scrubbing in tyres?

[pete m]

hi everyone.
im looking at putting some new dunlop tyres on a historic formula junior single seater racing car.
The tyres are 13" CR65 tread dunlop wet compound compound and the car weighs 500kg inc driver.


Should i be scrubbing them in before race use and what should this involve?

thank you
Pete

[AU N EGL]

Hey Pete Welcome to the forum

Yes scrubbing them in or one heat cycle.

One heat cycle will remove the mold inhibiter on the rubber, and help set the tire. Getting the tire up to opperating temp ~180* F , a few short quick laps, Not too many. Then put the tires away for 24 hours before you race on them. This helps with tire grip.

Good Luck

[Adam43]

Scrubbing in, it is well worth it! I have felt the benefits, albeit in a totally different application. I find the benefit is with how long the tyres last, rather than ultimate lap time. With anything other than quallies that is probably what you are looking for.

For the reasons our precious bird mentions

[pete m]

thanks guys. sounds worth it i just need to find a way of getting a few laps in before the race

[Notso Swift]

Originally Posted by AdamAshmore

Scrubbing in, it is well worth it! I have felt the benefits, albeit in a totally different application. I find the benefit is with how long the tyres last, rather than ultimate lap time. With anything other than quallies that is probably what you are looking for.

For the reasons our precious bird mentions

This info is Gold, be aware though that different tyres have different requirements
Case in point
my class has a control tyre use to be an A032R and now A048 (post Yokohama, if you didn't know) With the 32 you use to bring it to 75-80% of max temp, while with the 48 it could only get to 50%. Just part of the nuance of the different tyres.

Now the difference.
I do not think (personal opinion) that the ultimate speed is any different, but, and this is the big thing, the consistancy is, the other thing is how the tyre bounces back after a heat cycle.

The 48 is a shocker, if you do not scrub them then they die, 2nd use and they are gone, by a huge margin, a fast flowing track like Phillip island with a couple of real balls and all corners (where the Moto GP and Superbikes run in Australia) it is 2 seconds in a 1.55 lap. The 32 was less than a 1 second.
Scrub them right and you measure it in tenths!

Also, when you rest them the best results are from stripping them from the rim, but that is not essential, in fact, it is not really worth it. because I have not got any definite data, just a subjective feeling

Can't tell you about your tyre, but I hope my experiance helps.

[AU N EGL]

The biggest thing I found for scubbing new tires, was to get the mold inhibitor off the new rubber. That chemical tend to be a bit slick if you just go out and race on a new tire.

Scrubbing also sets of the chemical bonds with in each tire to that stress load of that particular corner. ie dont change the tires from fron to rear or left to right. Scrub the tire in for that corner.

[Adam43]

Notso, I will be movign to the A048s. That is a useful tip, thanks.

[inamo]

If you give the tyre companies a call they'll usually be able to give you accurate advice on how best to scrub in that tyre and care for it generally.

[Notso Swift]

You are welcome Adam

Inamo, absolutely agree, but remember a couple of things
1/ The field guys we talk to are often learning themselves... from the experiance of competitors
2/ The Factory will never admit that a newer tyre is in anyway worse than the older one!
3/ The tyre guys want you to buy more tyres. If someone buys a new set for every race to get the best performance then fine, they guy running on older tyres is never at the front anyway so who cares? I do because I am am the one running on older tyres, I say make the most out of the same thing by just being careful on your run in and get many more laps out of them. Back to the A032r/A048 example, the tyre out of the box will produce the same lap time, it is how it repeats that is the big thing.

[Goran Malmberg]

One might just run a couple laps to scrub away the moulding layer, then use them direct as qualifyng tires. The heat comes in differnt then but they dont last to long.
Goran