Braking performance of SRAM DB8 Stealth brakes
- Thread starter tonyride
- Start date
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Disc brake bed-in. You’ve likely heard of it, or better yet, you know what it is. For anyone with disc brakes, it’s an important step in the initial setup that not only provides better braking power and smoother operation but also helps ward off unwanted noises and even premature wear.
If you’ve ever ridden a brand-new disc-equipped bike or rolled out the door with fresh brake pads, then you may have experienced a few scary moments where it felt like the brakes weren’t going to stop you. And you may have also experienced a few honk noises in the process. These are early indicators of brakes that have not been bedded in.
To some, the brake bed-in process is more an art than a science, a concept that cannot be described and only felt. To a rarer few it’s a mythical construct, perhaps held in similar regard to the tooth fairy or the perfect gravel tyre. In this edition of Threaded, I’m here to explain why it’s not only a critical assembly step, but also how easy it can be to do.
A moment of admission. I started writing this article two years ago and quickly became overwhelmed in the science and nuances from differing approaches and materials. Having climbed out of that hole, I’ve come to realise that just doing a basic bed-in is vastly better than none, and so while you’ll get differing approaches, a general quick process will get you firmly into the realm of good enough and safe.
Let’s begin.
On the flipside, not performing a dedicated bed-in can result in an uneven surface, leading to inconsistent braking, vibrations, and noise. Also, a brake that isn’t bed-in will offer no power for the first few stops. Ignoring the longer-term issues of not bedding in brakes, this lack of initial bite can present a dangerous scenario.
I’m strongly of the opinion that a basic bed-in should be done as a purposeful task that isn’t left to do during a ride where the process will almost certainly be compromised or ruined. I’m equally of the opinion that it should be considered part of the initial bicycle assembly or service, and that a build/repair is incomplete without it. More on this specific matter later on.
In addition to being quieter, more consistent, and often longer-lasting, a well-bed-in brake is significantly more powerful, with brake sensor creator BrakeAce seeing braking power doublefrom start to finish during the procedure.
While there can be nuanced differences between what each brand recommends, the bed-in process is largely consistent across all disc brake systems, whether that’s hydraulic or mechanical, from Shimano, SRAM, Campagnolo, Magura, TRP, Hope, Hayes, or just about any other brand – across mountain, road, gravel, and commuting bikes.
Before you begin, a brake bed-in needs to be done when everything is still brand new. It’s also recommended that you do a bed-in whenever changing brake pads and/or rotors. It’s a rabbit hole I want to avoid, but it’s worth noting that all brake manufacturers recommend against switching brake pad material (say from organic to metallic) without also changing the rotor.
As the pad friction material is bedded into the rotor, it's advised not to switch pad materials. More on this later.
And now for the quick safety notice. A topic like this assumes some level of mechanical know-how and a more than beginner riding level. If in doubt, consult a professional.
Clean is a word often used whenever discussing disc brakes, and unfortunately, new doesn’t necessarily mean clean. Chris Yankopoulos, a Shimano technical representative in the USA, often instructs dealers to clean brand new rotors, whether installed on a new bike or in aftermarket packaging, prior to use. It’s a tip that Boulder-based mechanic Colin Williams often shares on Instagram, too.
Cleaning a rotor doesn’t need to be complicated. I recommend the use of isopropyl alcohol and a fresh piece of paper towel (Scott’s Shop Towel is the GOAT). Most often the paper towel will come up clean, but occasionally, you’ll see how dirty new rotors can be.
Avoid the extremely harsh automotive brake cleaners. Rather a product like isopropyl alcohol is the common suggestion.
While rotors need to be cleaned, the brake pads should already be clean and ready to use from new. That said, for years I’ve taken a quick step to surface the pads in a way that I feel helps reduce the time of the initial bed-in. This optional step consists of taking the pads in your hand, spraying/splashing some clean water on them, and then rubbing them together until you feel them go from slippery to gripping. I’ll then spray some more water to rinse off the slurry, and I’ll then install them into the bike.
Rubbing two pads together with water. I find this quick step helps to cut down bed-in time.
