Zig-Zagging

[nightrider]

My mate who also rides fixed says zig-zagging up hills is a waste of time.I only zig-zag on the OMG this is steep type of hills,on quiet lanes.I think it helps,because it takes the edge of the gradient.My friend says whatever you do,you still have to drag the same rider up the same hill.He weighs about 10kgs less than me and climbs a bit faster.So do you zig-zag or ride straight up untill you have to get off and walk?

[Kim]

You still have to drag the same mass up the same hill, but you don't have to do it in the same amount of time.  Zig-zagging reduces the gradient by increasing the distance, which means you can increase the bicycle's ground speed for a given rate of climb.  Sometimes that can be the difference between being able to maintain balance (which is where it becomes particularly relevant on fixed, or at the other end of the spectrum, two-wheeled 'bents) and having to get off and walk.

Given a trike (with perfectly grippy tyres and all the gears you could wish for), it wouldn't gain you anything useful.

[nightrider]

That makes sense.I am no good at maths,but if you ride straight across the road it should be 0%.o riding at 45 degree angle should reduce the gradient from say 15% down to 10% and increases the distance by say 25%.But I am talking about the difference between staying on the bike or having to dismount and lose more time getting on again.

[Crumbling Nick]

Wot Kim said.

I zig-zag occasionally. It reduces the gradient. That's why roads up steep mountain passes zig-zag.

There are hazards, thobut. I discovered, wandering  up a hill to Ardens Grafton, that a quiet car with a very patient driver was following me  . My excuse is that I'd not climbed that one before with a few extra kg of fresh vegetables in the saddlebag, which was the purpose of the ride.

The "waste of time" aspect is complex. Obviously it's a bit of a put-down. But if you tour (or Audax, which is outwith my experience) on fixed, it becomes evident that speed up one steep hill is less important than time for the day's ride, and recovery for the following day.

[/pedant] It's not maths, it's physics. [pedant]

[Veloman]

[/pedant] It's not maths, it's physics. [pedant]

Isn't physics explained by using maths?

[Crumbling Nick]

[/pedant] It's not maths, it's physics. [pedant]

Isn't physics explained by using maths?

Yes & no. "Explained by" is ambiguous. The relation "not identically equal to" applies. Is that level of pure maths helpful to understanding the physical problem of climbing hills on a silly gear?

[The Seldom Killer]

Zig-zagging or tacking isn't necessarily a waste of time.

I've tacked up a hill next to someone who was straight-lining it and was able to get up the hill faster than them (you have to account for power and gear ratio variance). You also put yourself in less energy debt and will take less time to recover making the next stretch of road easier to ride.

[Chris S]

I tend to ride big gears (74-85") and I'm heavy (80-85Kg), so any hill over 14% is a proper challenge.

Tacking really helps; it turns a Must-Walk hill into a Rideable hill. There are issues though - obviously, there's a summit over which a surprise car can appear, so you have to keep your ears open for traffic. The road has to be wide enough - so there's no tacking up Colstrope Lane on the AAAnfractuous (20% - guaranteed walk for me), and finally - all my fixers have toe overlap, so good timing for each tack is essential if I'm not to end up in a bit of a tangle.

Tacking isn't just for fixies though. We've even tried it on the tandem - but that requires even more room!

[Jaded]

a few extra kg of fresh vegetables in the saddlebag

That's a great euphamism for being a little out of trim 

[DrMekon]

Tacking isn't just for fixies though.

<a href="http://www.youtube.com/v/kikCCWIq9Lw&rel=1" target="_blank">http://www.youtube.com/v/kikCCWIq9Lw&rel=1</a>

 

[red marley]

You may wish to ask your mate why there are so many bends up to the Col du Galibier (and a hundred thousand other climbs) if avoiding the direct route is such a waste of time.

BTW, nice Pendle video ESL. You have managed to capture the steepness of Hardknott, which all too readily gets flattened when filmed or photographed.

[red marley]

You may also wish to ask your mate why they aren't using a higher gear on their bike since they will be 'wasting' pedal revolutions by not doing so.

[Chris S]

Tacktastic stuff DrMekon!

[Nelson Longflap]

In theory I agree with the consensus here.

But yesterday I climbed a "testing" hill and in practice found that tacking just upset my climbing zen and seemed to make thing worse. Admittedly the test hill was a narrow road so the benefits of tacking were a bit limited anyway, but for me concentration on climbing style is a helpful factor in getting up the hill and zig zagging around is disruptive. 

[Peter]

Zig-zagging is a climbing style, surely?  And roads don't come much narrower than Hardknott Pass (or steeper).  It clearly worked for Dr Mekon.  I'm astonished at his cadence.