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Barkit mikelevy's article
Aug 15, 2017 at 4:27
3 days
Prototype Hayes DH Brake - Crankworx Whistler 2017
@b-wicked: You can also observe that with Formulas. I yet have to see this phenomenon occur with mineral oil-based brake systems though. I thus hypothesized that, as you said, since it appear mostly upon long storage time (typically in a wet environment like a garage), the hygroscopic nature of DOT makes it slowly trap ambiant water in the brake system. This in turn results in overfilling the reservoir (unscrewing the bleed screw you realize the system is almost systematically under pressure when you get this problem) and thus the luquid will be pushing the piston toward the disc ultimately resulting in locking the wheel. At this stage a full system bleed with fresh liquid will solve the issue, the old liquid probably has a significantly lower boiling temp. DOT brakes with bigger reservoirs seem to not suffer from this issue (or at least it'd require much more storage time). Typically, I observed that brake system affected by this problem suffer also from the disc locking issue when exposed to direct sunlight in summer (notably those painted in black) due to heat expansion of the brake fluid. This tends to confirm that reservoir size is too small by design in those brakes and as such any change in fluid volume will quickly result in moving the pistons to lock the wheel. Just my 2 cents...
Barkit mikelevy's article
Aug 13, 2017 at 2:49
Aug 13, 2017
Prototype Hayes DH Brake - Crankworx Whistler 2017
@Powderface: Mineral oil can indeed be found everywhere for cheap. And surely you could use it in your brake. But I would definitely not recommend using Magura oil in Shimano brake or the other way around, not even speaking of mineral oil oil you can find at the supermarket... Mineral oil properties are well known, but I doubt the composition of Shimano or Magura oil is as well defined and controlled as DOT is. Shimano and Magura oils are both proprietary formulations. Ok fair enough DOT is toxic, as is mineral oil. I wouldn't drink or live any of those two on my skin anyway. So yeah, I'll give you that one if you were to make a scale of toxicity.... People using the argument "DOT sucks because it's toxic" just fail to see mineral oil is a nasty stuff. You should definitely check how a brake performs once oil is contamined and chemically denatured due to lack of servicing... I do not pretend to be an all-knowing expert and I'm always willing to learn from anybody proving me wrong but regarding mineral oil seal compatibility with grease, I yet did not find any information about a mineral brake caliper grease that is proven to not cause seal swelling. I'm a bike mechanic, so I tend to back these things up from experience ;). I do my best to improve my knowledge, so if you where to have solid information please share it.
Barkit mikelevy's article
Aug 12, 2017 at 23:27
Aug 12, 2017
Prototype Hayes DH Brake - Crankworx Whistler 2017
- DOT can be found anywhere for cheap - DOT properties such as composition, lifetime, boiling point are well known due to its use in motorized vehicles and is strictly regulated. - DOT mixes with water - which is actually and advantage. Indeed, over time water gets in the brake system (hoses are always a bit porous, and water can also get in via the reservoir) and INCREMENATLLY decreases the boiling point of the fluid. With mineral oil, due to its hydrophobic nature, water will seat at the worst place of the system: the caliper thus drastically decreasing the boiling point locally. A friend of mine had some really bad surprise with Shimano brakes because of that... - contrary to common belief, DOT is nowhere more toxic than mineral oil-based brake fluid. - due to its hygroscopic nature, DOT can be washed with water while mineral oil needs use of degreaser. - a proper servicing of DOT brake piston seals can be made with commonly found caliper silicone grease while grease compatibility of mineral-based brake seals remain very obscure. - any mineral based brake fluid is proprietary and its composition remains elusive. - Usually DOT-based brakes will tend to start to perform poorly if service intervals are not respected (which in my mind at least is an advantage) while mineral oil-based brakes can usually "work" (in appearance) when the fluid turn like sewage. This makes mineral brakes somewhat dangerous because they seem fine when unserviced while they aren't. - I could probably find other advantages but I'll stop there...
Barkit jamieridesbikes's photo
Aug 12, 2017 at 11:39
Aug 12, 2017
Meanwhile in Great Britain... Edit: Ha! just figured it was in Morzine. You're sending it dude BTW, cool pictures.

Barkit rasoulution's article
Aug 8, 2017 at 14:10
Aug 8, 2017
5 Things We Have Learned in Mont-Sainte-Anne
That save was unreal. I literally had to pause the vid and watch frame by frame to understand how on earth she did that. Mad.
Aug 7, 2017 at 12:24
Aug 7, 2017
Barkit brigand's photo
Jul 28, 2017 at 10:52
Jul 28, 2017
Tricky slippery sketchy yummy.

Barkit dragonaut's photo
Jul 24, 2017 at 8:06
Jul 24, 2017
Ha! Got one in my backpack, very useful.

Barkit DoyenUK's photo
Jul 15, 2017 at 13:50
Jul 15, 2017
Amazing work, very impressive.

Jul 3, 2017 at 14:57
Jul 3, 2017
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