If it’s an old existing rotor and you’re just replacing the pads with a matching compound, then a quick rinse of the rotor with water and wipe with isopropyl alcohol is sufficient. For example, John Hall, the former mechanic to World Cup downhill racer Aaron Gwin, explained, “I avoid replacing rotors for as long as I can. The more pad material built up on a rotor without being worn out or contaminated the better.”
1. Find a level or light gradient road without traffic, an empty parking lot is perfect
2. Gently pull one brake lever with a consistent light force
3. Now ride around against the consistent force for approximately 20-30 seconds until you feel the braking begin to resist your pedaling force
4. Repeat with the other brake
This process will safely get some power into the system and reduce the risk of overzealous brake inputs for those new to the procedure. In doing this take care not to lock or skid the wheel, which can create an unwanted inconsistency on the rotor.
Now it’s time to increase the speed to a moderate level.
5. Remain in that level or light gradient road without traffic
6. Accelerate to approximately 25-30 km/ph (15-18 mph)
7. Smoothly and softly pull one brake lever until you decelerate to a walking speed
8. Repeat 10-20 times
9. Now do the same for the other brake
10. Catch your breath and grab a well-deserved drink
While doing this, it’s important not to brake heavily, come to a dead stop, or skid a wheel, which may unevenly deposit material on the rotor.
“The key is getting enough heat into the rotor and pad in order to evenly distribute material onto the rotor,” explained Aaron Pelttari, the former mechanic of pro downhill racer Troy Brosnan. “People use water and all kinds of tricks, but at the end of the day, you just need pad material on the rotor. Do it slowly and it’s sweet, do it fast and it’s not so sweet.”
Why the flat ground? As Peltarri notes, “too much heat is a concern." For example, dragging the brake for an extended period of time down a big hill can glaze the rotors and pads. This is why it’s important to do it moderately and with moments of cooling between.
In my experience, it’s quite normal for bikes with smaller rotors and organic pads (such as most road and gravel bikes) to feel good in braking power after 5-7 repetitions. Bigger brakes on mountain bikes, and those with metallic brake pads, will require more heat and therefore effort. I’ll repeat the process above until the brake feels effective and there’s no further noticeable improvement with additional repeats. Personally, I’ve found that’s often around the 10-repetition mark, and that 20 is typically overkill.
Bigger rotors and metallic pads will require more heat and effort.
It’s worth noting that at this point I consider a basic bed-in to be complete and that the brake is now safe and suitable to hand over to a customer. However, there may be more power in that brake to eke out if you so wish.
Still, if you want full power before your first ride, then continue with the following. Just be warned that your brakes will be reaching full power and so braking skill is required to not hit a sudden stop, skid, or even crash.
11. Stay on that level or light gradient road without traffic
12. Accelerate to approximately 25-30 km/ph (15-18 mph)
13. Firmly pull one brake lever until you quickly decelerate to a walking speed
14. Repeat 5-10 times
15. Now do the same for the other brake
16. Do a sweet front manual with your newly bed-in brake to prove you’re excellent at this
According to pro mechanic Colin Williams, if the bed-in procedure is done correctly, “you should feel the brake go from almost no power during the first few decelerations to full power by the end.”
The goal here is to resurface both the pads and rotors so that you can transfer a new and hopefully more consistent layer of pad material. Like anything, there are countless ways to achieve this, but a sheet of approximately 60-120 grit wet-and-dry (aka sandpaper) is typically sufficient. A sanding mesh sheet is also popular for this task as it resists clogging up.
Before I go further, it’s worth noting that brakes which lack bite or make excessive noise may simply be contaminated from oils, solvents, or themselves (brake fluid leak). I won’t detail how to solve this, but please be aware that a bed-in may not be the solution if you’re experiencing this issue. As always, if you’re unsure, I recommend seeking the help of a professional. Ok, back to the resurfacing.
Start by removing the brake pads from the caliper. A shiny braking surface means a glazed brake pad. Also look for uneven signs of wear which may point to a larger alignment or setup issue. Place the wet-and-dry on a flat surface, such as a bench top. Now rub the pad (braking surface side) on the paper (dry) until there is a consistent and matte-like finish. Repeat with the other pad.
