Cycle News - Archive Issues - 1970's

Th e side lu gs a re t hose used when the bike is leaned or when corne ring. T he re are tw o kinds of side lu gs ; bridged and unbridged. T he bridged a re tw o o r m ore lugs co nnec te d with reinforcing rubber b etween th e lu gs. T hey ar e d esign ed in this fashion to prevent th e side knobs . from foldin g ove r under h eavy corne ring and to add stability . Bridged ti res are ge n erally used for h a rd gro u n d. The Me tzler 4 .00 is the best e x am p le of brid ged lu gs. Un bridged treads a re those lugs without the rei n fo rce m e n t .. The logic behind this is the fle xin g sid e knobs allo ws the tire to get . the m a x im um · traction through turns. Unbridged tires are usu all y co n sid e re d th e h est for sandy o r mudd y co n d ition s. T he Baru m 4 .0 0 is a good exa mp le of an unbrid ged tire . A no ther tread d esign is the chevron o r self-clean in g d esign . This is ty pified by the Barum 4 .00/4.50. The design w as created for mud rid ing to keep m ud fro m buildi ng up between the knobs. The ti re is m ounted on th e wheel with the V p attern in ve rted. T hese d esign s are n o t known fo r th eir popularity fo r co rn eri n g ab ili t y as th ey te n d to slide mor e th an st raigh t designs. T his reasoni ng seems to b e sup ported b y testing. A th ird tr ead p attern is th e ins ide tr ead p a tte rn . T h is is a fine pattern in sid e th e casing wh ich contacts the inner tu be. T he reas on for this tread, I w as to ld , was to grip the in ner tube t o p reven t th e tire fr o m spi n ni ng on th e rim. But logic has it that as th e tire spins o the rim the in creased grip upon th e tube will cause it to sp in , possibly te aring out the valve s te m . Cord pl y is the numbe r o f lay ers of rubberized cl o th making up the cas ing or carcas s of th e tire. The purpose of these layers is to give ro ad sta bility to the ti re . As m entio n ed earlie r th ese p lies are laid d iagonally ' over each othe r, and th e a ngles at which these a re laid con trol th e stab ili ty. A lm o st all the t ires test ed h ad nyl on or rayon b ased c ord , an advance over the former co tt o n b ase d material in strength . Be cause th e se new ma terial s are stronger than cotto n , fe we r number of pli es are n eeded to attain the same str ength . The te rm " p ly rating" w as developed to d esc rib e the co rd strength of a sy n thetic b ased tire. T hese tires h ave th e impac t resistanc e of a similar tire w ith m ore lay ers of co tt on . T he re fore, a tire wi th a 6 pl y ra t in g might ac tuall y o nly h ave 3 or 4 pli es of synthetic material b ut h as the stre ngt h of 6 cotto n plies. T he U.S. Departmen t of T ra ns po rtat io n gove rns tire regula tions a n d sets th e stan dards of stre ng th an d size. The d ifferen ce b e tween co nven tio n al 4 p .r. and 6 p .r. tries is in te rms of strength and w eight. A 6 p .r , will h ave mo re resis te nce to punc tures and rim damage but it als o wei gh s qui t e a bi t more ; up to 3 or 4 p ounds o ve r a 4 p.r. An obvious cha rac te ris tic of tire s is th at they eve n tually we ar o u t. Some to p pro s ch ange tires afte r e ve ry race. However, few o f u s h ave th e c o in to b e ab le to keep a su pp ly stockpiled, so we tend to ge t the m ost from a tire b e fore r eplacing. T ire replacement shou ld occ u r wh en th ere is a n o t iceable loss of traction when c o mpared to a new tire. This will ge n erally take place a t approxima tel y half th e origin al kn ob height. This is not to say that the tall er the knobs th e longer the tire life for a tall knob tends to wear much more quickly than a sh o rte r o ne . When m aking a tire se lectio n kee p thes e cons truc tion" p oin ts in mind b ecau se p erformance may n ot be th e o n ly reason for a p u rchase. All th ings we re ke pt constant except fo r the di fferen t tir es. The tire pressure w as set a t 12 ps i for all t ire s. Manufacturers PERFORMANCE recommendations ran ged fr om a low o f In the p erformance