why does weight affect turning?

[delkampg]

i dont understand why weight affects turning radius. i understand how length affects turn radius, but not weight could someone explain this to me, like im a retarded monkey...thank you

[tmk7c9]

Where did you hear that?

I guess i've never really thought about it....but I can't think of any reason why weight would affect turning radius. Seems to me that turning radius is affected only by length, and the max angle of turn of the steering head. I don't think weight has anything to do with it.

Did someone tell you otherwise?

[Kreylyn]

i dont understand why weight affects turning radius. i understand how length affects turn radius, but not weight could someone explain this to me, like im a retarded monkey...thank you

The more mass, the more force that is needed to change it's direction. In this case, the "force" is directly related to tire traction. When you reach maximium traction and still need/force more out of the tire... you either get "push"... where your simultaniously gripping and sliding... or you just get all slip depending on road conditions and the tire.

This is primarily an effect at min/max type riding.

There are also other things, like transition aspects, power/weight ratio, etc... to keep in mind as well for high performance track riding.

Krey

[DreKat]

Take 2 bikes with the same weight, if one has a lower centre of gravity then the other one then the turns radius will be less. Weight is not the biggest factor but where most of the weight is located. Thats why I love Buells since the fuel is actualy in the frame and not in the tank.

[Vacuumdog]

If you are talking about "pushing your bike in your driveway" turning radius, then all that matters is the distance between the two wheels, and the maximum angle that your handlebars can turn.

If you are talking about high speed turning... such as going through curves or a racetrack.. then imagine two different bikes with the same tires. The bike that weighs more will generate more centrifugal force when going through the turn, therefore it will reach the limit of grip that the tires can provide, sooner than the lighter bike.

[allblackkat]

If you are talking about "pushing your bike in your driveway" turning radius, then all that matters is the distance between the two wheels, and the maximum angle that your handlebars can turn.

If you are talking about high speed turning... such as going through curves or a racetrack.. then imagine two different bikes with the same tires. The bike that weighs more will generate more centrifugal force when going through the turn, therefore it will reach the limit of grip that the tires can provide, sooner than the lighter bike.

Just about sums it up...

More weight = more momentum...

Like comparing a rabbit to an elephant... (well maybe not to that extreme...)

[Andy8982]

For the tightest turning radius at any speed you need the maxium lean angle you can sustain (as far as you can go without falling over in the corner). A lot of this is set by the tyres - but there's a lot of things going on in the chasis that affects the load the tyres see.

The total weight affects the cornering limit of the bike (grip limit as described above).

Additionally there's two types of weight. Unsprung weight and Sprung weight. How the weight is divided between them also greatly affects performance and so turning radius.

In short you want the unsprung weight as low as possible. Is essentially is a measure of the wheel/swing arm weights. Which affects rotational masses/moments of interia - which influence braking, acceleration, and rate of lean angle change (turning 'in' rate of the bike)

For the quickest corner you need a bike that want to tip in fast and has no resistance to direction changes (Inertia).

Sprung weight can be balanced out by suspension springs, but what you have to realise is that as you get into steeper lean angles more and more of the cornering load is carried by the chassis and swing arm. (If you don't believe me - think about where the suspension spring is at high lean and think where the weight of the bike is trying to go - straight down.) This acts to 'bend' your suspension rather than compress it.

To make the bike corner well you have to design to the cornering load and allow a certain amount of flexure of the chassis to suit. This is easy to do with low sprung weights but steel framed bikes tend to have high weights and very limited flexure in the chassis.

This is made worse by steel framed bikes having a tendency to have lower end/cheaper suspensions so amplifying the issue.

All this means that where chassis flexure would allow a bit of give in the cornering load without transmitting it to the tyres, steel (heavy) frames act like a welded rod and so when combined with the heavier weight overload the tyres quicker, so limiting your corner radius.

[kidblooper]

blah i want my 2 minutes back, can someone refund the two minutes i just spent reading this ?

[Badfaerie]

No refunds and no exchanges!

[H-2 CHARLIE]

going straight the most weight is in the rear .. but in a turn on a corner the weight is on the front tire now so a heavy bike will take more effort to turn in and out from shifting weight

[Psycho1]

I don't really think weight has much (if anything) to do with turning radius at speed. Sure a lighter bike is easier to lay over into a corner quickly, but a heavier bike should load the tires better for traction against the road surface (suspensions/hp being equal). I think any differences you find between a heavysport touring type bike and a light SS type bike are more than likely cause by lower quality suspensions generally used on the heavy bikes, and less aggressive steering angles etc.

[csjcsj]

Who are the scientists on here!

[loudnlow7484]

I subscribe to the centrifugal force theory. More weight= more push to the outside, and more force on the tires. More noticeable than ultimate exit-ramp-speed is how quick you can transition on a heavy bike. Going from hard left to hard right on a heavy bike with a relaxed geometry (like the kat) is like wrestling a pig around the corners compared to a lighter more aggressive bike (like my buddy's 636).

[delkampg]

lol, i had a few beers in me when i asked this i guess cause i dont remember asking it. but it is something ive always kinda wondered about, thanks

[DumbLuck]

take 2 3 foot pieces of string. tie a whiffle ball to one, and a softball to the other. now start swinging each around. which "pulls" the hardest when whipping around? the softball as it's heavier. inerta, mass and centrifigal force all tryin to keep the ball from changing direction (the pull exerted on the string)