The pad on the left is freshly resurfaced. While the pad on the right is half-way done, still showing some glazing in the centre.
Over to the rotor. Now is a good time to clean the rotor with isopropyl alcohol and a piece of paper towel. Continue until the paper towel is no longer collecting dirt. Now cut a small square of that wet-and-dry, just large enough that when folded in half it covers a section of the rotor’s brake track. Fold that squre over the rotor and run it over the full circumference of the rotor. The goal is remove the previous bedded-in brake pad material and lightly scour the surface. Try to move around the rotor with even effort. Finally, give the rotor another clean with the isopropyl alcohol and paper towel, making sure it's free of residue.
Just remember that rotors, like brake pads, are also a wear item. Once they';re worn below the minimum thickness they're ready for the bin.
If all has gone well, and it’s not a contamination issue, then you’re now ready to return to Step 2 above.
Disc brake bed-in. You’ve likely heard of it, or better yet, you know what it is. For anyone with disc brakes, it’s an important step in the initial setup that not only provides better braking power and smoother operation but also helps ward off unwanted noises and even premature wear.
If you’ve ever ridden a brand-new disc-equipped bike or rolled out the door with fresh brake pads, then you may have experienced a few scary moments where it felt like the brakes weren’t going to stop you. And you may have also experienced a few honk noises in the process. These are early indicators of brakes that have not been bedded in.
To some, the brake bed-in process is more an art than a science, a concept that cannot be described and only felt. To a rarer few it’s a mythical construct, perhaps held in similar regard to the tooth fairy or the perfect gravel tyre. In this edition of Threaded, I’m here to explain why it’s not only a critical assembly step, but also how easy it can be to do.
A moment of admission. I started writing this article two years ago and quickly became overwhelmed in the science and nuances from differing approaches and materials. Having climbed out of that hole, I’ve come to realise that just doing a basic bed-in is vastly better than none, and so while you’ll get differing approaches, a general quick process will get you firmly into the realm of good enough and safe.
Let’s begin.
The critical bed-in and a strong opinion
Brake bed-in is the process of transferring a layer of pad material onto the disc rotor surface. It’s this transfer of friction material that allows a disc brake to work efficiently and effectively. A proper bed-in procedure ensures a smooth and consistent material transfer.On the flipside, not performing a dedicated bed-in can result in an uneven surface, leading to inconsistent braking, vibrations, and noise. Also, a brake that isn’t bed-in will offer no power for the first few stops. Ignoring the longer-term issues of not bedding in brakes, this lack of initial bite can present a dangerous scenario.
I’m strongly of the opinion that a basic bed-in should be done as a purposeful task that isn’t left to do during a ride where the process will almost certainly be compromised or ruined. I’m equally of the opinion that it should be considered part of the initial bicycle assembly or service, and that a build/repair is incomplete without it. More on this specific matter later on.
In addition to being quieter, more consistent, and often longer-lasting, a well-bed-in brake is significantly more powerful, with brake sensor creator BrakeAce seeing braking power doublefrom start to finish during the procedure.
While there can be nuanced differences between what each brand recommends, the bed-in process is largely consistent across all disc brake systems, whether that’s hydraulic or mechanical, from Shimano, SRAM, Campagnolo, Magura, TRP, Hope, Hayes, or just about any other brand – across mountain, road, gravel, and commuting bikes.
Before you begin, a brake bed-in needs to be done when everything is still brand new. It’s also recommended that you do a bed-in whenever changing brake pads and/or rotors. It’s a rabbit hole I want to avoid, but it’s worth noting that all brake manufacturers recommend against switching brake pad material (say from organic to metallic) without also changing the rotor.
And now for the quick safety notice. A topic like this assumes some level of mechanical know-how and a more than beginner riding level. If in doubt, consult a professional.
