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NC30 Needs more bite on back brake any tips?

Posted: Mon May 14, 2018 4:39 pm
by mlevents
Hi,

I have an 89 NC30 which you can swing on the rear lever and it wont consider locking up, looking to replace pads, fit a braided hose whilst investigating, but is there more i can do, the system is not leaking, fluid is clean, disc is spot on.

Can the caliper or master cylinder need attention?

Have searched but couldnt find anything.

Re: NC30 Needs more bite on back brake any tips?

Posted: Mon May 14, 2018 10:33 pm
by Dynamohum
There not the most powerful of rear brakes even in tip top condition pads lines fluid etc but ample for most but if you feel the need for an upgrade contact rick oliver who sells parts for a brembo conversion.

Re: NC30 Needs more bite on back brake any tips?

Posted: Tue May 15, 2018 11:08 am
by NGneer
As has been said, the rear brake on the NC30 is not the most stunning thing ever designed, but then again all the braking is taken care of by the nice big twin discs up front. I know of some more track focused NC30s that don't even bother fitting a bear brake (a) to save weight and (b) because it is never used. Having said that I agree that on the road it is nice to have the option to scrub some speed of particularly in the wet with a properly working rear brake. :shock:

For my 2p worth:

Check that the brake is properly bled. I rebuilt my rear brake set up last night and even with a vacuum pump bleeder it still took some effort to get the last bit of air out. As soon as I had though, it was obvious and I am sure I could now "lock up the rear wheel" all day long if you were so inclined.

The standard rear brake hose should be fine but if you are swapping for a braided hose, whilst you are doing it I would also take the time to pull the rear calliper off and give that a good check over / service. Corrosion under the piston seals can make them effectively squeeze the pistons and make them stiff/difficult to move thus affecting the performance. Obviously also check the pistons are not corroded and can slide freely.

NGneer :peace:

P.S. "If" you decide to strip/service your calliper, remember to pump the pistons out using the brake before you disconnect it all, just to make life easier later ;)

Re: NC30 Needs more bite on back brake any tips?

Posted: Tue May 15, 2018 3:00 pm
by Neosophist
As above really, a good strip and clean and possibly new line, new seals.

My NC30 had a really decent back brake (it was easy enough to lock up the rear if you stomped on it).

It's 30 years old and neglected for god knows how long too.

make sure the sliders are all good and clean and greased with the proper stuff.

Re: NC30 Needs more bite on back brake any tips?

Posted: Tue May 15, 2018 11:11 pm
by CMSMJ1
NGneer wrote:
Tue May 15, 2018 11:08 am
I know of some more track focused NC30s that don't even bother fitting a bear brake (a) to save weight and (b) because it is never used
Indeed - I've ridden for a long time without even having a caliper fitted - until I got a DHL delivery

They are shit as std - shit when fettled and basically - not the best back brake you want.

new pads - maybe some low heat GG and just bloody well stand on it if you want it to work

Re: NC30 Needs more bite on back brake any tips?

Posted: Wed May 16, 2018 7:29 am
by Burbage
I'm sure I have been told or have read somewhere that a CBR600 caliper improves matters, no idea how the conversion is carried out though.
I took the bike (NC30) for its MOT test yesterday (it passed), watching the bike on the brake tester, the rear brake gave good numbers, I had a go on the tester (a small rolling road) and it felt good and progressive. On the ride home it felt as shit as usual, horribly "wooden". Not much help to the OP but I wonder if there is a clue in there as to why the brake isn't much good?
John

Re: NC30 Needs more bite on back brake any tips?

Posted: Wed May 16, 2018 8:18 am
by NGneer
Burbage wrote:
Wed May 16, 2018 7:29 am
I'm sure I have been told or have read somewhere that a CBR600 caliper improves matters, no idea how the conversion is carried out though.
I took the bike (NC30) for its MOT test yesterday (it passed), watching the bike on the brake tester, the rear brake gave good numbers, I had a go on the tester (a small rolling road) and it felt good and progressive. On the ride home it felt as shit as usual, horribly "wooden". Not much help to the OP but I wonder if there is a clue in there as to why the brake isn't much good?
John
I suspect that on the rolling road the rear wheel and brake have been isolated from all other factors so give a different feel. By that I mean when you are breaking under "normal" conditions you be using much more of the front brake and this will have a 'dynamic' effect on the rear. As progressive braking on the front builds up the contact patch on the front tyre the weight and momentum is shifting forward and (hopefully) being countered by the front suspension. Conversely at the same time due to the weight shift, and even without Moto GP style braking, the contact patch on the rear will be reducing thus becoming less and less efficient - thus (as I understand it) giving that numb / wooden sensation.

I will caveat that reply by saying of course a combination of both front and rear brakes will give the optimal braking effect (particularly in an emergency) but if you look at this test (https://riders.drivemag.com/how-to/emer ... s-combined) you will see how little effect the additional use of the rear brake has over just the front.

Re: NC30 Needs more bite on back brake any tips?

Posted: Wed May 16, 2018 4:14 pm
by Burbage
I was thinking more along the lines of master cylinder size, smaller(?) to try and get some feel.

Re: NC30 Needs more bite on back brake any tips?

Posted: Wed May 16, 2018 10:20 pm
by Speedy
Different pads might offer better feel; don't know which though.

@NGneer, watched that video and it seems that the difference the combined braking has, is actually significant at nearly half the distance and that's only at 50kph (30mph); plus it keeps things more stable.

Re: NC30 Needs more bite on back brake any tips?

Posted: Fri May 18, 2018 7:29 pm
by mlevents
my new pads and braided hose have arrived, so i removed the caliper from the back end and it is apparent that it needs to be stripped and overhauled, so that is being done and then i can put everything back together and see how we go.