New Tires or not ?

[gearwire]

Hi All,

I have a question for the forum regarding new tires and lap times. Assuming the same car, driver, track, etc etc what would be the expected lap time decrease by going from old tires ( 10 heat cycles) to new ones. Assuming the car is well set up, the driver is experienced with the car and the course is a twisty 1.25 mile. This is of course subjective but I would like an experienced ball park opinion.

[cliff]

i suppose it would depend on what your baseline tire is. Goodyear 160 fall off would be greater than a Hoosier Radial or typical vintage treaded tire.

[Daryl DeArman]

The bigger the fall-off on that particular compound, the bigger the difference to new tires obviously. Some tires might be 1/2%, some 2%+, that's assuming the driver is capable of getting the most out of both the new and the 10 heat cycle tires.

I know somebody is going to claim they went faster or set a track record on 15 heat cycle tires, but what they don't know is in those same conditions how much faster would they have been on new tires? Not enough of us get enough seat time for such objective tests. Heck, most can't drive 5 laps in a row all within .5 second/lap. How are we going to say new rubber was worth .5 second?

[swifttiga]

I asked this question of a pro driver once. This driver was driving a LAMS P2 car and a Vintage car owner hired him to co drive in an enduro. He was fast alright putting the S2 way up the grid and only behind the super fast group7 cars. He drove on used and new rubber and he said all things equal the new tires were 2 to 3 seconds faster over a 2 plus mile track. But he was a pro so I am not sure how that would match up with a backmaker like me.

[gearwire]

I should have noted that it is a formula continental on Goodyear slicks.

Thanks

[Garey Guzman]

I should have noted that it is a formula continental on Goodyear slicks.

Thanks

Which compound?

[JHerscher]

In my experience putting on new slicks will get you 1.0-1.5 seconds per lap on that track. Frame of reference is Hoosier bias R35 compound. Current generation AR less time difference.

As the abbreviation goes, YMMV.

[Purple Frog]

When is the last time Goodyear made a slick for FC cars?

[Keith Carter]

All depends on the tire falloff and age of the tire as mentioned before. 10 cycles is getting down to the cords, isn't it?

For us, new rubber was usually worth a second per lap with the Hoosiers we ran in FE... Unless we're talking about the second generation American Racer tires we had on the FE, then 10 cycles were just about as fast as new tires.

[Buc01]

My experience at Hallett in 1991 VD FC on Hoosier R35B is about 1 second per lap on 2-3 heat cycle set versus 10 heat cycle set.
Chords do not show for me on 10 heat cycle set as the max laps run per heat cycle is 12 laps.
Can't say how much faster a new set would be, because I have not ran on a new set with this car.
Not saying I would not LIKE TOO tho!

Aaron

[jtaphorn]

When is the last time Goodyear made a slick for FC cars?

2019, I bought a set at COTA from Sasco 2 weeks ago. They were to be the first set of new tires that I'd run in 20years. Unfortunately, a broken front suspension bracket on the Reynard during qualifying had me finish my weekend as a spectator. Otherwise, I may have had an opinion to share on old verses new Goodyears from a back marker.