Step one: Clean everything
To conduct a proper bed-in, it’s essential to begin with a fresh and clean system, one that’s correctly set up where the brake pads are evenly and squarely contacting the rotor. It’s also important to check that the brake is free from any defects, such as leaks from the caliper pistons or hose.Clean is a word often used whenever discussing disc brakes, and unfortunately, new doesn’t necessarily mean clean. Chris Yankopoulos, a Shimano technical representative in the USA, often instructs dealers to clean brand new rotors, whether installed on a new bike or in aftermarket packaging, prior to use. It’s a tip that Boulder-based mechanic Colin Williams often shares on Instagram, too.
Cleaning a rotor doesn’t need to be complicated. I recommend the use of isopropyl alcohol and a fresh piece of paper towel (Scott’s Shop Towel is the GOAT). Most often the paper towel will come up clean, but occasionally, you’ll see how dirty new rotors can be.
While rotors need to be cleaned, the brake pads should already be clean and ready to use from new. That said, for years I’ve taken a quick step to surface the pads in a way that I feel helps reduce the time of the initial bed-in. This optional step consists of taking the pads in your hand, spraying/splashing some clean water on them, and then rubbing them together until you feel them go from slippery to gripping. I’ll then spray some more water to rinse off the slurry, and I’ll then install them into the bike.
If it’s an old existing rotor and you’re just replacing the pads with a matching compound, then a quick rinse of the rotor with water and wipe with isopropyl alcohol is sufficient. For example, John Hall, the former mechanic to World Cup downhill racer Aaron Gwin, explained, “I avoid replacing rotors for as long as I can. The more pad material built up on a rotor without being worn out or contaminated the better.”
Step two: Smoothly does it
Bedding in a brake is a matter of repeatedly and smoothly applying stopping power at the lever. This process, and the heat that it creates, helps the pad material deposit onto the rotor and you’ll progressively feel the braking power become more effective. The initial step below is something that comes recommended from pro mountain bike mechanic (currently head mechanic of Specialized Off-Road Racing) and voice on the Geek Warning podcast, Brad Copeland:1. Find a level or light gradient road without traffic, an empty parking lot is perfect
2. Gently pull one brake lever with a consistent light force
3. Now ride around against the consistent force for approximately 20-30 seconds until you feel the braking begin to resist your pedaling force
4. Repeat with the other brake
This process will safely get some power into the system and reduce the risk of overzealous brake inputs for those new to the procedure. In doing this take care not to lock or skid the wheel, which can create an unwanted inconsistency on the rotor.
Now it’s time to increase the speed to a moderate level.
Step three: Harder braking
Now we get to the next step, a process that most manufacturers outline and typically agree upon.5. Remain in that level or light gradient road without traffic
6. Accelerate to approximately 25-30 km/ph (15-18 mph)
7. Smoothly and softly pull one brake lever until you decelerate to a walking speed
8. Repeat 10-20 times
9. Now do the same for the other brake
10. Catch your breath and grab a well-deserved drink
While doing this, it’s important not to brake heavily, come to a dead stop, or skid a wheel, which may unevenly deposit material on the rotor.
“The key is getting enough heat into the rotor and pad in order to evenly distribute material onto the rotor,” explained Aaron Pelttari, the former mechanic of pro downhill racer Troy Brosnan. “People use water and all kinds of tricks, but at the end of the day, you just need pad material on the rotor. Do it slowly and it’s sweet, do it fast and it’s not so sweet.”
Why the flat ground? As Peltarri notes, “too much heat is a concern." For example, dragging the brake for an extended period of time down a big hill can glaze the rotors and pads. This is why it’s important to do it moderately and with moments of cooling between.
In my experience, it’s quite normal for bikes with smaller rotors and organic pads (such as most road and gravel bikes) to feel good in braking power after 5-7 repetitions. Bigger brakes on mountain bikes, and those with metallic brake pads, will require more heat and therefore effort. I’ll repeat the process above until the brake feels effective and there’s no further noticeable improvement with additional repeats. Personally, I’ve found that’s often around the 10-repetition mark, and that 20 is typically overkill.
It’s worth noting that at this point I consider a basic bed-in to be complete and that the brake is now safe and suitable to hand over to a customer. However, there may be more power in that brake to eke out if you so wish.
