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TdF and recumbents
Hank Wirtz wrote:
On Jul 27, 8:52 am, Tim McNamara wrote: Pat writes: How would a recumbent handle the Tour? You mean, if the UCI rules permitted the use of recumbents? They'd like have some advantage on flat breakaways and time trials, but the disadvantages in sprinting and climbing would scupper them compared to regular bikes. Another factor is that recumbents are heavier than regular bikes, although there are now some 20-22 lb recumbents (e.gg., Bacchetta) that can be bought by Joe Everedge. That would go a long way towards improving climbing. My friend Don's titanium Bacchetta seems to work pretty good on climbs. I'm wondering how well they'd handle switchbacks, since all lowracers are LWB, right? Plus, having the rider closer to the ground reduces lean clearance. Every commercially produced lowracer and most homebuilt ones are short wheelbase [1]. I can only think of a few homebuilt lowracers that are long wheelbase. What limits the turning radius on many lowracers is running the chain by the front wheel for less drive train friction. This limits the turning diameter to about 20 to 30 feet, or similar to most front wheel drive subcompact cars on the market. So no problems on any road built for automobiles. Ground clearance is not an issue. On my lowracers the BB is about 46 cm above the ground, and the bike can be leaned over by hand to more than 60° from the vertical before any "ground strike". As Jobst Brandt has pointed out, if your lean angle goes much beyond 45°, you are crashing. It is uprights that typically have the clearance issues (pedal strike) with their lower bottom brackets and preferences for longer cranks than are optimum on recumbents. I think they'd be great for TTs and probably flat road stages. In the mountains, both climbing and descending (unless the descent is a straightaway), not so much. With some vertical compliance built into the frame while retaining torsional stiffness [2], passive suspension occurs which can help greatly when traversing high speed bumps. The limited sight line over obstructions is much less of an issue on a closed road that can be pre-ridden (as is the case in the TdF). As for cornering grip/speed, I see no theoretical or practical reasons which this should differ significantly from that of an upright bicycle. I will not repeat my discussion on climbing performance here that is posted elsewhere in this thread. And every time Tom uses the phrase "foam hat" I want to punch him in the neck. Not that I'm pro- or anti-helmet, it's just a jackass thing to call it. Not in the face? butbutbut, the primary component is expanded polystyrene which is commonly known as Styrofoam®, and it is worn in the same location as clothing items known as hats. Is it also not being a jackass to spew pro-bicycle alleged protective headgear propaganda that is not backed by evidence? [1] This is defined by the BB being ahead of the head tube (SWB), adjacent to the head tube (MWB) or behind the head tube (LWB). Actual wheel base length does not factor, except to distinguish compact long wheel base (CLWB) which is less than 1.5-m from LWB (1.5-m or greater). [2] Quite possible on a single tube CFRP frame, and possible to a lesser extent on metal single tube frames and only partially triangulated metal frames. -- Tom Sherman - Holstein-Friesland Bovinia “Mary had a little lamb / And when she saw it sicken / She shipped it off to Packingtown / And now it’s labeled chicken.” |
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