56 replies to this topic

[manus]

The DS2500 pads make too much noise (screaming ) and the pads rattle when driving slowly. I will replace the DS2500 with Pagid RS14 and have ordered a pair of anti-rattle clips. Will solve both inconveniences I'm sure.

Hi-specs worked well on the Nordschleife. Didn't know the circuit before and it takes time to learn

We have been informed by the factory, that NO anti rattle clips are available for those rear calipers.
Hmmmm.... The standard front clips will do the job
We have been informed by the factory, that the ONLY Pagid pad available for that caliper is called a BLUE
Hmmmm. ... Orderd those, expect them any day now, now looking forward to BLUE

[jasvxt]

Just to add i am of the same opinion as Fluffy, and Mr M on this, the rear brakes have fook all to do with the car squirming. Driving style, braking points, tyre pressures, and geo is more likely to be the cause Jas

[Jase_MK]

Also, I know this is an old thread but there's some odd theories being thrown about up there ... Fitting wider/stickier tyres will transfer more weight forwards and more weight away from the rear wheels under extreme threshold braking. To maintain a perfect balance, you could do with actually REDUCING braking to the rear wheels or increasing the front. Standard brakes and sticky tyres can leave the rears being very unweighted and prone to locking with the std balance. Unlikely, as this relies on the std brake balance being nigh on perfect whereas it's probably biased slightly forwards for safety, although Ricky2772 did experience some rear locking when going to sticky tyres on a certain hot circuit in germany. It's the same reason you increase the rear bias in wet or slippy conditions as there is less weight transfer in that case. Fitting bigger rear brakes and sticky tyres sounds like a recipe for disaster IMO.

[manus]

Fitting bigger rear brakes and sticky tyres sounds like a recipe for disaster IMO.

First, there's ABS that helps preventing rear wheel lock. (provided you keep ABS switched on)
Second, start with upgrading your front brakes first before you do the rear.
Third, Adding a 'reverse-wing' on the back of the car will help putting pressure on the back or at least compensate for the lift produced while driving.
Fourth, the same reason why Porshes brake pretty good is the 40/60 balance of the car. Even after some weight shift, the back wheels are still capable of serious assistance in braking
Fifth, as we are not only braking in a perfectly straight line, it is likely to be your inner wheel(s) that will lock first.
Sixt, losing unsprung weight helps at lot in keeping road contact.
Last, as your car may be in a much better balance with upgraded rear disks (less safe for the unexperienced driver), be gentle on the clutch shifting down.
I experience small periods of ABS-intervention on the rear wheels when braking hard and shifting gears down. This is my signal for having found the near perfect balance!

Attached Files

•  P1010416_small.jpg   59.26KB   2 downloads

Edited by manus, 18 October 2007 - 08:11 PM.

[Jase_MK]

Effect of extra weight transfer due to wider front tyres (this would be worse with something like 048s or 888s):





The more weight you're transferring forwards, the further forwards your brake balance needs to be. Stiffer shocks will reduce the weight transfer, although my shocks in the pics above were pretty hard. And ABS is not a cure for improper brake balance

be gentle on the clutch shifting down.

Heel and Toe?

[manus]

The more weight you're transferring forwards, the further forwards your brake balance needs to be. Stiffer shocks will reduce the weight transfer, although my shocks in the pics above were pretty hard. And ABS is not a cure for improper brake balance
be gentle on the clutch shifting down.

Does anyone know (calcutale, measure) exactly how many kg's are transferred?
My guess: 100kg's max. bringing the balance from 400/600 to 500/500

Heel and Toe?

Now and then trying hard, whith different results

[chris]

Exact weight of Hi-spec rear caliper (without pad)




30% of difference between Hi-spec announced weight and reel weight !

[manus]

Measured the exact weight of the original ones? Looking forward to your experiences on the road/track

[chris]

Measured the exact weight of the original ones?

