How fast could I go on my bike?

You think you’re fast, you know you could be faster, but what is the fastest speed phys­i­cally pos­si­ble?

Cyclist - - Cycle Science - Words JAMES WITTS Il­lus­tra­tion ROB MIL­TON

here you are, speed­ing down­hill like your life de­pended on it. Crouched over the bars, white knuck­les grip­ping the drops, you look down at your bike com­puter and you see the fig­ure click up to 70kmh. Oh yes, you’re re­ally fly­ing now. But be­fore you can gain any more speed, the road sign sig­nals a junc­tion ahead and you squeeze the brakes to bring you safely to a halt.

But what if that junc­tion wasn’t there? What if there were no ob­sta­cles or bends or dogs wan­der­ing into the road, and the slope was as long and smooth and steep as you could pos­si­bly wish for? How fast could you go then? Let’s be­gin to an­swer that ques­tion by look­ing at what’s hold­ing you back.

Life’s a drag

‘That would be ter­mi­nal ve­loc­ity,’ ex­plains Rob Kitch­ing, founder of on­line aero­dy­namic out­fit Cy­cling Power Lab. ‘In cy­cling terms, this is the point where the joint stop­ping forces of aero­dy­namic drag and rolling re­sis­tance equal the forces pro­vided by grav­ity and power out­put.’

How much im­pact grav­ity has de­pends on the sever­ity of the slope. ‘If you set the slope to in­fi­nite – in other words, a wall – there’d be no load on the tyres or the bike’s struc­ture,’ says Ing­mar Jung­nickel, R&D engi­neer for Spe­cial­ized. ‘Ef­fec­tively that would make both re­dun­dant and you’d be sky­div­ing.’

Or more tech­ni­cally ‘speed sky­div­ing’, where the goal is to achieve and main­tain the high­est pos­si­ble ter­mi­nal ve­loc­ity. Drop a hu­man out of a plane belly down and they’ll reach speeds of up to 200kmh; head first and we’re talk­ing 250-300kmh; head first and wear­ing spe­cial­ist stream­lined ap­parel al­lows for speeds of up to 450kmh.

‘But that’s not cy­cling, so let’s ig­nore that and use an ac­tual road,’ con­tin­ues Jung­nickel. Scan­ning the world’s streets, Bald­win Street in Dunedin, New Zealand, holds the du­bi­ous hon­our of be­ing the steep­est road on the planet at 35-38°, depend­ing on who you be­lieve.

‘On this road’s gra­di­ent – but

Newspapers in English

Newspapers from UK

© PressReader. All rights reserved.