What your Mother didn't tell you about Hydraulic Disc Brakes...feat. Crest Tool

Рет қаралды 10,806

Күн бұрын

WARNING...this may result in throwing everything you thought you knew about hydraulic disc brakes right out the window or the uncontrollable desire to furiously argue in the comments. In this video, Danielle goes over TWO of the biggest misconceptions about bicycle hydraulic disc brakes - firmly held incorrect beliefs defended by many a mechanic in the industry including (at some points in history) herself.
Also featured is the Crest Brake Pad Advancement Tool:
crest-tool.com/
Love it or not, it fills a hole that you or your customers might be looking for - and it works!
For UCI Hood Angle tools, Dropper Buddies, and awesome SWAG go here:
www.neutralsupport.net

Пікірлер: 73

@Longtimerolling 5 ай бұрын

I would say this is the best explanation on how brakes work, and contact point adjustment theory on KZfaq.. love ya work!

@NeutralSupportNews 5 ай бұрын

Thanks!

@nickk1658 5 ай бұрын

Hallelujah! I've long wondered what mechanism caused disc-brake pistons to retract, but could never achieve the right Google search combo to find the answer. Great video! So nice to come across such detailed information.

@NeutralSupportNews 5 ай бұрын

Happy to provide some closure!

@zedtony8110 5 ай бұрын

I just adjusted the brake bite point on my bike yesterday by using a woren disc rotor. Worked like a champ Thanks Danielle.

@jagfrediani 16 күн бұрын

Can you please, please, make a video like this for more parts of the bike? I just discovered your channel and I love how you explain things!

@SomeGuyOnHisDreamBike Ай бұрын

I don't understand why I just discover your channel just right now. I love bikes, I love tools, I love to learn and understand. Your channel is amazing. It's fun, clear, interesting (would even say fascinating). if only all teachers in the world had these qualities... The dark side of that is now I am aware that there's not only Park Tool, Enduro Bearing, Abbey, Wheel Manufacturing... so many great tools waaaaaay too expensive for my garage. But I want them all, they are too beautiful and well made... Do I need two kidneys 🤔

@NeutralSupportNews Ай бұрын

I can help with one part of that - you most certainly do not need 2 kidneys 🤣

@belmontst 5 ай бұрын

I’ve only been a tech for 3 years so this is going to be make explaining hydraulic brakes a lot more simple to new bike customers. Much appreciated!

@alanduncan7591 5 ай бұрын

one learns something new every day - thank you Danielle

@CrestTool 5 ай бұрын

Thanks for sharing! Great explanation of how things work.

@pablocarbajo5545 5 ай бұрын

Your channel is pure gold! Just discovered it. Thank you for the the great content.

@NeutralSupportNews 5 ай бұрын

Glad you enjoy it!

@watsonthedog264 5 ай бұрын

just found your channel, every video you make is so well considered and explained! somewhat a-la park tool but without the singular brand product placement. super encouraging stuff, hoping you make it big!

@NeutralSupportNews 5 ай бұрын

Thanks! Trying to maintain that "neutral" part as much as possible

@bicyclerider8218 5 ай бұрын

Excellent video, very informative. This video provides the explanation of how disc brakes works I've ever seen. You're awesome.

@NeutralSupportNews 5 ай бұрын

Glad you enjoyed it!

@Thepelabiker 5 ай бұрын

Thank you for this video, very informative

@ed0078 5 ай бұрын

Keep up the detailed explanations of how things work, concepts are important

@arden0 5 ай бұрын

Best bike tech geek channel going. this seems a lot more reliable than how I'd usually do it - a few half-pulls of the lever with no disc in the caliper. It's a great trick but for me this never worked beyond a ride or two, as your pads wear it will catch up with the piston. And as I'm typing this you note exactly that... anyway, great stuff! thank you!

@NeutralSupportNews 5 ай бұрын

Glad we agree 😜

@FuchsHorst 5 ай бұрын

Great Video! I wish my Magura HS would have a reservoir as it requires regular refilling (every year or so)

@NeutralSupportNews 5 ай бұрын

I was just thinking through if an open system with a reservoir would be able to accommodate the rim width differences and the gaps necessary for that style of brake - I'll have to ask Jude why they chose a closed system next time I see him. Everything is a trade off!!!

