TRP CX9 front/rear question...

[benb]

Does anyone know if there is actually any difference between the CX9/CX8.4 front and rear calipers? ISTR when I got mine they were labeled in the box as front and rear. I can't really see any difference in them now.

My rear has frozen up from road salt.. The front is perfect. I was hoping if I buy another set I can end up using both of them for the rear as the front will probably last that long.

I'm not sure I've ever had a set of V-brakes survive a whole NE winter. These probably have ~1000 winter miles on them.

[zank]

No difference. They just mount the pad holders for front or rear.

[benb]

Thanks!

[AngryScientist]

what exactly freezes up out of curiosity? can you not disassemble them and lube them up?

[benb]

So they have an aluminum sleeve that mounts onto the frame's brake post and then the brake arm is pressed onto that sleeve and pivots on it.

No matter what you do eventually a little bit of salt gets in there and corrodes either the arm or the sleeve and you start getting corrosion. I usually spray the brakes off with alcohol to try and keep anything from getting in there but I was away for vacation for 2 weeks and this morning I went out and the brakes are totally frozen solid. AFAICT there is no way to disassemble this and clean up the corrosion. It manifests as the brake getting more and more friction as salt gets in there till eventually it won't move.

This year my town seems to have been heavily into using a liquid solution instead of normal old rock salt, it seems to be VERY tough on bikes.

I have full coverage fenders on my bike which maybe helped.. I got outside a lot this winter.

It's been years since I ran V-brakes or Cantis in the winter but back when I ran them on my MTB I was constantly killing rear brakes. I've never found anything that doesn't do this. Avid, Shimano, now TRP, etc.. It makes me wonder if there is a Ti brake. If the sleeve + arm were both Ti it would probably solve this issue. Otherwise I don't care. It's ~$50 a year in maintenance.

[nooneline]

yeah, that corrosion is especially noticeable with mini-v's because they're a more sensitive brake than cantis.

preventive maintenance - and lots of it - goes a long way, even if it's just squirting some tri-flow or similar light lube into that pivot point every few weeks.

[batman1425]

Yep, you are correct, you cannot disassemble the pivot. I've been using them for 3 years on my cross bike and typically I squirt some oil in there at the same intervals that I lube the chain. Little squeeze, work the lever a bunch to distribute it around, wipe off the excess.

You may have some luck with an aerosol based lubricant or penetrating oil that you can spray in there to try and blast out all the junk and corrosion that is building up. I avoid degreasers in that area because it is hard to wash that stuff out before putting a lubricant of your choice back in.

Another tip - if you pull the arms off the bike, you can spin the pivots a full 360, making it easier to work the junk out rather than using the 20 or 30 deg of movement they have when installed.

[benb]

For sure it's just unfortunately I'm time crunched and eventually a big ride followed by family concerns happens and you add up a few of those and it's time for new brakes. It's easy for maintenance to fall by the wayside these days for me. I'm going from 2->3 bikes and this one will be the only one that gets ridden in bad weather so hopefully that helps.

edit: Actually an element of laziness too since my garage is unheated. e.x. at the end of December I did a 4 hour ride when it was 25 degrees out. I was totally shelled, by the time I had time to go work on the bike it was like 15F that night in my garage, that takes a lot of motivation!