| Author | Message | ||
     Drfudd |
I've gotten into the habit to use the engine to aid in braking. I still use the brakes while doing this to at least light up the brake light. But I use it all the way down to second gear, downshifting the whole time. When I downshift into first I use only the brakes for a smoother stop. Is this common practice? Is there too much wear and tear on the drivetrain and I should avoid doing it? What does everyone hear do and what if any adverse effects is there? | ||
| Andymnelson |
Common practice. No real adverse wear on drivetrain unless you are doing it way too early and the engine is winding up to too high or RPMs. The other thing is you are placing more wear on your clutch- clutches are more expensive and a bigger PITA to replace than brakes pads! | ||
| Akbuell |
I got out of the habit of doing that due to rear tire wear. Try an experiment, on a low/no traffic road where you can repeat the results. Assume you are approaching a red light, doing 50MPH. Your first marker will be where you let the clutch out on the first downshift. The second marker will be where you pull the clutch in for the last time as you complete the stop. Note your speed at the second marker. Do it again, only this time pull the clutch in and apply rear brake only at the first marker, breaking hard enough to be at your final speed at the second marker. That's how much work your rear tire is doing. I prefer using brakes only. YMMV | ||
| Saratoga |
How is it any easier on the tires if you use the brakes to slow vs downshifitng? I don't really understand that argument. Tire wear from using the rear brake seems that it is far outweighed by the wear caused by acceleration IMO. Not disputing your theory, just confused, that's all. I've always chopped the throttle before downshifting and it seems to be a smoother transition, kind of like driving a semi. | ||
| Bumblebee |
I've gotten into the habit to use the engine to aid in braking. I still use the brakes while doing this to at least light up the brake light. But I use it all the way down to second gear, downshifting the whole time. When I downshift into first I use only the brakes for a smoother stop. That's exactly right. Do that on/in any motor vehicle, be it motorcycle, car or semi. | ||
| Barker |
Buells have engine braking? | ||
| Ft_bstrd |
Using braking only shifts the majority (70%-90%) of the tire wear to your front tire whereas downshifing shifts only an additional 15-20% to the rear tire. As you increase the brake force, the weight of the bike shifts toward the front tire and unweights the rear. At some point in time, the downshift force will brake the rear tire loose. I would say that acceleration does more for rear tire wear than downshifting, but you can shift a substantial amount of wear to the front by using ONLY the brakes. I down shift because it's "free". The engine is already spinning, and using that mass to slow the bike makes sense. It does place wear on the clutch, but it also allows for greater bike control. By shifting some of the brake force to the rear tire, it permits an additional amount of brake force to be utilized with the front brakes. It also keeps the chassis composed and settled. Loading the brakes up, unsettles the chassis and decreases handling. Do you "rev match"? Doing so allows you to use the engine to brake but doesn't put quite as much strain on the clutch plates because the differential between engine speed and wheel speed is more closely matched. | ||
| Hmartin |
If you match revs when you're downshifting, wear on the drivetrain should be minimal. Sometimes, when I'm harder on the brakes, the lower gear will go in before I even get the clutch pulled in, just by matching revs. I love the sound of a good downshift. Engine braking is the cheapest way to reduce speed. Ask any trucker about the use of his jake brake. My rear tire is squaring off, too, but I don't buy that downshifting is the reason. Looking inside my tire tread, the edges are feathered on the forward edge of the tread block (rear edge of the groove), indicating that it's the engine torque, not the overrun, that's squaring off my tires. Oh, but it's fun, though. (Message edited by hmartin on May 11, 2009) | ||
| Srwitt |
I use my engine to brake almost always when railing. I don't like going fast enough to where I need to be on the brakes to make a corner, just hold a nice pace where changes in throttle are all I need. When I am coming to a stop from speed though, its front brake, rear brake, and engine braking with rev matched downshifts thrown in. | ||
| Figitt |
As the engine gets more miles on it, you will start to see increased oil consumption as a result of your engine braking excersize. It sucks air/oil past the rings and valve guides, and will belch a puff of smoke when you get back on the gas.... Wear and tear on the drive train is slight i agree, but it is there,.... and brakes are much cheaper than clutches and gearboxes (belts) Keep in mind tho, this is a long term effect.... kinda like skipping an oil change or two. This doesnt stop me from doing it tho... | ||
| Ft_bstrd |
Given my riding style, engine braking is a must. vacuum assisted oil blow by is a minor concern. | ||
| Bishopjb1124 |
Buells have brakes?????????????????  | ||
| Doughnut |
Someone needs to put an exhaust brake on a bike. | ||
| Petereid |
Wow, I didn't think there was anyone out there that wouldn't down shift properly and take advantage of the "engine braking". Be it in a car, truck or bike if done properly there is less wear then accelerating. If your on a long downhill grade what do the "non-shifters" out there do? Ride the brake? | ||
| Pogue_mahone |
WHEN NO brake or engine brake,i let the air drag and slow me down,or the grade of the road.more so when on emtpy roads with just me around. | ||
| Sleez |