Reaching full power
Now the optional extra for those who want maximum power. I don’t consider this part of the process to be a must-do, and in fact, it’s common for professional mountain bike mechanics to stop at the previous stage of the bed-in, and rather have the athletes complete some hard braking on the first practice lap or two in order to emulate this final bed-in stage.Still, if you want full power before your first ride, then continue with the following. Just be warned that your brakes will be reaching full power and so braking skill is required to not hit a sudden stop, skid, or even crash.
11. Stay on that level or light gradient road without traffic
12. Accelerate to approximately 25-30 km/ph (15-18 mph)
13. Firmly pull one brake lever until you quickly decelerate to a walking speed
14. Repeat 5-10 times
15. Now do the same for the other brake
16. Do a sweet front manual with your newly bed-in brake to prove you’re excellent at this
According to pro mechanic Colin Williams, if the bed-in procedure is done correctly, “you should feel the brake go from almost no power during the first few decelerations to full power by the end.”
Resetting an existing brake for bed-in
Ok, so you’ve only just learned about brake bed-in and want to fix those noisy and pulsing brakes. It can be done, but expect varied and compromised results. And while not recommended by any brake manufacturer, the following approach can also be attempted if switching pad material on an existing rotor.The goal here is to resurface both the pads and rotors so that you can transfer a new and hopefully more consistent layer of pad material. Like anything, there are countless ways to achieve this, but a sheet of approximately 60-120 grit wet-and-dry (aka sandpaper) is typically sufficient. A sanding mesh sheet is also popular for this task as it resists clogging up.
Before I go further, it’s worth noting that brakes which lack bite or make excessive noise may simply be contaminated from oils, solvents, or themselves (brake fluid leak). I won’t detail how to solve this, but please be aware that a bed-in may not be the solution if you’re experiencing this issue. As always, if you’re unsure, I recommend seeking the help of a professional. Ok, back to the resurfacing.
Start by removing the brake pads from the caliper. A shiny braking surface means a glazed brake pad. Also look for uneven signs of wear which may point to a larger alignment or setup issue. Place the wet-and-dry on a flat surface, such as a bench top. Now rub the pad (braking surface side) on the paper (dry) until there is a consistent and matte-like finish. Repeat with the other pad.
Over to the rotor. Now is a good time to clean the rotor with isopropyl alcohol and a piece of paper towel. Continue until the paper towel is no longer collecting dirt. Now cut a small square of that wet-and-dry, just large enough that when folded in half it covers a section of the rotor’s brake track. Fold that squre over the rotor and run it over the full circumference of the rotor. The goal is remove the previous bedded-in brake pad material and lightly scour the surface. Try to move around the rotor with even effort. Finally, give the rotor another clean with the isopropyl alcohol and paper towel, making sure it's free of residue.
If all has gone well, and it’s not a contamination issue, then you’re now ready to return to Step 2 above.
Cole
Well-Known Member
This seems like a lot of work lol. Just put new pads in tonight...
there is a problem if the levers go to the bars and the tires aren't locked........
wet rim brakes maybe......
I haven’t either tbh. I ride to the top of my road then ride the brakes down the hill a few times.
But I have skipped the process completely and it never works out. I either get pulsing or screeching brakes.
Same here. Just go down a hill and alternate between front/back without allowing the brakes to get too hot or to fully stop.
Brakes working at 100% without noise or issues is worth the extra steps every time.
Also, people don't realize how much better riding is when the brakes are working as well as they can. Sure they can send you over the bars, that doesn't mean modulation is there to allow you to brake as hard as possible before a turn or technical feature. Nor does it mean they won't overheat on a long descent or make godawful noises.
Brakes working at 100% without noise or issues is worth the extra steps every time.
Also, people don't realize how much better riding is when the brakes are working as well as they can. Sure they can send you over the bars, that doesn't mean modulation is there to allow you to brake as hard as possible before a turn or technical feature. Nor does it mean they won't overheat on a long descent or make godawful noises.
Red Mosquito
Formerly RLB the Scrapple Boy
It’s about time to change the pads on my sram brakes (G2 RSC). What’s the go-to? I never had complaints with the stock pads but wondering if I’m leaving anything on the table going with them again.
