[risky_analyst]

I know that you are supposed to apply 70% of the braking on the front wheel and 30% on the rear.. what is the true reasoning behind that?

 

[Flatline]

As you brake, the front forks compress and the bike's overall weight tends to load toward the front. More weight, more braking power. I'll leave the physics for somebody smarter than me, but that's the basic answer.

 

[JaredMcDonley]

Read this my friend and all answers are there.
http://www.webbikeworld.com/Motorcycle-Safety/braking-tips.htm

Short snip:

1. Which brake is the most effective?

The front brake is the most effective, giving between 60 & 80% of the bike's stopping power in hard stops, depending upon surface conditions. This is because most of the weight of the bike and rider transfers forward onto the front wheel when the brakes are applied. A common example of weight transfer is when you trip on a gutter - your feet stop but momentum keeps the top of you going and you fall flat on your face. The weight transfer that takes place under braking on a motorcycle pushes the front wheel onto the ground and makes it grip very well.

2. Is the front wheel likely to skid if you apply the front brake hard?

No. The front wheel is likely to skid uncontrollably and bring you down only if you jam the front brake on hard. If you apply the front brake in a staged (progressive) process, the front wheel may skid but that skid is normally quite controllable.

3. Is the rear wheel likely to skid if you apply the brakes hard?

With most of the weight being on the front wheel, the rear wheel tends to be light under braking and will therefore lock up and skid very easily.

 

[schultzboy]

I know that you are supposed to apply 70% of the braking on the front wheel and 30% on the rear..  what is the true reasoning behind that?

it is not that you are supposed to apply the brakes like that. it is a fact of life no matter what you do. if you just stood on the rear brake by itself trying to stop suddenly, all you would do is slow down a little but life would be really interesting for those next few seconds while you try to keep your bike from fishtailing out from under you.

here is the best way i can think to explain it. say you are on some kind of rolling platform where you can put your feet down to stop yourself. now imagine you were rolling along at a decent pace and wanted to stop. in your first attempt you sit facing backwards and drag your feet to stop yourself. you would eventually stop but your feet would have been sliding more than necessary because you are trying to stop something "from behind" if that makes any sense.

now imagine that same scenario but you are facing forward and put your feet down to stop. when you put your feet down the weight of you and your platform are now pushing into your legs which are pushing into the ground. instead of fighting you, the entire mass is helping you stop.

if that didn't help any, or now you are more confused, all i can say is the front brake just works better because it does.

 

[risky_analyst]

thanks.. those explainations make perfect sense.. especially the last one.