| Author | Message | ||
     Americanmadexb |
is this necessary to do this everytime you stop? i know it helps stopping but does it do harm to the engine/tranny? i do it every time i slow down but i was just curious on how everyone does this!!!!! | ||
| Saintly |
Yes, it is necessary everytime you stop, otherwise you will burn out your clutch trying to take off in 5th. | ||
| Pipefittermike |
I am going to go out on a limb here and guess he meant downshifting as a means of slowing the bike rather than just using the brakes. If that is the case then no, I have never heard of this damaging the trans or motor. That is unless you decide to downshift from 5th to 1st doing 90 and let out the clutch. That would be bad.  | ||
| Bake |
I use the tranny for braking purposes knowing brakes are cheaper to maintain. The transmission was built to take the stress! | ||
| Xbeau12s |
hell yeah, That beefy V-twin does the best engine breaking there is. Your in trouble if it doesn't! | ||
| Snakedriver |
But the moral or the story is NOT to use the clutch, but rather the engine as a break. | ||
| Thumper2811 |
I'd say stick with your brakes they are much cheaper to maintain | ||
| Djkaplan |
It's important to be able to match the rpm of the engine to the gear you've selected when downshifting. Compression braking is fine if you're stopping for a red light, but you have to be able to control it when braking heavily and downshifting before approaching a corner. I always practice matching rpm to gear selection with every downshift. The payoff comes when you are able to downshift while leaned over without breaking traction on the rear tire. | ||
| Josh_cox |
FWIW engine braking is not good for ANY engine or transmission. All is does is creates side loads in both directions instead of just one. You bore will be out of round much faster. Brakes are there for a reason, to stop the vehicle. Engines/drivetrains are designed to not break under these stresses, but they will wear faster. | ||
| M1combat |
"hell yeah, That beefy V-twin does the best engine breaking there is. Your in trouble if it doesn't!" Just so you know... The Buells have significantly less engine braking than the IL4 bikes... They run more compression and lighter rotating assembly. There's less energy stored in their drivetrain so they produce more engine braking. | ||
| Buelltroll |
I don't know what I4's you rode with less engine braking then an XB, but EVERY I4 I've ridden has had hardly ANY engine braking compared to my bike. I hardly ever use the brakes in the canyons because the engine braking is usually enough to slow me down enough to drop it in. | ||
| Patrickh |
I4's have more engine braking than V-twins. There are a greater number of parts spinning inside which create more drag on the motor when it is spinning down. The engine braking in a twin is very controlled and tractable which is why it feels different. I downshift when slowing down, I want the power where it needs to be in case something bad happens. I can't imagine doing it any other way. | ||
| M1combat |
The first half of your post makes no sense... The XB's have less engine braking than the IL4's... Unless you're talking a newer bike with a slipper... | ||
| Americanmadexb |
yes i was talking about slowing the bike down! i do it almost everytime! i just didnt know if it would harm the tranny at all to go down 2 or 3 gears without letting the clutch out every gear. | ||
| Josh_cox |
You do not have to let the clutch out  Just hold your clutch in a shift down when stopping. | ||
| M1combat |
You want to match revs though... Don't just pull in the clutch at 105 in fourth and drop three gears instantly. You need to match revs whether you let out the clutch or not (I recommend letting out the clutch for every shift myself, and learn to modulate the brake lever while doing it...) | ||
| Buckinfuell |
Josh, I don't understand why downshifting and letting the engine decelerate the bike puts any more wear and tear on the parts than during upshifting and acceleration. Load on the engine the same regardless of whether you are slowing down or speeding up. Unless, of course, you drop down too fast. I also think it is good practice to have power to the back wheel as much as possible for contingency maneuvers. Just my 2 cents. Ray | ||
| Eric_m |
"I4's have more engine braking than V-twins. There are a greater number of parts spinning inside which create more drag on the motor when it is spinning down." That makes no sense.  The trick to avoid engine damage when downshifting is to match your rpm to your roadspeed. It is like "heel-toeing" in a car. Your v-twin might not approve if you send it from idle to 7,000 rpm in .25 seconds. | ||
| Saintly |
I don't understand why downshifting and letting the engine decelerate the bike puts any more wear and tear on the parts than during upshifting and acceleration. actually, Josh is right. Accel & decel do wear the engine differently. While accelerating the engine is pulling(rotating) all the other driveline components. But during decell, all the other components are pulling the engine around instead. Consider your primary tensioner shoe as an example: its on the slack side during accel, but on decel it's the tension side and it's digging into the nylon shoe. Same goes for all the engine components, the sprocket shaft(left side of crank) timken bearings have a thrust side that gets most of the load while rpm increases, but during engine braking the opposite bearing is getting the load. The pinion gear that spins the cams is a good example too. The load on the engine is different when its not the thing doing the turning. P.S. My first post above was just an attempt at humor, I didn't really think that the guy who started this thread was not returning his gearbox to low gear at each stop. | ||