Stock is fine. Just pick organic or sintered.
Steve Vai
Endurance Guy: Tolerates most of us.
absoluteBLACK: We have Proven OVAL chainrings. More Performance – Less Fatigue. Go oval.
GRAPHENpads World's best Disc Brake Pads. Disc 31 The Ultimate bicycle chain lubricant. Winner of Yellow, White and Polka dot jersey in general classification of Le Tour de France 2020 & 2021 and winner of Red and Green jersey in general classification of La Vuelta 2020 . Most wanted lube...
absoluteblack.cc
tonyride
Don't piss off the red guy
I took the bike out for a quick ride at Chimney Rock yesterday to test out the adjustments and I gotta say the brakes feel great, more than adequate for regular trail riding without long downhill runs at the bike park. Since they're all nicely bedded in and working fine, I'm just going to keep using them until they wear out then I'll put the metallic pads on. Now the trick is to put the new pads somewhere, so I'll be able to find them when I need them.
Magic
Formerly 1sh0t1b33r
Lol, just do a loop at 6M to bed in your brakes. Faster than reading this article.If you like this, you should subscribe to escape collective
Disc brake bed-in. You’ve likely heard of it, or better yet, you know what it is. For anyone with disc brakes, it’s an important step in the initial setup that not only provides better braking power and smoother operation but also helps ward off unwanted noises and even premature wear.
If you’ve ever ridden a brand-new disc-equipped bike or rolled out the door with fresh brake pads, then you may have experienced a few scary moments where it felt like the brakes weren’t going to stop you. And you may have also experienced a few honk noises in the process. These are early indicators of brakes that have not been bedded in.
To some, the brake bed-in process is more an art than a science, a concept that cannot be described and only felt. To a rarer few it’s a mythical construct, perhaps held in similar regard to the tooth fairy or the perfect gravel tyre. In this edition of Threaded, I’m here to explain why it’s not only a critical assembly step, but also how easy it can be to do.
A moment of admission. I started writing this article two years ago and quickly became overwhelmed in the science and nuances from differing approaches and materials. Having climbed out of that hole, I’ve come to realise that just doing a basic bed-in is vastly better than none, and so while you’ll get differing approaches, a general quick process will get you firmly into the realm of good enough and safe.
Let’s begin.
The critical bed-in and a strong opinion
Brake bed-in is the process of transferring a layer of pad material onto the disc rotor surface. It’s this transfer of friction material that allows a disc brake to work efficiently and effectively. A proper bed-in procedure ensures a smooth and consistent material transfer.
On the flipside, not performing a dedicated bed-in can result in an uneven surface, leading to inconsistent braking, vibrations, and noise. Also, a brake that isn’t bed-in will offer no power for the first few stops. Ignoring the longer-term issues of not bedding in brakes, this lack of initial bite can present a dangerous scenario.
I’m strongly of the opinion that a basic bed-in should be done as a purposeful task that isn’t left to do during a ride where the process will almost certainly be compromised or ruined. I’m equally of the opinion that it should be considered part of the initial bicycle assembly or service, and that a build/repair is incomplete without it. More on this specific matter later on.
In addition to being quieter, more consistent, and often longer-lasting, a well-bed-in brake is significantly more powerful, with brake sensor creator BrakeAce seeing braking power doublefrom start to finish during the procedure.
While there can be nuanced differences between what each brand recommends, the bed-in process is largely consistent across all disc brake systems, whether that’s hydraulic or mechanical, from Shimano, SRAM, Campagnolo, Magura, TRP, Hope, Hayes, or just about any other brand – across mountain, road, gravel, and commuting bikes.
Before you begin, a brake bed-in needs to be done when everything is still brand new. It’s also recommended that you do a bed-in whenever changing brake pads and/or rotors. It’s a rabbit hole I want to avoid, but it’s worth noting that all brake manufacturers recommend against switching brake pad material (say from organic to metallic) without also changing the rotor.
As the pad friction material is bedded into the rotor, it's advised not to switch pad materials. More on this later.
