when to change gear??

[adriel]

Hi all gurus out there.....

 

me and black plastic spec was having a discussion that day about time to shift up on the gears......

 

my take was to shift up one gear up when cruising but black plastic spec was saying that it actually harms the engine???

 

is this true???

 

anyone care to clarify????

[Strong Eagle]

I am not totally sure I understand the question so let me toss a couple of things out.

 

a) In general, you get the best fuel economy at the slowest engine speeds, and thus, want to ride in the highest gear possible. This is because of internal engine friction/drag which increases as RPM increases. So, for maximum economy, you would upshift at relatively low RPM's each time.

 

b) Max HP and torque are usually generated farther up the RPM band. For example, my bike with a max RPM of 6750 has max torque at about 4800 and max HP at about 5200 RPM. Thus, if I really want to accelerate hard, I will rev the engine to about 3000 RPM, climb close to 6000 RPM, then shift to the next gear. Not good for fuel economy on a 1500 cc engine but the bike does move out fast.

 

c) It is possible to have your engine turning to slowly for a given speed. This is called lugging the engine. If you look at a typcal HP/torque curve you will see that torque is very low at lower RPM's. If you run your motor at these RPM's you will need more open throttle to get sufficient torque to drive the bike. But, spark timing, etc generally is set for higher RPM's so it is possible to put additional strain on the engine, and encounter knock. As a rule of thumb, your RPM's should be somewhere where the torque curve starts to climb in order to avoid lugging the engine.

[adriel]

thanks Strong Eagle for the info.... apologise for not being clearer on the topic.....

 

I've been experimenting with shifting at different speeds ....not so much for speed of acceleration but more to create a smooth ride.... sucker for smoothness....

 

was discussing with this other forumer and he mentioned something abt shifting to the 4th gear at 90km/hr and above..... the point that he brought up was that at speeds lower than 90km/hr if he were to shift up, it seems that it may cause damage to the engine i nthe long run..... >>>plasticblackspecs .... you may wanna elaborate more on this.....

 

That was what set me of thinking about which gear I should be in and the consequences of being in a "wrong gear"

 

It doesn't help that my bike din have a tacho installed....so its all about feel.....

[maniahk]

hmm.. like u said adriel.. its about feel.. personalli i think its about my mood on that particular ride.. if i'm feeling in for more acceleration, i'd rev higher b4 changing.. if i'm feeling relaxed, i'll change at much lower speeds n open less throttle.. differs as much as 25-40-60-80, to 20-30-45-60

 

it'll definitely cause dmg if lets say i'm at low spd high gear, den i open throttle to try to force it to accelerate fast.. but if i open small n slow i think its perfectly ok.. juz listen to the exhaust notes n feel the bike.. u'r lugging it if u hear e exhaust coughing out wad sounds like too much air, and the engine feels kinda like u'r riding a horse..

[adriel]

right.... cool. seldom experience that..... means i'm in a relatively "correct" gear then....hahah good stuff

[plasticblackspecs]

Adriel, your bike too smooth la. hahaha..

 

Ok. What I was saying was, for my bike, I seldom get to use the 4th gear and almost never the 5th gear for Singapore roads cos my 4th gear kicks in and runs smoothly from 90km/h onwards and 5th gear only 110km/h (or sometimes 100).

 

Adriel was saying to just use 5th gear to cruise but I find it lugs the engine to much. So I was explaining to him that when I hit the expressways, I cruise on 4th gear and never get to use 5th gears and am afraid of it being under used. I also seldom hit the expressways so most of the time it's 3rd gear tops. grrr...

 

Also the topic of if I'm riding at say 100km/h, would 4th or 5th gear be better. For my bike, I feel that 100km/h is very in between. It's on the high rev end of 4th but low end of 5th. And that's where the riding at high rev or lugging the engine topic came in. It's like I can't do a comfortable cruise of 100km/h. 90km/h or 110km/h only. heh.

[William Tan]

Adriel, your bike too smooth la. hahaha..

 

Ok. What I was saying was, for my bike, I seldom get to use the 4th gear and almost never the 5th gear for Singapore roads cos my 4th gear kicks in and runs smoothly from 90km/h onwards and 5th gear only 110km/h (or sometimes 100).

 

Adriel was saying to just use 5th gear to cruise but I find it lugs the engine to much. So I was explaining to him that when I hit the expressways, I cruise on 4th gear and never get to use 5th gears and am afraid of it being under used. I also seldom hit the expressways so most of the time it's 3rd gear tops. grrr...

 

Also the topic of if I'm riding at say 100km/h, would 4th or 5th gear be better. For my bike, I feel that 100km/h is very in between. It's on the high rev end of 4th but low end of 5th. And that's where the riding at high rev or lugging the engine topic came in. It's like I can't do a comfortable cruise of 100km/h. 90km/h or 110km/h only. heh.

