Wednesday, February 21, 2007 - 03:24 pm, by: Jeff Bedsor(Jeff_bedsor)
Quote from your post above - Going too low will deform the tyre and provide less grip which is something I simply cannot understand why guys at the drags go to 25psi with street tyres as this should produce less grip.
Sorry- didn't read the bit where it said you run this thread. I thought it was relevant in that it shows what happens to tyres under high load and stresses. Whether they are drag tyres or road tyres the forces are still the same, to much pressure is not going to allow any give in the tyre and make it much more likely to lose traction.
Wednesday, February 21, 2007 - 04:24 pm, by: Damian Ware(Frozenpod)
Read my post and the part you quoted, going too low will deform the tyre and provide less grip.
Drag tyres are built differently as are racing slicks and the tyre pressure required is completely different to obtain maximum grip.
Too lower pressure in any tyre but particularly street tyres will result in the tyre being deformed and a reduce contact patch, and hence reduce the grip.
Given Craig's post above I believe he understands this and was sort of making reference to it. Craig correct me if I am wrong.
In the application you showed the forces are no where near the same to what a street car applies to them. Since when did someone run a 5 sec pass or have the horsepower to do so with street tyres.
Another reason there is so much more force on drag slicks is the extra grip they provide where as the street tyres would have slipped with a much lower force being applied. Once the tyre is slipping/spining the coefficient of friction further reduced and again the result is no where near as much force applied to the tyre.
Sorry mate but I cant begin to see any relevance or comparison.
Dan McColl Goo Roo Victoria Active V8 and a Factory Manual XF.
Wednesday, February 21, 2007 - 05:28 pm, by: David Vaughan(Davidv)
Bugger all, really, if you are actually telling us that pressure in a specialised tyre at a drag strip is in any respect whatsoever relevant to street tyre pressure and use.
If you were simply making the point that there is good reason for drag racers to run lower rather than higher pressures then I agree entirely.
Wednesday, February 21, 2007 - 07:33 pm, by: Jeff Bedsor(Jeff_bedsor)
That was part of the point I was trying to make, that yes there is an advantage to running lower pressures on street tyres at the drags. I know this from practical experience last weekend at the drags, 38 psi spun like hell of the line, whereas 26 psi hardly at all, Damian states that he thinks 25psi should get less grip. There is still things to be learnt from the video whether street or drags tires are used, the tires will still flex although to a lesser extent on street tyres. Just got up my nose that I post up an interesting link(I thought so anyway)and this guy reads me the riot act. Come on guys , we are arguing about tyre pressures. Btw I run 38 front and 36 rear in my WRX and Soarer, any harder I feel makes the ride way to harsh, any less and the front shoulders wear badly on the dozens of bloody roundabouts where I am.
Wednesday, February 21, 2007 - 07:46 pm, by: David Vaughan(Davidv)
Yes, in the context of the drags then lower pressures work better. From what I have been told (I do not drag race myself) the reasons are that the tyres initially create a clutch effect between the axle and the road enabling the drivetrain to spool up, as it were. When the tyres start to spin they expand and create a more rigid connection with the road, providing also some spring-recoil effect. This is 2nd hand information but it made sense when explained.
Monday, March 26, 2007 - 05:17 am, by: David Hill(Davesrave24)
Thank you all for your opinions, at least that is now all cleared up! I thought I might be able to get a little quick info on tyre inflation. HA! But seriously, thanks everyone.
Saturday, June 02, 2007 - 12:16 pm, by: David Vaughan(Davidv)
What is that support? A vendor of nitrogen inflation products is giving money to a commercial lobby group for tyres?
Nothing to do with nitrogen. I just do not see how a vendor giving money to a lobby group which acts in their interest is an argument in favour of the vendor's product.
If I manufacture nail guns and give some money to ("become a supporter of") the Master Builders' Association, does that make my nail guns really good?
Saturday, June 02, 2007 - 12:26 pm, by: David Vaughan(Davidv)
Interesting that if you look at their "Tyre Safety Information" there is no reference to nitrogen at all, even though they assert their sole interest is the safety and welfare of tyre users and they have been at it for sixteen years. In fact, if you search the entire web site the sole reference you find to nitrogen is to the new sponsorship by the vendor, Pneu-Air.
What do you think are the odds that within a couple of months of welcoming these new friends they will have an article explaining the virtues of nitrogen?
Saturday, June 02, 2007 - 03:53 pm, by: David Vaughan(Davidv)
Oh, you mean the ones selling the product. They praise it. That's bloody amazing!
Funny, I was talking about the [negligible] value of an endorsement which is in the commercial interests of the party making the endorsement. I said further that the lobby group for tyre manufacturers and retailers in Britain had not yet said a single word about nitrogen but I [cynically] expected it to do so shortly now that it had taken money from a seller of nitrogen.
Those were my points. I did not enter the nitrogen debate at all in this thread.