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How much power…

I know I’ve covered this before, but this (slightly re-written) article from the archives is still highly relevant, and relates to a RiDE article in 2006.

I won’t say I told you so…

…but I told you so. Check out the “How much power do you need?” article I wrote several years ago.

The June 06 edition of RiDE magazine has a very interesting article on how much power four of their riders actually needed to ride their bikes round their test route. With the advantage of a data-logger on their GSX-R600 they were able to get real figures.

Steve Rose lapped their 40 mile ‘TT circuit’, with (in his words) “the speedo barely dropping below 100mph” for an average speed of just over 60mph. He needed an average of just 26.3hp on the ride. He used a peak power of 72hp, some 30hp short of the maximum output of the bike and the average throttle opening was just 15% – he never got it more than half open.

The more legal sounding 47.4mph averaged by Emma Franklin required just 11.1hp. Yep, you read that right – ELEVEN HORSEPOWER! That’s what a CG125 makes. She used an average of 10.4% throttle and a maximum of 39.4hp, or rather less than the output of a DAS trainee’s 500.

Ed Tim Skelton lapped at 51mph, using an average of 13.5hp with a peak of 94hp. His average throttle opening was just 13.5%.

Only racer Kev Smith managed to get the throttle fully open and to hit 110hp whilst blasting his way round at an average speed of 65mph. Even he only used an average of 36hp with the average revs only half way to the red line.

So what’s this all about?

It’s all basically what I have talked about before. Serious hp is only needed when you are accelerating, and with the sort of bike used here where peak power lives just under the red line, even hard acceleration rarely gets to use maximum power.

Unless you max out the revs AT THE SAME TIME as you nudge the red line, you simply don’t ever get to use the maximum power output of a bike like a supersport 600 or 1000!

Think about it – with a typical 600 geared to hit around 70mph at the red line IN FIRST GEAR, it’s pretty obvious that unless you are riding at extremely silly speeds, you can’t get near peak power in the higher gears – even if you ride around in second, that means nudging 100mph. And in any case, try to use full throttle in first gear and as the power climbs, the front wheel will smack you in the forehead before you get to peak power.

A more practical motor even for a road-going sports bike would have the peak power lower down, with a long “tail” so that the rider could use the “bump” of the torque curve, but 40 -80 overtaking times don’t sell bikes – it’s the extra 3 or 4 hp at the peak that shifts bikes.

About Kevin Williams / Survival Skills

Motorcycle trainer, motorcycle author, motorcycle safety consultant, motorcycle forum moderator, former courier and ever a recreational rider. Is there a common theme here?

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