se ction o f the 5 p si up to 18 psi. 12 psi was chosen as article , we attempt to sh ow, by actual a happy medium for all . testing, which o f th e major accessory We se lected tires to be fi tted rear knob by man ufac turers h ad th e b est r andoml y after pr ac t icing starts p erformers in fo u r m ajor ca tego rie s. sufficie n tly to record co ns t an t tim es . Th e se ca tegories are d rags, turns, T he tires were divided in to two groups, braking an d w e ar . We w an ted to sh o w the 4 .00s firs t a n d the bi g tires se con d . the p os sible p erformance diffe rence s O ur t um cons is te d of a n e ve n ly b e tw e e n m anufa cturers an d th e sh ape d 18 0 d egree curve , 100 y ards di ff eren t tire si zes. T he tire sizes chosen long, comple tely fl a t an d virtuall y were 4 .0 0x 18 an d what we calle d the unmarred b y ruts and bumps. A simple "big" tires which ranged f ro m the tum lik e this was ch osen to eliminate o the r variables su ch as rough gr ound, claimed 4.20x1 8 t o 4.60xI 8. T he testing w as d one at Indian Dunes ro c ks, a n d b erms which could di st ort Park in Valenci a, Cali fornia, wh e re a 5 0 tim es. T h e t otal length of th e curve w as yard d irt d rag strip and a 10 0 y ard , 18 0 10 0 yards, sufficiently in le ngth to ge t de gree tum , w e re used . T he gro und was into third gear. T he pl an again was . to d ry and varied fro m hard p ac ked to soft get from start to fin ish in the shortest san d. time. T he d rag was used to si m ulate starts In the b rake test we ran the Ossa u p o f races and to get p er forman ce fr o m to 30 MPH , and once at that speed we loc k ed u p th e rear w heel an d m easured the ce n te r line kn ob s of th e tire s. T he tum w as us ed to find out how t he tir e d id the di st a nce needed t o co me to a in o th er than straight drags. Asl o th e co mp le te h alt. Th e bike was kept tu m ga ve p erforman ce figu res o f ' th e upright with th e re ar brak e only b eing sidewa ll ad he sion. T he t hird test wa s u sed. designed to ch ec k the stopp ing ability Wear cal cu la tion was d iffic ul t b ut o f th e tires. T his was accomplishe d b y n o t as difficult as o ne mi gh t h ave lo c kin g u p th e tire at 30 MPH and im a gin e d. Be caus e w e h ad n o measuring the d is tan ce requ ired to stop. instru ments to me asu re the wear, we All runs were d one b y the same rid e r t o had to estim ate by com p ari n g all tires. avo id extraneous vairab les , T he fin al It was really amazing to se e h ow mu ch test was a subje ct ive rat ing of e ach tire 's tires reall y di d wear. Th e di ffe rence we ar ch arac te ristic s. be tw e en th e best we arer and th e wor st T h ese tests .reve a led wh ich tire was weare r w as phen omenal con sid eri n g th e b est for our test bike, a 2 50 Ossa short am oun t o f time e ach tire was run , Stilletto , but do not n ec essarily appl y to Ea ch tire h ad th e sa me ' tim e on the Ossa all bikes , riders an d tracks. Fo r in stance, o ver the same te st course so wear was our O ssa is quit e a torquey bike wi th strictly a fa ctor of th e tire itself. low gearin g, so for a high revin g, hi ghl y So what d o all of th ese te sts show geared bike a dif feren t tire m a y b e, more . collectively? After assigning a fin ishing app ropriate. We can o nly expose th e . p os ition to ea ch tire af ter each te st was general ch arac t eris tics of each tire and com p leted an d ga thering all th e tires leave th e ch o ice up to y o u. finishi ng p osi tio ns, we were abl e to T h e length o f th e dirt drag was set at assign an overall pl acing t o eac h tire. In 50 yards be cause this was th e distance eac h o f th e tw o tire ca tegorie s it was needed t o accelerate up to third gear on eas)' to d etermine the first three the Os sa. Th e third gear limit was p ositions becau se th ese tires really stood ch ose n because it is in the fir st three ou t.