Brake pad & rotor replacement

[smorgasbord]

I think it's about time to replace my brake pads. Running stock Shimano setups on our two bikes now (one with BR-M8120 and one with (I think) BR-MT400).

Looks like the M8120 takes pads with cooling fins, so I think N04C was stock. That's sintered, but I think I want to switch to semi-metallic. Thoughts?
The MT400s probably have B01S pads (resin). Again, thinking of switching to semi-metallic.

Bikes are used in coastal areas, and the rotors have some rust (not where the pad hit since that wears off). Any have good/bad thoughts on stainless steel rotors, such as the kind Miles Racing sells?

I'm also thinking of using the Miles Racing semi-metallic pads - any thoughts or other suggestions?

TIA!

 

[fooferdoggie]

I have debated on if the fins do anything but add a lot to the cost. I have these on the tandem and so far they have been great. quieter too. should last longer but only time will tell.
now what I like about the fins is it makes it easy to put the pads in and you always know what's right and what's left. the metallic pads are better but they do add noise.

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Braking components for the mountain bike, road bike and cycling industry. We manufacture mtb brake rotors, ceramic and traditional brake pads

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[Stefan Mikes]

I will only tell you I always was using dedicated (and very expensive) semi-metallic TRP (Tektro Racing Products) brake pads for my TRP Zurich brakes; on the rebuild of my Vado, Specialized guys replaced my old pads with extremely cheap Tektro Auriga ones. If I didn't peruse the repair bill, I would have even not noticed the difference. The stopping power is excellent, and the brakes are silent. The TRP pads tended to scream!

 

[m@Robertson]

I wouldn't upgrade pad compound unless you have a problem with what you have now. Specifically, if you are seeing brake fade from extended use. Say... a regular run down a long steep hill and you aren't making it to the bottom before issues start creeping up.

Race pads generally take more time to heat up, and when they are under their preferred temp they squeal. But they are better for extreme duty where the brakes get heated up and stay that way. Most riders don't get up into those pads' butter zone enough to put up with the squeal all the other times. Lower performance pads tend to be quiet, but when you use them hard they fade and wear faster. I usually try and pick the middle of the road and get a 'performance' grade pad. Leaving either extreme out of it. My gut tells me that finned pads and rotors are more about marketing and premium price than they are performance. Part of that comes from my use of downhill brake parts and those have lots of steel and no fins. the increased material is there to sink in increased heat in place of fins, which I think are more about providing cooling while staying light weight (that and relieving suckers of their excess money).

As to rotors, I would always pick the ones that are more substantial (less holey) and as thick as my calipers are allowed to take. Usually thats 1.8mm for a normal caliper, but beware some rotors can be thinner. Avids used to be infamous for this and I had one set that was 1.4 new out of the box. About the holeyness: Rotors are a heat sink and as such more material means more ability to soak up heat. Super holey rotors are less effective for that reason. But the holes do serve a purpose and a completely solid rotor would let too much heat build up. As a real-world example, my bikes take thicker rotors and the Magura Storm SL.2 was too holey to be really effective, but the Storm HC was fine.

 

[smorgasbord]

On our two bikes, I upgraded my wife's brakes to Deore XT's, which turned out to be M8120, which turn out to have the "sintered" (aka metallic) pads. Which is probably not right for her. And my bike still has what I think are MT400's, which have resin pads, and even the newer version of those pads (now version 5 from Shimano) is twice as good as my 2018 pads.
So, I think the semi-metallic (in the middle) is the way to go for us.
My wife's bike as SRAM centerline rotors, which are pretty well reviewed. I don't know what low-level Shimano rotors mine are (203 fr and 180 rear).
Again - given the rust anyone know anything about stainless steel rotors? Supposedly SS isn't the best material wear wise.

 

[m@Robertson]

Again - given the rust anyone know anything about stainless steel rotors? Supposedly SS isn't the best material wear wise.

I am having exactly the same issue with my rotors on my coastal-living bikes. I can't justify a loss in braking performance for the cosmetic benefit of no surface rust. It hurts my sense of right and wrong in the universe but thats it. If I can't stand it anymore, I can take a sander to them and scrub for a few seconds. Every other nut/bolt/washer on those bikes are stainless steel. And every other bike at the bike racks on the beach / stores is in far worse shape so I'm in good company.

