Radial calipers & M/Cyl on REX

[TopCat]

Very nice TC, something i've been looking at doing on mine as well, good to hear they work with stock MC

You staying with the stock MC or planning on going radial?

Gedday James, staying with stock M/C as I don't know enough about radial M/Cs and they're working well as is and I don't need to. If I was to change I might use an EX500 M/C (GPZ500 here), 13mm piston that is different to the ZRX almost 16mm piston.

Cheers,
Tony

[TopCat]

I know on cars (lot bigger calipers) the ability of the caliper to withstand flexing when the brakes are applied contributes to better braking performance so maybe the Nissins are better at this than some others.

Your answer is consistent witn the article I reposted rom the ZRXOA website. I think its the mounting points that aids this to happen more so than differences between Nissin or Tokico calipers.
TC

[TopCat]

it's not only the pressure per square inch because even fitting a 18/19 Brembo on the Tokkico calipers doesnt completely fix the problem.

I would be guessing but it would have alot to do with the piston and seal components used in the Nissin's compared to other calipers.

Blur, just out of interest, what does 18 / 19 mean? I've seen that before but never knew.
Thanks,
TC

[Blurr]

it is the bore size in the MC. Bigger the bore bigger the amount of fluid it moves. I think it is measured in mm's

[Wattie]

it is the bore size in the MC. Bigger the bore bigger the amount of fluid it moves. I think it is measured in mm's

the 19 is the bore size in mm

the 18 is the distance from the pivot point of the lever to the contact point on the piston.


brembo also do a 19/20 with has a greater distance from leverage point to the piston which means more fluid moving to less movement of fingers compared to the 18.

radial mount master cylinders have the piston pointing forwards on the bike (right angle to the handle bar) and the piston sits between the hinge where the lever meets the mount, and where the fingers grap the lever. this gives more direct feel and less room for flex in the metals.

there isnt really any extra perfomance from having a radial m/c just better "feel" and more direct.

[dave#3]

Thanks TC. It looks like he only does them for the older 9 with the 6 pot callipers

[Gosling1]

..... If I was to change I might use an EX500 M/C (GPZ500 here), 13mm piston that is different to the ZRX almost 16mm piston......

whatever you do - don't drop your m/c piston size. Going from stock 16mm (5/8") to 13mm (1/2") would be a disaster - the smaller piston simply won't push enough fluid to give you effective brakes.

The best way to improve the m/c , is to go up in size - generally to 19mm (3/4") - and a lot of radial m/c out there use 19mm pistons.

I upgraded the m/c on the MFP12 last year, with a radial m/c from a gixxer 750. Not sure what year model - it really does not make any difference, as long as the piston is a larger size, and the m/c and fittings physically fit your bike. On a naked bike like the Rex, this should be no problem.

The best thing about the radial m/c - is the total lack of fade after repeated heavy braking - the stock m/c on the 12 would see the lever back to the bars after a hard strop down a mountain (say....Hotham ) - but the radial m/c ?? No fading at all. 2 finger stopping is dead easy, even pulling up the weight of a sports-barge.

That is a great conversion you have done there - any chance of a link to the US site where you got these calipers from ?? This is the missing link in my brake upgrade.....

[TopCat]

Gos, the site is motorcycleparts2u.com , Mark is the man to talk to.
I can highly recommend them, got the parts on time with tracking and well packaged.

Thanks for the info on brake piston size. I'll post up why it was recommended to go smaller over the coming days and would appreciate your view.

Cheers,
Tony

[Gosling1]

no worries mate - I am interested in how the applications where a smaller m/c would be recommended.....

[TopCat]

Gos, have a look at the following thread on the zrxoa site. I couldn't work out what to cut / paste (actually I couldn't work out WTF they were talking about).
See if you can make sense of it and translate it into english .....

http://zrxoa.org/forums/showthread.php? ... ight=Ex500

Good luck !
Tony

[Wattie]

if you are using the nissin calipers, they wont fade like the tociko ones. you could possibly get away with smaller m/c, but if they do fade a bit, your fucked

even brembo motogp gear fades, thats why they have a remote adjuster mounted on the left hand bar for mid race adjustment.

[TopCat]

I'm not going to change the m/c, the rec came from one of the zrxoa guys as an improvement for use with stock calipers. I'm as happy as a dog wiv 2 dicks!

If I was to change anything it would be to fit EBC HH pads - is there much diff these days between stock sintered pads and EBC HHs
Thanks
Tony

[Wattie]

stock pads are fine mate.

[J-rex]

Apart from recent ZX6 and ZX14 models, does anyone know which other bikes come with these Nissin calipers?.
Can't seem to find too many and most sellers list them under model rather than caliper brand..

Tony, let us know how the perform in the long term, after you've been on a few decent rides with them

Cheers..

[Wattie]

z1000 07 onwards.

gtr1400 aswell