Vented disk rotors

[Carboy0]

I have a pair of Austin Princess 4 pot calipers which bolt straight onto the Stag caliper mounts. I am interested in spacing them out for vented disks. Is there a 270mm diameter vented disk that I can substitute for the Stag unvented disks?

I want to keep the standard wheels, so I don't want to increase the rotor diameter.

I am sure I can't be the first person to do this, so any advice would be appreciated.

[mjheathcote]

Aren't princess calipers smaller in total piston area than the 2-pot standard Stag caliper, thus giving reduced braking performance.
Yes 4 pot calipers give the advantage of even pad pressure, but not good if smaller in total piston area!

Edit: Piston area Princes calipers 7.069, Stag 7.950 square inches, so Princes calipers have 11% less area and why you never see Princes 4 pot calipers being fitted to Stag's. Sorry.

[new to this]

i used citroen picasso

Dave

[Carboy0]

Thanks for the tip on piston areas. Looking at the pads, they are bigger than Stag. Citroen Picasso disks, hmmm time for some research.

[Carboy0]

i used citroen picasso

Dave

Looks good Dave what calipers have you used?

Here are the disk dimensions for the Picasso

IMG_0469.jpg

IMG_0472.jpg

I also found these at 266mm from a Mazda E-Van. They are very shallow and would need a spacer between the disk and hub.

IMG_0470.jpg

IMG_0471.jpg

[mjheathcote]

Thanks for the tip on piston areas. Looking at the pads, they are bigger than Stag. Citroen Picasso disks, hmmm time for some research.

Unfortunately you could have pads twice as big but the braking force will not change, you will always have less braking force than a standard Stag. The benefit of the larger pad area being more area for reduced brake fade, the heat is distributed over a larger area.
Personally, you cannot fit a caliper with less piston area than standard.

[Carboy0]

OK I get what you are saying. Are any of the SD1 4 pot calipers a better match, as I think they have bigger pistons that the Princess?

[Richard G]

Why do you need to change original setup?

I find my brakes good, having renewed a few parts, discs etc, all good for a car of its age and performance.

I have a pair of Austin Princess 4 pot calipers which bolt straight onto the Stag caliper mounts. I am interested in spacing them out for vented disks. Is there a 270mm diameter vented disk that I can substitute for the Stag unvented disks?

I want to keep the standard wheels, so I don't want to increase the rotor diameter.

I am sure I can't be the first person to do this, so any advice would be appreciated.

[mjheathcote]

A relatively budget option a few years ago was the Jaguar XJS calipers with vented brake discs. You gained a massive increase in piston area but the pay off was that they were heavy, very heavy, so an increase in unsprung weight.
The wilwood brake kits would get my vote.
Saying that, the standard set up when in tip top condition is not bad you know!

[Carboy0]

I must admit, the question was prompted by the fact I already have the Princess calipers in the garage

[DJT]

I must admit, the question was prompted by the fact I already have the Princess calipers in the garage

Flog them off on eBay and stick with the original setup. Check existing discs for corrosion on the inner face as that is where they deteriorate and the brakes become less efficient, leading some to think the original brakes aren't up to the job. Whereas, in fact, they are ideal for normal road use.

[Guest]

Flog them off on eBay and stick with the original setup. Check existing discs for corrosion on the inner face as that is where they deteriorate and the brakes become less efficient, leading some to think the original brakes aren't up to the job. Whereas, in fact, they are ideal for normal road use.

+1

i re hewed my discs and pads, all standard and are fine with a good feel. However, when the pads need doing again I'll go with EBC yellow stuff

[Richard G]

I have some rod operated drums off a Ford E93A but I am not tempted to fit them to my Stag!

I must admit, the question was prompted by the fact I already have the Princess calipers in the garage

[TR5convalescent]

One thing I found with my TR was that replacing the standard discs with grooved and dimpled ones and EBC pads did improve 'bite'. I don't suppose the dimpled discs are available for Stags are they?

[mjheathcote]

One thing I found with my TR was that replacing the standard discs with grooved and dimpled ones and EBC pads did improve 'bite'. I don't suppose the dimpled discs are available for Stags are they?

I believe they are.