@jokermtb 5 ай бұрын

I 3D printed a slightly narrower brake block (9.5 vs 10mm ) to set my pistons a little closer together than stock. I do have to remove the pads to use my ‘narrower’ block

@mtbboy1993 5 ай бұрын

Nothing new to me, but this is well explained. It had to go in my Bicycle brake Maintenance playlist.

@Max-ek6nn 5 ай бұрын

Do you watch every mtb video on the internet? I swear that I’ve seen your comments on every platform.

@mtbboy1993 5 ай бұрын

@@Max-ek6nn I guess we might have same or similar interests. 😜

@jokermtb 5 ай бұрын

The blade spring that separates the pads does more padding retracing than the seals

@NeutralSupportNews 5 ай бұрын

Two different things going on. That spring makes sure the pads stay in contact with the pistons (without it they would wander around and touch the rotor), but doesn't actually put pressure on the piston so that it retracts into the caliper. The same thing is achieved by other brands (like Magura) without a spring between the pads, but instead a magnet that holds the pad against the piston. The seal is what is pulling the piston back into the caliper body.

@jokermtb 5 ай бұрын

I had no idea!~ thanks for the insights@@NeutralSupportNews

@aznwierdone 5 ай бұрын

Is the spring in the lever purely to aid in the lever retracting then? Also if the flex of the seal is causing the retraction, why would a shorter pull eventually push the pads back out? I'm enjoying the videos and eager to learn!

@NeutralSupportNews 5 ай бұрын

From my understading, the spring is to help the lever retract the lever piston past the opening of the fluid port every time to release the pressure from behind the seal. The shorter pull doesn't last because - let's say the seal "flexes" a typical maximum of 2mm, but the new "cheater" distance is only 1mm. It will flex 1mm and retract 1mm, like only partially stretching a rubber band. When the pads wear down 0.5mm, the seal will flex 1.5mm and back 1.5mm, still not at its max but within its capabilities. Then, when the pads wear down to 2mm, it'll flex 2mm because that's the distance it can flex. When the pads wear even more and the distance is 2.5mm (fake numbers), the seal will flex to its max of 2mm, and the fluid will force the piston out an additional 0.5 through the seal to contact the rotor. The seal will retract all the way to - you guessed it - 2mm gap starting right back where we began. It will always eventually self-adjust to the maximum distance the seal can flex.

@ztacos1949 5 ай бұрын

Hi, great explanations! Unrelated to brakes: I built a bike rack similar to what you have in the background at the beginning of this video (0:21). The hooks I used look similar to yours, but mine sag and twist when I put bikes on them. How did you get your hooks so straight? Is there a nut securing the hook on the other side of the 2x4?

@NeutralSupportNews 5 ай бұрын

I've used so many of those hooks it's crazy. No nut on them (they have wood screw threads). I typically drill the hole fairly undersized so there's a decent amount of grip for the threads as they carve their own way - then if I can I tighten the hook all the way to the coating as a little extra deterrent. They don't move so it must work! Heaviest bike on the hooks is in the 30s though - I don't put super heavy bikes up there.

@ztacos1949 5 ай бұрын

Thanks!!

@GokkunGuru 5 ай бұрын

Great video. When I replace my rotors I will need to push the pistons back into the caliper body. Do I need to open the system to do that? If I don’t will that damage any part of the brake? I’ve read about cases where fluid bursts out of the lever port due to pressure.

@NeutralSupportNews 5 ай бұрын

In a properly bled brake that is not overfilled, many times you can just push the pistons back with firm, even pressure without opening the port (since there is already a vent and there should be room in the reservoir to take the additional fluid). If you are feeling resistance, something else is up so opening the bleed port and rebleeding the brake is probably in order. There may be air trapped in the middle of the system that is creating an "overfill" type situation or debris trapped at any of the ports. Fluid forcing its way out is almost always the result of hamfisting when you should take a step back and evaluate 😅

@Surestick88 5 ай бұрын

If the brakes were last bled with new rotors and pads installed this shouldn't happen. When you bleed your brakes in between pad or rotor changes you're essentially "overfilling" the system and you can force fluid out of the system if you try to push the pistons all the way back into the calipers. It's really not a big deal as you can just open the bleed screw on the lever and use a rag to catch the excess fluid as you push the pistons back into the caliper.

