Eric Offenstadt, Pépé to the regulars, is an extraordinary character. A former Grand Prix driver, he has already competed against the greatest, starting with Giacomo Agostini himself.
But, with immeasurable energy and a spirit that could not be more inventive, the man insisted on doing it with his own motorcycles, always particularly original, whether it was a Kawasaki with a hull frame and disc brakes at the time, or HO 500 and But later. You can find all the details of his adventures on the forum where he spoke for years.
Aged 77, it would be a bad idea to think that he is enjoying a well-deserved retirement today... No, on the contrary, he is still continuing his quest for a faster, more rational motorcycle, this time with its latest prototype with a Yamaha engine, the GECO, named in homage to the reptile that sticks everywhere.
With no real resources other than those of the passionate about this project, a simple individual or a company like Yamaha, Eric Offenstadt fights daily to prove the merits of his approach.
A long-time friend of the editorial staff, we could not, and did not want to, refuse him this little spotlight…
He therefore gives you here a very brief summary of his project, to which we will only add a small point of the situation, at the end of the article.
Eric Offenstadt: “Let's move on to the erratic epic “Geco R09” based on an already outdated motorcycle, which I also made the mistake of wanting to develop with young, inexperienced riders.
However, this experience was fruitful in terms of lessons learned to validate the “GECO” calculation and design method, the main characteristic of which is to finally overcome the handling/stability and braking/traction compromises.
I must also admit that I had everything to learn in terms of tuning, my last experience dating back to 2001.
Above all, the R09 taught Jean Baptiste LABRUYERE and me how to really use data acquisition to scientifically develop a motorcycle.
With the Yamaha R1 2015 made available by Eric de Seynes, we finally had a powerful engine (195hp rear wheel) and a light and compact package.
From July 1 to August 15, 2015 we (Felix Chauveau, Cyril Meunier, Corentin Charton and I) calculated the kinematics and drew the 48 specific parts, including the "T-shirts", steering column, lower fork, 3rd rear shock absorber and everything the (patented) system controlling the constant velocity caliper supports.
We did around 1000km in February in Almeria without discovering much other than the lack of longevity of the axles of the constant braking torque rockers which we reinforced and mounted on needle bearings.
At the NOGARO “VIP” tests with all the big teams, at the beginning of March, we had Olivier GOMEZ as “data” engineer and were able to start comparing the pressures (BARS) that the different drivers could use. Nicolas Salchaud, kindly loaned by VILTAÏS, already showed a better partial “braking” and a time of 1.31.7 in just 5 laps with Bridgestone. For the first time a driver found the prototype really more stable than his R1 when braking and with the ability to put a lot of pressure on the angle. On the other hand, he complained of heaviness in the “S”.
Thanks to this ride, Jean-Baptiste and I already knew that we had to mount our bis “T-shirts” (with more offset) for more maneuverability.
The basic adjustment (shock absorber/fork) went very quickly and very well with Stéphane EGEA in Alès (invited by the circuit) to arrive at a very good time 1.1 seconds from Zarco's lap record in August 2016 .
Stéphane declared at the end of this last run that the bike was now “perfect”.
There was finally, thanks to Christophe Guyot and Eric de Seynes, the authorization given to Lucas MAHIAS to come and try the GECO in NOGARO on September 3, 2016: Lucas returning by car at night to be there in the morning in Nogaro (coming out of his victory in 1000 superstock in Magny-Cours). Thank you 1000 times to him!
In a public ride, among the "gentlemen riders", it took us 4 times 1/4 hour to adjust the bike for him and especially for the Pirellis (bigger at the front and smaller at the rear than the Bridgestones.)
It must be said that we discovered that we save a lot of time on tuning when it is done on a motorcycle whose geometries we have designed ourselves: we no longer go “in the opposite direction” half the time.
During the penultimate session (Lucas wanted to go to sleep), we fitted him with new tires, reassembled the bike a bit which was rubbing one of the engine casings, and in 6 laps, he twice achieved 1.29.5 times the best times of the official R1s at the “VIP” (2nd best FSBK practice time). The data gives the two times 2 seconds lost during overtaking, 0.4 bars of average pressure before lifting the rear wheel and 21,5ms13,17 of deceleration over 2 meters before turning compared to 150ms12.5 for the best SBKs.
But the most important thing is what Lucas told us at the end of the test and repeated to Christophe Guyot & Eric de Seynes:
1° The GECO brakes significantly later.
2° In a fight it is impregnable: “We pass in front when braking and the guy cannot get back in front. »
3° Finally, I remember that he said last (as if addressing himself): “And I have the impression that the more we attack, the easier it becomes”. (It must be said that Lucas only had a total of one hour of driving to sort everything out, with “standard” electronics, outdated according to him, standard tires and in the middle of moving chicanes.
We are going to the NOGARO VIP this year, with optimizations increasing the braking gain from 3.5% to 4.5%. This allows us to adjust the motorcycle for maximum traction. This corresponds to 23.5 bars to take off the rear wheel, for a gain of 9 meters over braking for 200 meters, but it is still modest and only corresponds to around 0.6 seconds per lap for the Bugatti.
We were warned that it was unrealistic to build a prototype with only the contributions of a group of enthusiasts, the help of a handful of unwavering partners and managed by the few volunteers and friends of www.progecomoto.fr
It was also completely impossible to develop it without a budget beyond the reach of even a private MotoGP team. But there you go: impossible is not French.
We now hope that the various interested authorities will act. »
In the meantime, Stéphane Egea took over from Lucas Mahias, last weekend in Pau, to validate the Öhlins suspensions, before Nicolas Salchaud takes over the handlebars very soon in Nogaro.
Photo credit: Pierre Gabrielle
