Is Yamaha Using A Seamless Gearbox? The Data Says No

Ask Jorge Lorenzo if there is one thing which the Yamaha needs to allow him to compete with the Hondas, and he will tell you it is a seamless gearbox. The system used by HRC on the Honda RC213V allows the riders to shift gear while the bike is still leaned over, without upsetting the machine. It is an important factor in the Honda’s better drive out of corners, as Dani Pedrosa, Marc Marquez, Stefan Bradl, and Alvaro Bautista can shift gear earlier and make optimum use of the rev range to accelerate harder.

That Yamaha is working on a seamless gearbox is no secret, with Yamaha’s test riders currently racking up the kilometers around tracks in Japan, testing the reliability of the maintenance-intensive system to the limit before using it in a race. Recently, however, Spanish magazine SoloMoto published an article suggesting that Yamaha has already been using its new seamless gearbox since the beginning of the season.

In evidence, the magazine pointed to an apparent difference in fuel consumption between the factory Yamahas and the satellite bike of Cal Crutchlow. While both Cal Crutchlow and Valentino Rossi made mistakes at Qatar, only Rossi was able to recover, and then battle with Marc Marquez for the podium. The theory put forward by SoloMoto was that the smoother transition between gears gave both better drive and lower fuel consumption, as the ignition is cut for a much shorter period, wasting less of the limited gasoline the MotoGP bikes are allowed.

My own enquiries to check whether Yamaha was using a seamless gearbox or not always received the same answer: no, Yamaha is not using the seamless gearbox. The reason given was simple: with Jorge Lorenzo defending his title and Valentino Rossi in the race for the championship, they simply cannot afford to have a single DNF down to a mechanical failure of the new-fangled seamless gearbox. The risks involved were just too great, especially when taking the reduction in engine allowance into account, with just five engines allowed all season, down from six in 2012.

To test this denial, I went out to the side of the track on Friday morning at Jerez to record the bikes as they went by. I sat at the exit of Turn 10, Peluqui, and recorded the bikes as they accelerated towards Turn 11. It is a spot where they change gear once, before braking briefly for Turn 11 and then powering on to Turn 12 and the final short straight and hairpin.

Once I had enough recordings, I analyzed the sound clips in Audacity, an open source audio software package, measuring the length of time the gear changes last. Given enough samples, it is a relatively simple task, as the point at which the ignition is cut is clear from the audio (see screenshots below).

I put those timings into a spreadsheet, and then averaged them, both for each rider, and for the Yamaha and the Honda as well. Below are the times I registered for Valentino Rossi and Jorge Lorenzo on the factory Yamahas, and Stefan Bradl and Marc Marquez on the Hondas. Both the LCR Honda of Bradl and Marquez’ Repsol Honda use Honda’s seamless transition.

Honda Gear Change Recording:

Yamaha Gear Change Recording:

Length of gear change, in seconds:

Averages for the Honda and the Yamaha:

What is clear from the timings is that the Yamaha is still significantly slower in changing gears than the Honda. The Yamaha takes an average of around 38 milliseconds, while the Honda takes just 9 milliseconds, a difference of nearly three hundredths of a second.

These results are nearly identical to the results I found when I first checked the data at Qatar back in 2011, when it became clear that Honda was using the seamless gearbox.

So what conclusion can we draw from this data? It seems clear to me that Yamaha are not using a seamless gearbox just yet, and that Wilco Zeelenberg was telling the truth when he denied to me that Yamaha were not using it.

The data from the sound clips is almost irrefutable, as the length of time each gear change is taking is almost the same as it was two years’ ago. If I am wrong, and Yamaha are using a seamless gearbox, then it is not a particularly good one.

What is clear from both the sound recordings and standing trackside is that the electronics package has been modified to handle gear changes better. Where once  each gear change was accompanied by an enormous bang, as fuel hitting the hot exhaust exploded, that noise has been greatly reduced.

Less fuel is being wasted in those gear changes, for certain. But a new electronics package does not a seamless gearbox make. The Yamaha riders will have to wait.

Photo: © 2013 Jensen Beeler / Asphalt & Rubber – Creative Commons – Attribution 3.0

This article was originally published on MotoMatters, and is republished here on Asphalt & Rubber with permission by the author.