172 Cup Rear Bias Valve Manual Adjustment

[chrispy.clio]

I have the excact 172 cup Non ABS set up on my track only 182.

Did a trackday last week and i noticed the rear disks were completly rusty still and the fronts were getting lots of abuse.

The set up was probably good because it was very wet but i'd like to actually have a tiny bit of rear brakes.

Which way should i adjust the rear bias valve to make the rear brakes actually work. Up?

 

[NorthloopCup]

Yeah if the valve is closed as in 'up' you will get full effort to the rear brakes. The arm should have a spring that attaches to the it and the body/chassis.

Mines actually seized in the up position and combined with ds2500's it stops incredibly well! Lol

It doesn't cause any lock ups in the rain either. I did a trackday at donington in the rain and it was completely fine.

 

[sporty-bloke]

dont listen to the above load of crap

 

[mr.pink87]

dont listen to the above load of crap

FLOL, here we go (hopefully)!

 

[NorthloopCup]

dont listen to the above load of crap

Enlighten me then mate. Which bit is, in your opinion 'crap'?

 

[The Chubby Pirate]

What is the standard bias set at on the Cup's?

I'm going to be replacing the brakes on my Cup shortly.

 

[MG cup]

What is the standard bias set at on the Cup's?

I'm going to be replacing the brakes on my Cup shortly.

Less than 25% iirc Danny

 

[Emma.]

Yeah if the valve is closed as in 'up' you will get full effort to the rear brakes. The arm should have a spring that attaches to the it and the body/chassis.

Mines actually seized in the up position and combined with ds2500's it stops incredibly well! Lol

It doesn't cause any lock ups in the rain either. I did a trackday at donington in the rain and it was completely fine.

Thats the bit that's 'crap'.

The cup set up doesn't have the arm.

 

[MG cup]

I think he's referring to the arm on the valve itself where as your referring to the arm that bridges between the valve and chassis like a FF 1*2.

Lets call it the "LEVER".......the spring holds that up on the cup until brake pressure is applied then it goes down where as the FF cars is held solid and changes proportioning depending on the load in the car.

 

[NorthloopCup]

I think he's referring to the arm on the valve itself where as your referring to the arm that bridges between the valve and chassis like a FF 1*2.

Lets call it the "LEVER".......the spring holds that up on the cup until brake pressure is applied then it goes down where as the FF cars is held solid and changes proportioning depending on the load in the car.

Yeah that's the bit I'm on about Swede cup!

 

[NorthloopCup]

I think he's referring to the arm on the valve itself where as your referring to the arm that bridges between the valve and chassis like a FF 1*2.

Lets call it the "LEVER".......the spring holds that up on the cup until brake pressure is applied then it goes down where as the FF cars is held solid and changes proportioning depending on the load in the car.

Yeah that's the bit I'm on about Swede cup!

 

[Toastfrenzy]

My spring is off and the valve tie wrapped up - was getting un-equal braking effort to the rears - now get equal effort to the rear. Will have to see how it goes and get some cheaper pads in the rear if the red stuff I put in at the weekend are to strong.

£129 for a new one I got qouted

 

[Cup_Phil]

^^ Exactly this

The spring is s**t

I put 2 big fat cable ties around the arm and there's a bit of bodywork above it you can fasten them too - holds the arm as high up to the car as possible which is where it's supposed to be

Braking force increased at the rear so it passed MOT and was even. It's been like that for 2 years lol

 

[mark123]

I put 2 big fat cable ties around the arm and there's a bit of bodywork above it you can fasten them too - holds the arm as high up to the car as possible which is where it's supposed to be Braking force increased at the rear so it passed MOT and was even. It's been like that for 2 years lol

That's not how it supposed to be though phil. You now have more rear effort than renault intended - I have locked the rears on mine with it cable tied up like that. I do it for the MoT just to avoid the hassle of explaining it to the garage but I remove it afterwards.

 

[chrispy.clio]

That's not how it supposed to be though phil. You now have more rear effort than renault intended - I have locked the rears on mine with it cable tied up like that. I do it for the MoT just to avoid the hassle of explaining it to the garage but I remove it afterwards.

Locked the rears in the dry or just the wet?

 

[mark123]

IIRC it was greasy but it was only approaching a set of lights that went yellow on me, wasn't going fast or braking hard.

James (BIGASH) had problems last year with his - although it was probably down to the aggressive pads.

My rear discs are spotless without it clamped up, which is minimum effort to rears. The nut at the bottom does adjust the bias I think, couldn't tell you which way though...

 

[Cup_Phil]

That is how renault intended it as that's the way the spring pulls the arm as standard. From what I can see it's just that the spring weakens over the years and the arm droops slightly
Those bias valves for the cup are valved to a minimal braking effort when the arm is fully open

I've never locked my rear wheels up and the rear discs still mostly go rusty lol

Without the cable tie if I run the engine and get a mate to press the brake pedal firmly I can still rotate the rear wheels :|

 

[mark123]

When you press the brake pedal a little piston in the bias valve pushes down on the lever. If the lever can't move the full pressure goes to the rear calipers. That little spring is just a return spring for the lever. So by cable tieing the lever up you get max effort to the rears where as Renault intended minimum effort to the rears - lever moves freely against the return spring.

 

[Cup_Phil]

Are you sure? That seems highly unlikely

The arm is normally on non-cups linked to the beam so that when you put luggage in the boot and the car lowers it applies more braking force to the rear of the car by pushing the arm up and opening the valve. I was told that renaultsport re-valve the cup ones so that the braking force is minimal with the arm fully up, and the spring is fitted to hold it up.

I find it hard to believe the arm is supposed to move when you brake. I've certainly never seen one move when applying the brake pedal and i've blead a fair few cliosports

 

[mark123]

Get under and get someone to press the pedal with your cable ties removed. If yours doesn't move it is seized.

The link to the rear beam when the unit is fitted to other models is via a spring again. The bar goes through the hole in the lever and there is a spring over the bar. This resists the lever moving down when you brake. The more weight you have in the more compressed the spring is before you brake so more effort to the rears.

 

[Cup_Phil]

Wow well you learn something new every day lol

I freed the bar up on mine - spent 2 hours covering it in wd40 and wiggling it up and down till it was completely loose - but it still failed the MOT.
As I said with the car jacked up and your foot fully on the brake pedal you could still turn the rear wheels

I think I'll leave mine cable tied up as it's never locked the rear and I have 4 pots on the front anyway so a bit more rear bias would be nice