Ariel.Club Forum

The water cooling is no longer a problem on Atom 2, 3, or 3.5 because solutions exist : electrical water pump (if not fitted), big front radiator , or despite what Steve is saying, second horizontal radiator with fan, which is, by far, the best water cooling solution. The 3.5R of [mention]autobackup...

with no proof yet that they work well ... with a good feeling pedal.

good news, thing to check in future will be the pads wear in case of pressure from the spring.

it seems that AP dismissed all options ... but are not able to explain what happen to our brake pedal.
If they give the same answer to ARIEL factory, it's not easy for the factory to improve the system !

Conclusion :
the factory [mention]HenryJS[/mention] should have to buy and test 16 springs, lowest force i imagine, and keep us informed here to try to solve this problem. ;-)
https://apracing.com/race-car/brake-cal ... ck-springs

I confirm that the problem is here with the one piece AP discs to.

pads in 14,5 mm , no thickness calibration to do : https://www.questmead.co.uk/Categories/Braking/Brake-Pads/Sorted-By-Caliper/AP-Racing/CP7645-145mm-Thick-Pads also : PAGID E8076 RST1 14,4 mm RST1-8076 friction 0,54 (very good) CARBONE LORRAINE / CL 5038W45T16 RC6 14,5 mm 5038W45T14.5-RC6 friction ...

Are you sure they are for the AP ? and i don't think 15 mm will fit as 14.5 mm is needed. to my opinion Friction 0,52 is low to try to reduce the brake pedal free travel. A real high friction pads (cold and hot) is needed so that the braking really begins when first contact between disc and pads eve...

Concerning the Atom 4 pads i have contacted the factory and can confirm that the thickness needed is 14,5 mm
So AP disc 24 mm and pads 14.5 mm ;-)

i have mesured them and it's written on a set of replacement ones i have received, so 24 mm for the AP discs (and it was 22 mm for the Alcon).

The Atom 4 discs with AP are 24 mm thick.

As you had the same problem with other 16 mm pads, i think you are right : it's perhaps a narrower caliper than the normal 7600.
So solution is to use 14,5 mm thick pads like this CL RC6 : 5038W45T14.5-RC6

[mention]Lew[/mention] the AP guy says that the AP 7600 are now obsolet ... but they still offer it on the AP website : https://apracing.com/performance-upgrades/performance-brake-calipers/4-piston-calipers/cp7600-family-130mm-mounting-centres-suits-o295x24mm-disc One of my Atom 4 customer is testin...

If the pistons are going back it's because they have "place" to do it. Imagine the hydraulic a little but on pressure, it's similar effect with no pressure but no possibility to go to much backwards.

I don't know if i'm supposed to write here about the new bleeding process, but i'll do  It appears that the main reason for long pedal travel with near no effect on braking is because the pistons in the calipers are going backward during driving between each braking, so the first travel of the brake...