Cycle News - Archive Issues - 1980's

"Believe me, when you're . making like afrisbee on wet cobblestones, hanging on isn 't easy, " The firs t words out of th e boss' mouth aren't exactly. "Trv it - you'l l like it. " But the message is a lmost the sa me. Instead he's likel y to sa y. "T a ke the Kawa sak i over to the skid pad and give me 25 laps in eac h directi on . Keep th e gee -meter at point ·85. Pay arren tion and d on 't play arou nd and d on 't fa ll off. \\Then you'r e done with th at . b ring back th e bi ke and measure th e tires . Then take it out on th e oval for 20 laps at 90 and measu re 'e m again ." The boss in this case is Manfred Kunz , chief of motorcycle tire development for .Continenta l Rubber Company. He heads a group of four young engineers who spend a great deal of time on the track and almost never see a crowd. They have a special high. speed test facility way off in the boonies in northern Germany . Their job is to thrash the daylights out of experimental tires in hopes of finding a combination that can take the abuse of today's high .performance' bikes. It 's not a bad job . Take their work place, for example. Called the "Contidrorn," it consists o! a giant 9.300·ft. high-speed oval . a 7 .200·ft. handling course. a 700 -ft .-d iameter circular test track. and a 170·ft. skid pad.. Hundreds of concealed sprinklers wet down or even flood the surfaces for "rain" testing. Clocks. timers. te lerneteri ng pick -ups, cameras, a cent ra l computer. and lots of other high-technology bits keep track of what 's happening and gi ve the riders time to co ncentr a te on riding. The oval, which the riders call " the wall ." is the real showpiece . Curves at th e ends are sloped a t 58 · degrees from the horizontal - so steep you can't even crawl up them. So-called "d esign- speed" of the oval is about 125 mph . Tha t is. you ca n d rive a sedan ~or even a bike ) at 125 mph near th e to p of the wa ll with hands off th e stee rin g a nd still track a perfect line. Of course . you ca n go cons iderably faster wit h hands on th e steering. The test team arrives at the track with a trailer fu ll of exp eriment a l tires. Som e are made u p wit h different profiles . some with di fferent tread com pounds. some with d iffer ent tread patterns. There are subtle va ria tions in casi ng fa b ric. pl y angle. and ply thickness. Just a bo u t a nythi ng that can be varie d on a tire is tri ed - and in many com b ina tions . The tea m blocks out a pr ogram and stays at th e track a nywher e from two to six weeks at a tim e. T he riders slee p a t a small country in n nearby and show up at t he track at 7 :30 in the mo rning. T he place , called "T he Lu en enber g Heath ," is c.old a ~d windy in th e morning . T est bik es are kept III a big hangar .like bu ild in g . and th ere is a mecha nic present to change tires and keep the bikes running . Other test cr ews are usually present, too . fro m th e passenger-car, truck . bus . and even agricu ltura l. implement divisions. The scen e can be busy and th e motor cycle team likes to get out on th e track first. They dress in leathers with lon gjohns under. After a briefin g on the ramp . they head for the oval to warm up d ie bikes . the brak es, and the tir es. A control roo m sched ules times slots on th e various tracks so that a 130-mph bike won't stuff itself into a comer behind a 55·mph truck. Going fast is great. but doing it for long hours is asking for trouble. Kunz tries to set u p his tests so that the workday will have a lot of variety with some riding time on each of the courses. Recently, Doring. the youngest member of the team, threw awa y a shaft-drive Honda on the skid pad , breaking his collar- bone in the process. "H e probably got bored and wrapped on throttle to liven th ings up ." speculates Kunz . After the wall , probably the most .exciting rid~ is astride Continental's famous outrigger test device , This looks like a pair of hydraulically-actuated training wheels bolted on wings to the side of the bike. Its purpose is to catch the bike after breakaway at the extreme limit of tire performance. You literally grind into a comer until the wheels let go. You can also try such amusements as front -wheel lock-up on wet pavement. Kunz and another engineer. Heuer. are the only riders to have mastered the outrigger. "You never get used to it ," sa ys Heuer. "You have to can cel out all the instincts you've developed in years of rid ing ." He explains , " Most of us instinctively bailout when a bike gets away from us . NOb.