I, AIDUE.NDUM _ A Bieye e with REAL

he Addendum team was ill runs inside the top tube to the Chicago in 'early March. for the head lube. where the handlebar is mount- National Manufacturing Week ed, In ide the lube is !he system' econd show, when .it saw something piral bevel set, two miter gears (34 unusual: a bicycle with gears. Real gears. mm D.D.,. ]5 teeth each). Spiral bevel gears, in fact. Amird drive shaft runs down the front The mountain bike was .at Suhner fork to the front wheel's hub and connects Manufacturing's booth. on a small plat- to the third spiralbevel gear et, The hub form, The bike was on loan for the show is a zero-backlash hub with a from its maker, Christ:ini Technologies roller clutch mechani m, The gear set is a Inc. of Philadelphia, PA. piral (83 mm D.D .• 48 teeth) Look clDse, (with I hel,pingl handl and WDu'l1see this lIike has I :spir Ibeval gear Iindl pinlDn~.ln Suhner was feamringti1e bike and (26 mm O.D., 1,2 teeth). Also, 'Itt. the bike, has Imea spi ralbevel gear selS. because it manufactur-e the bike's three the e steel gear sets have a coating sets for Christini. impregnated with Teflonlll lubricant. Steve came up with the idea for his Now, the Addendum team knows reg- The bikes' overall ratio is about system when he was riding his mountain ular bikies don't have gears .. Being gear ,0.94; I (rear wheel to front w.heel) .. bike in a. park. tIying to climbs muddy goofs, we've known for years that regu- 'That's the magic of the drive sy tern slope. While hi rear wheel wa lipping Iar bikes' "gears" are really , right there." says Steve Christini, presi- and sliding, Steve had the first, often exas- So, why do Christini bikes have real dent of Christini Technologie and inven- perated, though I. of invention-v'There gears? tor of the drive system. must be an easier. better way to do this." Because they're all-wheel-drive bicy- The rider drives the system so long as nun was the summer of 1994, before cle . Power can move back and forth both wheels are rotating at the same Steve (a mechanical engineering major, between the bikes' wheel via a.drive sys- speed. The slight gearing differential pre- of course) graduated from Villanova tem. and the gears are part of that ystem. vent power from being transferred University. That next school year, Steve Starting wi!h the rear wheel, the ys- between 'lhe wheel . developed hi idea into a prototype for tem has a spiral bevel gear (92 mrn 0.0., If the rear wheel slip, ir'll spin IDS senior deslgn project 45 teeth) and pinion (30 mm D.D .• 12 fasterthan the front wheel. At this point, fu the ummer of 2002, Steve's sy - teeth) (hat are opposite the bike's sprock- the system engages and transfers power tern became commercially available all et assembly. Thi gear set. connects to a from the rear, faster wheel tothe front, his all-wheel-drive mountain bike . drive shaft, which itself runs through the slower one to bring them back in sync, For National Manufacturing Week. bike's rear suspension, From there, the As Steve explains, the drive sy tern Steve made one of his bikes available to drive system goes inside the bike's won't allow the front wheel to go lower Joe Agro, field sales manager for Suimer. frame, in the top tube (the horizontal bar than. the rear wheel. located in Rome, GA. between the seat and han- The systemtransfers power to add Suhner's interest-and the Addendum dlebar). traction, so it helps riders maintain con- team's interest-in featuring a Chri tini trol when they're riding over wet roots or all-wheel-drive bike was imple, slippery rocks or whenclimbing a slip- "II.was a unique apptication for spiral pery grade. bevel gears," Joe says. 0 The system weigh 2 pounds 1] ounces and is Tell Us What You Think ... engaged with the flip Visit www.g.'t1tchnology,comto . of a switch on the han- • Rate this column , dlebar. When it isn't • Request more infolmlltion • CCHJtact the organizations mentioned engaged, the bike rides • Make I suggestion a distance, the like a reg-ular mountain Or cell 18471437-&604 to talk to HI 01 our goaredl drive systeml editors! blenlls imo'ihis moltn- bike. taln bike. 4:B MAY/JUNE 2003 • IGE.AIRUCIIfIN:'lnOGY • www ...yearfeclmolo{Jy ..com ., wWW.,pow8ftransmissioIJ.com