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Old 25th August 2006, 13:37   #1
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Default 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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Old 25th August 2006, 14:05   #2
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http://www.singster.co.uk/mascot%20m...003%20(4).html

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Old 25th August 2006, 14:38   #3
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Quote:
Originally Posted by Shan2nu
thats the googling effect, i know.

more original inputs please, in layman terms, from someone who knows
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Old 25th August 2006, 15:34   #4
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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
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Old 25th August 2006, 18:10   #5
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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.

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Old 25th August 2006, 18:15   #6
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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.
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Old 25th August 2006, 18:59   #7
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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.
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Old 25th August 2006, 20:39   #8
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What is dual-synchro ?
The Sumo has it. I have tried, but I am not able to get any explaination for this.
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Old 28th August 2006, 17:20   #9
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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.
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Old 28th August 2006, 23:00   #10
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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.

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