Engine Braking - which tire does it affect?!?

[wavyredlaurie]

This has been bothering me for some time. When you downshift to slow down, which tire (wheel) is affected? While I was still getting the hang of downshifting, one of my downshifts was very abrubt, right before I entered a slight curve. The rear tire slipped out on me. Not tip over slip out, but definitely a loss of control. So, when you're downshifting to slow down, do you change your amount of front vs. rear brake???

[Trapper]

I find if you let the clutch out slower that doesn't happen so much. Personally I read that taper breaking thing and I am using as much front brake as I feel comfortable doing. Hope that helps.

[sicrx69]

Sup,
Yea when u slip down to a lower gear going too fast the toque and lack of weight on the rear wheel causes it to skip or slide., can be pretty dangerous if you lock it. I usually only downshift to 4th or 3rd never second or first unless i am going really slow, i am by NO means a pro but just though i would share my 2 cents.
John
'00 Gsxr 600

[TL chris]

Originally Posted by sicrx69

Sup,
Yea when u slip down to a lower gear going too fast the toque and lack of weight on the rear wheel causes it to skip or slide., can be pretty dangerous if you lock it. I usually only downshift to 4th or 3rd never second or first unless i am going really slow, i am by NO means a pro but just though i would share my 2 cents.
John
'00 Gsxr 600

True. Unless your bike has a slipper clutch. Some bikes come equipped with them to prevent the wheel from locking up when downshifting too fast.

[Freakinout]

The wheel slipped based on what the other guys said.

Now to the weight shifts:

If you are braking, either with brakes, or engine breaking, the weight gets transferred to the front (ie. another reason the rear slips so much easier). If you slow down then the weight goes to the front wheel. If you accelerate the weight goes to the back, reguardless of means.

[GIXXER-Mike]

Good points. I'm still trying different things when stopping to see which feels best & causes the least amount of wear & tear .

Downshifting should be good but then again I still have to use the front brakes because it doesn't stop me properly & I always end up using the throttle to get closer to the cage in front of me . Also, using both front & rear brakes has been tried as well but this makes me burn my pads more? Heck, the more I read the more I try but nothing is definite for me at this point.

Seems like you have two choices when it comes to braking...over time you will either:

1. Wear out your brake pads
2. Strain or wear out your gears.

To me, the pads are easier to replace . No sense in ruining both. Any suggestions from the experts?

[Freakinout]

I'd suggest you do whatever feels best to you. I know V-twin people (twin cylinder engines too) like to use engine braking a lot more than most I-4 riders. (all sportbikes here). When you are riding on the streets within your limits then its just whatever you feel is best. I wouldn't worry about wear of the chain drive or pads when you are deciding on how you are going to brake.

[inspiron]

In "More Proficient Motorcycling", Hough repeats several times that engine braking is basically the same as hitting the REAR brake (obviously, since the engine is connected to the rear wheel through the chain or belt). If you lock up the rear wheel by hitting the rear brake too hard or by downshifting too agressively, the physics are the same. No worries, though. Locking up the rear end can be practiced and is no cause for panic. As the instructor in my last safety course said as we were practicing braking on dirt - just relax and look where you want to go ... your a$$ knows what to do to keep the bike straight.

And remember, about 70% to 80% of your braking power comes from the front brakes, so always use the front and rear brakes together to get the maximum braking effect. And a new set of brake pads is still alot cheaper than repairing ANY accident damage.

[GIXXER-Mike]

I've been reading slowly & carefully. Right now I'm on page 81 of "Proficient Motorcycling: The Ultimate Guide To Riding Well," the section titled Quick Stop Practice.

Still reading & awaiting something in the book to reach out & grab me. It's got a lot of good stuff but nothing has grabbed me just yet (I'm on page 81).

[SDSUsnowboards]

Does engine braking really put any more stress on your engine than accelerating? I nomally engine brake. I'll blip it and let the clutch out as fast as possible while letting the rear tire keep traction. I'll never use engine braking where I have to blip it faster than 9K to make the trasition smooth... it can also be pretty easy to lock up your rear tire at that speed I understand. I'm pretty good cuz that's what I've been doing with my car since the day I started driving. I use the brakes for hard stops or stopping completely. Anyways, my original question though. Dunno if I should keep engine braking or not... it's fun though and sounds cool.

[inspiron]

As long as you aren't reving over the redline by downshifting, there is no harm to the engine or gearbox. Geez, the're designed for that! The stress on the components is no different than accellerating - it's just reversed.

When accellerating, more gas/air is forced into the cylinder, which causes is to explode more violently, pushing faster on the camshaft, which speeds up the gearbox and the rear tire. There is a loss of energy in each of these steps - the pistons have friction within the cylinder walls and in the connection to the camshaft, the gearbox has internal resistance, alot of energy is lost through the flex of the chain. You don't notice this, though, since you are accellerating.

When using engine braking, the rear tire wants more speed from the gearbox, which transfers this to the camshaft, making it turn faster and causing the pistons to rise and fall faster, pulling more mix into the cylinders. Since each of these components introduces some resistance (none of these can transfer 100% of the energy onto the next component), the net result is an engine brake.

[wavyredlaurie]

Man, lots of great responses here!!! Thanks a lot. I'm getting pretty good at the downshifting/engine braking now. My goal with it is to make it very smooth, slowing down without making a lot of engine noise, or jerking the bike around at all, especially when I have a passenger behind me. I am usually using a combination of front brake and the engine, so it's probably a good balance. I only spun out the back tire that one time, and lately have been coming to a stop very smoothly, and where I want to. I don't find I end up using first gear much for stopping - once I get down to second, I end up putting the clutch in, popping it into first, and then coasting to my stopping point. It leaves me the option to stay in second, if traffic starts moving again, and since I'm below 10 or 12 mph at that point, the brakes alone are good.

I guess I'll keep playing with it till it gets just right! I like to make the engine purr, more than to make it roar!

[Freakinout]

Really if you are downshift you want to make sure your RPMs in the lower gear are less than 5 or 6K.