Road Disc Brake Maintenance

flatface

I need a few tips from ye experts.

1. The Alloy front pads look pretty close to 1mm after just one year, back have more. What about swapping front and back pads - is it an OK idea?

2. The lever travel has always surprised me, I need to pull the brake right to the limit before the braking kicks in and it doesnt feel particularly firm. Maybe its just the way it is as a bike shop did a full bleed at one point over the year, didnt notice a massive difference. Thoughts?

3. I would like to try a top up of the mineral. I have all the right bleed set, but when I went to put in the bleed block, the pistons are extended out slightly so I cant insert it. How do I safely get the pistons in?

Thanks!

Deano12345

flatface wrote: »

I need a few tips from ye experts.

1. The Alloy front pads look pretty close to 1mm after just one year, back have more. What about swapping front and back pads - is it an OK idea?

2. The lever travel has always surprised me, I need to pull the brake right to the limit before the braking kicks in and it doesnt feel particularly firm. Maybe its just the way it is as a bike shop did a full bleed at one point over the year, didnt notice a massive difference. Thoughts?

3. I would like to try a top up of the mineral. I have all the right bleed set, but when I went to put in the bleed block, the pistons are extended out slightly so I cant insert it. How do I safely get the pistons in?

Thanks!

I’ve only had a summer riding on hydros so someone will probably better placed to answer the question.

The pads in mine were no different back to front so unless you have different calipers I wouldn’t see any problem swapping them front to rear, that being said, pads are cheap so I’d swap the set.

The feel is an odd thing, cause it’s personal, that being said, I get more than enough power and feel pretty much the whole travel of the lever. It could be that your shifters need an adjustment (I think it’s called the free stroke adjustment). What lines are you running? I’ve read different hoses give a different feel!

Pushing the pistons back in is the easy one, just get a tire lever and push it back in by pushing on the middle of the piston. Make sure to get a flat edge, not a point!

paddydriver

I got a Canyon end of 2018 and had to replace rear pads after circa 2k Miles - they were down to the metal! I had expected to get more out of them but I am 95kg and do a lot of hills so what goes up must go down and that would be heavy on the rear pads trying to stop me on the bends and at the bottom. Pads are so cheap it's best just replace rather than swapping etc. Its a 5 min job - just don't pull brake levers when wheel out and especially when pads off. Lots of videos online from GCN etc on it.

Travel on the rear levers had increased massively and that should have been the giveaway. Now very little travel since replacing but did take a few miles to get rid of a slight rub on the new pads as I just couldn't get it perfect by balancing them etc.

Much more reassured braking once I changed pads. The fronts look like they have another few thousand miles in them. FYI.. I got Shimano pads on amazon.co.uk for very cheap.

Zen0

paddydriver sounds like you’re relying too much on your rear brake. Most of your braking should be happening at the front. Here’s what Sheldon Brown has to say on the matter https://www.sheldonbrown.com/brakturn.html

On swapping front and rear callipers, there’s probably a risk, if there’s uneven wear on the callipers, that they might not contact fully with the disc when swapped. Just replace them.

magicbastarder

swapping any pads - replacing new, or swapping front to back - will require a little time for the pads to bed in anyway.
i wouldn't see any benefit in swapping front and back around though.

you might see more wear on the rear pads - my experience is that they attract dirt (thrown up from the front wheel) more readily, and the extra abrasion wears the pads down quicker.

smacl

flatface wrote: »

I need a few tips from ye experts.

1. The Alloy front pads look pretty close to 1mm after just one year, back have more. What about swapping front and back pads - is it an OK idea?

I'd replace both and keep the pair that have some life left as an emergency spare set in the saddle bag. If you go for new sintered pads they'll give the best life and solid braking but can be a bit noisy while they bed in.

2. The lever travel has always surprised me, I need to pull the brake right to the limit before the braking kicks in and it doesnt feel particularly firm. Maybe its just the way it is as a bike shop did a full bleed at one point over the year, didnt notice a massive difference. Thoughts?

