Replacing Avid Shorty Ultimate brake pads

[backnotes]

Hello, I have Avid Shorty Ultimate cantilever brakes, but I have never managed to get the pads/inserts out of the shoes when the time comes to change them. The pad is held in place in the shoe by a bar that goes top to bottom that has a 1.5mm hex key detent in the top.

These turn fine when brand new, but after a while in the salt and spray, they seem to lock in tight and the hex detent gets rounded off whenever you try and remove them.

I am about to replace worn pads by fitting new shoes and pads and wondered if anyone has come up with a way to keep these retaining bars removable in real world use? I could try and remember to remove and retighten the bars every few months, or I could simply use a completely different style of brake shoe. I feel as if I must be missing something, as putting a tiny 1.5mm hex insert in something that will be exposed to salt and spray seems optimistic. I have seen split pins, and bigger hex bolts that fit in detents in the back of brake pads on other designs of brake shoe, and these all seem less likely to jam. Thanks for any tips, even if it is less willful neglect and more regular maintenance!

[Brucey]

the holders look like they accept standard (shimano pattern) road inserts. There are gazillions of other holders for these inserts which also allow some articulation. You can fit longer M5 threaded screws and spacers as required to most holders.

Most road holders have a small M4 threaded retaining screw; most have a tiny 2mm hex key fitting but some have a phillips head screw instead.



These screws also seize up and commonly need the attentions of Mr Pipe Wrench, Mr Drill or Mr Scrap Bin as a result. If you remove the screws when new and daub them in anti-seize they have a fighting chance of coming undone when needed. The 2mm allen key fitting is better than a 1.5mm allen key fitting but it is still absolute rubbish in the grand scheme of things.


You could try fitting split pins in your extant shoes; the ones from XTR-type V-brake shoes might work. Downsides to split pins incude that

a) they can get knocked (upwards) when the wheel is replaced
b) if they stick up from the holder very far, they can poke into the side wall of the tyre when the brake block gets worn.

FWIW if you want to delay seizure of the screws in the holders you have, a small amount of silicone grease might work; this has the advantage that it doesn't attack rubber and it doesn't melt when heated, so it should stay put pretty well.

A suggestion; if the screws won't shift, you can cut the old insert up in situ/pry it out, and this allows better access to the shank of the screw; it may then be gripped using miniature pliers or similar.

Overall I'd agree it is basically a stupid design; fancy for the sake of being fancy it seems to me. Maybe you could fit different screw (with a more conventional head) instead? As long as the screw head doesn't go into the tyre then it ought to be OK?

cheers

[backnotes]

Thanks very much for these suggestions Brucey. I am pleased to hear that the design looks a bit dumb to you as well!

I will put some silicone grease on the threads of the retaining pins on the new set of shoes for now, and will then experiment with some of the other suggestions on the old set, having removed the old pads with the help of Mr. Vice, Mr. Drill and their violent known associates.

If I can't improve on how they are, a different make of shoe that will fit will be easy enough to find, as you note.

Thanks again for this great range of things to try.

[Gattonero]

That design was soon abandoned on the first generations of Sram road brakes, for a reason!
Now it seems they're using the old stock in whatever way can do.

Unless you are on tight budget (but since those brakes are expensive, you may not be), I'd simply put them in the "useful (?) spare parts tin" and maybe one day you can reuse the fixing bolts for the holder, if not just put them in the bin.

Like said above, most of the holders would use a side-facing screw, which is not exempt from problems either.
If you want my advice: the Shimano 105 pad holders do use a JIS cross head screw, which can handle better torque than most 2mm allen keys.
The latter, can vary a lot: the Shimano and Swissstop ones have a nice deep fitting for the 2mm allen key, but since they use threadlock you want to use a good allen key and screw-unscrew them a few times until the threadlock is gone (or just brush it off, though not easy on such small screw) and the thread is clean on the screw and holder; Tektro/TRP do use a 2.5mm allen key that s very shallow, and this does not help.

The best thing to use for those screws when seized, is the Knipex "wrench-pliers", but in some cases all you can do is to cut a slot with a Junior hacksaw, and use a good quality flat screwdriver bit with a small ratchet (so you can push down and turn at the same time).

Greasing: never found a real reason for this, not on the screws for the holder, you're not meant to have them tight at all, they just have to stay in place. More important, grease the thread of the bolts that fix the holder on the caliper, those tend to rust badly.
At the end of the day, if big corrosion happens in the small screws of the pad holder, the rest of the bike will be seriously compromised as well