Brake Pads

[THR]

we are trying to find out about which pads to use.

the car is way underbraked, due to the rules. two pot calipers with solid discs. on a single seater.

which pads should we use?
and wot grades?

currently using mintex 1144.

ferodo? pagid? mintex? ebc? any others?

any ideas? wot do u use?

[enzo]

What kind of car?

There are many ways to increase the braking power - it depends on just how the "underbraked" manifests itself.

Nothing wrong with 2-pot calipers for most small formula cars. American F2000's use them to great effect (LD-20's on all 4 corners).

If it is a case where the rotor temps are exceedingly high - average over 650C - then an upgrade may be necessary to bigger dia disks, and/or some cooling ducts.

Are your disks floaters? If not, extra heat can be generated when they lean against the pad in the corners (the British cars I'm familiar all have rather flexy hub and bearing arrangements).

Most likely the complaint stems from the use of the 1144's. They don't have much bite and require a ton of leg (though they a damn good in the rain where finess is paramount!).

Have you tried the Ferodo 3000's yet (or is it 4000?). Most of my drivers use them and like them a LOT better than the 1144's.

PFC also supposedly has a new compound - 02 or something - that finally addresses the can't-trail-brake problem of their older compounds.

[THR]

FRenault single seater, about 500kgs.

im not sure how u mean by floaters?
the discs are bolted rigidly to the hub.

by underbrake i mean we can have full fornt bias and the fronts will still not lock up no matter how hard he pushes them. to me, thats underbraked.

the discs (and wheels) get very hot, but we havent actually got a temperature off of them. they dont warp, or change colour, so they must be ok.
upgrading the brakes isnt allowed, all we have to play with is the pads.
the pads float til the piston pushes against them, like in every other brake ive seen.

we tried red EBC pads, but that was last year when he didnt have the confidence to really push hard of them anyway, so might try them again.

who are PFC?

[JR Ewing]

EBC will tell you to run GREEN in that car. People often get excited by discs and think heavy duty needed but think of the weight of your car and the GREEN is fine. The 1144s should be OK too, perhaps try the 1155s. Ferodos are the same as the Mintex in my experience

[JR Ewing]

also, can you lock the rears easily (not with downchanging). If not that just reinforces what i said about needing softer GREEN pads. REDS are rock hard and would suit a heavy Le Mans type car....

[JR Ewing]

again, floating discs are where the discs are not fixed laterally and can move from side to side and are held inplace by the pads. They are generally better as they ensure more even braking and also less uneven pad wear.
I'm not sure if FRS has these but i would think so - FF Zetecs do.

[THR]

ahhh na they arent floating then, i know wot u mean now.

we can lock the rears with the 1144's
arent the 1155's harder?

ebc's site suggests redstuff for this use.

ive just emailed everyone... so we shall see wot they say! ill put it here if u like after i get replies.

keep replying tho!!

[Lola]

Dont use green,
Last season when we had a double header at Rockingham (you parked next to me THR and your light kept me awake all night grrrr)

I was marginal on pads by the end of the second race in my ff1600

[THR]

lol, sorry hehe.... i make him not take that bloody light now too!!
two races is a little expensive isnt it!!

[enzo]

Now we're getting somewhere!

Did you recently change pad componds? If so, did you scrub the rotor CLEAN of the old material? If you don't, it's a guarantee that you will have lousy brakes.

So you can lock the rears but not the fronts with the bias full front? By chance is the rear master cylinder smaller than the front? If it is, swap 'em around to get the relationship correct.

PFC = Performance Friction, carbon metallic

[THR]

running two .75 pistons.
recently changed the front one from 5/8ths to .75.
was running the smaller one last year as he found it easier to stop, as he had little confidence in the car, now it handles better and is more predictable we are hunting for braking performance.

we are thinking its more pads than cylinders, as he is really pushing them as hard as he can but nothing more is happening.

Found PFC's rather poor website!! and mintex's too. EBC's wasnt bad, and Ferodo's was the most helpful.

we did clean the discs b4 changing the pads, with scotch bright (not sure wot thats called in america tho!).

your correct about the bias.

[enzo]

Switch back the front MC to either the 5/8th or to a .7. The jump in piston area from a .625 to .75 dia is BIG, so it is no surprise at all that he hasn't got the leg for it! I've NEVER seen a successfull brake system with both MC's the same dia - you need the smaller dia at the front to get higher line pressure at the front - the bias bar alone cannot give you the necessary difference.

Scotchbrite usually is sufficient, but not always (it also is tough on the wrist, a 3" air disk grinder is the way to go, with LOTS of new scotchbrite disks) - it depends on the compound material that was used. On most high metallic compounds, you actually have to remove about .010 on a lathe to get below the affected zone.

CHANGE THE MC"s !!!!!!

