Birzman Disc Brake Piston Pusher

Is it just me that gets one initial squeal on the first stop in the wet, then pretty much nothing afterwards? I'd honestly say that on balance, I find rim brakes slightly noisier in the wet than disks. I ran Shimano GRX R800 on my commuter.

BalladOfStruth wrote:

Is it just me that gets one initial squeal on the first stop in the wet, then pretty much nothing afterwards? I'd honestly say that on balance, I find rim brakes slightly noisier in the wet than disks. I ran Shimano GRX R800 on my commuter.

Ditto for me. 

Mine kept squealing this morning, but it was very very wet.

Boopop wrote:

That's a shame, pushing pistons back can be tedious. I spent an hour or so trying to get them back in my mechanic stand, then each time it was still rubbing. This tool would be great if it worked.

On the other hand I had to replace brake pads in Italy last month with the bike upside down and just bikepacking kit with me, and my attempt with plastic tyre levers worked first time! 😅

I've always used plastic tyre levers, i did buy a piston pusher but it didn't fit (too wide for my calipers). I think the important thing is to clean the pistons (with the correct brake fluid) before pushing them back in.

I have always used plastic tyre levers and had no problems when replacing pads but recently my local mechanic warned me only to use them with the old pads still inserted. Apparently he finds that if you don't you can crack the pistons if they are too badly stuck. Not sure if this tool would help in that regard or not.

I prefer to use my plastic tyre levers....to do just that.
There's more room in my kit bag for more important items than say, a rotor truing tool or a piston popper. I can instead pack a delicious pastie or loaf of bread. And a packet of minstrels. All because I don't need to pack mineral oil too.
You see, I'm very grateful to my simple and very effective rim brakes for being completely and utterly maintenance free. Every day...

You guys are bonkers!
Ditch those disks.

I love rim brakes. I get to charge customers for new housing, cables, noodles, pads, and eventually rims too. The more they ride, the more often these things need replacing. 

Disc brakes just don't need as much work, mile for mile. Swap pads now and then, quicker and easier than on rim brakes. A 10min bleed every 4-5 years for mineral systems. So yeah, bring back rim brakes, your local mechanic thanks you!

Sorry could you repeat that I couldn't hear you over the constant rubbing of disc break pads.

Seems no matter how many times I take the bike back to the smug mecanic in the shop he can't fix it either.  It's alway 1 puddle away from that foresaking rub, rub, rub sound.

Find a better mechanic mate. Sorted. 

KiwiMike wrote:

A 10min bleed every 4-5 years for mineral systems. 

What make of brake is this that only needs bleeding every five years? We have three out of six bikes with discs, so I'm hardly an anti, but the longest any of them go without needing a bleed is eighteen months.

You've also left out the need to straighten warped rotors in your "discs are so much easier" eulogy, something I spend quite a few hours on every year! Additionally disc pads need replacing much more frequently than blocks and at a greater cost each time, I reckon we spend at least twice as much annually on pads and bleeding for the disc bikes as we do on parts for the rim brakes, and in forty years I've never worn a brake track out before the hub or the rim has worn out; the longest a rim brake wheel has lasted me has been about 20,000 kms before some bugger nicked the bike.

Rendel Harris wrote:

KiwiMike wrote:

A 10min bleed every 4-5 years for mineral systems. 

What make of brake is this that only needs bleeding every five years? We have three out of six bikes with discs, so I'm hardly an anti, but the longest any of them go without needing a bleed is eighteen months.

Mineral systems mentioned, so typically that would be Shimano. Systems that use a DOT hydraulic fluid (such as SRAM) need bleeding more frequently as the fluid is hygroscopic so it absorbs moisture, mineral oils are not and last much longer, at the expense of slightly lower performance at high temperatures. 

All three of ours are Shimano and use mineral oil, they still need bleeding round about once every 18 months. Admittedly they are mainly used in very traffic-heavy central London, so probably do a lot more work than some others, but I'd be really surprised if a system only needed bleeding once every five years unless the bike is really lightly used, as in below 2000 km per year.

