Upgraded Brakes And Now Front Wheels Locking Up

[Husky33]

Hey guys,

As of thursday i upgraded my stock R32 brakes with shit pads for:

RDA slotted rotors all round

Braided brake lines all round

Project MU Street front pads

Bendix Ultimate rear pads

Cusco master cylinder brace

Motul RBF600 brake fluid

Now after bedding in etc, it brakes damn well. Hella noisy but braking is just phenomenal, well compared to my previous anyway.

Only problem is, when i brake hard/suddenly, the front lock up. It happens at 40 km, 80km and scarily happened when i braked hard at 120km. I have shitty bridgestone tyres with good tread.

Anyone know why/what is happening, and is there anything i can do to stop it. No abs btw

Thanks

[shozbot]

You've already answered your own question

I have shitty bridgestone tyres

Fit some decent tyres and you will not be locking up the brakes so easily

The best brakes in the world are no good if your tyres lack adhesion

[Scooby]

you might just need to get used to modulating the braking a bit better now you have something that's good but i'd say either;

tyres. if they are as bad as you say then they will not be your friend.

suspension. what are your spring and rebound rates? if the are too hard they will really hurt braking performance as the tyre/rim will have a tendency to skip between bumps in the road rather than grip.

[T04GTR]

miss matched brake pads dude.

ultimates are shiet compard to a decent "sporty" type.

[Husky33]

I know ultimates aren't as good as the project mu ones, but i thought being on the rear it should be fine.

I have Koni suspension, and it is quite hard.

About tyres though, how would it cause lock up. I mean if the brakes are locking up why would it matter what tyres you have on there? Anyone car to expain. Cheers

[shozbot]

The purpose of brakes is to slow the revolution of your wheels, and your tyres are connecting your wheels to the road surface. Once the link between wheel and road is broken (ie tyres lose traction) there is no force still turning the wheel so the brakes easily lock up. The better grip your tyres have on the road, the better your brakes ability to slow the wheel rotation. It helps explain why all us “crazy” people spend $1500 on a set of road tyres when you can pick up “cheapies” for $600

If you think about this principle you can see why ABS was invented. The sensors tell when the wheel stops turning and momentarily diverts braking pressure to avoid lockup and allow the wheel to still turn which helps maintain traction instead of skidding. (Very simple explanation but gives you the idea)

I hope this helps, but all this assumes your steering and suspension are set up correctly otherwise your “sticky tyres” will not get the chance to do their stuff anyway

[Husky33]

Cheers, that clears it up then. The tyres on there were put on by the previous owner. I think i may need to upgrade shortly.

Yeah suspension is getting a serious overhaul next, i think every one of my bushes is stuffed

[tacker]

Mate i run project Mu level 900 pads on the front and bendex ultima on the rear of my R32 and i dont have any problems with the fronts locking up. In fact they stop quite well, even had my mate do some laps and he thought they were spot on for some standard brakes.

Not quite as good as his Lambo but and i quote " not f*%kin bad considering".

[dangerous_daveo]

*jumps up and down* I KNOW!!!

Well I would take a fair stab at knowing anyway.

#1 your old braking system you had to stand on the pedal, old brake lines, fluid, and your brake booster moving a bit, along with worn pads and disks = a fair bit of slack. Now you have taken littlerly allll of that slack away. You jump on it its going to lock up as there is NO give other than the tyre. I kinda had the same prob. You need to adjust your braking style to suit the new brake package. I really think its that simple.

[Kinks]

The purpose of brakes is to slow the revolution of your wheels, and your tyres are connecting your wheels to the road surface. Once the link between wheel and road is broken (ie tyres lose traction) there is no force still turning the wheel so the brakes easily lock up. The better grip your tyres have on the road, the better your brakes ability to slow the wheel rotation. It helps explain why all us “crazy” people spend $1500 on a set of road tyres when you can pick up “cheapies” for $600

Cliffs: brakes stop the wheels, tyres stop the car!

Edit - unless you've faded your brakes.. then they do nothing

Edited October 22, 2006 by Kinks

[Busky2k]

Yeah I had this problem too. Problem was that my front suspension was pretty much on bump stops so there was no real weight transfer to the front wheels under braking. Moreover if the surface was bumpy, the car would skip all over the place as the ABS is trying its best to slow the car. Threw out the shitty springs/shocks for a good set coilovers and the braking as improved dramatically, thanks to having a good amount of suspension travel and the spring rate is not as hard as before allowing weight transfer.

[Duncan]

Cliffs: brakes stop the wheels, tyres stop the car!

That is the best explaination I have ever seen! It really is that simple

[MrStabby]

miss matched brake pads dude.

ultimates are shiet compard to a decent "sporty" type.

I agree with this response. If you were locking up all 4 then the tyre answer would be correct. You've effectively stuffed the brake balance between front and rear by putting pads with different co-efficient of friction, and therefore different braking force. Putting the same type pads on the rear is definately the first step in troubleshooting this one.

EDIT: Actually check the co-efficient of friction specs first. If the MUs are more than a little higher than the ultimates, put the MUs on the back. If there the same, refer to the other posts in this thread...

Cheers,

Kot

Edited October 23, 2006 by MrKotter