As mentioned above, free stroke adjustment controls this which is a small hex nut in the hoods. They vary in position depending on which brake type you've got but if you do a search online for your brake / groupset part number you can download a service manual. The trick is to make sure the free stroke nut is not all the way in or out when you do a bleed as you need to bring it in our out to reduce or increase the free stroke. Mine was shipped all the way in so no chance to adjust without doing a bleed. Also loads of youtube videos on this if you search for <your brake type> free stroke adjustment,

3. I would like to try a top up of the mineral. I have all the right bleed set, but when I went to put in the bleed block, the pistons are extended out slightly so I cant insert it. How do I safely get the pistons in?

I inserted a couple of folded business cards and then inserted a knife blade between them to push the pistons back. From memory, the crowd I got the bleed kit from actually recommended this method and provided cards for this purpose. The advantage is that the card prevents you from inadvertently damaging the pistons by trying to manipulate them directly with a metal edge.

flatface

Thanks for all the good advice. I have ultegra r8000 levers so will look into the adjustment. Cards and knife or a lever sounds like a good plan. Cheers.

paddydriver

Zen0 wrote: »

paddydriver sounds like you’re relying too much on your rear brake. Most of your braking should be happening at the front. Here’s what Sheldon Brown has to say on the matter https://www.sheldonbrown.com/brakturn.html

On swapping front and rear callipers, there’s probably a risk, if there’s uneven wear on the callipers, that they might not contact fully with the disc when swapped. Just replace them.

I'm definitely rear brake heavy... goes back to my BMX days and running just the rear brakes; ironically my 11 y/o is badgering me every day wanting to take the front brake off his BMX and I am hypocritically refusing to allow him.

I save the fronts for those emergency situations and would distribute weight well to "try" avoid the over the bars event.

two wheels good

Clean the pistons before you push them back into calipers.

flatface

two wheels good wrote: »

Clean the pistons before you push them back into calipers.

Any tips on this?

Peter T

To add you might get away with pushing the piston back by hand before sticking bits in there. Plastic tyre leaver would do the job if needed. If your just swapping back pads to front you can do it without taking the wheels off . If you decide to go with sintered pads make sure your discs are compatible. I swap pads around on my mtb (rear to front) and after a squeeze or two on the brakes you wont feel any difference

To clean the piston a quick rub to knock off any grit should do the trick

sin_26

It looks like bad bleeding. Re- bleed them but make sure you have no free stroke set. Had similar with my store xt. Guy at LBS didn't knew that he has to set free stroke to zero before bleeding.

flatface

Thanks! last question, alloy vs sintered pads?

Peter T

What are your discs compatible with ?

two wheels good

flatface wrote: »

Any tips on this?

Brake cleaner - in an aerosol. Toothbrush wrapped in cotton cloth.
But brake cleaner isn't essential. Any bike cleaner or even soapy water. Dry cloth on dry dirty pistons might result in scratches - but maybe I'm being unnecess. fussy.

smacl

flatface wrote: »

Thanks! last question, alloy vs sintered pads?

My CX shipped with sintered and I tried out resin and organic but wasn't happy with the stopping power. I'm also on the heavier side at 88kg FWIW. I hadn't realised some discs aren't compatible with sintered so check that first. My experience has been that sintered are a bit noisy while bedding in and take longer to bed in but way better long term. From what I gather, alloy backed pads are sintered, see https://www.chainreactioncycles.com/ie/en/shimano-road-disc-brake-pads-alloy-backed/rp-prod151619

flatface

smacl wrote: »

My CX shipped with sintered and I tried out resin and organic but wasn't happy with the stopping power. I'm also on the heavier side at 88kg FWIW. I hadn't realised some discs aren't compatible with sintered so check that first. My experience has been that sintered are a bit noisy while bedding in and take longer to bed in but way better long term. From what I gather, alloy backed pads are sintered, see https://www.chainreactioncycles.com/ie/en/shimano-road-disc-brake-pads-alloy-backed/rp-prod151619

Actually I think my pads are resin. I have these rotors - ugly as hell!

https://bike.shimano.com/en-EU/product/component/ultegra-r8000/SM-RT800.html



I reckon should be ok