I was told not to coast with the clutch pulled in and no throttle - why?
- Thread starter wideiris
- Start date
Out of curiosity, why do you feel you should be coasting the bike?
In my opinion, you should never coast because you always want to ride a bike under power. If your clutch is in and you need to react to a situation, a) your reaction time could be slower, and b) you could overreact, or mis-time your reaction, resulting in a much worse situation (think, crack the throttle, dump the clutch, dump the bike).
I'm not sure what your brother is on about "the change can catch". The chain is always going 'round and 'round anyway. There's nothing for it to catch on.
In my opinion, you should never coast because you always want to ride a bike under power. If your clutch is in and you need to react to a situation, a) your reaction time could be slower, and b) you could overreact, or mis-time your reaction, resulting in a much worse situation (think, crack the throttle, dump the clutch, dump the bike).
I'm not sure what your brother is on about "the change can catch". The chain is always going 'round and 'round anyway. There's nothing for it to catch on.
Can't see any reason why this could cause a problem with the chain. Given the right circumstances, you could seize a 2 stroke doing it, but the chance of you riding a 2 stroke on the streets (and using full throttle for a reasonable period of time followed by coasting) is almost zero.
RonnieRev
Well-known member
How is coasting going to seize a 2-stroke ?
I'm with mroberto in that you should always have full control. Coasting lets the bike get out of sync with the regular speed / gear combination so you can either bog / stall the engine or lock up the rear if you are in the wrong gear and have to change plans. Rider experience is a factor.
I don't see a chain issue unless the chain is so slack it's going to fall off anyway or the sprockets are insanely worn. Some bikes can't be towed with the rear wheel on the ground due to oil pressure / lube issues. I don't know if idle speed is enough to avoid problems.
I don't see a chain issue unless the chain is so slack it's going to fall off anyway or the sprockets are insanely worn. Some bikes can't be towed with the rear wheel on the ground due to oil pressure / lube issues. I don't know if idle speed is enough to avoid problems.
bobjohnson
Well-known member
If you gun a 2 stroke at full throttle for a long time, its going to be really hot. Pulling in the clutch and letting it basically idle for long periods while its really hot has a chance to starve it of oil, depending on the bike and what kind of mix system its using (almost impossible with premix since its getting a constant amount of oil). Its unlikely, but its possible.
OP, your brother is wrong about the reasons, riding the clutch is fine for the chain. I think what he means is that if your chain is horribly out of adjustment, putting load back on the chain when you release the clutch at speed could cause it to jump teeth or otherwise bind up, but a properly maintained bike could do this all day long without issue. The reason you dont want to do it is that you always have more control over the bike if the engine is actively driving the rear wheel, so its not good practice to coast around with the clutch pulled. Plus, going down a hill, the bike will be slower with the clutch out, because the engine will provide some braking power as well. Coasting down a hill, the only control you have over your speed is with your brakes.
One mechanical reason (and which may only apply to some bikes), one mechanical reason that applies to all bikes, one safety reason.
The mechanical reason that only applies to some bikes is that SOME engines - not all - may have a bearing or bushing on the transmission input shaft that is not designed for continuous duty. Bike stopped, engine idling and clutch pulled in with transmission in gear is OK because the shafts are not spinning. Rolling down the road, the shaft and the bearing in question are spinning but there is no load on it because you are not holding the clutch lever in and applying pressure to it - OK. Shifting gears - OK because it's only a moment at a time. Rolling down the road for extended periods with the clutch lever pulled in - on SOME engines - could overheat that bearing.
The mechanical reason that applies to all bikes is that it's really tempting to forget which gear you are in, and if you start doing this in one of the lower gears, by the time you let out the clutch, the engine could be mechanically driven beyond its maximum revs. The engine's rev limiter is of no help when the clutch is mechanically spinning the engine beyond the rev limit RPM. On a ZX10R, with 100 mph 1st gear capability, perhaps it's not an issue so much. But on a small bike, in which redline in 1st might only be around 40 km/h ... letting it spin up to highway speed in 1st and then letting out the clutch will make badness occur.
Another factor is that if you do a gear change in this situation, the gearbox is not gonna be happy about it. This is another good way of turning gear teeth into metal shrapnel inside. Bad bad bad.
