installing planet x ultralight brakes

Discuss light weight issues concerning road bikes & parts.
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by tinchy

righty, got me a pair of these brakes the other day. In terms of centering them, what is the best technique? Being a young chap haven't had much experience with single pivot brakes and so these look a little confusing - any tips would be appreciated, seen a loads of these on bikes around here.


by Weenie

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by bicicleta

Not sure this will be a lot of help, but what I found out when I installed mine was that the cable housing routing and LENGTH had to be spot on so that the caliper would stay centered after squeezing the levers. To me that made the biggest difference than anything else. The rear caliper seems to be not as sensitive as the front to this, at least on my frame.

My 2 cents.

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by Rick

My method:
1. Install into approximate position with mounting bolt slightly loose.
2. Adjust cable tension to give proper total rim clearance.
3. Squeeze the calipers down onto the rim with one hand and tighten the mounting bolt so the calipers are fixed at that "centered" position. Tighten to full final torque. You don't want them moving from here.
4. With calipers relaxed, check symmetry of centering and make final fine adjustments with the tiny set screw on the caliper arm.

I don't like to have my brakes ride really close to the rims anyway, so I can usually pull a 23mm clincher out without even loosening the brake cable. When I change wheels, the centering usually remains good enough that I don't have to readjust, or can get by with a small adjustment to the set screw.
Last edited by Rick on Sat Apr 06, 2013 9:42 pm, edited 1 time in total.

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by system787

I found that adjusting them and keeping them centered was fairly simple. There's two 2mm screws in the center bolt. I loosened those, and used a 4mm to turn the whole brake in the direction that I wanted, and locked the two small bolts.

Haven't had an issue with centering yet, and my front brake housing is definitely too long. If the brakes get knocked out of center, a quick pull of the brake lever re-centers everything.

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by Bianchi10

Hmmmm I have to recenter mine after every ride. furstrating. And I had Planet X install mine for me and i still have issues.

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by Beancouter

I'm with rick; don't have problems with mine.

One suggestion would be to leave yourself a bit of slack on the cable and tension up with the adjuster.

If you run your pads close to the rim it will allow you to get enough movement on the cable to pull the barrel from the arm (which will release the caliper arms) and slide your wheel out.

The other thing I have noticed is that I'd ever I mess around with them (eg taking wheel off) the little centering screw needs to be tweaked. I tend to loosen mine off as far as possible, squeeze the brake levers a couple of times, and them adjust until they are centred.

Not sure if that makes much sense!!!

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by tinchy

thanks guys !

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by juanacity

I like to think that I am for the most part pretty competent at working on my own bike and usually feel like I actually do a better job working on my own bike than most bike shop mechanics just because I am willing to spend lot of my own time to get things JUST right. That being said, I was pretty frustrated with setting up my Planet X brakes and couldn't get them really well centered despite spending quite a bit of time on them (there is some weird brake arm travel asymmetry on these when you use the fine adjustment screw on the caliper arm to extremes). Then I met some Planet X people at a bike show and they showed me a method to help centering that I haven't noticed mentioned online (or at least didn't understand).

RIck's method above is pretty spot on, but in between steps 3 and 4 you can take a 13mm spanner wrench and rotate the entire brake assembly around the main fixing bolt as I tried to show in my crappy picture below. Using this I am now able to set up the brakes so that each pad is equi-distant from the rim without braking, and then each pad contacts the rim at the same time during brake lever pull-ie properly centered. The performance of these brakes seems pretty great so far.

On a side note-the brakes have a somewhat interesting design feature that I'm not sure is intentional. No matter how poorly centered I had the brakes, they never really seem to push the rim off center under actually braking loads. Seems to me that upon contacting the rim, the arms are essentially self centering under load.


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by wojchiech

I've found a way to get these brakes centered nearly perfectly when installing (similar to what juanacity did with the spanner wrench and system787 did with the 2mm screws), except my method just requires a 4mm hex wrench - the trick is to loosen the mounting bolt, then use the 4mm wrench to hold the brake centered in place at the Ti center bolt while at the same time tightening down the brake mount bolt (preferably with a ratchet type wrench). As the brake mount bolt gets tighter, the turning force might move the brake a bit if you're not holding the 4mm wrench in place tight enough, but you just have to use the 4mm to re-center the brake and keep tightening the mounting bolt until it's secure.

If you did it right little to no adjustment of the side spring tension bolt is needed.


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by CharlesM

5 minute set up and zero cable length concern (but that might be different with different cables).

Zero issues in use.

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by stubob

One thing that helped me get them dialed in was to squeeze the brake levers a couple times and re-adjust. I don't know if it's stress-relieving the bolts, or the spring, but it took a couple go's to get them to return to center correctly.

After a couple rides, they've been good so far. A little grabbier than 7800, but no lack of power.

by Weenie

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