Street Savvy

Clear­ing up con­fu­sion over how a mo­tor­cy­cle turns

Motorcyclist - - Contents - —Ken Con­don

A WHILE BACK I had a pri­vate trackday stu­dent. We’ll call him Earl.

Earl said that he was hav­ing a hard time get­ting close to the apexes and some­times found him­self run­ning wide at the ex­its. He won­dered whether his body po­si­tion was to blame. It took a to­tal of one lap to see that his real prob­lem was with slug­gish countersteering in­puts. Back in the garage, Earl ad­mit­ted that he’d heard of countersteering but wasn’t sure ex­actly how it worked.

You’ve surely heard about countersteering too, but the ba­sics are worth re­vis­it­ing: Get­ting a bike leaned re­quires over­com­ing the pow­er­ful forces keep­ing the bike up­right at speed—in­clud­ing in­er­tia and the gy­ro­scopic forces of spin­ning wheels. And that’s where countersteering comes in.

Countersteering is used to ini­ti­ate the lean you need to be­gin turn­ing. To turn right, lean right by press­ing for­ward (and a bit down­ward) on the right han­dle­bar. Press on the left han­dle­bar to lean left. What you’re do­ing is “steer­ing ” the front tire out from un­der the mo­tor­cy­cle. This “out track­ing” of the front con­tact patch un-bal­ances the bike so that it falls into a lean. Imag­ine kick­ing the feet out from un­der some­one; their feet go right, but their body falls to the left. There are other forces at play on a mo­tor­cy­cle, in­clud­ing gy­ro­scopic pre­ces­sion and cen­tripetal force, but this ba­sic ex­pla­na­tion is suf­fi­cient.

So what about body lean? Like many rid­ers, Earl had the im­pres­sion that mov­ing his body in­side the turn gets the bike leaned, which is why he as­sumed his body po­si­tion was to blame. It’s im­por­tant to re­al­ize that body po­si­tion can as­sist in the lean­ing process, but that po­si­tion­ing alone is not nearly strong enough to get the bike to lean quickly— es­pe­cially when rid­ing fast.

Back on track, Earl con­sciously added more han­dle­bar force, and by the end of the ses­sion he was turn­ing with much more author­ity and ac­cu­racy. He is now able to get the bike heeled over rapidly on com­mand, clip the apex, and is bet­ter po­si­tioned at the ex­its to al­low ear­lier ac­cel­er­a­tion.

No mat­ter if you’re an aspir­ing road­racer or a reg­u­lar street rider, countersteering is the pri­mary method for ini­ti­at­ing a change of di­rec­tion. Rid­ers can gain con­fi­dence when they fully grasp the con­cept and coun­ter­steer with more aware­ness. Prac­tice press­ing the han­dle­bars with the right amount of force and du­ra­tion to cause the bike to arc into turns—without the need for fur­ther mid­corner cor­rec­tions. As Earl so thought­fully demon­strated, without this abil­ity rid­ers are at a greater risk of run­ning wide in cor­ners and when need­ing to turn in quickly.

Thank­fully, you don’t have to get hung up on the physics; you’ve been countersteering since the day you learned to ride a bi­cy­cle. For those who want to dive into the de­tails though, I’d sug­gest Tony Foale’s book Mo­tor­cy­cle Han­dling and Chas­sis De­sign to ex­plore the deep­est, dark­est se­crets of countersteering.

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