The safety reason is that you should always be ready to accelerate at any moment. Can't do that if you don't know what revs the engine will be at when you let out the clutch. If the engine is already in a suitable rev range, it's not an issue.
The mechanical reason that only applies to some bikes is that SOME engines - not all - may have a bearing or bushing on the transmission input shaft that is not designed for continuous duty. Bike stopped, engine idling and clutch pulled in with transmission in gear is OK because the shafts are not spinning. Rolling down the road, the shaft and the bearing in question are spinning but there is no load on it because you are not holding the clutch lever in and applying pressure to it - OK. Shifting gears - OK because it's only a moment at a time. Rolling down the road for extended periods with the clutch lever pulled in - on SOME engines - could overheat that bearing.
The mechanical reason that applies to all bikes is that it's really tempting to forget which gear you are in, and if you start doing this in one of the lower gears, by the time you let out the clutch, the engine could be mechanically driven beyond its maximum revs. The engine's rev limiter is of no help when the clutch is mechanically spinning the engine beyond the rev limit RPM. On a ZX10R, with 100 mph 1st gear capability, perhaps it's not an issue so much. But on a small bike, in which redline in 1st might only be around 40 km/h ... letting it spin up to highway speed in 1st and then letting out the clutch will make badness occur.
Another factor is that if you do a gear change in this situation, the gearbox is not gonna be happy about it. This is another good way of turning gear teeth into metal shrapnel inside. Bad bad bad.
The safety reason is that you should always be ready to accelerate at any moment. Can't do that if you don't know what revs the engine will be at when you let out the clutch. If the engine is already in a suitable rev range, it's not an issue.
redridernl
Well-known member
Nope. Fuel injection can be "hitchy" at low revs on some bikes. I'm assuming that he meant it was hitchy at low revs. If he meant all through first gear then disregard.
conundrum
Well-known member
My 250's first is so short I never really shift into it when slowing down (red would be about 30km/h or slower), so I typically rev-match downshift into 2nd until I hit near stall speed (feathering the clutch in and out), then just coast the last few feet at sub 10km/h and click it down into first before coming to a 100% stop.
In theory I could do down into 1st until stopped by why -- I'd have to spin the engine up so high to match the 2nd to 1st shift, and then put more wear on the clutch to keep things smooth. Also should I need to pull away quickly or the light goes green, I'd want to be in 2nd anyways unless I'm below 10km/h in which case I'm already in 1st with clutch in. Also it's a different story if I need to be in first, say after turning into a parking lot/structure, or similar.
In theory I could do down into 1st until stopped by why -- I'd have to spin the engine up so high to match the 2nd to 1st shift, and then put more wear on the clutch to keep things smooth. Also should I need to pull away quickly or the light goes green, I'd want to be in 2nd anyways unless I'm below 10km/h in which case I'm already in 1st with clutch in. Also it's a different story if I need to be in first, say after turning into a parking lot/structure, or similar.
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Low revs.
Generally I don't downshift from 2nd until around 30-40km with a blip. 1st gear at 40 is smoother than 2nd gear at 40 though (likely due to lower revs as you said lol). Stupid residential speed limits!
EDIT: Though he has a 600RR. Maybe it's smoother on those? I'm too lazy to feather the clutch to inch up to the light lol
Your I4 600cc has virtually no engine compression braking and at low RPM, very little torque/hp, so you'll find it very smooth down low. My injected Superduke and my previous injected TL1000S (Suzuki's 1st attempt at injection), both litre-bike sport v-twins, with significant torque numbers from tickover, would prove you horribly wrong. Although a bunch of modding smoothened both bikes out.
I do both. I engine brake when I'm not in my neighbourhood (or other residential neighbourhoods), thus as to not offend the neighbours with my "character" Supertrapp exhaust and the inherent decel burble. But when I'm on the open road, I much prefer to have full control of the throttle to get out of sticky situations. As said many times over in this thread, there is NOTHING wrong with coasting with the clutch disengaged.
My 125 is like that, and it has a really short 1st gear. Normally, when coming up to a stop, I downshift and rev-match through 2nd gear, but once the speed is down far enough to be near idle speed in 2nd (probably around 15 km/h), I clutch in and downshift to 1st but leave the clutch in until stopped (not using engine braking in 1st). It's smoother that way.
