Why is SWB faster?

[dbg]

So I was looking at a Burley Canto recently with conversion option from short to longer wheelbase. I have no riding experience on this thing but am hearing everywhere that SWB is clearly a faster configuration.

Maneuverability aside, why would moving the fork from the forward position to the rear position on this bike make it faster?

[SoonerBent]

I don't know that changing the wheelbase on a bent would make it any faster. The idea that SWB bents are faster is based on SWBs being a completely different design. Volae, RANS, Bacchetta and others that build high performance SWBs design smaller, lighter frames with smaller, lighter seats and other components. The wheelbase isn't the real factor for the speed difference.

SB

[Nightshade]

Yep, It's all a rider "perception" of speed. Short reacts quicker to all rider
inputs so it "feels" faster.

[sch]

It also helps the perception of speed that Volae and Bacchetta have sponsored teams that make a splash in events where speed is a prominent part, including RAAM. Their riders have moderate to large motors and this has attracted a lot of people. OTOH all the HPVA records have been set with LWB faired or fully faired bikes which SWB can't touch but the fairings disguise the LWB origins.
Steve

[SoonerBent]

OTOH all the HPVA records have been set with LWB faired or fully faired bikes which SWB can't touch but the fairings disguise the LWB origins.
SteveThat's true of the faired classes. However in the stock classes where there are no fairings the SWBs pretty much have a handle on things.

Yep, It's all a rider "perception" of speed. Short reacts quicker to all rider
inputs so it "feels" faster.I really wasn't talking about perception but real speed. What I meant was that you can't take a 30 to 35 pound LWB and move the move the headtube location and call it the same as a 20 to 25 pound Volae or Bacchetta.

SB

[BlazingPedals]

The original assumption was made in the days when it was a 'given' that SWB bikes were lighter than LWB offerings, and typically placed the riders in more aero positions, too. At the time, LWB was for touring, and SWB was for sporty riding. That isn't necessarily true anymore - although I'd take it as a given that lowracers and highracers, both of which are short wheelbase formats, are faster than current commercially-available long wheelbase models, IF you compare unfaired to unfaired.

[jmR&D]

Comparing 'bents with general purpose cockpits, a SWB often has a higher BB and a more reclined seat back. This presents a smaller wind profile, reducing drag. A LWB often has a lower BB and a more upright seat back, presenting a relatively larger wind profile. Fairings may favor the LWB, though I'm not sure of that.

Either design can feel faster, depending on the circumstances, road condition, etc.

[JohnH]

Here's a real-world example:

I ride a Rotator Tiger (http://rotatorrecumbent.com/main_content.html), a classic high-crank, reclined (more than the pics) SWB. My wife rides a RANS Stratus (http://www.ransbikes.com/Stratus.htm), a classic LWB. I can climb the nearby 1.5-mile, 9% hill at about the same speed on either bike, even though they are set up quite differently. However, coasting back down that hill is a different story. I have yet to reach the Tigers's max speed - I always end up braking just under 50 mph. On the Stratus, I have to pedal to maintain 35 mph.

While both bikes are quite comfy to me, and I can ride either one at 16-18 mph for miles, a headwind affects the Stratus almost like a DF whereas the Tiger almost ignores headwinds. So for (unfaired) racing, or real-world battling headwinds, the reclined SWB Tiger wins hands-down. For sheer crusing comfort, especially on rough roads, the flexibility in the Stratus' long frame is great.