Wilwood Two Piston Brakes

[robert mueller]

G'day,

Look what I stumbled on to researching calipers for the Kingsley:

Full URL:

https://www.speedwaymotors.com/Wilwood-140-11290-D52-Front-Brake-Caliper-Kit-2-In-Piston-1-28-Rotor,101356.html

Tiny URL:

https://tinyurl.com/ya8k9jmb

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808
 

 

[john r. lebetski]

They show piston area but not volume. Wonder if it reqs more volume.
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[Ken H.]

Seems to me the volume required is determined by the pad wear (plus caliper
deflection, bearing looseness, and disc runout), so there should be no
difference unless one caliper is stronger.

Ken H.

On Wed, May 16, 2018 at 11:44 AM John R. Lebetski
wrote:

> They show piston area but not volume. Wonder if it reqs more volume.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
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> Unsubscribe or Change List Options:
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[Keith V]

I used to sell Wilwood brake kits for C3 Corvettes and learned a lot about brakes. Willwood make great brakes but thay are not what I'd use for street use, mostly because they don't have dust seals, and believe it or not because they are multi piston.
Multi piston is of use when you are using the brakes really hard all the time. Multiple pistons distribute the force more evenly so you don't get as much pad taper. Why is pad taper bad? Pad taper being defined as a difference in thickness across the length of the pad causes extra pedal deflection as the pad has to flex on application, this flex requires more piston movement and thus more pedal travel.

A stiffer caliper basically gives you better ( stiffer ) pedal feel.

In a GMC? Meh, I'd rather have a single piston, off the shelf rugged caliper. Probably not as stiff, but I'm not going into a corner at 120mph and braking at the last second either...well I hope not!
________________________________
From: Gmclist on behalf of Ken Henderson
Sent: Wednesday, May 16, 2018 1:13 PM
To: GMC Mail List
Subject: Re: [GMCnet] Wilwood Two Piston Brakes

Seems to me the volume required is determined by the pad wear (plus caliper
deflection, bearing looseness, and disc runout), so there should be no
difference unless one caliper is stronger.

Ken H.

On Wed, May 16, 2018 at 11:44 AM John R. Lebetski
wrote:

> They show piston area but not volume. Wonder if it reqs more volume.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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[richard h staples]

They look very nice, appear to be good quality, etc. But.... Their piston area (6.28 sq in.) is even LESS than the original 74mm GMC calipers I threw
away 15 years ago (6.63 sq. in.), and substantially less than the 80mm (7.79 sq, in.) calipers I use now. That means ~20% less pressure on the pads
and 20% less braking for a given pedal/hydraulic pressure. Not what we need in our coaches, especially those of us who have upgraded our rear brakes
with slightly oversize mid-axle cylinders (as I have) or disc brakes (for those who hate to downshift in mountains).
Just my .02.
Rick Staples
'75 Eleganza
Johnstown, CO
--
Rick Staples, '75 Eleganza, Johnstown, CO

"Advice is a dangerous gift, even from the Wise to the Wise, and all paths may run ill." -Tolkien

 

[robert mueller]

Rick,

Thanks! I got all excited for nothing!

I was upset because I have just installed 80mm calipers on the front disks and had bought two more for the Caddy disc setup I have
for the middle wheels on the Kingsley.

I am replicating the system I have on the Avion here in the USA as it's served me well since I've had it.

I guess the silver lining is that I saved myself $374 x 2 as I was going to buy two pairs of the Wilwood calipers, DOUH!

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Richard H Staples
Sent: Wednesday, May 16, 2018 9:31 PM
To: gmclist
Subject: Re: [GMCnet] Wilwood Two Piston Brakes

They look very nice, appear to be good quality, etc. But.... Their piston area (6.28 sq in.) is even LESS than the original 74mm
GMC calipers I threw away 15 years ago (6.63 sq. in.), and substantially less than the 80mm (7.79 sq, in.) calipers I use now. That
means ~20% less pressure on the pads and 20% less braking for a given pedal/hydraulic pressure. Not what we need in our coaches,
especially those of us who have upgraded our rear brakes with slightly oversize mid-axle cylinders (as I have) or disc brakes (for
those who hate to downshift in mountains).
Just my .02.
Rick Staples
'75 Eleganza
Johnstown, CO
--
Rick Staples, '75 Eleganza, Johnstown, CO

"Advice is a dangerous gift, even from the Wise to the Wise, and all paths may run ill." -Tolkien

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