•T he remaining p ositions were ofte n h ard to se para te, se ve ral times w e gears that the most wheelsp in oc cu rs and wh ere trac tion is needed th e most. n eeded t o resort to so me individual Cnt . Side Max. Max. Knob Knob Brid. Ht . HI. Ht. WI. Ply Ral ing .629 .593 .600 .640 .615 .622 .25 .30 25 15 12 13 6 4 4 5 .05 4.36 4.50 4.47 .477 .472 .510 .477 00 00 13.5 13 4 4 26.50 21.95 4.81 4 28 4.97 4.40 .569 .520 .370 .344 00 00 15 13 6 6 3120 2725 4.60 4 .47 4.32 4.37 .567 .491 .427 .460 00 16 13 4 4 Price Wdt . Ht . Trelleborg 4.50 161 Trelleborg 4 .00 MX Trelleborg 4.50 MX 35.80. 27 .75 30 .50 4.80 4.48 4.52 4.45 4.80 4.59 Yokohama 4.60 Yokohama 4 .00 23 .00 21 .00 Cheng Sh in 4.50 Cheng Shin 4.00 Barum 425 Barum 4.00 A 'test ' such as this is ob viously full of many variab les. lVe don't reco m m end t hat yo u go ou t and bu y tires based o n t he result s of the p erf orma nce data co ntained on t h ese tw o pag es. If y ou are f amiliar with t he place where th e tires were t ested th en y ou can pr obably take it m or e serio usly . St ill, we fe el t hat the t echn ical and m easur em en t inform ation co ntained here is we ll worthw hile, and t hat there is so me basis for th e p erf orma nce conclusion s w hic h th e testers have reach ed... Ed. HOW THEY SCORE HOVV THEY MEASURE Name q ui c k times to break ties. A lso bear in mind that so me ti res were design ed no t for all a ro un d t raction , b u t a fe w we re design ed f or mud. Th e final tally showed th at Metzler was th e bi g winner in the 4 .00 class. It had two firsts, a secon d and a la st in th e f our test categories. S econd was Yo koh am a with a fi rst , two thirds an d a sixth . Pir el li w as third wi th a secon d, th ird, f o urth and f ifth p la ce finishes. Ch en g S hi n came out on top in th e big tire division w ith a firs t , two thi rd s and a fou rth. S econd agai n was Y okohama w ith two firsts, a fo u r th and a seve n th . Trell eborg copped th ird with tw o twos an d two fives. S0 , wh at d o es thi s me an to you , the cons u me r? Lo ok a t th e p erformance of each ti re an d bear in mind the conditions . un der which each tire wa s tested when selecting n ew rubber. These res u lts a re n ot absolute, but they are an in di cation of eac h tire' s characteristics. Also bear in m in d th e p ric es o f each tire . Wh en com paring 4 .0 0s wi th th e bi g tires for your bi g bike , lo ok closely a t th e bi g g e r ti res b e c au s e their p er f o rm an ce o ve ral l tends to be be tte r than the sm al le r 4 .00s in most respec ts. So th e re yo u have it, the great rear ween ie co mp ari so n test. T he ch arts will h elp y o u decid ed on the tire y ou wa nt. If you're a real h o t dog, look fo r the tire wh ich wi ll give you th e p er form an ce in t he a reas desi red. If you 're an econo -racer, loo k a t th e top tires in each class for the overall b est . T ak e a cl ose look at all tires, they 're to o exp en sive not to . .. 00 Inside Tread Overall Nam e 37 .10 4 .58 4.08 4 .31 4.35 .605 .591 .579 .546 .119 .118 12 11 Metzler 4.50 Metzler 4.00 30 .00 25 .10 4 .65 4.50 4.31 4.52 .629 .604 .625 .575 .124 .318 14.5, 13 Fullbore Pirelli 4.00 2729 26.50 4 .68 4.19 4.08 4.35 .516 .535 .500 .403 .19 1 .10 13 12 4 4 Metzler Yokohama Pirell i yes yes Good year Trellebo rg Cheng Sh in (Secs.) Pas. (Sees.l Pos. Braking Pas. Wear 1 2 2 4 5 6 7 4 .02 3.98 4.00 3.94 3.98 3.96 4 .00 3 .98 7 3 5 1 4 2 6 9 .86 9.96 10.00 10.02 10.10 10.00 10 .08 10.00 1 2 3 5 7 4 6 114ft 6 in 123ft 11in 117ft 6 in ' 141t 11in 102ft 8 in 131ft 5 in 118ft 0 in 117ft 6 in 2 6 4 3 1 7 5 1 3 2 7 5 4 6 S a rum 1 1 3' 4 4 6 7 8 3.88 3.94 3.90 3.94 4 .00 4.00 4 .02 4 .06 1 3 2 4 5 6 7 8 9 .96 9.86 9.90 10.00 9.98 10.12 9 .96 9.96 3 1 2 7 6 8 4 5 108ft 6in 1171t 1in 110 ft5 in 1071t 5in 103ft 2 in 97ft 9 in 115ft 8 in 125ft 8 in 4 \7 5 3 2 1 6 8 4 1 5 2 3 8 7 6 To ta l Average Big Tires: Cheng Shin yes yes Treeleborg MX Full Bo re Barurn Goody ear Trelleborg Bpr M etzler 4 4 Pos. 100 Yard urn 400s : Yo koh ama Goody ear 4.50 Goodyear 4.00 50 Yard Drag T otal Average 3 .97 9.96 110ft8in

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