[MooseLoad]

I am getting ready to put on my stainless lines up front and a buddy of mine is telling me to go with DOT 5.1 instead of the DOT 4. Any pros or cons to this? Will it really make a differance? I figure since 4 is what the bike calls for it was a no brainer until talking with my buddy....
Thanks

 

[Hammer 4]

Motul RF600.......

 

[Ibidu1]

Stay FAR away from dot 5, that stuff is sillicone. If its in there long enough it can gum up. DOT 4 is more then plenty good

 

[twistandpiss]

Stay FAR away from dot 5, that stuff is sillicone. If its in there long enough it can gum up. DOT 4 is more then plenty good

Yes stay away from 5, but 5.1 on is not 5. The 5.1 one is fine.

 

[markbsae]

Sillicone brake fluid has a tendenct to swell the seals in the calipers really bad. Dot 4 is fine unless you are Mat Mladin.

 

[MooseLoad]

Thanks guys....sounds like 4 it is. I was planning on the Motul, so its good to see that gets a thumbs up as well.

 

[SVS]

Sillicone brake fluid has a tendenct to swell the seals in the calipers really bad.

Yeah, but that's still Dot 5. 5.1 is basically just a better Dot 4, with a higher boiling point.

5.1 is directly interchangeable with 4 and will not hurt anything but it'll really only make a difference on the track. Even if you're not Mladin, it keeps the brakes from fading longer and it's not much more expensive than 4...

 

[Jon no h]

I used 5.1 before. Definitely good feel, but it took a toll on all my rubber caps (the ones under each of the covers for the brake fluid, front and back). They got deformed so badly I had to replace them. I've been running 4, but might switch back to 5.1 since I plan on doing more track days.

You can't go wrong with 4.

 

[gimpsta]

yep I run motul dot 4.

while i've heard he same thing about the 5 and 5.1 differences compared to dot 4, it just comes down to you.

 

[drtymex]

Hmm, I thought you can't run Dot 5 or 5.1 on the track, and SVS, not so sure that you can MIX dot 4 with 5. I know you can mix 3 and 4 but not 5.

 

[SHWELL]

Never mix the brake fluids.. (My opinion and practice)

I know some can work together, but why take the chance.. Just do the safe thing in this case and stick with 1 or the other,, And what has been said about the 5.1 is true, I have used it and liked it, but went back to 4 because I couldn't always guarantee that my shop would have the 5.1 in stock..

 

[shortround]

never use motul, its the worst fluid i've ever used and its the most expensive. castrol makes a DOT 4 for bikes thats really good but hard to find. the belray super DOT 4 isn't bad either. i had to change the motul in 8 weeks. but i do live in south FLA so that might have had something to do with it. but the belray has been in the bike for 5 months with no discoloration.

 

[ric o'chet]

As DOT 5.1 is more hygroscopic than DOT 4 and therefore absorbs more moisture, it will need to be changed more often. However, the benefit of 5.1 with its higher boiling point, is that it can experience higher temperatures than DOT 4 before it starts to affect braking efficiency. Although, a good quality DOT 4 fluid such as the Super DOT4 which has a dry boiling point which exceeds the 5.1 minimum will be able to contend with the temperature levels it would experience on a track day, for example. The Super DOT4, like the DOT 5.1 will need to be changed more often than DOT4 with the obvious budget implications.

As has been said DOT 4 and 5.1 can be mixed , DOT 5 is different and cant be mixed with anything else.

All the above courtesy of Venhill.co.uk, worth a read if you're interested