 

[m@Robertson]

huh interesting the Tektro Type 17 rotors I use turn out to be stainless, but the Magura Storm HCs aren't. At least Magura says nothing about their material. Closest statement I can find is on Amazon and says "alloy steel" ... if that can be believed. Jenson USA says "aluminum" and I know thats wrong.

The Tektro 17's offer no noticeable difference in performance, although they are on different bikes than the ones with Magura rotors. All of my bikes use Magura MT5e's so at least thats the same. Looking at the Tektro line, every one I clicked on was stainless steel.

I looked at Miles Racing and their SS2 is a twin to the Tektro 17. And its cheap for any size. I'd ask them what the thickness is before buying as thats a big deal. Too thin and the pads might extend too far. I had a set of Maguras leak when that happened once. The Tektro 17's almost certainly will not work as they require a caliper designed to handle a very thick rotor.

 

[smorgasbord]

So I ended up cleaning the rotors with a SandFlex block. Still some rust on the rotor's spokes, but didn't feel like removing the rotors and doing a full rust removal.
I replaced the pads with Shimano's latest organic and so far they're quiet as a mouse.
I did, however, find that on the front brake for one of the bikes (using the cheaper MT400 brakes, not the Deore M8120 XT brakes), one of the pistons was almost stuck. I tried all the techniques for fixing the problem (Park Tools and other videos), but didn't really fix the problem. I was able to wedge the good piston open with metal bars and the old pads while pumping the lever to get the stuck piston unstuck, but after a dozen cleaning and push back, push out attempts, it still doesn't want to move as well.
I ended up leaving the "stuck" piston (it's not really stuck) out a small bit when reinstalling the caliper, and then did the squeeze/centering thing and I can see both pistons move a tiny bit when braking and move back when releasing, so I may be OK for now.
The next step is either buying a new caliper for the front, which means either eBay for NOS or whatever Shimano caliper is compatible with the BH59 hose, or a whole new lever/caliper setup.
OR - and I only found one video on this, taking the old caliper apart and cleaning everything manually. Anyone done that? It looks straightforward, as long as you can keep everything really clean and can tighten the caliper assembly bolts tight enough (and keep track of which bolt is which since they're often different due to fluid channeling).

 

[fooferdoggie]

I would ride it to see how it goes. spray the piston with alcohol and then go ride O have had pistons do that on the deore 4 piston set and they seem to get better after riding.

 

[smorgasbord]

For $31 I just ordered a Shimano MT-500 caliper. Takes same hose and connections and same basic layout as my existing MT-400 so should be an easy swap.

 

[PDoz]

For $31 I just ordered a Shimano MT-500 caliper. Takes same hose and connections and same basic layout as my existing MT-400 so should be an easy swap.

Next time, consider getting 4 pot - and as big a pad as you can. The pads last longer, are more fade resistant , and have twice as many pistons to get stuck for if you want to upgrade later.

My old giant full e came with the mt500's , they were OK , but I used to carry new pads in by backpack because they wore out so rapidly ( eg one day at thredbo - but in their defense I was dropping 560 m in 3.5 km and did about 10 runs chasing my teenage daughter) .

BTW , I've been running the purple galfer pads on a few of our bikes lately - similar initial bite to shimano , the noise is more a grind than squeal which is less distracting, and they seem to get grippier as they work harder instead of fading like shimano do.

 

[smorgasbord]

Next time, consider getting 4 pot - and as big a pad as you can.

Yeah, I upgraded my wife's bike to Deore XTs, which are 4 piston brakes. But, for my bike I wanted to keep my levers since the cockpit is so optimally laid out and didn't want to spend the money to upgrade the whole front system. For $31, I was able to restore my previous pretty decent braking with a slightly newer model caliper that is fully compatible with my existing lever and hose.

 

[fooferdoggie]

Yeah, I upgraded my wife's bike to Deore XTs, which are 4 piston brakes. But, for my bike I wanted to keep my levers since the cockpit is so optimally laid out and didn't want to spend the money to upgrade the whole front system. For $31, I was able to restore my previous pretty decent braking with a slightly newer model caliper that is fully compatible with my existing lever and hose.

its nice though going to single finger levers. I love them though they take some getting used to as they are so sensitive. I can stop out 400# tandem with one finger on each lever on a steep hill.

 

[smorgasbord]

I looked at Miles Racing and their SS2 is a twin to the Tektro 17. And its cheap for any size. I'd ask them what the thickness is before buying as thats a big deal. Too thin and the pads might extend too far. I had a set of Maguras leak when that happened once. The Tektro 17's almost certainly will not work as they require a caliper designed to handle a very thick rotor.

