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September_Squall
Forums Junkie

Location:
Melbourne, Australia
Registered:
March 2005

Full-face clutch [cf.] Puck clutch	Wed, 24 August 2005 14:07

Hi, Seems to me a puck clutch has less contact area with the flywheel than an identical-diameter full-face clutch. Why, then, does a puck/paddle design clutch disc tend to be more durable and effective for any given power output than the full face clutch with an equivilent diameter? [Updated on: Wed, 24 August 2005 16:33] [Report message to a moderator]

mrshin
Forums Junkie

Location:
Montrose, VIC
Registered:
May 2002

Re: Full-face clutch [cf.] Puck clutch	Wed, 24 August 2005 14:51

force = pressure x area less area (only small bits of friction surface) with the same pressure (from the pressure plate) = more force As is usually given as a comparison in magazines etc. - think of a stilleto vs. a flat shoe in the mud. What this means is that the point where the clutch begins to slip will be higher, but also that it will wear like a bitch, will be more contankerous to drive, and will eat at your frying wheel if you let it slip. [Report message to a moderator]

September_Squall
Forums Junkie

Location:
Melbourne, Australia
Registered:
March 2005

Re: Full-face clutch [cf.] Puck clutch	Wed, 24 August 2005 16:35

Sense is made. Cheers. [Report message to a moderator]

RobertoX
Regular

Location:
Adelaide
Registered:
May 2002

Re: Full-face clutch [cf.] Puck clutch

Wed, 24 August 2005 22:24

mrshin... your argument is slightly flawed.

Quote:

force = pressure x area

less area (only small bits of friction surface) with the same pressure (from the pressure plate) = more force

I think you'll find that if you reduce the area in this equation you will also reduce the force (for a fixed pressure)

What actually happens is that the pressure plate spring exerts a fixed force, so if the area of the clutch decreases then the pressure on the clutch surface will increase.

From a basic physics point of view, it should not matter what the area of the friction area is (frictional force is dependant on normal force (ie the force exerted by the pressure plate) and the coefficent of friction. This is due to things like interlocking the micro surface irregularities and that sort of thing.
But in reality different materials exhibit different coefficents of friction under different pressure (Tyres are a perfec example of this, besides their adhesive effect, this is one of the many reasons why wider tires grip better but I think that is another thread Smile

)

Also the geometry of the clutch arrangement could come into effect, With a 3 puck clutch the pressure is more likely to be spread more evenly across the surface of the clutch. (think of a tripod resting on an uneven surface as opposed to a hoola-hoop). I'm not too sure on this argument effecting clutch operation though....

[Updated on: Wed, 24 August 2005 22:25]

[Report message to a moderator]

MR 1JZ
Forums Junkie

I supported Toymods

Location:
Adelaide
Registered:
July 2004

Re: Full-face clutch [cf.] Puck clutch	Wed, 24 August 2005 23:26

just to add some more intellectualism into this argument... full face clutches bite the wang if you are serious about "driving" your car puck clutch all the way [Report message to a moderator]

Skip
Forums Junkie

Location:
Perth
Registered:
October 2003

Re: Full-face clutch [cf.] Puck clutch	Wed, 24 August 2005 23:49

It should read pressure = force x area Im sure it all has to do with the coefficient of friction as Roberto suggests. Puck clutches are usually made of ceramic or brass buttons etc. which have a much higher coefficient of friction than organic, so much so a couple of pucks will provide more friction than a full face organic. Id say the reason they puck the material is to give you some sort of ability to slip the clutch still, if it was full face you would have no chance to slip the clutch. Id say the puck arrangement also aids relieving heat from the flywheel??? [Report message to a moderator]

RobertoX
Regular

Location:
Adelaide
Registered:
May 2002

Re: Full-face clutch [cf.] Puck clutch

Wed, 24 August 2005 23:57

Quote:

It should read pressure = force x area

Nah, sorry this is wrong, mrshin had it right the first time...

force = pressure x Area

====>>> Pressure = Force / Area

think about it, the more area you have, the with the same force, the more that force will be distributed over that area. Hence less pressure...

ie Pressure is inversely proportinal to area for a force

[Report message to a moderator]