@tedwingate 5 ай бұрын

Can you now explain Shimano XT wandering bite point and pump up, because it seems a lot more involved than, "improper bleed".

@NeutralSupportNews 5 ай бұрын

Typically, it is air in the line. Air compresses, brake fluid / mineral oil doesn't. So my understanding is: when you "pump up" the brakes, what you are actually doing is compressing the air trapped in the system and allowing more fluid to back fill from the reservoir as that space is created. That makes the brake feel good suddenly because the space is taken up. Then, when the brake lever sits open, the compressed air in the line actually pushes the fluid back into the reservoir (since the port is open when the lever is open). That's why the first pull or two is soft, firms up as you compress it, and then eases back as there is no pressure on the system. The air could come from a bad bleed, or a leak somewhere, or low fluid in the reservoir. But it is typically air.

@BalintPeter4 5 ай бұрын

awesome explanation! made me curious if it is healthy to simply push back the seals when you get a new, wider rotor?

@NeutralSupportNews 5 ай бұрын

Seating the pistons back into the caliper through the seals is a completely normal thing to do in general maintenance, new pads, new rotor etc. They are designed to let the piston slide under a certain amount of pressure. You just have to be careful not to damage the piston or put too much force. Otherwise totally fine.

@BalintPeter4 5 ай бұрын

@@NeutralSupportNews Thank you for your answer! I'm happy to hear that

@charliesullivan4304 5 ай бұрын

I'm trying to follow your advice to understand things thoroughly but I think I'm going to need a higher resolution version of the diagram at 1:08

@NeutralSupportNews 5 ай бұрын

🤣 Just your average full internal routing through the upper headset bearing...

@DaveReedDR 5 ай бұрын

Would it work to reverse this tool and essentially make a trimmed down bleed block that would allow for a touch more fluid during the bleed? That way you'd heve the pistons slightly more out to start but they wouldn't retract all the way back in making this "fix" more permanent?

@NeutralSupportNews 5 ай бұрын

I thought the same thing initially, but since the seal flexing is the only thing actually controlling how far the piston retracts - pad wear will reset the distance no matter what (unless you bleed it again which will essentially be doing the same thing as the tool). Overfilling will work temporarily just like the advancement of the piston. I also initially thought it would be a good idea to top off the reservoir to avoid additional air space - the only caveat to that would be that when you needed a full piston reset you would need to open the reservoir to allow the excess to escape to fully set the pistons back.

@DaveReedDR 5 ай бұрын

Ahhh yes that makes total sense actually, thanks!

@StanEby1 5 ай бұрын

Brilliant. Wow!

@namdarbolour9890 3 ай бұрын

Seems like a waste of time and money to me. If the change is only temporary, what's the use?! As you mentioned yourself, I think, the system reverts to the stock designed-in pad clearance after some use. Did I miss something?

@NeutralSupportNews 3 ай бұрын

Finite gains only affect the few - I likely wouldn't do this to a normal customer's bike but for those massively concerned with bite point on unadjustable levers (think racers) this would be the only option. I understand not wanting to switch to one of the very few options of brakes just to get bite point adjustment. Never been this particular about my brakes, but understand the appeal for those that are! The adjustment stays for a decent time, until the pad wears down. Not likely to be a single ride etc. but might be quick if you're running DH or something 😁

@oreocarlton3343 5 ай бұрын

Hood angle measurement tool? It measures the angle of your hoodie?!

@NeutralSupportNews 5 ай бұрын

I'm sure it could measure lots of things, but the intention is for the UCI to save your life from the perils of angling your road shifters inward too far

@nlmaxgaming1 5 ай бұрын

Park Tool has a great video about brakes: 'How To Clean Hydraulic Brake Pistons - Tech Tuesday #104'

@cosinus_square 5 ай бұрын

well, on non adjustable hydros, one can start with a thicker rotor to begin with.

@NeutralSupportNews 5 ай бұрын

Yep! The nice thing about the tool is you are adjusting at a 0.1mm rate per pad so you can do it on just about any rotor, and adjust it as the pads wear even slightly. The gap with the thicker rotor will just return to the normal gap created by the seal, so your only option would be to replace the pads early to get back to the braking you liked. It's all about how important this is to you 😅

@EMTBAFV 5 ай бұрын

You can 3D print this tool I've got one in tool box

@josephphillips865 5 ай бұрын

This is race mechanic stuff.

