Alistair

        BigOldummyMe ~ I knew that ~ Haven't had enough sleep lately & it's  
still too early

to have a drink. When I was doin the math, I was tellin myself there  
was something wrong

but I just didn't listen well enough. Thanks AB

                                                        ORR ~ DeanB

On 4 Feb , 2012, at 2:54 PM, Alistair Bell wrote:

> sheesh you guys, come on now
>
> A = pi X (radius squared)
>
> (circumference = diameter X pi)
>
>
> 3" piston:
>
> A = Pi X(1.5 squared)
> = 7.07 square inches
>
> 1.5" piston
>
> A = Pi X (0.75" squared)
> = 1.77 square inches
>
> So two 1.5" diameter pistons would have a total area of:
>
> 2 X 1.77 = 3.54 square inches
>
>
> alistair
>
>
>
>
> On 2012-02-04, at 1:03 PM, OlRivrRat wrote:
>
>>              Dennis
>>
>>      Also ~ the area of a circle is found by ~ Pi x Diameter. The  
>> vol' of a cylinder is Pi x (Radius x Radius).
>>
>> So your 3" piston has an "FootPrint" of 9.428 Sq" & your two 1.5s  
>> will also = 9.428 Sq".
>>
>>                                                      ORR ~ DeanB
>>
>> On 3 Feb , 2012, at 8:11 PM, Dennis Haynes wrote:
>>
>>> My concern is both the threads and the face of the hub cracking  
>>> from the center. Yes most front drive vehicles use a flange hub  
>>> with the rotors slipped on or over and many use bolts threaded  
>>> into those hubs but those hubs-flanges are from a solid machined  
>>> piece of steel, not a casting. The rotor casting is designed to  
>>> work as is. That hat and disc adds strength to the flange.  Did  
>>> anyone notice my error in the area calculations? I used the  
>>> diameter, not the radius.
>>>
>>> Dennis
>>>
>>> -----Original Message-----
>>> From: Chris S. [mailto:szpejankowski@gmail.com]
>>> Sent: Friday, February 03, 2012 4:03 PM
>>> To: Dennis Haynes
>>> Cc: vanagon@GERRY.VANAGON.COM
>>> Subject: Re: Jaguar vs. Passat brakes on Vanagon
>>>
>>> So your concern are the threads going into the machined hub.
>>>
>>> Newer VW vehicles use front hubs and hub-centric rotors which do  
>>> not utilize press-in studs. The pressure of lug bolts holds the  
>>> wheel and rotors in place. Perhaps the hub material in those hubs  
>>> are of different hardness to handle the extra load. It would seem  
>>> that the forces would be transferred by the hub face and not the  
>>> lug bolts themselves. The lug bolts merely provide the clamping  
>>> force.
>>>
>>> Chris.
>>>
>>> Wysłane z iPhone'a
>>>
>>> Dnia Feb 3, 2012 o godz. 6:43 Dennis Haynes  
>>> <d23haynes57@HOTMAIL.COM> napisał(a):
>>>
>>>> What you really want to know is the total surface area of the
>>>> piston(S) combination. This is calculated by the radius squared x  
>>>> pi.
>>>> A 3" piston has an area of 28.274 cu in. Two 1.5" piston have a  
>>>> total of only 14.137 cu in.
>>>>
>>>> With the original rotors being cast the wheel flange gets much of  
>>>> its
>>>> strength from the complete rotor piece. There is no way I would  
>>>> rely
>>>> on the wheel flange part to mount the tire with the rotor disk  
>>>> and hat
>>>> cut off and flange cut down to fit inside a different rotor. The
>>>> threads alone are an issue as the rotors have a defined lifespan  
>>>> and
>>>> each time a wheel is mounted there is some wear and distorting of
>>>> these threads. Have a machine shop make a hub from solid steel  
>>>> and use
>>>> pressed in studs instead of lug bolts. This will also allow the  
>>>> flange
>>>> to be placed for proper disk alignment or wheel spacing.
>>>>
>>>> I would also consider that a major change to the front brakes  
>>>> should
>>>> also include a matching change to the rears. The rears contribute a
>>>> lot more to stopping than many would think. A properly working rear
>>>> set up has a lot of surface area. A real problem with the rears is
>>>> that the aftermarket shoes do not have thick enough linings and
>>>> without some compensation only part of the shoes contact the  
>>>> drums. I
>>>> have posted a number times shimming the lower shoe rests out the  
>>>> get
>>>> more of the shoe to contact the drums. Also the rear brake pressure
>>>> valve can fail causing poor rear brake action. With good pads up  
>>>> front
>>>> and the rears working properly the stock brakes can work quite  
>>>> well until you go to larger tires.
>>>>
>>>> Dennis
>>>>
>>>> -----Original Message-----
>>>> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
>>>> Behalf Of ralph meyermann
>>>> Sent: Thursday, February 02, 2012 8:58 PM
>>>> To: vanagon@GERRY.VANAGON.COM
>>>> Subject: Re: Jaguar vs Passat brakes on Vanagon
>>>>
>>>> Whats the total of piston diameters?
>>>>
>>>> Velma 82diesel 1.6 na westy
>>>>
>>>> On Feb 2, 2012 7:54 PM, "BenT Syncro" <syncro@gmail.com> wrote:
>>>>
>>>> Chris,
>>>>
>>>> At quick glance, the biggest difference is twin piston calipers for
>>>> the Jag and single for the Passat's.
>>>>
>>>>
>>>> BenT
>>>>
>>>> sent from my electronic leash
>>>>
>>>>
>>>> On Feb 2, 2012, at 4:45 PM, "Chris S." <szpejankowski@GMAIL.COM>  
>>>> wrote:
>>>>
>>>>> What's the list opinion ...
>