And now for the quick safety notice. A topic like this assumes some level of mechanical know-how and a more than beginner riding level. If in doubt, consult a professional.
Step one: Clean everything
To conduct a proper bed-in, it’s essential to begin with a fresh and clean system, one that’s correctly set up where the brake pads are evenly and squarely contacting the rotor. It’s also important to check that the brake is free from any defects, such as leaks from the caliper pistons or hose.
Clean is a word often used whenever discussing disc brakes, and unfortunately, new doesn’t necessarily mean clean. Chris Yankopoulos, a Shimano technical representative in the USA, often instructs dealers to clean brand new rotors, whether installed on a new bike or in aftermarket packaging, prior to use. It’s a tip that Boulder-based mechanic Colin Williams often shares on Instagram, too.
Cleaning a rotor doesn’t need to be complicated. I recommend the use of isopropyl alcohol and a fresh piece of paper towel (Scott’s Shop Towel is the GOAT). Most often the paper towel will come up clean, but occasionally, you’ll see how dirty new rotors can be.
Avoid the extremely harsh automotive brake cleaners. Rather a product like isopropyl alcohol is the common suggestion.
While rotors need to be cleaned, the brake pads should already be clean and ready to use from new. That said, for years I’ve taken a quick step to surface the pads in a way that I feel helps reduce the time of the initial bed-in. This optional step consists of taking the pads in your hand, spraying/splashing some clean water on them, and then rubbing them together until you feel them go from slippery to gripping. I’ll then spray some more water to rinse off the slurry, and I’ll then install them into the bike.
Rubbing two pads together with water. I find this quick step helps to cut down bed-in time.
If it’s an old existing rotor and you’re just replacing the pads with a matching compound, then a quick rinse of the rotor with water and wipe with isopropyl alcohol is sufficient. For example, John Hall, the former mechanic to World Cup downhill racer Aaron Gwin, explained, “I avoid replacing rotors for as long as I can. The more pad material built up on a rotor without being worn out or contaminated the better.”
Step two: Smoothly does it
Bedding in a brake is a matter of repeatedly and smoothly applying stopping power at the lever. This process, and the heat that it creates, helps the pad material deposit onto the rotor and you’ll progressively feel the braking power become more effective. The initial step below is something that comes recommended from pro mountain bike mechanic (currently head mechanic of Specialized Off-Road Racing) and voice on the Geek Warning podcast, Brad Copeland:
1. Find a level or light gradient road without traffic, an empty parking lot is perfect
2. Gently pull one brake lever with a consistent light force
3. Now ride around against the consistent force for approximately 20-30 seconds until you feel the braking begin to resist your pedaling force
4. Repeat with the other brake
This process will safely get some power into the system and reduce the risk of overzealous brake inputs for those new to the procedure. In doing this take care not to lock or skid the wheel, which can create an unwanted inconsistency on the rotor.
Now it’s time to increase the speed to a moderate level.
Step three: Harder braking
Now we get to the next step, a process that most manufacturers outline and typically agree upon.
5. Remain in that level or light gradient road without traffic
6. Accelerate to approximately 25-30 km/ph (15-18 mph)
7. Smoothly and softly pull one brake lever until you decelerate to a walking speed
8. Repeat 10-20 times
9. Now do the same for the other brake
10. Catch your breath and grab a well-deserved drink
While doing this, it’s important not to brake heavily, come to a dead stop, or skid a wheel, which may unevenly deposit material on the rotor.
“The key is getting enough heat into the rotor and pad in order to evenly distribute material onto the rotor,” explained Aaron Pelttari, the former mechanic of pro downhill racer Troy Brosnan. “People use water and all kinds of tricks, but at the end of the day, you just need pad material on the rotor. Do it slowly and it’s sweet, do it fast and it’s not so sweet.”
Why the flat ground? As Peltarri notes, “too much heat is a concern." For example, dragging the brake for an extended period of time down a big hill can glaze the rotors and pads. This is why it’s important to do it moderately and with moments of cooling between.
