The principle here is exactly the same and since you can obviously mix shimano and other brands it stands to reason the fluids are all the same!
Being compatible doesn't mean the fluids are the same. It's possible that seals may react with non-spec fluids and cause problems. To me, it's just not worth the potential issues given that a liter of Shimano fluid isn't really that expensive.
The big issue is warranty. If you use a different spec fluid and then send the brakes back under warranty, Shimano would be within their rights to refuse a warranty claim. Putting in some green or blue coloured oil is just asking for a warranty rejection.
Mineral oil is mineral oil is mineral oil. Spec sheets are there for a reason, as long as the specs match it makes bugger all difference what name is on the bottle or what dye pack has been added to the oil.
The issue with mineral oil is that there isn't a standard. DOT fluid is made to standard that is literally in its name. There isn't the same system for mineral oil.
I've used LHM and various brands over the years. Can't say I've noticed much difference but I have had zero issues since using pink shimano fluid so its easy to stick to that for the small cost difference for me.
Mineral oil is mineral oil is mineral oil. Spec sheets are there for a reason, as long as the specs match it makes bugger all difference what name is on the bottle or what dye pack has been added to the oil. Magura have been quite explicit on this in the past, they sold HS33’s for touring based on the fact they will run on anything and you can use water in a pinch. The principle here is exactly the same and since you can obviously mix shimano and other brands it stands to reason the fluids are all the same!
Point of curiosity, do all of you who only use manufacturers oil apply the same principle to whatever Castrol/Total/whatever oil is named in the user manual and only fill up with whatever petrol is advertised inside the filler cap?
My van doesn't state the warranty is void if I use a different make. (Not that its in warranty)
My van doesn’t state the warranty is void if I use a different make.
No, but you need to use an oil that is certified to the specified performance level. If you put cheap rubbish oil into a high-performance turbo engine, it will trash the engine and you won't be eligible for a warranty claim.
https://www.api.org/products-and-services/engine-oil/eolcs-categories-and-classifications/latest-oil-categories
DOT brake fluid has a system like that (DOT 3, DOT 4, DOT 5.1), but mineral oil brake fluid doesn't.
Just spend £20 on a litre of the Shimano stuff and never worry about it ever again. Even with 5 sets of Shimano brakes in our garage, I am not even half way through the bottle in 4 years! I suspect the bottle will still be on the shelf when I'm long gone 🙂
Being compatible doesn’t mean the fluids are the same.
Umm, it kind of does. How else do you mate a Hope RX caliper to a GRX or whatever lever if the seals are different and require different fluids?
It’s possible that seals may react with non-spec fluids and cause problems.
Whilst true, what makes you think Shimano use some sort of proprietary seal composition? They don't, they're industrial seals bought in bulk because the alternative is horrifically expensive. The only mineral oil likely to muck them up would be shock oil with seal sweller additives. As long as it's a similar viscosity and doesn't have any weird additives then it should work fine.
But you do you, if you want to pay over the odds for branded fluid to match every system you own batter in, if you want to use Mobil DTE Light for everything then feel equally free.
No, but you need to use an oil that is certified to the specified performance level
But the manual says Castrol 🤔
DOT brake fluid has a system like that (DOT 3, DOT 4, DOT 5.1), but mineral oil brake fluid doesn’t.
Why do you suppose that is?
My van doesn’t state the warranty is void if I use a different make. (Not that its in warranty)
No. But Shimano do, and its their warranty.
Being compatible doesn’t mean the fluids are the same.
Umm, it kind of does.
I don't think it does. Most people would understand "compatible" to mean the different fluid will work acceptably for a reasonable time, not that it's the same stuff with a different logo/colouring.
I've had the same litre bottle of Shimano red stuff since forever. Seals on my various brakes never leak so I almost never need to bleed. I think I've used more on friends' bikes than my own. Think I paid about £6 for the bottle.
Seals on my various brakes never leak so I almost never need to bleed.
Your fluid must be like treacle. Ahimano brakes run dirty IME.
If it tasted that good I'd go through it far quicker.
jairaj
Not in my experience! This was from around ~2010 ish so things maybe different now. But I found it to create a very wooden / dead feeling lever and increased resistance. Don’t know if the seals and gaskets reacted incorrectly to the oil or what but the brakes were not same after that.
I always use Shimano or Shimano compatible oil. Epic bleed do their own brand stuff that is Shimano compatible, Halfords do Shimano compatible brake oil. etc …
Same problem here, it's not worth the saving IMO.
I don’t think it does. Most people would understand “compatible” to mean the different fluid will work acceptably for a reasonable time, not that it’s the same stuff with a different logo/colouring.
Then most people would be wrong. By your logic water, urine and buckfast are all compatible brake fluids for mineral systems.
As an engineer I can assure you that your definition is wrong.
I don’t think it does. Most people would understand “compatible” to mean the different fluid will work acceptably for a reasonable time, not that it’s the same stuff with a different logo/colouring.
Compatible doesn't mean identical. To me, it mostly means that it won't damage the system, but it may not perform to the same level. Water is compatible with both DOT and mineral oil based brakes. It will work well enough to get you home in an emergency and won't cause any permanent damage, but it won't perform as well as the proper fluid. Urine is probably not compatible with any brake system, but would probably get you home in an emergency and not cause damage if you flushed it as soon as you got home.
Then most people would be wrong. By your logic water, urine and buckfast are all compatible brake fluids for mineral systems.
That isn't my logic. You responded to "Being compatible doesn’t mean the fluids are the same" with "Umm, it kind of does" - which I was disagreeing with. I have no idea whether water, urine and buckfast are all compatible brake fluids for mineral systems as I have 2/3 of a tub of treacle to use. Mmmm, treacle.
Really?
compatible
adjective(of two things) able to exist or occur together without problems or conflict.
https://www.google.com/search?client=firefox-b-d&q=compatible+definition
Yes really, compatible doesn't mean "the same".
