Shimano "Small Hands" Road Bike Disc Brake Bleed Block (R7020 and others)

thingiverse

Shimano "Small Hands" Road Bike Disc Brake Bleed Block (ST-R7020 and others)Problem: Free stroke adjustment is not available on midrange shimano hydraulic road and gravel components, such that the brake pressure point might be undesired, sometimes too close to the handlebar, especially if "reach" was set for small hands.Solution: Using this block to bleed your disc brakes instead of the original 10mm width/thick block can help adjust ST-R7020/BR-R7070 and similar brake/lever combinations (GRX 400, 600) for an earlier pressure point. Only risks are: 1. Fresh brake pads might rub on the disc initially. I will try to come up with good default values for that. 2. I do not know what other risks come with slightly "overfilling" disc brakes with too much mineral oil. It works for me, but you act in your own responsibility. This is a HACK.Results from my Tests:9.8 (new assembled bicycle, with Shimano brake pads and brake disc installed) - seems to have a minor improvement over the 10.0 bleed block, maybe about 5mm less free stroke.9.0 was too much for brand new brake pads, the disc could be barely pushed between them, so would constantly rub on them9.5 still left quite some spaceI used 9.4 and later brought it to the bicycle shop without telling details, just to ask what they think about it. They told me I overfilled them and while they understand what I want to achieve, they think that could damage my brakes. Not sure if that warning was warranted.So I can't say if that is really safe anymore, even if here in this text I previously recommended 9.4. - But anyhow, a bit can't hurt, right? So I would currently recommend 9.6 if you still want to be safe.Using this bleed block you can 100% reproduce the cumbersome process described in the following video, and at the same time it will hopefully stay over the lifetime of the brake pads. The process described in the video will never help when the brake pads wear down, since it is just based on the autoadjust feature. I hope it will work when already using a smaller block while bleeding (I will give updates while riding the bike and wearing down my brake pads). Video: https://www.youtube.com/watch?v=thGBWhfIaB8 Here is a video to understand what the free stroke adjustment actually does: https://www.youtube.com/watch?v=DXqEJ7_P3Z8 - in short, push in the brake actuator more per default.Longer version with longer explanations:Shimano brake levers typically have a "reach" and a "free stroke" adjustment screw. The reach adjustment brings it closer to the handlebar, while the free stroke can define the pressure point of the lever to be closer or further away from the handle bar. For some reasons, Shimano does not have the free stroke adjustment on at least ST-R7020 ST-R7025 ST-4720 and ST-4725.That means, when you have really small hands and adjust the "reach" to the max, it can happen that the actual brake pressure point is too close to the handlebar or almost touch it (on brand new brake pads it's ok, but it will be bad pretty quickly). Even if the brakes were correctly bled with the Shimano bleed block!I am not sure if a different lever with the "free stroke" screw is the best solution to be able to get the stroke adjustment (Ultegra, GRX800+, ..). But it's at least a lot of effort and cost to change the lever. A simple solution might be to use this modified bleed block instead of the original one. When using this modified block, it allows to overfill your hydraulic to a certain extent, hopefully as if the free stroke screw was already screwed in somewhat.I did this with some improvised tool where I can't tell the exact thickness. I did NOT YET test this specific 3D Model, but will do it very soon. I will try to come up with a good default thickness (body_thickness variable). In the meantime you can customize this value right here on thingiverse when clicking on "customize".Please keep in mind, this is considered a HACK. Using this modified bleed block is your own responsibility. I can just say that using a smaller thickness than 10mm helped me personally to get the brake point earlier even on my levers that do not have the "free stroke" adjustment screw. I could even go down to 9.4, but in that case my bicycle shop told me on the next maintenance that at least my rear brake was overfilled, and that it isn't good - not sure if they are actually right!Remixed - attribution to original creators:renschler: https://www.thingiverse.com/thing:4837781PhyMaus: https://www.thingiverse.com/thing:4394992