In my experience, it’s quite normal for bikes with smaller rotors and organic pads (such as most road and gravel bikes) to feel good in braking power after 5-7 repetitions. Bigger brakes on mountain bikes, and those with metallic brake pads, will require more heat and therefore effort. I’ll repeat the process above until the brake feels effective and there’s no further noticeable improvement with additional repeats. Personally, I’ve found that’s often around the 10-repetition mark, and that 20 is typically overkill.
Bigger rotors and metallic pads will require more heat and effort.
It’s worth noting that at this point I consider a basic bed-in to be complete and that the brake is now safe and suitable to hand over to a customer. However, there may be more power in that brake to eke out if you so wish.
Reaching full power
Now the optional extra for those who want maximum power. I don’t consider this part of the process to be a must-do, and in fact, it’s common for professional mountain bike mechanics to stop at the previous stage of the bed-in, and rather have the athletes complete some hard braking on the first practice lap or two in order to emulate this final bed-in stage.
Still, if you want full power before your first ride, then continue with the following. Just be warned that your brakes will be reaching full power and so braking skill is required to not hit a sudden stop, skid, or even crash.
11. Stay on that level or light gradient road without traffic
12. Accelerate to approximately 25-30 km/ph (15-18 mph)
13. Firmly pull one brake lever until you quickly decelerate to a walking speed
14. Repeat 5-10 times
15. Now do the same for the other brake
16. Do a sweet front manual with your newly bed-in brake to prove you’re excellent at this
According to pro mechanic Colin Williams, if the bed-in procedure is done correctly, “you should feel the brake go from almost no power during the first few decelerations to full power by the end.”
Resetting an existing brake for bed-in
Ok, so you’ve only just learned about brake bed-in and want to fix those noisy and pulsing brakes. It can be done, but expect varied and compromised results. And while not recommended by any brake manufacturer, the following approach can also be attempted if switching pad material on an existing rotor.
The goal here is to resurface both the pads and rotors so that you can transfer a new and hopefully more consistent layer of pad material. Like anything, there are countless ways to achieve this, but a sheet of approximately 60-120 grit wet-and-dry (aka sandpaper) is typically sufficient. A sanding mesh sheet is also popular for this task as it resists clogging up.
Before I go further, it’s worth noting that brakes which lack bite or make excessive noise may simply be contaminated from oils, solvents, or themselves (brake fluid leak). I won’t detail how to solve this, but please be aware that a bed-in may not be the solution if you’re experiencing this issue. As always, if you’re unsure, I recommend seeking the help of a professional. Ok, back to the resurfacing.
Start by removing the brake pads from the caliper. A shiny braking surface means a glazed brake pad. Also look for uneven signs of wear which may point to a larger alignment or setup issue. Place the wet-and-dry on a flat surface, such as a bench top. Now rub the pad (braking surface side) on the paper (dry) until there is a consistent and matte-like finish. Repeat with the other pad.
The pad on the left is freshly resurfaced. While the pad on the right is half-way done, still showing some glazing in the centre.
Over to the rotor. Now is a good time to clean the rotor with isopropyl alcohol and a piece of paper towel. Continue until the paper towel is no longer collecting dirt. Now cut a small square of that wet-and-dry, just large enough that when folded in half it covers a section of the rotor’s brake track. Fold that squre over the rotor and run it over the full circumference of the rotor. The goal is remove the previous bedded-in brake pad material and lightly scour the surface. Try to move around the rotor with even effort. Finally, give the rotor another clean with the isopropyl alcohol and paper towel, making sure it's free of residue.
Just remember that rotors, like brake pads, are also a wear item. Once they';re worn below the minimum thickness they're ready for the bin.
If all has gone well, and it’s not a contamination issue, then you’re now ready to return to Step 2 above.
Cool article that includes legendary bike mechanic Colin, best mechanic to ever work on my bikes.
This article is the difference between brakes that work and brakes that work to their fullest potential. Honestly it takes a small amount of time for better braking.
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Some people just like the long way
Steve Vai
Endurance Guy: Tolerates most of us.
Would take Magic 4-hours to do a loop at 6-Mile 😂
Magic
Formerly 1sh0t1b33r
In 2014 it has a half day affair with friends.😂
I think that included replacing a bridge.