Skip
Forums Junkie

Location:
Perth
Registered:
October 2003

Re: Full-face clutch [cf.] Puck clutch	Thu, 25 August 2005 00:13

Yep you are right, brain fart. [Report message to a moderator]

RobertoX
Regular

Location:
Adelaide
Registered:
May 2002

Re: Full-face clutch [cf.] Puck clutch	Thu, 25 August 2005 00:25

Dont worry I understand all too well Does anyone have a good reason to use a puck clutch? I'm interested in this but my response is just a stab in the dark and dont have any firsthand experience with them... [Report message to a moderator]

MR 1JZ
Forums Junkie

I supported Toymods

Location:
Adelaide
Registered:
July 2004

Re: Full-face clutch [cf.] Puck clutch

Thu, 25 August 2005 00:33

RobertoX wrote on Thu, 25 August 2005 09:55

Does anyone have a good reason to use a puck clutch? I'm interested in this but my response is just a stab in the dark and dont have any firsthand experience with them...

Having the ability to clutch kick the soarer in 4th gear at 150+ kph and know that its going to induce wheelspin is a good reason Razz

[Report message to a moderator]

4agte
Forums Junkie

Location:
Toronto, Downtown
Registered:
September 2004

Re: Full-face clutch [cf.] Puck clutch	Thu, 25 August 2005 01:21

it drives nicely dosnt make rattling noises at idle like multi plate setups dont cost the earth and the pedal dosent get much if any heavier If i had another 1000 buks to spend i would have bought a twin plate instead [Report message to a moderator]

Kyosho
Regular

Location:
Wollongong
Registered:
November 2004

Re: Full-face clutch [cf.] Puck clutch	Thu, 25 August 2005 02:05

It will stop most of your mates wanting to drive your car when they can't get the clutch and accelerator right... [Report message to a moderator]

MR 1JZ
Forums Junkie

I supported Toymods

Location:
Adelaide
Registered:
July 2004

Re: Full-face clutch [cf.] Puck clutch

Thu, 25 August 2005 02:12

Kyosho wrote on Thu, 25 August 2005 11:35

It will stop most of your mates wanting to drive your car when they can't get the clutch and accelerator right... Razz

yeah its good, my mum cant even reverse my car out of the driveway Laughing

[Report message to a moderator]

4agte
Forums Junkie

Location:
Toronto, Downtown
Registered:
September 2004

Re: Full-face clutch [cf.] Puck clutch	Thu, 25 August 2005 23:33

One thing with ceramic puck clutches is that they tend to chew the flywheel and pressure plate which i am finding out atm.. Im replacing my gearbox on my mr2 and asked the mechanic to check out the flywheel and the clutch.. The clutch has pleanty of meat on it but the flywheel needed machining and the pressure plate was rooted.. This was after only 15000km or so of sedate driving.. Now i dont know if thats because ive been slipping it or just normal wear and tear but exedy have advised me that it is normal. Edit: at $355 for a new pressure plate and no doubt $20-$50 to get the flywheel machined it starts to get $$$ fast. Guess i wont be slipping my clutch too much in the future!!! [Updated on: Thu, 25 August 2005 23:42] [Report message to a moderator]

Iceman
Regular

Location:
Sydney
Registered:
January 2003

Re: Full-face clutch [cf.] Puck clutch

Mon, 29 August 2005 01:10

RobertoX wrote on Thu, 25 August 2005 09:57

Quote:

It should read pressure = force x area

OK you guys need to go back to high school for maths..... These two equations are the SAME!! Just sit and look at them for a while.

a x c = b
.
a x c / c = b / c
.
a = b / c

[Report message to a moderator]

RobertoX
Regular

Location:
Adelaide
Registered:
May 2002

Re: Full-face clutch [cf.] Puck clutch

Mon, 29 August 2005 02:34

Iceman wrote on Mon, 29 August 2005 11:10

RobertoX wrote on Thu, 25 August 2005 09:57

Quote:

It should read pressure = force x area

OK you guys need to go back to high school for maths..... These two equations are the SAME!! Just sit and look at them for a while.

a x c = b
.
a x c / c = b / c
.
a = b / c

pressure = force x area
Pressure = Force / Area

read it again buddy, these two aren't the same, they vary by an opperand. Your demonstration is quite correct but you need to look a little closer.

Cheers
Rob

[Report message to a moderator]

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