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Standing on the Pegs "Lowers Your Centre of Gravity"?

Posted: Thu Sep 19, 2013 4:36 pm
by gocytocis
It's clear that getting up on the pegs gives the rider greater control of the bike off road. Many riders, even knowlegible ones, will claim that it's because you are "lowering your centre of gravity" by placing your weight on the pegs rather than on the seat. I am not a physicist, but this explanation has never washed with me.

Firstly, when folks talk about the centre of "gravity", I believe they actually mean the centre of "mass".

Second, the centre of mass of an assembly of objects, such as a person on a bike, is totally independent of where those objects are connected, or if they are even connected at all for that matter.

Third, standing on the pegs should actually RAISE the centre of mass because there is more mass of the rider distributed higher than when seated.

The dynamics of single-track vehicles is complex & beyond the comprehension of my simple mind, but I have always suspected that, contrary to popular belief, it's actually this HIGHER centre of mass that makes a bike more 'flickable' than a low centre of mass. The reason is because of the increased leverage that the higher centre of mass gives the rider over the bike. I also believe that regardless of whether the overall COM has been raised or lowered, the more important factor is that the COMs of the bike and the rider are 'de-coupled' by standing, thus allowing a more complex & variable relationship with the terrain.

Anyone out there smarter than me able to confirm this, or tell me I'm wrong?

Re: Standing on the Pegs "Lowers Your Centre of Gravity"?

Posted: Thu Sep 19, 2013 5:24 pm
by Mal S7
Sounds like a much better explanation to me.
But I flunked physics.

Re: Standing on the Pegs "Lowers Your Centre of Gravity"?

Posted: Thu Sep 19, 2013 5:57 pm
by Steve in Golden
This comes up on advrider often.

Supposedly having your full weight on the pegs instead of most of it on the seat is more better for maneuvering the bike in rough territory.

I didn't know until just now that it is illegal to ride on the street standing on the pegs in many places. Figures.

Re: Standing on the Pegs "Lowers Your Centre of Gravity"?

Posted: Fri Sep 20, 2013 11:22 am
by gocytocis
Steve in Golden wrote:I didn't know until just now that it is illegal to ride on the street standing on the pegs in many places. Figures.
I assume you're in BC Steve (?). If so, I understand that yours is one of the provinces where standing on the pegs, on ANY public road, paved or not, is illegal! Another clear case of law-makers being ignorant of the sport of motorcycling, and what constitutes safe & proper technique on a bike. :x
I'd gladly take a ticket for standing on the pegs just to have the chance to challenge it in court! :D

Re: Standing on the Pegs "Lowers Your Centre of Gravity"?

Posted: Fri Sep 20, 2013 11:32 am
by gocytocis
Steve in Golden wrote:This comes up on advrider often.
You're right! I just did a little search on advrider and opinions abound. Plenty of folks over there willing to emphatically state that standing on the pegs lowers your COG too. Again, I'm no Physicist, but there is simply no way for a rider to lower the COG of a motorcycle, unless of course he's laying underneath it! :lol:

Re: Standing on the Pegs "Lowers Your Centre of Gravity"?

Posted: Fri Sep 20, 2013 11:57 am
by melville
gocytocis wrote:
Steve in Golden wrote:This comes up on advrider often.
You're right! I just did a little search on advrider and opinions abound. Plenty of folks over there willing to emphatically state that standing on the pegs lowers your COG too. Again, I'm no Physicist, but there is simply no way for a rider to lower the COG of a motorcycle, unless of course he's laying underneath it! :lol:
I did that Wednesday, and I can't recommend it.

Re: Standing on the Pegs "Lowers Your Centre of Gravity"?

Posted: Fri Sep 20, 2013 12:55 pm
by Steve in Golden
melville wrote:
gocytocis wrote:Again, I'm no Physicist, but there is simply no way for a rider to lower the COG of a motorcycle, unless of course he's laying underneath it! :lol:
I did that Wednesday, and I can't recommend it.
What do you mean melville, I hope you didn't have a get-off!? :shock:
gocytocis wrote:I assume you're in BC Steve (?).
No, I am in Golden, CO, US of A. I used to have an uncle that lived in BC though. Beautiful place.

Re: Standing on the Pegs "Lowers Your Centre of Gravity"?

Posted: Fri Sep 20, 2013 1:28 pm
by melville
Steve in Golden wrote:
melville wrote:
gocytocis wrote:Again, I'm no Physicist, but there is simply no way for a rider to lower the COG of a motorcycle, unless of course he's laying underneath it! :lol:
I did that Wednesday, and I can't recommend it.
What do you mean melville, I hope you didn't have a get-off!? :shock:
New post in my Alderpoint loop thread in Motorcycling. :oops: After some VW work this afternoon, I'll be doing a re-bling on parts of the /6. :evil:

As regards standing on the pegs, I do it for the same reason I stand up whilst descending on the mountain bike--it lets the bike move around and find its path on rough dirt without knocking me in the ass.