 

Change your primary gear ratio man.

For your Harley, its very accessable on the left side.

But you would have to spend some money....

[Strong Eagle]

thanks Strong Eagle for the info.... apologise for not being clearer on the topic.....

 

I've been experimenting with shifting at different speeds ....not so much for speed of acceleration but more to create a smooth ride.... sucker for smoothness....

 

was discussing with this other forumer and he mentioned something abt shifting to the 4th gear at 90km/hr and above..... the point that he brought up was that at speeds lower than 90km/hr if he were to shift up, it seems that it may cause damage to the engine i nthe long run..... >>>plasticblackspecs .... you may wanna elaborate more on this.....

 

That was what set me of thinking about which gear I should be in and the consequences of being in a "wrong gear"

 

It doesn't help that my bike din have a tacho installed....so its all about feel.....

 

What bike are you riding and how many cc's?

[lunloon]

Adriel, your bike too smooth la. hahaha..

 

Ok. What I was saying was, for my bike, I seldom get to use the 4th gear and almost never the 5th gear for Singapore roads cos my 4th gear kicks in and runs smoothly from 90km/h onwards and 5th gear only 110km/h (or sometimes 100).

 

Adriel was saying to just use 5th gear to cruise but I find it lugs the engine to much. So I was explaining to him that when I hit the expressways, I cruise on 4th gear and never get to use 5th gears and am afraid of it being under used. I also seldom hit the expressways so most of the time it's 3rd gear tops. grrr...

 

Also the topic of if I'm riding at say 100km/h, would 4th or 5th gear be better. For my bike, I feel that 100km/h is very in between. It's on the high rev end of 4th but low end of 5th. And that's where the riding at high rev or lugging the engine topic came in. It's like I can't do a comfortable cruise of 100km/h. 90km/h or 110km/h only. heh.

 

same, most times i just pop up 5th when i hit 100 and up

[kmax]

does half clutch hurts engine ? coz sometimes i'm lazy to down gear that half clutch and rev up!

 

then again at upslope traffic light stops, usually hold bike at gear 1 half clutch too. does it hurt gear and engine ?

[adriel]

What bike are you riding and how many cc's?

 

I'm on a 96 Yamummy Royal Star..... and plasticblackspecs is on a 04 883 HD sporty...

[plasticblackspecs]

not 04. 05.

[plasticblackspecs]

so......does not using a gear often result in under use? Will anything happen to it?

[maxxmadness]

so......does not using a gear often result in under use? Will anything happen to it?

 

ride more, worry less...

[plasticblackspecs]

Cannot. A but worrying. heh.

[nights]

so......does not using a gear often result in under use? Will anything happen to it?

 

Nope. Nothing will happen to the fifth gear. I think the concern is fuel efficiency since your fourth gear is not an overdrive gear so, your fuel consumption would be a little off the mark compared to a same bike that travel frequent on the expressway in its fifth gear so to said.

[plasticblackspecs]

ahh...good to know. Thanks Joe

[adriel]

hmmm...read in the overseas forum that the royalstar riders over there tend to change gears with the vmax..... wonder wat that will do.......

[plasticblackspecs]

Change your gear ratio for better FC? hee

[grassmere]

hmmm...read in the overseas forum that the royalstar riders over there tend to change gears with the vmax..... wonder wat that will do.......

 

With the vmax gear you will get more acceleration feel!

 

why?

Coz of different gear ratio. With the same rpm, vmax gear provides cruising in higher speed than royalstar's gear.

Drawback is that with vmax gear you will easily hit the rpm red line...,

[adriel]

based on wat grassmere said.. i think my fc will be worst man........ahhaha more power=bad FC

[jB]

does half clutch hurts engine ? coz sometimes i'm lazy to down gear that half clutch and rev up!

 

then again at upslope traffic light stops, usually hold bike at gear 1 half clutch too. does it hurt gear and engine ?

 

half clutch too often does hurt sth. read up on your RTT book i believe, an instructor did remind me before. hmm i'd do gear 1 and open throttle slowly up a hill instead of half clutch. I'd rather control my throttle then controlling clutch with more throttle which I feel is more troublesome and harder for me.

[plasticblackspecs]

Here's something new, or old, for thought. Why is it when your tank is 3/4-1/2 full, your bike runs at peak performance but when it's near empty or running on reserves, it running pretty poorly.

[Blackenese]

When more than half, there is more volume forcing down the petrol tube/line......?????

[dreamwalk]

hmmm... my bike seems to run at peak performance when petrol left about 10%?

 

maybe bcoz its lighter?