Synchromesh / Constant Mesh - What is the basic difference

esteem_lover · 25th August 2006, 13:37

what is the basic difference between these two types of gearboxes, in layman terms, which one is better & which is found in what car ??

Shan2nu · 25th August 2006, 14:05

http://www.singster.co.uk/mascot%20m...003%20(4).html

Shan2nu

esteem_lover · 25th August 2006, 14:38

Quote:

Originally Posted by Shan2nu

http://www.singster.co.uk/mascot%20m...003%20(4).html

Shan2nu

thats the googling effect, i know.

more original inputs please, in layman terms, from someone who knows

sbasak · 25th August 2006, 15:34

Now all modern cars use synchromesh gears. Two synchromesh gears can engage with one another [running at different speeds] without any jerking. Where as non-synchromesh gears will cause jerking unless their mating speeds are equal.

Synchromesh is nothing but "helical" gears - which gradually transfers mating speed from the periphery of gears towards its inside mesh.
Some old buses don't have synchromesh gears - so often double declutching is necessary to match the speeds of mating gears.

Needless to say, synchromesh gears are always better

Shan2nu · 25th August 2006, 18:10

Quote:

Needless to say, synchromesh gears are always better

But i wonder what race cars use. Coz constant-mesh boxes are said to be stronger.

Shan2nu

Rtech · 25th August 2006, 18:15

Race cars don't need to bother about ease of shift. They are worried about saving weight, making htings compact and strong. Hence they don't run syncro's. But then they also revv-match on downshifting which is in effect what the syncro does on our street gearboxes.

Mpower · 25th August 2006, 18:59

Quote:

Originally Posted by sbasak

Synchromesh is nothing but "helical" gears - which gradually transfers mating speed from the periphery of gears towards its inside mesh.

.Syncromesh is not a gear. Its a device that attached to a gear.

Race cars use straight cut gears with dog engagement, similar to bikes. Hewland, Xtrac, Emco etc.

condor · 25th August 2006, 20:39

What is dual-synchro ?
The Sumo has it. I have tried, but I am not able to get any explaination for this.

esteem_lover · 28th August 2006, 17:20

can anyone help me on this ??

i heard that in a constant mesh, you cannot engage lower gears without the grrrr sound or slowing down, whereas in a synchromesh, you can do that. is that true. i never had to try it from 5th to 1st. but i have made from 40kmph to 1st in my esteem & felt what it was like. there was no sound.

Shan2nu · 28th August 2006, 23:00

Quote:

i heard that in a constant mesh, you cannot engage lower gears without the grrrr sound or slowing down, whereas in a synchromesh, you can do that. is that true. i never had to try it from 5th to 1st. but i have made from 40kmph to 1st in my esteem & felt what it was like. there was no sound.

You can, as long as you double clutch. With synchro gearboxes the need for double clutching is wiped out.

But revv matching has to be done on any gearbox for the downshift to be efficient and smooth.

I've done 5th-2nd and 4th-1st downshifts on my car and never felt anything wrong.

Shan2nu

25th August 2006, 13:37	#1
esteem_lover Senior - BHPian Join Date: Jul 2006 Location: Madras/Py Posts: 7,556 Thanked: 513 Times View My Garage	Synchromesh / Constant Mesh - What is the basic difference what is the basic difference between these two types of gearboxes, in layman terms, which one is better & which is found in what car ??
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25th August 2006, 14:05	#2
Shan2nu Senior - BHPian Join Date: Feb 2004 Location: Hubli - Karnata Posts: 5,533 Thanked: 127 Times View My Garage	http://www.singster.co.uk/mascot%20m...003%20(4).html Shan2nu
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25th August 2006, 15:34	#4
sbasak BHPian Join Date: Nov 2005 Location: CCU-LTN Posts: 607 Thanked: 16 Times	Now all modern cars use synchromesh gears. Two synchromesh gears can engage with one another [running at different speeds] without any jerking. Where as non-synchromesh gears will cause jerking unless their mating speeds are equal. Synchromesh is nothing but "helical" gears - which gradually transfers mating speed from the periphery of gears towards its inside mesh. Some old buses don't have synchromesh gears - so often double declutching is necessary to match the speeds of mating gears. Needless to say, synchromesh gears are always better
	() Thanks

25th August 2006, 18:15	#6
Rtech Team-BHP Support Join Date: Apr 2004 Location: Bombay Posts: 5,765 Thanked: 371 Times View My Garage	Race cars don't need to bother about ease of shift. They are worried about saving weight, making htings compact and strong. Hence they don't run syncro's. But then they also revv-match on downshifting which is in effect what the syncro does on our street gearboxes.
	() Thanks

25th August 2006, 20:39	#8
condor Distinguished - BHPian Join Date: Jun 2006 Location: Speed-brkr City Posts: 16,236 Thanked: 16,862 Times View My Garage	What is dual-synchro ? The Sumo has it. I have tried, but I am not able to get any explaination for this.
	() Thanks

28th August 2006, 17:20	#9
esteem_lover Senior - BHPian Join Date: Jul 2006 Location: Madras/Py Posts: 7,556 Thanked: 513 Times View My Garage	can anyone help me on this ?? i heard that in a constant mesh, you cannot engage lower gears without the grrrr sound or slowing down, whereas in a synchromesh, you can do that. is that true. i never had to try it from 5th to 1st. but i have made from 40kmph to 1st in my esteem & felt what it was like. there was no sound.
	() Thanks