I had a GT i-Drive with Shimano discs that I 100% know went eight years before being bled, and that was only because I was selling it. Of course it's all down to how often a bike is being ridden, the type of trail and climate. It's impossible to generalise, apart from mineral lasting way longer than DOT. 

Straightening rotors is only needed if you've been careless putting it down, racking it or have crashed, and the technique is easily learned.

I'll categorically state that you are 100% flat out wrong that disc pads 'need replacing much more frequently'. ***Riding the same bike over the same terrain, through the same filth*** - ie a fair apples-apples comparison - rim-brake block will wear far quicker than a disc pad. Sorry, zero correspondence will be entered into here, the entire world's experienced rider/mechanic population disagrees with you. 

And you're ignoring the massive performance benefits and rider equality (smaller/weaker/disabled hands etc) afforded by discs.

Finally, I've worn two MTB rear rims totally through on V-brakes. I have a cross-section of road bike rim on my desk, where a friend and customer collapsed it through wear riding around Hampshire lanes over a few years. He was a few rides away from a very nasty explosive failure of the rim, likely under hard braking. I own a dental caliper specifically to measure rim wear, and mfrs include wear indicators for safety reasons. I've destroyed a set of rim brake blocks in *one day* on an extremely steep and muddy 80km ride - but rode an entire Scottish winter of enduro trails (1300km) on one pair of sintered pads, on a 26kg eMTB. 

Just because you lack the maintenance skills and analytical approach to understanding brake system wear and cost doesn't mean rim brakes are better. 

KiwiMike wrote:

 Just because you lack the maintenance skills and analytical approach to understanding brake system wear and cost doesn't mean rim brakes are better.

Nowhere have I said that rim brakes are "better" - if I believed that why, as I stated above, does half our garage have discs? - I simply politely and reasonably pointed out some drawbacks to discs that you didn't mention. I'm not clear as to why you think that warrants such rudeness; you ought to remember the dignity of your office as apparent spokesperson for "the entire world's experienced rider/mechanic population".

Quote:

Straightening rotors is only needed if you've been careless putting it down, racking it or have crashed, and the technique is easily learned.

Nope. Rotors can warp just from heat, I've fitted new pads and rotors, gone out to bed them in (a 'maintenance' task nobody every mentions for disc brakes) and they've come back warped enough to catch the pads.

I've got Shimano disc brakes on my Bullitt cargo bike that haven't needed bleeding once in the almost ten years I've had it. I've changed the rotors a handful of times and the pads once or twice a year, but aside from that they've been maintenance free. I don't do massive distances on it, but ride it almost every day, and being a cargo bike it's often carrying a load.

Every single cyclist that I know who wear discs MOAN about their performance. Everyone. Thing is. I never intrude. Never offer advice. I don't think it's my place to do so. IMO. They are, mostly, dedicated followers of fashion.

On here is different.

I find it difficult to believe any cycle mechanic doesn't profit more from disc system work versus the humble rim brake.

I've over 30 years fixing bikes and know how tricky disc systems can be. And to get back to point. I don't need to carry all the sos kit should the disc system FAIL, WARP or STICK.

Are you serious? I mean, really? You think every cyclist should be on rim brakes because every cyclist you know is a fashionista (ie you look down on them) who moans about discs?

Here's a counterpoint: in the real world where I live, everyone on discs - and I include pretty much all my customers here - prefers them over rim brakes for power, all-weather performance (ie SAFETY) and lower maintenance. Yes, they are aware that if not set up using OEM pads, or if contaminated, they can be noisy. And if they aren't moderately careful, rotors might need a 30-second truing. These are compromises people are happy to accept in return for massive benefits  

Pro tip: if your mechanic can't stop your discs squealing, *find a better mechanic*.

And what's a 'SOS kit' for disc brakes? I ride enduro trails almost daily. I don't carry a single item of brake-related kit, because in 30 years riding discs, I've not had a single brake-related failure mid-ride. I *have* worn out new rim brake pads in a single ride (42 Traverse, North Island NZ, winter, Shimano Exage 300 canti pads), had brake cables freeze solid, seen sticks destroy canti arms, etc etc. Do you carry a rim brake SOS kit? Yeah?