~O~d~y_W~a~n~ts~h=a_n_d_ ' to- hand with a th ras h ing motorcycle on hard pavement . But with the outrigger you have to ha ng on . You ha ve to' rid e it down to a sta nd still . Believe me . when you're making like a frisbee on wet cobblestones. hanging on isn't easy. " But it wor ks. Event u a lly the rid er does come to a sta nds till with no lasting damage to himself or th e bike. And hopefu lly he's learned someth ing : Where it is and un der wha t ci rc u msta nces th e b ike gets irretrie va blv out of control. Desp ite th e fa ct that the Contin ent al team spends ma ny weeks 'of test rid ing every yea r . the y like to th ink of th emsel ves as ent husiastic ama teu rs . " I cou ld n't offe r th is job to tra ined professional racers, " says Kunz. "They're too com petitive and th ey're only happy at t he ex treme edge of motorcycle performance. " ''Notice all the bikes are stock. That's because if we crash one, we can replace it right away. " He goes on . "True. we're developing only highperformance tires. But most everyday riders ride most of th e time at moderate speeds. Most tire characteristics that are im port a nt at high speed also show up at moderate speeds. And at moderate speeds our powers of observation a re keener." Unskilled riders also make mistakes that a pro wouldn't , a nd Conti has to des ign a measure of forgiveness into its tires. ''Every bump (on the uiall} feels like a sledgehammer, and where you feel it is at the back ofyour neck. " T he team's fourth m ember , Wempel . was asked to pose with Kunz for some photos at the top of the wall . W empel admi tt ed he ha d never been near the wall ex cept on a bike . Look ing d own from th e top he was visibl y sh ake n . " A man co uld get hurt down the rel," he ex plaine d . Later he co nfesse d tha t he really does like to go fast . Aft er co m p leting a seri es of 130 'mph la ps . he was ask ed why he doesn't try ro ad racing . "O h , no ," sa id W empel , " I' m much too an xious." "I couldn't offer thisjob to trained professional racers. They're too competitive, and they're only happy at the ' extreme edge of motorcycle performance. " "':~ "In the laboratory we have all kinds of trick machines. On a small test" sample, we can duplicate almost any physical circumstance encountered at the track, " th e rest of us d o. T hey ho nk th e bikes arou nd town, over hill-a nd -dale , d own Germany's fam ous nospeed -limi t "Au tob a hns" (freeways). Ra in or shine. su m mer and winter, these guys a re ou t there trying to make tir es d o things they shou ld n't. "Notice the bikes are all stock. " says Heuer. "That's because if we crash one we can replace it right awa y. Also because we want to test tires on bikes just like everybody else is riding. A tire doesn't act the same way on a 240 ·lb. road racer that it does on a 700·lb. water-cooled dresser." Of course they do spend a lot of time in laboratories, at computer consoles , and behind drafting boards. "But whenever you begin to get groggy ," says Doring, "You can always think up some test that has to be done on the street." Asked if there's anything he doesn 't like about the job, Wempel says, "You bet. It's the stiff neck. Believe me, you never get used to a stiff neck." He explains that the riders get a little soft when they're away from the test track. When they return and . begin riding the high-speed oval , the abrupt change is inevitably painful. " Rid ing the wall is brutal to the muscles at the back of you neck," says Wempel. " You 're in a racing crouch and you ha ve to lift you r head to see forward . This isn't so eas y when you realize that centrifugal a cceleration on the banking ca n be I.7g. (A lm ost twice the f orce of gTavity . . . Editor.) With a full coverage helmet you r head must effecti vely weigh about 80 pounds." He adds , "T o make thin gs worse , tfle bike's suspe nsion is full y compressed. Every bump feelslike a sledgehammer and where you feel it is at th e back of your ne ck . It takes a good week of riding before your neck muscles strengthen and t he ache goes away." Riding th e wall takes getting used to in other ways . . Although it looks eas y enough from th e ground , the rider's im p ression is quite different. Spatial disorienta tion is almost total. A rider can't feel the normal downward pull of gravit y and ca n't see the horizon line . All you see is grey pavement straight ahead of you , cu rving up out of sight. The extra g's tend to tug at th e skin of your face , distorting you r eyes. It takes a co ncent r a ted effort to lift you r arm from the handgrip - if you 're fool enough to try. "And we mostly test at moderate speeds." reminds Do ring . "It really gets fun when we make our speedcertifica tion trials." He refers to the European tirerating system , in which tires are government certified to be "safe" at certain speed limits. "S" -ra ted tires are safe to sustained speed to IIO -mph , H -rated to 130mph. and V-rated to 150·mph. Certification requires actually riding a bik e equipped with the tires at those speeds for one hour und'er scrutin y of a government examiner . "W e go to a track with longer straights than the Contidrom, " says Kunz . "An d , naturally, we don't always use stock bikes. " "Talk about a stiff neck," a dds Wempe!. "Try one hour at a hundred and thirty-five miles per hourl" The riders also grouse about the time away from home and the repetitiveness of some of the tests . Yet if you ask them what they do on their days off, Kunz's answer is typical. "Well, if my kids are busy and the weather's good , I get out my bike and go for a ride... • 15 •••••••••••••••••••••

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