Making BFGoodrich® Dakar tires: where genius and artistry merge
Creating a new tire need a precise step-by-step process.Matt Hanlon, Project Engineer and Tire Designer at BFGoodrich® (lien vers son interview), explains to us how BFGoodrich® mastered this exercise.
The Dakar is organised by A.S.O. (Amaury Sport Organisation). Preparing for the world’s biggest cross-country rally is a year-long job that monopolises a team of some 500 staff. The Dakar’s Sporting Director Marc Coma, a former five-time winner of the event on two wheels, talked us through the mission…
Step 1: The Mold
Before we make a tire from scratch, we need a mold. For Dakar 2017, we did a complete redesign based on the work we had done in Baja. This year Carlos Sainz, one of the drivers from the Peugeot team, also had strong ideas about what he wanted. After many hours on the phone and lots of emails, we came up with a tread pattern proposal that met both our objectives. A 3D model is then made, and send off to the mold shop in Akron, Ohio, where they make a 1:1 scale tire out of foam to be inspected. Our designers go to the model shop for the first cutting so that they can see the size of all the tread blocks. For this project, there were also some questions around groove thicknesses and depths. After, the model is sent to the foundry where it’s made into the final aluminum tire mold and finished to make sure it can interface properly with our presses and also to add the sidewall lettering.
Step 2: Tire Building
With an all-new tire, we have some ideas of what we want to do with compound and construction but anything is possible. In general, we pick a few different constructions that highlight several different types of performance, sometimes at the expense of others. For the compound, it’s tough to tell what level of hardness or softness is needed so several options are usually built. For the first build, we made 4 different compounds and 3 different constructions.
Step 3: Testing
We then took all the different options out to test. For Dakar, we tested in Erfoud, Morocco. We set up a test circuit and compared lap times and driver feedback on each of the test tires. In the end, we came up with a preferred compound, construction, and a wish list of what other performance modifications are desired.
There is also “machine” testing going on in parallel, where we assess the tire’s high speed capability, mounting pressures, rigidities, etc.
Step 4: Repeat
Based on the results and feedback from the test, new designs are created. Sometimes the designs can be as simple as combining the preferred construction with the preferred compound but it’s usually much more in-depth than that. Durability in the race, as well as performance, are key factors and sometimes we go back to step one.
Step 5: Validation
How will the tire hold up on the track? Will it get punctured easily? Will the tread wear too fast? Will we not have enough grip? These are questions that can only be answered in a race, and preferably that race is not Dakar. For Dakar development, we used the China Grand Rallye, Morocco Rallye, and Baja as test races before Dakar.
Step 6: Finishing
Finishing a tire never feels like finishing. You don’t ever get to a point where you say “okay, its done; good to go”. Instead, you always have new ideas of what you want to try next but you just run out of time. You try to get the most performance in the first few loops so that you don’t leave too much performance on the table. It’s always encouraging to look at the ground that’s been covered and the differences in lap times from the start of the program but it’s hard not to focus on stones left unturned.