Bigger disks, same calipers?

[cat007]

Hey all

Can you use bigger disks with same calipers, albeit with a slightly different bracket?

I assume also pads would need to be changed?

[matt dunn]

Q. Can you use bigger disks with same calipers?
A. Yes you can.

Q. albeit with a slightly different bracket?
A. Yes, you will need modified caliper mounts.

Q. I assume also pads would need to be changed?
A. No, as the same pads will still fit the same calipers,
cant fit bigger pads in there.

[cat007]

Q. Can you use bigger disks with same calipers?
A. Yes you can.

Q. albeit with a slightly different bracket?
A. Yes, you will need modified caliper mounts.

Q. I assume also pads would need to be changed?
A. No, as the same pads will still fit the same calipers,
cant fit bigger pads in there.

Ok so with that though, my pads have like 3-4mm around the outside of the backing plate.....could that not be better utlized?

[cat007]

Ok so with that though, my pads have like 3-4mm around the outside of the backing plate.....could that not be better utlized?

That came out wrong - what I mean is, it looks like the pad could be 3-4mm bigger.....???

[Adamal]

You'd need bigger calipers for bigger pads, otherwise you wouldn't be able to get even force on the pads I'd imagine

[matt dunn]

Pads and disc's dont really work like you think.

i.e. my car has too much rear bias, and the bias adjuster has not got enough travel on it,
so to get less rear braking, I am fitting bigger brakes on the rear.

Sounds wierd but that's the go.

and pad size is determined by caliper size, not disc size.

[the fallen303]

is the bigger caliper due to requiring more fluid/force from brake pedal to apply the same amount of pressure on the pad, so therefore doing less work for same brake pedal application?

[matt dunn]

same force applied to a smaller area gives better braking,

so a smaller pad gives better braking,
bigger pad gives less braking.

But,
bigger gives less fade and length of life.

[the fallen303]

when changing from single to twin, or twin to 4pot calipers, do you see any point in changing the master cylinder or any other component to take better advantage of going to the bigger caliper? i've changed from single pot to twin pot and i feel like the brakes are a little more spongy, where as dad who did the change, doesn't notice the difference...

[matt dunn]

when changing from single to twin, or twin to 4pot calipers, do you see any point in changing the master cylinder or any other component to take better advantage of going to the bigger caliper? i've changed from single pot to twin pot and i feel like the brakes are a little more spongy, where as dad who did the change, doesn't notice the difference...

Yes, if the calipers need a different volume of fluid, you will need to do something with the master cylinder,

[Adoom]

You might have to get a slightly bigger bore master cylinder. The bore diameter should be stamped on the side of the master cylinder.(its in inches).

Say your original calipers held 10cc of brake fluid and you had to push the brake pedal 40mm to move enough fluid to engage the brakes.

If you got bigger or twin pot brake calipers that might hold 18cc of fluid. You will have to move the brake pedal further to move enough fluid to engage the brakes.

Also, the smaller the master cylinder bore is compared to the caliper bore the more pressure you get, but you also get more pedal travel.
And the pedal is easier to push.

You can increase the bore of the master cylinder to move more fluid and have shorter pedal travel before the brakes come on. But to get the same pressure at the callipers you have to push the pedal much harder.
How strong is your left leg?

You need to find the middle ground. Or find a bigger brake booster and run huge bore master cylinders!

[KinLoud]

What do you want to do?
Most braking systems have more than enough power to lock up the wheels at any speed... So I guess this isn't your problem...

Is your problem:
1 - brake pad fade (pedal still hard, but car won't stop after repeated stops)
2 - brake fluid boiled (pedal soft, goes to floor, need to pump it up)
3 - long pedal (brakes work fine but pedal has to move some distance before resistance is felt)
4 - you want bigger brakes, just because...
5 - you want to stop harder.

Solution
1 - change to better pads (a good semi metallic, avoid pads that don't work well cold unless only for racing)
2 - Change brake fluid to new/better fluid, reinstall backing/anti squeal plates (helps insulate the piston from the hot pads), upgrade to a thicker disk (more mass = lower temperature).
3 - check/tighten/replace wheel bearings, get bigger diameter brake master)
4 - check out what bigger brake options are fitted to the same car (thicker/bigger diameter/twin pot calipers) before you spend big $ on aftermarket stuff. Remember that you may need a cert for your upgrade.
5 - Do what I do, push real hard on the pedal! Go out and practice stopping, learn what locking a wheel feels like, how the car squirms and pulls on different surfaces.


I raced my 4age carina for 2 seasons with the standard brake calipers and disks.
I used Metal King brake pads and Repco 5.1 fluid. Never ran out of brakes on the old (short) Taupo track.

Season 3, I powered up to a gen3 3sge. So I "upgraded" to Supra brakes... same disk diameters but 2mm thicker (from 18 to 20mm!). Wow, outrageous!
Also used mintex 1166 pads (better cold, similar feel hot compared to the metal kings). Pads didn't last quite as long, (see viewtopic.php?t=43987&highlight=cook).

Right front outer pad with a bit of pad remaining where the backing plate buckled away from the disk

Ken
Auck
021 408 863

[cat007]

Thanks for a great reply

The plan for my supra is to make it a fun take to the track whenever I want. I've got 1166's in there and will be getting Motul RBF600 fluid but just wondering if keeping the stock calipers and putting bigger, say, 320-330mm disks on (currently are 297mm), would help with head dissipation?

[KinLoud]

Easiest to go for thicker disks if you are worried about heat, or fit cooling ducts and hoses. will later model supra disks and calipers fit?

I have driven Glenn's (ezy10s) 1uz V8 powered carina around Pukekohe doing low 1min11sec laps with standard carina brakes... crappy pads and old fluid, pedal felt a bit long but the brakes were handling the workload (just).

Mintex pads are happy being hot, just get out there and drive. Pukekohe isn't really hard on brakes, a couple of big stops but there is some time to cool the brakes before the next big stop.

Ken

[cat007]

Well I'll see how I go

Last time out I was running crap generic fluid from repco with the 1166's and after braking from about 230km/h into the hairpin at one point I think the pedal felt a little soft.

I'll get some rbf600 fluid and do a full flush and see how I go.

Its hard to go to a thicker disk? I guess I should measure the width of the calipers when fully retracted.

Also - would it be worth finding same size (297mm) disks but slotted ones?