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evening all,
just a quick one.....my guides need a bleed and I need fluid. Is all dot 5.1 equal? Thinking about picking up a bottle from car parts place like gsf or something as it works out much cheaper an bike stuff. What is the consensus? A good idea or not? Only thing I was wondering about is a big bottle from a motor factor might spoil after being opened, so ideally need a smallish bottle rather than an industrial one!!! Thoughts please....
Yes, any 5.1.
I prefer motul rbf600. Beats the spec of 5.1 in most categories. I think it was viscosity that stops it being classed as a 5.1
I think the only thing with a higher wet boiling point is the 660 version but that only comes in 1 litre bottles so seems a bit wasteful.
+1 for RBF600. 660 is good, but absorbs water much more quickly, good for racing/trackdays etc when you bleed all the time. If you dont need it I would stick with a more normal fluid.
Have you had issues boiling the stock 5.1?
Thanks guys. No, not had any issue with 5.1, just looking for cost effective ways to up and seems much cheaper to buy motor grade stuff than mtb specific. What's this rbf600 all about then? New to that one.....is it compatible with 5.1 brakes like my guides then? Worth a look....
You can mix DOT 3, 4 and 5.1. The minimum specs for the higher dots have higher boiling points, but the manufacturers can exceed them. DOT 5 is silicone based and cant be mixed.
RBF600 exceeds 5.1 standards except for viscosity at -40
If you have not had any issue I would just buy whatever 5.1 is avaliable. I upgraded when I was boiling brake fluid so have lots of bottles of fancy stuff to use up.
http://www.mossmotoring.com/brake-fluid-tech/
http://www.eurol.com/en/37-products/1952-eurol-brakefluid-dot-4-lv.html
FMVSS116
"Brake fluid means a liquid designed for use in a motor vehicle hydraulic brake system in which it will contact elastomeric components made of styrene and butadiene rubber (SBR), ethylene and propylene rubber (EPR), polychloroprene (CR) brake hose inner tube stock or natural rubber (NR)."
https://www.gpo.gov/fdsys/pkg/CFR-2012-title49-vol6/xml/CFR-2012-title49-vol6-sec571-116.xml
I use halfords 5.1 in hopes and halford LHM in shimanos / tecktros. Never had the slightest issue relating to fluids
RBF600 here, mainly because I get it for free from a Motul sponsored friend (although will be on to RBF660 when this bottle runs out as that's all he had last time I liberated it from his garage)
Halfords and motorbike focussed places often have 250ml bottles so you don't have so much waste.
Have you had boiling issues in the past? High end fluids are grand but it's basically a hurdle, there's no significant benefit if your current fluid works. (though, a high wet boiling point can be an advantage if you're a lazy mechanic- basically means that once the fluid is old and knackered it works better)
I use the wee bottles of Halfords 5.1, they're a sensible size for bike use and it works grand, never had a hiccup even while coward-braking the entire way down fort william 😉 I kind of feel like brake heat is a problem that's well and truly solved in pushbikes, even my decade-old Formula Oros were up for anything so if you need posh fluid, finned pads etc it's not because of heat, it's because your brakes suck.