| Josh_cox |
Acelleration force = ---------> this direction Deceleration force = <--------- this direction It is the same idea as to why rear tires wear more than fronts. They are dealing with two different forces rather than just braking. Engine braking doesn't put on more stress than accelerating by any means, it just doubles the amount of time your bike is under stress. I'll usually pull my clutch in around 30 mph to stop. Anything above that and I'll revmatch and engine brake and use the front and rear as well. Slowing is different than stopping to me. I guess I read the post differently. (Message edited by josh_cox on June 26, 2006) | ||
| Patrickh |
an inline four having more off power engine braking makes perfect sense. twice the number of cylinders; con rods; rings; valves; valve trains; chains; gears; ect. I4's have more pieces rubbing together causing friction than do v-twins. You don't have to take my word for it though, I will dig out the Kevin Cameron article that explains it. I think it was written in 2002. Suprised me the first time I read it too. | ||
| Cmm213 |
This is not rocket science guys, everyone rides different. If you want to down shift do it, if not just hold the clutch in and use the brake while going down through the gears. Me myself I usually ride aggressive and match gears and blip the gas when down shifting. | ||
| Ducxl |
V-twins have significantly less engine braking force compared to an I-4.True statement.Kevin Cameron wrote a fine article on it.Has to do with flywheels and how a v-twin has more mass and inertia preventing a sudden slowdown.Just the opposite with I-4 engines(no flywheel inertia).That Cameron dude is brilliant. | ||
| Eric_m |
First off- all engines have some sort of flywheel. Second- If friction is what is causing engine braking, you have something wrong. Compression is the key to engine braking... Which inline 4 cylinders do create more of. | ||
| Jackbequick |
All I know is that, by the seat of the pants impression and to the ear, there is nothing prettier or better than a couple of perfectly executed downshifts and a little off throttle time to set up for a city corner turn with a Buell. I usually make it a point to give the front brake a gentle touch just to get the Back Off! device flashing my brake light so the cage behind me is not confused by my not needing to use the brakes much around town. We can argue to death which engine has the best engine braking, but no one in their right mind will argue that the Buell does not have plenty enough of it. And there is no argument that two big cylinders sound better than a bunch of them itty bitty HoKawSuYa cylinders imitating a pack of lawnmowers. Jack | ||
| M1combat |
Eric_m - I don't think that he meant that friction is the dominant force in engine braking. Just that it all adds up. | ||
| Buckinfuell |
Saintly and Josh, I understand your points in the wear bias of acceleration versus deceleration. I do not, however, think that the additional wear is that significant. Granted, if you know you are coming to a full stop over a short distance, by all means, pull the clutch in, hold it in, apply both brakes and downshift to first. Trying to accomplish this with engine braking would put undue stress and excessive wear on the components. The original poster, however, was talking about slowing down, in which case, I think it is poor riding practice to have the engine disengaged any longer than is necessary to switch gears. But then again, I suppose a lot has to do with why you are slowing down... i.e. entering a turn, avoiding an obstacle, etc. Anyway, I think we're all on the same page now. | ||
| Slaughter |
I don't tend to use engine for braking but keep the gear selection matched to the speed I'm travelling. Kinda like if you need it, it's there. | ||
| Buckinfuell |
I'd like to remind everyone here that every time you roll off the throttle, you are engine braking. Unless, of course, you pull the clutch every time you roll off, which would just be plain stupid. Engine breaking does not necessarily mean you are throwing the bike into a lower gear and bouncing the back tire around as you heave yourself over the tank... | ||
| Rhun |
per homecoming: The hardest thing on the belt is hard downshifts. I believe they were referring to the kind that makes your rear tire squeal or slide. | ||
| Freyke |
three factors are in play in engine braking: 1. Engine Displacement 2. Comrpression Ratio and finally and prob most inportant is... 3. Engine to drive wheel(s) reduction ratio (what gear are you in?) Go from 5th to 2nd at 60mph and you will likely lock up the rear if you don't apply a whole lot of throttle.... garanteed.. | ||
| Patrickh |
I think of it like this. If you downshift an I4 from 4th to 3rd gear at 8,500rpm you will hardly feel any engine braking. If on the same bike you spin her up to 12,000rpm, where the bike is making near max power, and bang down a gear without matching revs you will get a good amount of engine braking. There are not a lot of riders who are clipping around at 10,000+ rpm on the street on their sport bikes...at least I don't hear it when they ride near me. This is why a V-twin makes a terrific street bike. You can use a all of the motor's power more frequently because you don't need to wind up the engine to make max power, it always available to you at lower rpm's. Because you are always riding the bike "in it's power band" the effect of rolling off the throttle is more noticeable. |
