Underneath Aleix’s Suzuki GSX-RR

Suzuki’s last MotoGP bike was a bit of a dud. During 10 years of racing, the GSV-R scored a single victory, and that was in the rain at Le Mans with rain-master Chris Vermeulen on board. So how are Suzuki engineering a reversal in their fortunes?

ou could blame the bike’s lack of success on many factors, but perhaps at the very heart is Suzuki’s lack of long-term dedication to GP racing. Over the decades they have come and gone according to company whim. They raced the RG500 from 1974 to 1983, then took a three-year break before returning with the RGV500. In 2002 they entered the fray with the GSV-R, then at the end of 2011 took another three-year break before  unleashing this year’s GSX-RR. Meanwhile Honda have been there non-stop since 1982 and Yamaha since 1974. Suzuki’s holidays play havoc with development and leave them with too much catching up to do.

Nonetheless, the 2015 bike is already doing better than expected, especially in qualifying (thanks to the softer rear tyre given to privateer teams and factories who haven’t won in yonks), so what’s the difference between the GSV-R and GSX-RR?

Obvious things first, the GSX-RR is powered by an inline four, not a V4. This was a marketing decision: why race a V4 when you sell inline fours?

“Both engines have advantages and disadvantages,” says project leader Satoru Terada. “It’s a little more difficult to find good geometry with the inline four, but once we found it, we think it allows better handling.”

Chassis performance is the bike’s greatest strength but Suzuki are coy about how they’ve achieved the bike’s miraculous corner entry speed. “I’d like to tell you, but I can’t,” says Espargaro’s Irish crew chief Tom O’Kane, who has been in GPs since the late 1980s. “All I can say is some very clever engineering went into it.”

Terada won’t go much deeper than that. “Our concept for the bike was good handling, good cornering and better turning for acceleration,” he adds. “Also, chassis stiffness is optimised and we have a very good swingarm pivot position.”

The only chassis problem they’ve had was a nasty vibration in high-speed corners. “It wasn’t chatter,” says O’Kane. “Chatter is a specific thing where the vibration comes up from the tyres, and it’s the kind of frequency that’s transmitted through the suspension, from the front of the bike to the back. It tends to come on corner entry, then when the rider opens the throttle and there’s weight transfer to the rear, it goes away. The vibration we had was different; it happened only during hard acceleration. It was partly chassis stiffness-related, but Suzuki fixed it really quickly.”

The chassis may work superbly, but Suzuki know they have work to do in other areas. “We need maybe 15 more horsepower to run with the fastest bikes,” says Terada, wincing at the thought of squeezing another seven percent more power out of his engine.

Espargaro and team-mate Maverick Vinales can’t wait for the next upgrades, including a seamless clutch which should improve both straight-line and cornering speed, and a revised engine spec in September.

They certainly need improvements. Their best race so far was Mugello in May, where they finished 23.8 seconds behind the winner, a difference of 1.03 seconds per lap. Their worst was Indianapolis, where they finished 39 seconds down, a gap of 1.44 seconds. The problem isn’t only that Suzuki need to catch up; Honda and Yamaha also keep getting faster as they fight for the title.

“Now the level is really high, the other bikes are working really well in all areas,” says O’Kane. “Look at the Honda, you can see how well the guys can steer the bike and how early they can get on the gas without unsettling the bike. And Yamaha seem to have worked out exactly how much torque you can deliver to the tyre without upsetting the bike. It’s all in the details.”

Next year’s unified software may help close the gap. “It will level the playing field a touch,” adds O’Kane, who doesn’t expect Honda to make their best technology available to everyone. “I think they’ll give the Fisher Price version of what they’re running now to the control ECU and be content to run that themselves.”

Longer swingarm
In Catalunya, to go with the new motor, a longer swingarm was introduced. Just enough to keep the bike calm under acceleration, not long enough to disturb the balance of what is clearly an exceptionally good-handling bike. The design still looks a little delicate; we can expect more strength when the next step up in power arrives.

Development plan
Suzuki have come out of their corner fighting. Their decision to start a new team means they haven’t received any of the normal financial support from Dorna, but it has given them complete independence in the way they have operated. Their determined ‘stage by stage’ development programme is a lesson to others on how to build up from nothing to become a serious player.

Rolling dyno
Suzuki used a Torductor-style power measuring device at the Jerez test after the race there in May, to make sure the team had a record of the way their machine made its power at that point in its development. It was only used for one hour during the test and isn’t intended to be used during races like the version used by Honda. Having a decent comparison will have many benefits, not least in greatly helping with the fine-tuning of their next-generation motor’s throttle system.

More pipe
The new engine arrived in Catalunya at the middle of June, with perhaps 10bhp more, but it took until Assen a few weeks later for new exhausts designed to work well with it to turn up. A longer pipe is an indication of tuning for midrange power. More power is still needed but achieving this without upsetting the delivery is the trick. 

Words Mat Oxley, Neil Spalding / Pictures Neil Spalding