road or track.Gassing Station | Suspension, Brakes & Tyres | Top of Page | What's New | My Stuff