Bike India – August 2019

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Copyright:

Honda

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Copyright:

Honda

Image

Copyright:

Honda

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Copyright:

Hesketh

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Copyright:

Image Honda

Copyright:

Bimota

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Copyright:

Honda

AroundthesametimeHondaintroducedtheComstar,UK-basedAstralite

introduceda similarprinciplefortheirafter-marketwheel,usingpressedaluminium

centresrivetedontoa castrimwitha Kevlarlayerinbetween.Thereweresomestories

ofelectrolyticcorrosioncausedbyusingsteelrivetsonanaluminiumwheel,butthe

branddevelopedquitea followingamongsportbikeenthusiasts.Astraliteswerea

standardfittingontheshort-livedHeskethbrand.Bimotabuilta similarproductusing

aluminiumrivets,whichfeaturedonmodelssuchastheHB2andDB1inthe1980s.

Sincethen,alloycastinghasbecometheindustrystandardforseriousstreetbikes,

althoughwirewheelspersistincertaincategories.Forpurelyaestheticreasons,themore

traditionalcustommodelsstilllookrightwithspokesandtheyareclearlyobligatoryon

retro-styledscramblersandcaféracers.Trueoff-roadbikesneedtheflexofspoked

wheelstoabsorbtheimpactinjumps,asdostreetbikesinmanydevelopingmarketsor

ruralareaswithpoorroadsurfaces.Bycontrast,alloywheelsoffera stiffnessthatis

desirableinsportridingorracing,especiallygiventheextremewidthofmanymodern

tyres.Fortheultimateinstrengthandlightness,carbon-fibre

wheelsarealsonowavailable,but,again,at a considerableprice.

Upthereoncost,CNCmillingoffersindividualdesign

freedomfrombilletandis especiallypopularforone-offcustom

bikes.Wantflamesorskullsoranyoftheotherpredictable

imagerysomefolkfeelobligedtopersonalizetheirHarleyswith?

CNCwilldowhateveritsdatatellsit todoandwillneverjudge

youontaste,justonyourwallet.Asa developmentoftheCNC

direction,surelysomeonemusthave3D-printeda wheel,evenif

it’sjustthecentreboltedontoa regularrim.If not,thenbrace

yourselfforthenextthingtocome.

Ultimately,therearewheelswithnocentresat all.Theempty

rimsrotateonouterbearings,eitherregular(whichhugely

increasesthespeedofrotation)orshell-type(whichhave

functionedperfectlyonjetenginesandICEcrankcasesfor

decades)locatedona peripheralframe.Powerandbraking

forcesarethenapplieddirectlytotherim.Centre-lesswheels

haveappearedona fewcustomshowbikesinrecentyears,no

doubtpromptedbytheTronbike,althoughseveralproposalsexistedbefore.Oddball

Swisscar-builderFrancoSbarrodisplayedtwomodelsat the 1989 GenevaAutomobile

Show,bothofwhichdestroyedthewholepointofair-lightrimsbyhavingheavy,slab-

sidedbodies.Despiteclaimingtobetheinventor,hub-lesswheelsexisteddecades

beforeSbarrointheformofpoweredmono-wheels,inwhichtheriderandenginewere

locatedinsidea hugesinglerevolvingwheel.Sbarro’sconceptswerefollowedinthe

early1990sbya proposalcalledtheApachefromOhio-basedNextWorldDesign,

predictinga futuristicAmericanV-twin.Aswithalltheotherhub-lessdesigns,it

remaineda one-off.Despitethehighnoveltyvalue,practicalconsiderationsseemto

havewonout.

Aswheelwidthsgrew,theincreasingsizeofthespokestomaintainrigidityincast

wheelsdemandedcreativesolutionstoavoidanequivalentincreaseinweight.Some

companies,suchasYamaha,wentwithhollowspokes,whichrequiredexpensivemould

insertsthatcouldberemovedordrainedoncethecastwasset.Others,suchasHonda,

preferreda solidbutasymmetricdesign,withthedesiredreliefononesidebeing

counteredbythenegativeresultontheother.Indesigncircles,thiswasknownasthe

ABOVE: 1979 worldTTFormula 1

championRonHaslamposes,somewhat

uncomfortably,aboardthe49-ccHonda

MB-5

BELOW:Designsketchforthe49-cc

HondaMB-5,completewiththree-spoke

Comstarwheels

ABOVE:ComstarandComcastwheels

werefittedonHondamodelsfrom 50 cc

uptotheGL1100

BELOW:Astralitewheelswerestandard

ontheshort-livedBritishmotorcycle,

Hesketh

Honda may have been

the first to produce a wire

wheel for tubeless tyres

with the XL600L/R of the

mid-1980s

ABOVE:Hondawerethefirsttooffer

tubelesstyresona productionmodel

thankstotheComstarwheel

BELOW:Bimotawheelsoftheearly-

to-mid1980swereverysimilartothe

Astralite

44 BikeIndia^ August 2019 http://www.bikeindia.in

DESIGN TRENDS