@mtbboy1993 5 ай бұрын

5:43 And then there is Shimano Deore brakes where the reach adjustment effects the power, as you can't press the piston far enough in for the brakes to go past barely touching the rotors when adjusted for short fingers. This is due to the adjustment of the reach being on the Servo Wave mechanism. Absurd. So this tool won't help with this. Simple answer is Don't buy these brakes!

@NeutralSupportNews 5 ай бұрын

Odd choice for sure! Reach should be wholly separate from actuation.

@ReZG 5 ай бұрын

Have mercy, there is a screw on the lever for this very purpose! just use it!

@NeutralSupportNews 5 ай бұрын

I guess I should have thrown in a note about the difference between reach adjust (just moving the lever distance from the handlebar with the screw but keeping the total lever travel the same) and contact point adjust (reducing the distance the lever travels in total, not the distance from the handlebar - what the video is talking about). If someone just wants their reach to be longer or shorter, by all means just use the reach adjustment screw on the lever 🙂

@s31720 5 ай бұрын

I don't understand this at all. The seal does not work in exactly the same way as the spring in a derrailleur. It adjusts to the wear on the pads and the pistons do not return to their starting point, they move out. So it would appear to be a "closed system" to some extent as this is decided by the amount of oil in the main system (as it trickles down, as pads wear, from the resevoir). This being the case, I don't see the point of your fancy crest tool at all. If it is to make up for worn discs, merely place the calliper over the disc in question, squeeze the brakes a few times and the callipers move in.

@phillstrader5305 5 ай бұрын

The point of the tool is to adjust the actuation distance of the brake lever

@NeutralSupportNews 5 ай бұрын

I held those misconceptions about the purpose of the seals also before getting into some lengthy conversations with brake experts over the last month 🙂 Good luck on your journey! 🤘 (And it is indeed a lever pull adjustment tool, I didn't make it but it does what it advertises to do!)

@boxsterpontus 5 ай бұрын

If you ask you granddad how car brakes works, he would tell you this exact same thing. If he was a car mechanic.

@NeutralSupportNews 5 ай бұрын

Tale as old as time or something to that effect 😁

@owenanstey436 5 ай бұрын

Ace

@gob8056 5 ай бұрын

thanks for blowing my eardrums as soon as i clicked the vid

@a8f235 5 ай бұрын

I understand the desire to adjust to one's liking, but isn't this only going to make the brakes rub at the first attempt of turning the wheel? Personally I own the Birzman brake piston pusher(to avoid cracking ceramic pistons as well as easier and quicker way to push pistons back) and that thin metal "clam" you place between your pads and rotor in an attempt to avoid pad rub during adjustments. Now with this video it at least looks like it is going the other direction and that's why I just did not feel it was evident how to avoid pad rub if you use this tool. My M8100 brakes from Shimano have reach adjust and freestroke, and even from day one I have not had the bitepoint far enough out as I like it. I've heard Shimano have deliberatly tried to go against what they used to be known for with a socalled not modular feel, when they went in on the 4-piston caliper train(I got the M8120 calipers btw) This is why I've just been a bit on the fence about my brakes since I got my new bike 1.5 years ago. They do work, but they just don't have the confidence I'd expect from brakes in this pricerange. I really want the bitepoint to come as early as possible and socalled modulation just simply demands less effort. I have the icetech rotors as well as the finned pads, and thought it might be good to just try something different as well as a service(which I will be doing for the upcoming season anyhow) but I'm still curious about the actual value of the tool you are showing here, because I have maxed my reach adjust as well as free stroke so no more adjustments, and I'd like to sit somewhere in the middle so I actually have adjustments available for when I should need it.

@NeutralSupportNews 5 ай бұрын

The tool moves the pads inward at a rate of 0.1mm per side (about the thickness of a sheet of copy paper) - most properly bled brakes have that amount of free space to give. If you go too far or have a warped rotor, you'll definitely find it difficult to adjust the brake to clear. In the example, the first adjustment would have cleared fine but the second where I had advanced the pads 0.2 on each side would not have. Feasibility depends on your starting gap! Crest has some great instructions and tips on their website that briefly address rubbing - if you go too far it will definitely rub.

@a8f235 5 ай бұрын

@@NeutralSupportNews Ok, I'll do some research on this. Willing to try new things as long as it makes sense.