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g-force in dh

Downhiller

Turbo Monkey
Sep 20, 2004
1,498
0
CROATIA....europe....CROATIA
today me and my friend was talking about g-forces in auto-moto sport,and dh and fr comes up...

he said that in dh and fr (we was talking more about dh) there is no g-force when you go downhill, he said that g-force is only in cars, moto-bikes, planes and all stuff which is fast, and i told him that even bicycle is slower that all stuff which goes on fuel there is still g-force, because dh isnt easy to ride and you go realy fast...
But he say that there is no g-force in bicycle world but i say that there is so can someone tell which is truth...?!

or does someone know cca. how much is g-force on dh race ?!

thx

g-force = gravity force

ps. maybe thread is little stupid but i everyone i ask nobody knows..
 

PatBranch

Turbo Monkey
Sep 24, 2004
10,461
8
wine country
THere is definatly g-forces in the bike world. An example -doing a berm or wall ride, the most g-forces will be at the apex.

I don't know how it applies to jumps and drops though.
 

Zark

Hey little girl, do you want some candy?
Oct 18, 2001
6,257
7
Reno 911
There are lateral g-forces involved in cornering and vertical g-forces involved in G-outs (obviously!) Now the level of forces are nowhere near extreme as in moto or aviation applications, but they are there.
 

Fulton

Monkey
Nov 9, 2001
825
0
you experience g-forces in anything you do in life, no matter how small. INERTIA. my hands are experiencing g-forces as I type this. them may be extremely small, but it's still happening.
 

Jayridesacove

Turbo Monkey
Feb 21, 2004
1,336
0
Falls Church, VA
you experience the force of gravity every single day of your life.

sitting on your ass, you pull 1g.

when I take a dump, still 1g.

do me a favor and smack your friend in the forehead for me, then tell him that both of you were pulling 1g's from that maneuver.

if the earth had no gravity, we would be at 0g or weightless.
 

Downhiller

Turbo Monkey
Sep 20, 2004
1,498
0
CROATIA....europe....CROATIA
except normal g-force which you expirence everyday---i mean just in mountain biking, to be more accure - downhill

its not only my friend , when i ask some other riders they say that they dont know and never hear about g-force in mtb world..little stupid of them

when you go on dh race i think that is more that 1 g on your bike and you .(?!)
 

Jayridesacove

Turbo Monkey
Feb 21, 2004
1,336
0
Falls Church, VA
well yes, any form of accelleration or decelleration will give you some slight change in experienced g's. this also applies to any cornering you and the bike do. the most g's you could experience would be coming off a drop or railing a steep berm. the feeling is just not as intense as the feeling you'd get driving say, a Formula 1 car around a track.
 

Zutroy

Turbo Monkey
Dec 9, 2004
2,445
0
Ventura,CA
There are some good g-forces in mountain bike racing both vertical and laterial. Vertical g-loads are not as common as laterial, although on a banked oval you get some decent veritical load. DH has it from all directions and angles, not to mention and Gs involved in falling off or hitting a tree.....you can generate a few there.
 

zmtber

Turbo Monkey
Aug 13, 2005
2,437
0
g-force is most visible in the berms it has to do with speed and angle you enter the berm in steeper angle of the berm with more speed cause more g-force
 

Kornphlake

Turbo Monkey
Oct 8, 2002
2,639
0
Portland, OR
In a way your friends are correct, ridding straight down a hill you experiance exactly 1 G, the same as you would sitting watching your TV. If the path you choose down the hill has bumps or curves you'll feel more or less than 1 G. More than the feeling of multiple G's mountain biking is known for zero G's or negative G forces, where you jump a double and have the moment of floating between going up and comming back down. That moment of zero G's would less often be felt in a motor vehicle, with the exception of a dirtbike.
 

Freefall

Chimp
Apr 26, 2005
45
0
Prince George B.C.
Everytime you take a drop or catch big air your feeling zero g's until you land. Obviously in motocross they get rediculous air and so have a longer sensation of weightlessness. Sometimes when you bike you go into a depression that curves up pretty fast and you have a hard time keeping your head off the handlebars but its not that common in mountain biking or motorcross. The only G force that would be more extreme in motorcross is the acceleration becuase biking has none of that really. Its either gravity or your legs that moves you.

Anyone who has ridden a powerfull bike knows that feeling where the bike is trying to get out from under you and your arms are hanging on. Its actually pretty sweet.
 

PatBranch

Turbo Monkey
Sep 24, 2004
10,461
8
wine country
WHat about if you went into a dip/hole jump. A jump where you went down, then shot up to the lip. WOuldn't that be the same as a berm where you feel the most g's at the apex?
 

563 740

Chimp
Jul 23, 2002
73
0
North of Albany
A "g" is just an acceleration measurement like everyone said. 1 g = 32.2 ft/s^2 = 9.8 m/s^2. You jam on the brakes hard coming off a straightaway into a corner, there's some negative g. You crank hard coming out of a corner, there's some positive g. You slam a big rock, there's some negative g. You land a nice drop to tranny and pick up speed, there's some positive g.

Anything that changes your speed is a change in acceleration. A change in acceleration can be measured in g forces. Simple as that. :dancing:

In the case of berms and loops, you're experiencing centrifugal acceleration. Just acceleration in a direction other than up/down or forward/backward.
 

ChrisKring

Turbo Monkey
Jan 30, 2002
2,395
4
Grand Haven, MI
The biggest G force you will experience on a bike is a big drop to flat.

While this is a momentary acceleration (g-force). It is very high. Get a physics book.