cheaper and easier to replace brake pads than clutch plates! something to think about, i have gotten into the habit of saving my clutch on my truck by using brakes more than i had in the past. doesn't exactly correlate to the bike, but something to consider??? | ||
| Ft_bstrd |
I've replace the clutch. It's only marginally more difficult and expensive. It's a wear part. | ||
| Buellinachinashop |
I just use both brakes. | ||
| Fast1075 |
I match rpm carefully...I use the engine braking, but cautiously...don't know about an XB, but a Blast will very easily slide the rear tire if you aren't careful...and when I wear the stock brake pads out, I will get some new ones with TEETH. | ||
| 1_mike |
Cheaper....? When you use the engine to do the braking work...it puts a heavier load on the rod bearings than is normal. A semi truck...yea...have you ever the bearings on a diesel rig? Just a LITTLE wider than every other car, small truck, bike (etc.) on the road. Ever notice when a Top Fuel engine breaks most of the time.....AFTER the throttle is lifted..! I'd much rather wear out a few sets of brake pads and only use the engine where nesessary/required. Check into the Mercury outboard engine experiments done about 20 years ago....you might change your mind about engine braking except on a race engine, (where it's torn down and freshened once or twice a year. Mike | ||
| Iamarchangel |
Yep, Rossi uses engine braking every time, that tells me how good an idea it is. (You should realize I'm being ironic.) The clutch is there to prevent engine braking. Use it. Strange argument about tire wear. It's not "either/or", it's "and". They both generate wear only one is unnecessary. Besides all the shock transmitted to every component, there's no oil moving at that instant either. Comparing 13 gears and 18 wheels to 5 and 2. That makes no sense at all. | ||
| Augustus74 |
Engine braking sounds cooler. 'Nuff said. | ||
| Ft_bstrd |
a heavier load on the rod bearings than is normal Ummmmm....What? I'm pretty sure that Erik would disagree with you. After he stopped laughing. | ||
| Ft_bstrd |
Five gears and two wheels. Try to keep up. I'm trying to figure out how much of a problem I have. | ||
| Saratoga |
Heavier load on the rod bearings???} Where did that come from? Pretty sure acceleration under power puts much more stress on the rod bearings than having the crank turn the rods ever would. My truck can only rev to 3250 under power, but can go up to 4800 under engine braking when the transmission downshifts. | ||
| Old_man |
Here in the Pittsburgh area there is nothing but hills. I use the engine compression to keep the bike back when coasting down the hills. I don't use it to initially slow the bike, but to keep it from picking up too much speed on the way down. | ||
| Hmartin |
Wow. I never thought overrunning an engine while braking could be that big a deal. I'm trying to get my mind around how engine braking could overstress the rod bearings. Compression braking? Sure, if the engine's not built for it, but regular-old closed-throttle engine braking? There may be more tensile stress on the rod bolts, I guess, but an engine that can't handle a vacuum in the intake manifold wouldn't be running for long. About the Mercury Outboard study, were they testing two strokes or 4-strokes? Chop the power at high RPM on a two stroke and you've just cut off the engine's oil supply, like Iamarchangel says. But on a 4-stroke, the oil pump works whether the throttle is open or closed. Interesting comparison to top fuel drag racing, where the engine is running on the verge of hydrolock, so much so that a single misfire could bend a rod. I wouldn't want to overrun that engine, either. As for shock and stress, that is perhaps true if you just mash on the gearshift lever or pop the clutch out on every downshift. I'll agree with you that if you're not practiced at it, don't do it - just pull in the clutch. My daily driver is a fairly high-powered sedan with a stick (a cage; sorry), and I live for double clutch downshifts. Done wrong, the drivetrain tells you, and yeah, it's not good for it in the long run. Oh, but done right, it's freakin' awesome; hard right-handers are never more sweet. All that being said, so much much concern over the wear and tear of engine braking is foreign to me. In the grand scheme of things, when compared to the total useful life of the bike, how much does it matter? Abuse the machine and it'll abuse you, but it's not all about saving every last bit of clutch or saving the brakes or saving the tires; it's about riding the d@mn thing, improving your riding skills and having a blast while doing it.  | ||
| Blake |
Ft B, Actually, I recall Erik advising once that using the engine as a brake is one of the harshest conditions to which it is subject. I don't recall the details. | ||
| Drfudd |
wow, I never knew such a heated discussion and difference of opinions could come of it. and yeah the bike does make a F$^%^ing awesome sound done right. now I'm an engineer and I don't buy the whole loaded rod bearing thing, the only worry I would have is maybe the belt and transmission since A. your reverse loading the belt teeth and slack B. I do know from an engineering exercise I did, reverse loading straight cut gear teeth can cause major unwanted stresses. But I have an 07 and I'm pretty sure they have the helical cut gears which are not as susceptible to that issue. aside from changing the transmission or tearing apart the engine I have no problem replacing a belt or clutch parts when need be. | ||
| Ft_bstrd |
Ft B, Actually, I recall Erik advising once that using the engine as a brake is one of the harshest conditions to which it is subject. I don't recall the details. I'd like to see the details of that discussion. I don't see why the stresses would be any more in downshifting than upshifting. If you view the engine as a pump, the impact of a "bang" is increased velocity. The impact of a "not bang" is deceleration. Automatic transmissions "downshift" as well. |
