Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/126045
The suspension revolution in motorcycle competition and production . is over. What was radical two years ago is now a way of life. In previous issues, you 've been exposed to riding tests and analyses of the nitr ogencharged Girting from Great Britain , the UeCarbon system Bilstein of West Gennany, and the bladder/reservoir Marzocchi of Italy . They are all fine dampers with at least the Girling and the Marzocchi appearing on production racers from Husqvarna, Maico, and KTM. But this test is all-American: a riding evaluation of the current models of damper from S&W, Boge/Mulholland, Curnutt, Works Performance, and Fox Shox . BASIC PREMISES First of all , they are absolutely so m uch better in performan ce than just about anything we were accustomed to up until 18 months ago that it is st aggering. None o f them faded or broke, all of them fit the motorcycle for whi ch they were requested (co ntrary to o ur experience with the las t shock test some years ba ck) , and all of them ca me with so me su ppo rting literat ure 'or lit tle bags with the ne cessary bushings and spacers to adap t them sim ply to varying bolt size , bracket dimensions , e tc . The bike use d as a tes t be d was a current model RM370 Su zuki. There were good reasons for the choice. The big bore (and long stroke) RM is the hottest thing o n the circ uit. It is reliable, fast, an d has in trinsically good handling manners. It also u ses very long dampers mounted cantilever to the fram e. The negative argument regarding th e choice is th at we determined only which sh oc ks work well on an RM. The two positive aspects of the choice are th at a can t ilever arran gement puts more stress o n a sh ock so that you ca n draw the reasonable conclusion th at if it works we ll in th at co n figu ration , it will work as well o r better in a more ver t ica l se t-up . Th e ot he r extra streng th item comes from the shock length itself wh ich ne cessitates a very st ro ng rod, body , eyes , bushings, etc. to hold u p to the fo rces trying to ';'ake a shock that long flex. We think . t he RM turned out to be an excellent choice . We went a little further in trying to eliminate any variable fa ctors that could influence the hand ling of the ma chine . The atte mp t was to isol ate any positive or negative aspects of the bike's handling down to the .particular set of shocks being evaluated. This elimination of variables in the Su zuki's performance turned out to be a sub-project of fair-sized dimensions in itself. There are some general characteristics in the engi neering of the America n-built shocks. With ou t bei ng ' artificial in th e co m par iso n , you can arri ve a t so me dist incti on s co mpared to European-built dam pers, I ) The American shocks emplo y st aged valving in th e da mping action. Designed to co n tro l b ump damping, rebound damping, and the internal pressures a t which the sta ges come in to effect var y with manufacturer bu t the ideas are simil ar, even with the Fo x Sh ock whi ch u se a single variable jet to co n tro l rebound damping. Well get into the details in the discussion of each damper . 2) A merican shocks are big. Everything abo u t t hem is " m o re " . They tend to be overbuilt an d understressed. For exam ple. all o f them feature half-in ch diameter chro me d steel shafts whi ch loo k even bi gger than .5 inches round. These dampers are solution-oriented p ieces of ma chinery in an overkill way rather t han , say, th e intricacy to ach ieve pe rf orm an ce found in the It alian Marzocchi or the pre cis ion of closely-he ld toleran ces as in the German Bilstein. lt almost m akes you believe in the myth of nation al ch aracter." As usual, in co mparison s of this so rt . the U.S . models work compara tively gross ly but just as well - 'o r bett er - in the fina l res ult. 3) The design er-builders o f th ese American shocks are all genuine maver ic ks. The pe ople beh in d ea ch of the differ en t shocks considered em body a tal e of Yankee ingenuity though in reali ty, the y are all West ern America ns in terms of th eir pro duct . Kn owin g the pe rso nalities wh o sta nd behind t heir pr oduct s tends to put us in a favorable mood about using the m . 27