I haven't done anything on the rotors yet - I'll probably wait until the end of this upcoming season, but the SRAM HS2 rotors look pretty nice. They're 0.2mm thicker as well.

 

[smorgasbord]

Just to close this out - received the MT500 caliper. Completely plug-and-play compatible with the MT400 that was originally there. The bleed open/close screw is so close to the top mounting bolt that I decided to bleed the system before final mounting of the caliper to the fork. Caliper didn't come with the yellow spacer pad, so made do with the old pads, the orange spacer, and some masking tape. Didn't want to use the new pads since I didn't want to risk mineral oil contamination..

And since I had it off the bike, I spent 2 minutes trying to open the old MT400 caliper. The Torx bolts are really tight and it's hard to get the caliper body clamped securely. Since it was only $31 for replacement, I decided not to spend any more time on it.

Thanks all!

 

[TrevorB]

When I swapped rear from MT200 to M6000(level + caliper) I used old hose without any issues even though they are different. May not be optimum braking but huge step up from MT200s. Not sure how well MT400 level would work with M6100 caliper but be interesting experiment.

 

[smorgasbord]

What I've read is that the new Shimano hoses have a smaller inside diameter but the same outside diameter. So, the walls are thicker. But, it makes sense that the old hose would fit a new caliper since the connections depend on the olive on the outside of the hose. I've also read you can't mix the olive and inserts between the hoses.

 

[Stefan Mikes]

New Disk Brake Rotor Considerations

Having my Vado 5.0 rebuilt into the Specialized Turbo Vado 6.0, and taking into consideration the original bike had been used heavily for 3 years, I am now inspecting the components to make my Roadrunner a perfect new e-bike. Especially, as the number of original components left on that e-bike is surprisingly small!

So I had to go through a "Disk Brake Crash Course".

Let me start with the current thickness of the TRP TR180-29 rotors on my bike is:

• Front: 1.67 mm
• Rear: 1.57 mm

This is rather a surprising discovery, as one might expect the front rotor would wear faster! There is still a lot of life in the rotors, as the limit thickness would be 1.4 mm, and the original thickness was 1.8 mm.

The model number is barely visible on the rotor.

The Tektro e-bike magnet holder for 6-bolt rotors.

I have found TRP now offers new matching TR180-33 rotors in ICE technology. Not only expensive but I would also need to order them from Germany. So I went on a quest to find compatible rotors locally.

The disk brake rotor compatibility parameters

1. Mounting system: 6-bolt or Centerlock: 6-bolt in my case
2. The outer diameter of the rotor: 180 mm
3. The thickness of the rotor: 1.8 mm
4. The braking area width matching the brake pads (and effectively, the brake callipers): See the discussion below
5. A flat rotor, or one with an anti-loosen plate: See the discussion below
6. The magnet holder for the rear brake if necessary: I already own the magnet holder
7. Technology, or how well given rotor can handle the grime, and dissipate the heat released on braking: See below

(3) It is vital that your new rotor would match the existing callipers and brake pads. Now, something interesting...

It looks that my TRP Q20.11 brake pads are identical in shape with some top class Shimano ones. Therefore, a Shimano rotor of a given groupset could be used.

(4) Flat or with an anti-loosen plate?

Shimano uses anti-loosen plates on some rotors to secure the bolt heads against loosening. Such a plate cannot be used with the Tektro magnet holder (which requires a flat rotor surface to be mounted).

(5) Rear wheel magnet holder.
It is very difficult to find and order the proper part here. Shimano is happy to deliver a combo of a rotor with matching e-bike magnet holder; at an absurd price, taking into account the magnet holder price is some US$10, were it available!

(7) The technology used.
A classic rotor is as good as it can be. Nowadays, the ICE Technology is widely advertised as the one quickly dissipating the big amount of heat building up in the disk brakes; hot brakes lead to "brake fading" or you cannot stop your bike when you need it the most. The ICE rotors are far more expensive than the traditional ones. Also, a good rotor should be able to remove the dirt/grime accumulated when the bike is riding through the mud.

I had to make a decision. My choice:

• Front: Shimano Deore XT SM-RT86, 6-bolts, 180 mm diameter, ICE technology, anti-loosen plate
• Rear: Shimano Deore SM-RT66, 6-bolts, 180 mm diameter, traditional.

I hope my decision was good!