Date: Sat, 4 Feb 2012 16:58:41 -0700
Reply-To: OlRivrRat <OlRivrRat@COMCAST.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: OlRivrRat <OlRivrRat@COMCAST.NET>
Subject: Re: Jaguar vs. Passat brakes on Vanagon
In-Reply-To: <6B1A8917-BF81-4DA0-B151-298E134C59F9@shaw.ca>
Content-Type: text/plain; charset=UTF-8; format=flowed; delsp=yes
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 ...
>