Hi all

I'm currently using Avid Elixirs Carbons with Ashima rotors and I tend to find that the brakes drag wearing the pads down whenever I'm somewhere gritty. (Wales or Peaks etc). They work fine when I actually pull the lever but I can hear them wearing out when just riding along…

Is there something I can do to increase the clearance between the retracted pads and the rotor? Should I be bedding the pads in more? Should I buy new brakes? 🙂 (Quite like the Formula R1s!)

Any advice appreciated..

Bed the pads in properly. As for the dragging, most pads will drag a little when wet and gritty but not really enough to cause any considerable wear – you'd have a hard time pedalling otherwise! Elixirs are great stoppers, just get the pads bedded in properly

We did the red route at Dalby Forest last year, it rained the whole time we were there. I have a mix of brakes on my bike, the front Hope Mono M4 with pads that were at least a year old worked fine for the whole trip. The rear Avid Juicy 3 with brand new sintered pads didn't manage two thirds of the ride before they were down to the metal.

wet grit/sand wear pads, full stop

I've found that my Hope calipers retract the pads far better than the Hayes brakes I had before. I still buy the same brand of sintered pads, bed them in the same as ever, and find they're lasting 4x longer.

There has been much discussion on here and in other places about this. Myself I use hopes and never get this rapid pad wear even riding in places and conditions where others do get the rapid wear.

its obviously a combination of circumstances that leads to this and certainly not having the pads bedded in will have a big effect as a part of bedding in is curing the pads – hardening them under heat and pressure.

However scienceofficer of this forum came up with an idea that could account for this – if the brakes are cold and gritty the boundary layer where adherent friction occurs wears away quicker than it can be replenished as the brakes are not getting hot – this then means the brakes only work with abrasive friction which can cause the rapid wear.

I am convinced lack of heat in the brakes has a large part to play – the brakes on the tandem which get used / dragged a lot but do get very hot last far longer than the pads on my solo bike.

However there remain variables not accounted for. Some formulations of pad and some makes of brake seem to be worse for this – and riding style seems to play a part as well. Some rock and soil types seem to have an effect.

I have both Hope & XTR.
Last week I had to free up the pistons on both systems on 2x bikes as this very same thing was happening.

Take the wheel out & then the pads out, WD40 the whole caliper / piston area.
Work the brake lever forcing the pistons out (not so they drop out!) and clean. Push the pistons back in manually. Repeat.

Re-assemble and ensure the caliper(s) sit with the pads centrally making that the gaps are equal on each side of the rotor; I have added some thin washers to two calipers to make the gap more even.

Apologies if this sounds like a Hayes Manual!

I would be wary of using WD40 on anything with rubber seals as I believe it causes them to swell and degrade.
Years ago a tech buletin went around Rover/Landrover saying do not use WD40 to lube suspension bushes when fitting due to this effect.
I used to clean my old Honda's caliper up using it and when I stripped it all the rubber stuff looked like it came out of a caliper twice the size!
Recently I have stripped a couple of sets of Juicies and found the O ring on the piston in the lever to be swollen and I suspect WD40/GT85 contamination.

use ti29er's process, but use disk cleaner first time and brake fluid second time to clean/lube the pistons

As above, DO NOT USE GT85/WD40/TF2 anywhere near anything involving sliding surfaces or rubber seals.

To get an idea, put some oil on your fingers press hard together, and slide them over each other, works fine?

Repeat with WD40/GT58 etc, they stick together because they are dispersants, not lubricants, they actualy dissolve lubricants (eg the natural oil in your skin) and take them away.

Use either a cotton bud soaked in brake fluid (wear gloves) or DOT compatible grease.

You learn something every day! 😉

In a word no. I typically get at least 3 -6 months out of pads in the UK even over the winter I used one set (cheap sintered superstars in Juicy sevens).

I fit mine then ride up my street and brake hard a few times at each end just for forms sake really but I do notice that the first time I brake with new pads is not as sharp as the third or forth pull. That's as far as I go with bedding in and I have never used a set of pads up that quickly.

Righto, remove pads, clean piston area with disc brake cleaner, lube with brake fluid and make sure I bed pads in properly… (I also open the springs alot to give them more err spring..*ahem*)

In terms of bedding in whats usual number of stop/starts? 10 ish or so? Also, for the elixirs which are the most hard wearing pads?

Again, thanks muchly.. 🙂

Dunno about normal, and one ride sounds a bit extreme, but I've gone through a set in 2 rides a few times. Bedding in is a big factor (the brand new pair I put in 2/3rds of the way round the Crickhowell Merida last year were gone by the end) but I've found that even well bedded in ones can go very quickly if the conditions are right (or wrong!)

Aren't XTs supposed to have some clever lever pull that allows the pads to sit further from the rotor when you're not using them?

I'm one of those who has issues with pad wear. I've got through F&R pads (brand new, properly bedded in) in well under 10 miles before if it's proper wet. The climb will be enough to kill them. – the rotors get covered in wet grit splashing up the hill, and I can hear the pads grinding on the rotor. I'll start down the other side, grab a handful of brake and I can literally feel chunks of pad tearing off through the lever.

Thing is, I'm light, like big brakes, don't drag them, then just use them hard when needed. In the winter, they probably never get much above ambient temperature.

Avids and Formulas seem to be pretty dire. The Hopes I bought to replace the Formula Oros, have been much better – 1 rear set of pads since September. The fronts are still original. The pads do retract noticeably further from the rotor than Avid or Formula, but I also wonder how much difference the first 2 weeks worth of riding made – dayin, day out 1200m descents in the Pyrenees. They got proper hot then!

So I had a long chat with a very helpful guy called Toby (I think) from Fishers about Formula brakes and the issues that I have been having with my Avids. He said not to clean the calipers with disc brake cleaner as some of them have additives which could bugger things or somefink… he suggests using Isopropyl alcohol to thoroughly clean the pistons as he said the biggest cause of dragging brakes is dirty/grotty pistons that don't retract properly thereby causing excessive pad wear.

He said a can of electrical contact cleaner from Halfords would do the job very well.

He also said not to lube the pistons with brake fluid as it would attract loads of crap and gunk itself exacerbating the problem.

Makes sense I guess…

I agree with the bloke above.

Bike brakes work very much like car brakes (except that most car brakes us a single piston). To be very specific, they're like motorbike or car race brakes, as they have no dust seals (road car brakes have a rubber bellows attached near the end of the piston to keep muck out of the actual seals and off the piston).

The piston slides in a bore that is a very close fit – almost to the point of being an inteference fit, so dirty pistons can stop them moving properly in the bore. The seal is a square section o-ring. As the piston is pushed out hydraulic pressure, it deforms into a parallelogram sort of shape, due to the fact that it's gripping the piston slightly. When braking pressure is release, the o-ring goes back to a square profile, dragging the piston back away from the pad.

In my experience of brakes that are dragging and I have dismantled then rebuilt, you either have dirty pistons or ruined seals. Far more often than not, it's dirty pistons. I suspect all the procedures that are around involving pumping the pistons out, then manually pushing them back in are actually about cleaning the pistons, rather than getting something to lubricate the piston / seal interface. The seals are far too tight on the piston, and you want them to grip the piston anyway to provide the self retract mechanism!

I clean my rotors with lighter fluid (from the corner shop) & paper towels. It might work just as well and be less £?