Cycling UK Forum

atlas_shrugged wrote:This makes me think that any light, frictionless, and simple technique for making a bike glide over the boulders that our UK roads have become will provide a big speed advantage.

You’ve just described fat, supple tyres!

atlas_shrugged wrote:I ride a recumbent (~20mph) and in winter a conventional hybrid (~15mph).

Similar wheel sizes / tyre section ?

on a recumbent you can't easily decouple your mass from the bike which makes the bike jiggle around less and makes your body absorb a lot more energy; more suspension losses if you like.

A simple way of reducing these losses (potentially by about half) is simply to decouple the body and its contact points from 'the chassis' in terms of vertical movement. The wheels can then ride the bumps without moving the CoG so much and potentially pedalling is not affected.

The earliest example of this approach is the 'the whippet' of 1888



but -despite the obvious benefits on offer- I don't think this approach has been applied to a recumbent machine..... unless someone knows different?

cheers

On an upeightbisnt that done by taking more weight on the pedals.. pretty sure some bents have ‘seat’ suspension don’t they?

[XAP]Bob wrote:On an upeightbisnt that done by taking more weight on the pedals.. pretty sure some bents have ‘seat’ suspension don’t they?

there are all kinds of suspension on 'bents, but AFAICT not that particular one, i.e. where all the rider contact points are rigidly coupled within one structure and both wheels are rigidly coupled in another, separate one.

cheers

Samuel D wrote:You’ve just described fat, supple tyres!

Compare a ride on a narrow tyre-ed Moulton to a Raleigh 20 (shopper or chopper) you'll know what riding through treacle is like.

Brucey wrote:However what is less obvious is that just pedalling hard tends to excite a type a) resonance and this tends to absorb energy all the time, even when the suspension has little or no work to do. Hence my earlier comments about needing to pedal in a specific fashion. I have yet to meet a rider that could pedal smoothly at 10/10ths aerobic effort up a draggy climb without bobbing like crazy on a suspension bike, which is why lockouts were invented. On many suspension bikes without lockout, trying to ride out of the saddle is basically a complete waste of time.

+1
precisely why I sold my Moulton AM7 but still have my Moulton Safari. The AM7 space-frame suspension was underdamped (friction dampers) and bobbed all the time when climbing - specially out of the saddle. Much more effort required for climbing (not mitigated enough by the great descending!) The Safari F-frame rubber damped suspension much reduced bobbing I can live with when climbing, while the vibration reduction and descending is still good. Shame about the weight though.

I know the later Moulton NSs had a front suspension lock of sorts but it seemed a bit of a bodge to me considering they are very silly money. I'd have thought a handlebar fine damping control should have been incorporated for the price.