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Old 24th July 2008, 13:25   #16
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Doing this every day on my bike. The key to do this perfectly is basically the engine speed.

The engine should also repond very quicky to the inputs of throttle. Then only one can achieve this. Only for very, very advanced enthusiasts.

This is not recomended as this can reduce the cog life. Even if done with proper precesion i.e. engine speed, this can lead to damage.
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Old 24th July 2008, 13:59   #17
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I have seen a lot of DTC bus drivers do this. Thought it was real cool (as a little kid in school) our bus driver used to "show off" that he does not need the clutch !! He actually used to drive with his left leg folded up on the seat.

Even from standstill he would rev the engine & slot 1st or 2nd gear, mostly with a clang sound. Not a smart thing to do I'd say UNLESS you can achieve precision shifting.

I remember when I had a bike (Yezdi) one could shift without the clutch without any problem, even scooters (Bajaj Super)

In todays cars one can move the gear into neutral without using the clutch. My kid did accidentally do that once. But engaging gears ?

I don't think I want to try that UNLESS I am driving an automatic



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Last edited by Ricky_63 : 24th July 2008 at 14:02.
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Old 24th July 2008, 17:13   #18
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Originally Posted by ashthedivx View Post
Oh god... I have been holding clutch on inclines and straight lines to get better fuel economy, so as i'll not need to revv my engine and car flows in usual speed and once pickup is required i can release clutch and come back to previous gear easily. Didn't knew that it will wear clutch faster then normal circumstances.

But, I am still confused how come clutch will wear fastly when practically we ain't using the clutch. Can you clarify the doubt ???
@ashthedivx : don't get confused. holding clutch on incline means stopping the car from going backwards while climbing causes friction and reduces clutch life. I think what you are trying to say is holding the clutch while going down on inclines. however that too is dangerous since you loose on engine braking while going down. Its like riding downhill in soap box car. please stop that practice. there might be minor gains in FE but safety will be compromised in a urgent braking situation..
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Old 24th July 2008, 17:33   #19
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I was using this in my old 1983 model Bajaj Super (Hamara Bajaj). After that I hardly tried in my Hero Honda and Car.

But I see in my hometown most of the Bus Driver won't use clutch to change gears. Mostly state trasnport buses.

I do not think this technique is healthy for modern gearbox and do not recommend this.
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Old 24th July 2008, 18:27   #20
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Originally Posted by Thad E Ginathom View Post
....Suggesting it to prolong clutch life is utter nonsense.......
Completely agree 100% with Thad E Ginathom on this ....

Allegedly save a minor part like the clutch / pressure plate and throw your gear box out ... Not a sensible trade off !!!
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Old 24th July 2008, 23:10   #21
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I have done it sometimes accidentally in my Indigo. Will release the clutch before the gear is engaged fully. The result - a teeth-grinding sound from the gears and vibration in the gear lever.. enough to stop anyone to try it any more time

Some parts are designed to wear-out. With proper usage it can last for quite a long time!!
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Old 25th July 2008, 07:50   #22
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Quote:
Originally Posted by aaggoswami View Post
Doing this every day on my bike. ....
Doing a clutchless shift on a bike is very different (easier) since bike gearboxes are straight cut / dog-teeth and car's forward gears are helical w/ synchros.

Quote:
Originally Posted by leadf00t View Post
...there might be minor gains in FE...
There will NOT be a gain in FE. It will be quite the opposite!!

This is the fourth time i am posting a link to this post this week, so please take a look

http://www.team-bhp.com/forum/techni...tml#post226145 (Shifting to Neutral or Pressing the Clutch when Braking - Is this right?)

cya
R

Last edited by Rehaan : 25th July 2008 at 07:52.
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Old 25th July 2008, 10:33   #23
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Quote:
Originally Posted by Rehaan View Post

Doing a clutchless shift on a bike is very different (easier) since bike gearboxes are straight cut / dog-teeth and car's forward gears are helical w/ synchros.
Yes it is very easy on bike, but it also leads to reduced life of gears.

Yes the diagonal cut helical gears are not best for cluthch less shifting. However, when I was not very experienced, I did this in Civic, Baleno and Verna ( petrol ). Only to hear the scaring sound of gear meshing.
Will never try again in cars for sure.
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Old 25th July 2008, 10:45   #24
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Originally Posted by sudev View Post
In theory the two gears inside your gear box have to be at same revs to slot in (further helped by synchro rings) The driving gear is rotating as per engine rpm's and the driven gear (while not slotted) is rotating with wheel rpm's. If you can get both at same rpm's you can slot in the gears to lock with each other. When you press the clutch this is what is happening. The engine side gear is free wheeling because of clutch and can easily slot with driven gear.
I am not sure, but I think Sudev is trying to imply that when a gear change is made the driven gear meshes with the driving gear. If not, my apologies, mea culpa. I say this, because of the last sentence in the above quote.

If yes, read on.

The gears(driven and driving) are always in mesh. i.e turning each other. What happens when the clutch is pressed is that the layshaft(the shaft that is driven by the engine) is disengaged from the engine and turn independently(if in gear, it rotates at the same speed as drive shaft, if in neutral, it rotates independently of the driveshaft as well) of the engine.

When a gear is changed, dogs on the splined layshaft move and slot in with the selected gear, thereby making the drive gear rotate at the same speed as the layshaft(engine) and the driven gear takes a speed multiplied by the gear ratio for that particular selection.(Say 1:1 for 4th gear).

I would suggest everyone to readup on "How gearboxes work" on auto.howstuffworks.com, it is explained with an animation, to make things clear. It's more lucid than my dumb post.
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Old 25th July 2008, 16:19   #25
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@kuttapan...same difference ;-) Imagine changing gears when engine is off with or without clutch. The gears have to be in mesh when they are approaching engagement. You are confusing between drive and driven shafts vis drive and driven gears.

IAC nice pointer how things work.
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Old 25th July 2008, 21:52   #26
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Quote:
Originally Posted by sudev View Post
@kuttapan...same difference ;-) Imagine changing gears when engine is off with or without clutch. The gears have to be in mesh when they are approaching engagement. You are confusing between drive and driven shafts vis drive and driven gears.

IAC nice pointer how things work.
No I don't have any confusion. maybe I wasn't able to explain it clearly, which is why I asked to check Howstuffworks.

The gears are ALWAYS in mesh ! not when approaching engagement. Please get that right.
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Old 28th July 2008, 14:29   #27
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I cant believe this , do you actually mean what you have typed?
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Old 28th July 2008, 23:57   #28
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Quote:
Originally Posted by KSM-Vtec View Post
I cant believe this , do you actually mean what you have typed?
If you directed this question to me, I very well do mean what I typed.

HowStuffWorks "Shifting Gears"

Quote -
"When you make a mistake while shifting and hear a horrible grinding sound, you are not hearing the sound of gear teeth mis-meshing. As you can see in these diagrams, all gear teeth are all fully meshed at all times. The grinding is the sound of the dog teeth trying unsuccessfully to engage the holes in the side of a blue gear."
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Old 29th July 2008, 00:16   #29
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But why do you need to do that? If its there for a purpose use it. Its like using a 'bail gaddi' to plough, even if you have a tractor parked.
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Old 29th July 2008, 01:41   #30
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OK, dog teeth, not gear teeth; yes, I see that is how it actual works, but the distinction is academic.

Interesting stuff on that page though; interesting animations showing what happens.
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