Tips on how to centre Planet X CNC brakes

othello

I am *this* close to loosing the will to live trying to centre a set of Planet X CNC brakes! :evil:

Does anyone have any tips on how to get them centered?

I have a set fitted to my sons Ridley (in an effort to keep the weight as low as possible and I got them for a song off eBay). The front works fine. The back one I just cannot get right. The left side (with cable attached) is a long way from the rim, and the right is almost touching. No amount of playing with the spring screw will centre them up.

wishitwasallflat

Take it you've read this ..

Tips on fitting the calipers:
Mount the brake as centrally as possible using the main frame securing allen bolt.
The small allen key screw located in the central barrel which secures down on to the central pivot bolt is to assist in centring the caliper arms once the main securing bolt has been tightened.
There's also a small allen key grub screw On-One of the caliper arms which tightens on to the main spring. Once the caliper has been centred using the main mounting bolt, the small allen grub screw can be used to 'fine-tune' the adjustment. By tightening it up, the tension on the spring will be increased and that caliper arm will move away from the rim. Loosen it off and the tension is released and the caliper arm will move towards the rim. It's very clever and kept some of us amused for hours.

If you have all I could add is loosen the mounting bolt so the brakes can move, pull them on hard and the tighten the mounting bolt while still holding them on hard, fine tune as above.

If no joy are you sure wheel is cantered and true?

DiscoBoy

Am I alone in not having found these difficult? Hold them central whilst doing up the bolt at the back, then adjust using a spanner on the nut at the front.

I think I only used the screw on the back on one of them.

BillyMansell

This old perennial that gets divided responses between those of us who have no problem with setting up these brakes and those who find them impossible to set up.

Before adjusting the grub screw on the side of the spring it should be noted that there are also two flats on the spacer behind the caliper that will accommodate a cone spanner. I would ideally try and hold the caliper central with a cone spanner on the flats whilst tightening the bolt but alternatively you could try centring the brakes in this order; first try to hold the caliper central whilst tightening the bolt up, then try to get the caliper centred using a cone spanner on the flats and then use the grub screw for fine adjustments.

DiscoBoy

BillyMansell wrote:

first try to hold the caliper central whilst tightening the bolt up, then try to get the caliper centred using a cone spanner on the flats and then use the grub screw for fine adjustments.

This is how I did it.

darkhairedlord

Never adjusted px brakes but for old style centre pivot brakes I had as boy in the 70's I used to leave the centre bolts loose, apply the brakes and hold on with a piece of string wrapped around the lever and bar, then tighten the centre bolt. This way they are centred when the brakes are on irrespective of the evenness of spring tension when off.

napoleond

Simple to fit as was all my other equipment. In fact I used the same technique. I just hit it with a mallet and shout a lot until it fvcking works.

spankwilder

othello wrote:

I am *this* close to loosing the will to live trying to centre a set of Planet X CNC brakes! :evil:

Does anyone have any tips on how to get them centered?

I have a set fitted to my sons Ridley (in an effort to keep the weight as low as possible and I got them for a song off eBay). The front works fine. The back one I just cannot get right. The left side (with cable attached) is a long way from the rim, and the right is almost touching. No amount of playing with the spring screw will centre them up.

Check to make sure you've got enough cable outer between the caliper and frame mount, too short and the caliper won't centre

term1te

spankwilder wrote:

othello wrote:

I am *this* close to loosing the will to live trying to centre a set of Planet X CNC brakes! :evil:

Does anyone have any tips on how to get them centered?

I have a set fitted to my sons Ridley (in an effort to keep the weight as low as possible and I got them for a song off eBay). The front works fine. The back one I just cannot get right. The left side (with cable attached) is a long way from the rim, and the right is almost touching. No amount of playing with the spring screw will centre them up.

Check to make sure you've got enough cable outer between the caliper and frame mount, too short and the caliper won't centre

Too much cable housing is also a problem. Once I'd got the length right, I've had no problem with the centering at all. Very pleased with them, am considering getting some for the "best bike" to save a few grams over the current Ultegra 6600 brakes.

balthazar

NapoleonD wrote:

Simple to fit as was all my other equipment. In fact I used the same technique. I just hit it with a mallet and shout a lot until it ******* works.

A much underrated technique