Who Coasts? tips and techniques anyone

[theholycow]

If by "vacuum being made by the towing car" you're referring to drafting, I sure hope you weren't towing fast enough for drafting to matter. To get a useful draft, a 53' trailer needs to be going probably >40 MPH...and a pickup or car probably needs to be going >50 mph to have a useful draft at 8 feet.

Slack comes from the tow vehicle engine braking while the towed vehicle coasts in neutral, and possibly from rolling resistance in tires/wheel bearings/diff/driveshaft/tranny.

[ShadowWorks]

Originally Posted by theholycow

If by "vacuum being made by the towing car" you're referring to drafting.

You guys call it drafting , I do it when I'm cycling behind buses and trucks

I did it once behind a truck moving at 65mph on the motorway, I did it just for a giggle.

[theholycow]

It's extremely effective at low speeds on a bicycle. It's also quite effective in a car behind a big truck at 65mph (see the drafting link in my sig).

[GasSavers_JoeBob]

Originally Posted by theholycow

If by "vacuum being made by the towing car" you're referring to drafting, I sure hope you weren't towing fast enough for drafting to matter. To get a useful draft, a 53' trailer needs to be going probably >40 MPH...and a pickup or car probably needs to be going >50 mph to have a useful draft at 8 feet.

I remember my dad telling me stories when I was young and impressionable about people getting up behind 18-wheelers, up really close, then shutting off their engines and being pulled by the vacuum behind the trucks. Can't verify the stories for accuracy, nor can I access the source any longer (he passed away in '88) but that is what I remember him telling me. Of course, he also said they were so close that it wouldn't be very safe...

[GasSavers_JoeBob]

Originally Posted by ShadowWorks

You guys call it drafting , I do it when I'm cycling behind buses and trucks

I did it once behind a truck moving at 65mph on the motorway, I did it just for a giggle.

Years ago I had a copy of Motorsport magazine from the early '50s which had an article about the world's bicycle speed record...120mph, behind an Indy-type car towing a special barrier, with the bicyclist riding a bike with a HUGE front sprocket very close to the barrier to eliminate wind resistance.

[ShadowWorks]

Originally Posted by JoeBob

Years ago I had a copy of Motorsport magazine from the early '50s which had an article about the world's bicycle speed record...120mph

That is something amazing, I had a 68 tooth front crank and 11 tooth rear sprocket on my bike and I was in the superman position made famous by Graham Obree an obscure Scottish guy that did things his way and beat everybody and a few records to on a bike made from washing machine parts

He understood the aerodynamics drag on the human body and adjusted his whole bike to suit, they only way I see 100 meter sprinters breaking the nine second barrier is with some kind of aero dynamic suit.

[theholycow]

Yikes, 68x11! I thought I was bad for turning 53x11 on the occasional downhill..