The only place I see people following fashion is on here, where it's fashionable to make out that discs are forced on a gullible population by The Man. 

Quote:

Pro tip: if your mechanic can't stop your discs squealing, *find a better mechanic*.

Nope. Disc brakes squeal, not always, not for everyone (I'm hugely jealous of those who don't experience it) but they can squeal, especially in the wet.

Manufacturers have admitted it, I've had different mechanics in different shops admit there is nothing they can do about it, and as a competent home mechanic who can keep discs running sweet and quiet in the dry, I've yet to figure out how to keep them running sweet and quiet in the wet. It's why I still won't use discs even on gravel or CX, I'll take the downsides of rims brakes for a (literally) quiet life.

For what it's worth I think it's something to do with extended bedding in, my MTB discs eventually quietened down after being absolutely cooked by the sort of prolonged braking my road or gravel bike will never experience.

Repairing thousands of bikes over the years, I can only recall one where I could not silence noise, even with new pads and rotors. It was a no-brand dirt-cheap set, that seemed to have in-built resonators, not helped at all by the loosely-fitting fork stanchions and headset/wheel bearings. Every other bike I have vanquished squealing brakes from by cleaning calipers, lubing pistons, replacing pads and either sanding, burning off or replacing rotors. Also facing mounts to be 100% square does wonders for noise and rotor rubbing.  And yes a proper really-hot bedding-in process does wonders. I suspect many bike shops don't bother with the multiple hard sprints needed to do this properly, or don't buy a Cyclon or Bonas bedding-in machine. 

I'm not discounting that many struggle to silence discs. Just saying that if you follow process, it's almost always successful. 

Yeah, I'd be interested to find a shop with a bedding in machine.

I don't brake hard enough or often enough on my gravel or road bikes to properly burnish the rotors I think, which means they work great in the dry but howl in the wet. The MTB brakes are OK but they get an occasional roasting on some steep local trails.

I think bedding in machines should be standard issue in shops now, but do they cause tyre wear?

IanEdward wrote:

I think bedding in machines should be standard issue in shops now, but do they cause tyre wear?

I wouldn't have thought so, I've just investigated the CyclOn SBR, it spins the wheel at 25km/h and you brake without locking up for 15-20 seconds, repeat 3-4 times. I very briefly considered that I really needed one in my life, but then quickly came back to the reality that I don't change brake pads & discs that frequently at all, and I could just carry on doing what I do now which is ride up to the end of my road and and return under braking several times.  

IMO. The point is. If you're well experienced at cycle repairs/general maintenance and enjoy/need extensive use of your bike. You'll be motivated and in a strong position to manage disc brake issues.
However, for the majority of cyclists. It is a casual and less essential leisure activity. It'll also mean they're likely to be less inclined to know how to solve the dreaded stick, squeal or squawk of disc brake issues.
My concern is that those who do have a bad experience using their disc brake bicycle may not be encouraged to continue with that experience. Primarily due to an over engineered brake system that is not necessary for casual riding around local cycle lanes, parks and tow paths.

We are supposed to encourage more and more people take up cycling. For the many benefits it brings. So, when the disc brake lot pipe up in their defence. Just think of those people who will have dropped their bicycle into the deep, dark recesses of their shed or garage. All because manufacturers have stopped adding rim brakes to almost all bicycles.
By way of encouragement. The cycling community needs to consider the wider implications of disc brake experience amongst the "General" population.
There is no doubt in my mind. People are put off from cycling because of the common problems introduced by the disc brake.

My first commuter bike (two years ago) had rim brakes and they annoyed me. No matter how much i "tweaked" them, I couldn't get them to sit clear of the rim & be close enough to actually press onto the wheels when I needed them.

When I "abused" that bike to being beyond feasible repairs (abused was the bike shop term) I replaced it and sought disc brakes (mechanial not hydraulic). Been much happier with them. I find them so much easier to "tweak". Pads are a little fiddly to replace, but so were the rim pads. I have had some pads squeal, but I am happy to ignore it if it means I am not cycling against the brakes!

Definitely not put off by disc brakes and find the maintenance much easier.