[THR]

hmm now im a little confused!
lol

in the book we have it says .75 recommended for both circuits, but this is french, and therefor probs wrong.

the reason we went to a bigger cylinder was to move more fluid as we felt he was using nearly the whole stroke and the actual brake pedel moved miles.

but yout saying try a smaller piston, but i cant see how that will actually improve the braking.

i kinda see wot u mean tho... ill have to do some sums i think, its fairly easy to work out the ratio that the bais can achieve.
ill tell ya wot i conclude!!

ten thou is a lot!! thats ummm .25mm!! but i can quite believe it.

[Griff]

Hi THR
enzo's right in what he say's the smaller bore cyl. is the way to go . The smaller bore gives more line pressure but less fluid displacement this will give a slightly longer pedal but this shouldn't be a problem, if it does check the hub and wheel bearings for play especially when hot, as the bearing can move in the hub if it's not a correct fit causing pad knock off.
I have run your system on a F2000 car,[ slicks and wing's and about 480kg's ] with no serious brake problems, but I did find the Mintex pad not to have a lot of feel and didnt inspire confedence under hard braking,So I went to Ferrodo
which transformed the car compleatly' better initial bite, more feel and better feedback as to when the wheels are about to lock. The only down side is they don't last as long !! Well enough of all this ,hope some of it helps all the best with your problem.
GRIFF.

[StuiE]

this is just what ive heard of EBC pads, although this is talking abou road use

http://forums.fastfours.com.au/messa...y&keyword1=ebc

[Barry Pomfret]

I have been following this post with some interest and felt it was important to let you know of my experience with EBC pads. JR Ewing suggests the green compound, this was also suggested by the distributor when I contacted them regarding a suitable pad for a Formula Ford Zetec, after reading the hardness and temp data I decided to go harder and purchased the red compound. We cleaned the discs and fitted the new pads, within 15 laps of Silverstone Club circuit they were down to the metal backing! I have tried many different pads, Pagid Blue compound is very good but expensive, for your application considering cost and effectiveness go for Ferodo 4003 compound. Contact Circuit Supplies on 01525 385888, they are main distributors for Ferodo racing pads and are very knowledgeable and helpful.

[THR]

hmmm... tending to go off ebc now!
i think we will plop for the feredo 4003, as this does seem to be the most popular choice around the paddock.

can anyone tell me a good reason not to just buy a set for the front?
id love to buy a full set... but im having trouble convincing him to pay for them. as he says "but the backs lock up already".

[enzo]

Is your driver suicidal? If so, mix the compounds!

Mixing compounds is a sure way to get all sorts of braking imbalance problems - the different performances front vs rear will drive you nuts.

Get the master cyls switched - most likely the .7 front will be the ticket for the right balance - and THEN switch compounds ON ALL 4!!!!!!

[alfasud]

I've heard similar to what enzo said. Front wheel drive tourers might be an exception to the rule... the rears always tend to lock, so you might go for lower c.o.f. on the rear, but I think the theory is that if you can balance the car via the hydralics and use the same brake pads all round, then that's the best way.

Problem with different compounds is that they don't warm up, or wear the same so while you might have the right balance for a while.....

Seem to recall that Ferrodo recommend the 4003, in light single seaters because it's a lower c.o.f (about 0.43?) than the DS3000 (0.63?).... suggesting that most light single seaters have the opposite problem (locking the fronts).

Things seem to be pointing to that master.

[THR]

glad u said that enzo! i will now force him to buy 4 sets! lol.

so you think then... ferodo pads all round, 5/8 front cyl and 3/4 rear?
or just try the pads first?

[enzo]

Your main problem isn't the pads! Get the hydraulic balance fixed first.

If you had a problem with a too-long pedal using the 5/8 mc, why go back to it? Use a .7 for the front instead. On just about every samll-bore formula car I've ever seen with the same bore calipers front and rear, that combination of mc's (,7F & .75R) is the most popular.

[THR]

got ya.

cheers

[Mackmot]

From what I have heard our team talking about pads, we use Ferodo 3000s in our fords because they are the best all round pad. Pagids are brilliant in hot conditions but far too expensive and mintex are cr*p and leave dust all over the wheels and side of the car.

[Stacy]

Two people make brake pads worth using - Ferodo, and PFC. I'd use PFC, but the limiting factor is the tyre grip and as Enzo pointed out you couldn't trail brake with them. Maybe the new compound is worth looking at.

You buy Mintex if you don't want to stop, and you buy EBC if you want to put brake pads which are made of cheese on the car, and want brake dust to shaft your wheels.

As for the driver moaning about pads, if he can't afford to buy brake pads he can't afford to race and if he wants to mix them up he shouldn't be on the track.

All in my humble opinion of course!

Stacy.

[josvandeperre]

Why not talk to the Ferodo people in Milton Keynes - they're very knowledgeble and helpful