Ride height with smaller rubber fitted
Discussion
Setting the ride height is plainly an important part of setting the suspension geo as it alters the wishbone angle. If I fit tyres that make the car sit lower and leave the spring bases as they are I am assuming that this will have no implications other than the practical issues of ground clearance and gearing. I am looking at some rubber that will lower the car by just under an inch front and rear. As it is for track use clearance is not an issue and I think I can drive around the lower gearing. Is there anything else I have missed, presumably going a bit lower will not have any aero implications ?
I'd have thought it would affect the suspension geometry as the effective diameter of the wheel and therefore the location of the contact patch of the tyre will be altered (the wheels move out of the vertical plane as the suspension moves). Although things like castor angle will be unchanged, the effective length of the castor distance (whatever it might be called) will be reduced.
Having said that I can't imagine it'll make a huge difference, and if you're only doing it on track you might as well have a go.
Having said that I can't imagine it'll make a huge difference, and if you're only doing it on track you might as well have a go.
The tyre changes will make the sidewall stiffer making the tyre more sensitive to geometry. It may well be that the optimum suspension settings for the high profile tyres are different to the optimum for the low profile ones, and even when you have found the new optimum you may find that you have compromised the ability to absorb bumps, steering kickback and feel.
Yes, as usual what appears simple may in fact be little more involved. I am not convinced that profile will change the settings that much, not that I would notice anyway. I currently have lower profile slicks on 17inch wheels and higher profile 1b rubber on the original 15 and 16 rims and use the same settings for both. To run the slicks with the compound I want it looks like I may have to fit smaller wheels, probabaly 15 all round with larger profile rubber.
Really I suppose in the end I have to buy them and try it out. Is anybody else running very soft compound slicks on a griff ? if so what have you done ? The A6 DOT Hoosiers are OK but not really soft enough.
Really I suppose in the end I have to buy them and try it out. Is anybody else running very soft compound slicks on a griff ? if so what have you done ? The A6 DOT Hoosiers are OK but not really soft enough.
I would have thought the ride height should reduce accordingly so that the wishbone alignment remains unchanged.
As for dialling back in the effect of lost sidewall flexibility, I don't believe that's possible. The sidewall contribution to the overall suspension is both soft initial compression and sideways flexing to absorb tread tracking and also provide a progressiveness to lateral grip loss. The mechanical suspension only works in compression so the sideways flexing element can't be provided. For track use the sideways flexing is less important because track surfaces are usually flat. The suddenness of lateral breakaway will probably increase though making it harder to catch oversteer.
As for dialling back in the effect of lost sidewall flexibility, I don't believe that's possible. The sidewall contribution to the overall suspension is both soft initial compression and sideways flexing to absorb tread tracking and also provide a progressiveness to lateral grip loss. The mechanical suspension only works in compression so the sideways flexing element can't be provided. For track use the sideways flexing is less important because track surfaces are usually flat. The suddenness of lateral breakaway will probably increase though making it harder to catch oversteer.
steve-V8s said:
The A6 DOT Hoosiers are OK but not really soft enough.
I could say I told you so but that would be childishThe moral of this story is not to get pissed out of your brain and then try to convince someone that is putting up faster times than you that the tyres he is advising you to use(AVONS) are the right choice.
All the information is there steve
Love and kisses and see you 21st june
PS I think it is really sporting of you to let your missus drive the car with you.
They are indeed not as soft as would be ideal but there are not really any Avons in the sizes to fit the car in the right compound otherwise I would have taken the advice.
Yes you are quite right she dives the Beemer with the tyres and other kit to most meetings.
You are obviously most welcome on here Ben and your comments and advice are obviously appreciated, I bow, sir, to you experience and knowledge but are you certain you are not missing something on the Z club forum.
By the way I seem to remember the Hoosiers worked well enough to beat you at the last meeting.
Yes you are quite right she dives the Beemer with the tyres and other kit to most meetings.
You are obviously most welcome on here Ben and your comments and advice are obviously appreciated, I bow, sir, to you experience and knowledge but are you certain you are not missing something on the Z club forum.
By the way I seem to remember the Hoosiers worked well enough to beat you at the last meeting.
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