[subiedude09]

Hi all, i did search this a little on this forum with no success.....I see that A LOT of racers/street riders use Motul RBF600 for brake fluid. My question is, has anyone used Motul's Racing RBF660 brake fluid? As far as I can see with a quick google search, the only difference is that it has a higher boiling point compaired to rbf600 (rbf660: 617F / rbf600: 594F). Both brake fluids are dot4.

I purchased a bottle from my local performance shop and am going to do a brake fluid flush in the front and rear soon. This performance shop use's RBF660 on all there high performance cars (500+whp) and RBF600 on everything else.

If anyone has used this fluid before, is there anything positive, or negative you would say about it? I get a great deal on motul products through this shop (i am very good friends with the owner) so the price of rbf660 isnt a problem, becuase i know its overly expensive for brake fluid. I actualy paid abouit the same amount most people pay for rbf600 . I also picked up motuls chain lube, and 300v. This will be the first time i will be trying there chain lube as well...

 

[subiedude09]

Has ANYONE ran rbf660 before?

 

[RedAndBlack]

Are you racing? Seems like overkill if it's priced a lot higher. I do track days and drive agresively and haven't seen the need to go with anything higher than some of the other trusted brand stuff. I guess if you're doing racing and worried about brake fade, but then at that point you should probably get a master cylinder and steel braided line upgrades and be changing your brake fluid more often.

 

[PainfullySlo]

I have used it. If I remember correctly it has a higher dry boiling point but a lower wet boiling point. I believe it is more hydroscopic, meaning it absorbs more moisture from the atmosphere than the RBF600...so it will need changing more often.

That is going from memory but my memory is crap so that could be off.

 

[subiedude09]

Are you racing? Seems like overkill if it's priced a lot higher. I do track days and drive agresively and haven't seen the need to go with anything higher than some of the other trusted brand stuff. I guess if you're doing racing and worried about brake fade, but then at that point you should probably get a master cylinder and steel braided line upgrades and be changing your brake fluid more often.

No i dont race. I will be attending some track days later this year though. I purchased this brake fluid because i get a great deal on Motul so price didnt realy bother me. Figured it was most likely overkill, but i know its good quality fluid reguardless.

 

[subiedude09]

flushed all the dirt old brake fluid out of the bike today . replaced with the 660, and bled all the air out of the lines. Brake fluid is now out of the way for this upcoming season. We were blessed with a realy nice 52 degree day here in MA so it was rather nice working on the bike for a little. Riding season is almost here!!!!!

 

[TheEvilTwin]

Wet boil point is the important number. There are DOT 4 fluids that have higher ratings than some DOT 5

 

[XPyrion]

I guess the question would then be, how long does it take for the 594F dry boiling point to become the 401F wet boiling point? At that point, what does it really take to reach the 401F boiling point? 1,2,3, etc. major braking points per lap?

 

[PainfullySlo]

I guess the question would then be, how long does it take for the 594F dry boiling point to become the 401F wet boiling point? At that point, what does it really take to reach the 401F boiling point? 1,2,3, etc. major braking points per lap?

There are way too many variables to assign simple numbers like that.

The more hyrdoscopic the fluid, the quicker it becomes "wet". For all intents and purposes, unless you have just changed it, assume that it is wet. I don't have exact numbers for a timeline.

My main track is very technical with lots of very aggressive braking zones. I once used standard brake fluid at a track day (non racing) just on a whim and it didnt even make it to the end of the session before I had nearly no brakes.

I use the RBF600 for the higher wet boiling point and need to change the fluid at least ever 3 months or it will start to give me fading issues. I do not know if it is fully 'wet' at that point but that is when the fade becomes troublesome.

I will try to get some rotor surface temperatures after the next time I come in off the track. While that wont give us fluid temps, it will give us a starting point for some data collection.

 

[XPyrion]

Yeah, I didn't think it would be straightforward like that but just throwing out things to ponder. While it won't matter in the bike, it would be nice if they designed the brake fluid bottles to have a collapsible bladder like wine boxes so it didn't start going bad as soon as opened.

When searching on Motul 600 and 660, most people seemed to mention Castrol SRF. The stats look amazing but at that price, seems only worth it if you plan to take home winnings or are being sponsored. I saw a few mention Endless but the stats don't seem too much better than Motul.

 

[PainfullySlo]

Yeah, I didn't think it would be straightforward like that but just throwing out things to ponder. While it won't matter in the bike, it would be nice if they designed the brake fluid bottles to have a collapsible bladder like wine boxes so it didn't start going bad as soon as opened.

When searching on Motul 600 and 660, most people seemed to mention Castrol SRF. The stats look amazing but at that price, seems only worth it if you plan to take home winnings or are being sponsored. I saw a few mention Endless but the stats don't seem too much better than Motul.

I have heard of the CRF but haven't felt the need to give it a shot just yet. Unless it allows me to essentially not change the fluid for a year or more, it simply wouldnt be worth it.

 

[devildogae]

I've used both and they are both very good. They both have the same wet boiling point, but 660 has higher dry boiling point, so that helps you if you have just changed and going racing. Other than than, I think the 600 would surpass anything you would need under normal conditions.

 

[PainfullySlo]

I stand corrected. The 600 and 660 have the same wet boiling point per Motul. The only difference is a 617 (660) and 594 (600) degree dry boiling point.

This is directly from Motul

RBF600
PROPERTIES
100% synthetic fluid, polyglycol bases.
Color Amber
Dry boiling point 312 °C / 594 °F
Wet boiling point 205 °C / 401 °F
Viscosity at -40°C (-40°F) 1750 mm²/s
Viscosity at 100°C (212°F) 2.5 mm²/s

RBF660
PROPERTIES
100% synthetic fluid, polyglycol bases.
Colour Amber
Dry boiling point 325 °C / 617 °F
Wet boiling point 205 °C / 401 °F
Viscosity at -40 °C (-40 °F) 1698 mm²/s
Viscosity at 100 °C (212 °F) 2.59 mm²/s

 

[subiedude09]

Thanks for all the input guys! I learned something new today lol :thumbup.