Looking forward to your experiences on the road/track

I had measured the OEM caliper's weight and the result was about 3 kg (without pad)

My first impressions regarding this caliper in comparison with technical description of Hi-spec web site, hereafter :

Features
Patent pending

CNC Machined Lightweight Aluminium Body
Fully Dust Sealed
Rigid Design
Internal Fluid Crossover
Integral Self Adjusting Handbrake Mechanism
Direct replacement for Vaxuall VX220 / Elise S2

Technical Specification

Disc Width 10mm, 12mm, 20mm, 24mm
Piston Size 2 x 38.6mm
Piston Material Hard Anodised Aluminium
Pad Size 76 x 65 x 14mm
Weight 950g
Hydraulic Thread M10 x 1.0

* These calipers are described as "Fully Dust Sealed" : I did not see any ruber below on the piston.
So for me this description is untrue and I am afraid that in the next futur, calipers pistons could be blocked by brake dust or other dirt.




* Handbrake mechanism seems to have "very poor design engineering" and Hi-spec disclamer reinforce myself in my convinction ...

(Hi-spec advice to put a gear while you operate hand brake mechanism )

* Indicated weight is wrong of about 30%

* Caliper alone is not a direct replacement of OEM caliper some adjustements are necessary to install it


To sump up : Hi-spec description is a bullshit.

I am not sure I will intall these calipers on my car especially regarding '"dust sealing" problem
(I think that life expectancy of such caliper without real dust seal, should be very short for a road use).

Sincerly, I regret this purchase ...

Edited by chris, 30 October 2007 - 05:11 AM.

[manus]

* Caliper alone is not a direct replacement of OEM caliper some adjustements are necessary to install it

I agree on the sales text not corresponding to the actual product delivered. It is a direct replacement only if you install the disks supplied by Hi-spec

I am not sure I will intall these calipers on my car especially regarding '"dust sealing" problem
(I think that life expectancy of such caliper without real dust seal, should be very short for a road use).

No problem (yet) after 8000km on very dirty roads I'll let you know as soon as I run into trouble.

I have no space left in my global limit on the forum to post any more images. If you PB me your email address I'll sent you all images I have on my installation.

[chris]

Thanks Manus for your clarifications, your photos are full of pieces of information.

To sum up : Hi-Spec rear callipers are impossible to install with OEM 288 mm disks.

It is necessary to buy complete Hi-spec Kit including 320 mm disks and associated ultralight rear callipers ...

As said in my previous post these calliper is a chimera with OEM disk.


Another question Manus, have you weighted your 320 mm Hi-Spec disk ?

[manus]

Another question Manus, have you weighted your 320 mm Hi-Spec disk ?

Not yet Christian, will do soon and let you know.

Edited by manus, 10 November 2007 - 02:19 PM.

[manus]

Another question Manus, have you weighted your 320 mm Hi-Spec disk ?

The Hi-Specs 320mm disks weigh 5.4 kg each.

[rapidos]

Another question Manus, have you weighted your 320 mm Hi-Spec disk ?

The Hi-Specs 320mm disks weigh 5.4 kg each.

That is light !!! So could be a nice solution to me associated with front 4 pots AP racing + 307 mm discs...

[siztenboots]

Another question Manus, have you weighted your 320 mm Hi-Spec disk ?

The Hi-Specs 320mm disks weigh 5.4 kg each.

That is light !!! So could be a nice solution to me associated with front 4 pots AP racing + 307 mm discs...

Manus, How much clearance is there for the caliper and 320mm disk compared to a 16" wheel ? It must be a bit tight , ~3mm left ? What pads are you using please?

Rapidos, which AP part no. do you use for the 307mm disk, I do not recognise that from the standard AP range?

Edited by siztenboots, 07 December 2007 - 03:16 PM.

[rapidos]

Rapidos, which AP part no. do you use for the 307mm disk, I do not recognise that from the standard AP range?

This one (stage 3)

http://www.thorneymo...bo_Brakes.shtml

[manus]

Manus, How much clearance is there for the caliper and 320mm disk compared to a 16" wheel ? It must be a bit tight , ~3mm left ? What pads are you using please?

I'll have to check/measure the clearance.
I use the RS-15's on the front. These are perfect!
Changed from RS2500 to RS-42 on the back to reduce friction level a bit.