Howdy I got a 02 Honda F4i Racebike and am Upgrading the master to a Brembo. What determines the Grade of Brake fluid to run (dot 4 dot 5.1 Dot ?) Is it the Master? the Lines? or the calipers?. What Should I use Thank you 441
The Castrol SRF stuff is some great stuff and at $70 for 1 Liter, it should be as good. The Dry Boiling point is 320C :wow: and the wet is down at 270C. The stuff is really good. For my limited budget, I feel less expensive alternatives are ok. I have some experience with extended brake usage in vehicles. The fact is even extended periods of time with the brakes applied does not bring the fluid beyond the 200C range. I do not have data for actual race bike fluid, but for vehicles the pistons don't transfer that much heat to the fluid. If you change your brake fluid before it goes brown, most Dot 4 stuff should be fine. I use Inexpensive Prestone Synthetic DOT 4 Brake Fluid, which has a Minimum Dry Boiling Point 260C. At $4 a bottle at wally world it is cheep enough to change twice a year, or every weekend if you feel the need.
Ok, guess we just wasted our hard earned cash on that stuff for the last 2 years, with nothing to show for it, didn't learn a thing. You can purchase cheaper fluid, I would say AP Super600 @ $18 a quart is ok,or the Neo Super DOT 610 @ $15.00 12oz. would be another good choice. I would go look at the Dry and Wet boiling points, pick the one with the closest spread, and work your pricing from there, a simple search of "Racing Brake Fluids" will give you atleast 2 hours worth of information on what will work well for Racing applications. If $4.00 fluid works for you Carry On, ( It is not so much the fluids DRY boiling point as it is the WET boiling point, and what the hygro-saturation rate of the fluid is, because it is the water that boils, along with the tiny air bubbles tha now compress, that causes the brake fade.) (I know SRF is rated at 518F wet) What is your $4.00 fluids W/BP? For educational purposes only:http://www.hrpworld.com/index.cfm?form_prod_id=680,587_606&action=product
I never said you wasted your money, if anything I supported that the SRF fluid is very good. But like I said, I feel the $70 a Liter is a bit expensive for my LIMITED BUDGET. The top end stuff is very good and works unbelievably well. I am sure that it may have been a great benefit to you. In my testing of brake systems, the WET point is not as important as the DRY point. I have experience with brake systems that have 100,000+mi of usage and pulled the fluid and did a moisture volume analysis. The amount of water in the fluid was so small (Less than 0.1% by volume) that it had very little effect to the boiling point (It dropped 6C from the control sample). The WET point is 3% of volume of water. If you have that much moisture in your brake fluid, I would be wondering where it is coming from. I know a brake system is not completely closed, but in general not that much moisture is absorbed. Plus the fluid in the caliper is in effect closed to moisture, because most brake systems to not recirculate the fluid. I also said the SRF stuff has a 270C (518F) WET boiling point. That is unbelievably high for a boiling point for the WET point. The Cheep stuff I suggested has only a 260C (500F) DRY boiling point, that falls to 155C (311F) when it is WET. There is no doubt that it not in the same class. Do you know what the fluid temp is inside a caliper on a race bike? I don't know, but I would love to learn that. I know what it is for Car's and Trucks and I have never seen a thermocouple exceed 170C (338F) when inside the caliper in the fluid chamber. When the fluid approached 170C (338F) the pads vaporized, the seals on the pistons were deformed and a registered a peek of 900C (1650F) rotor temperature was measured. BTW, I respect your skill and knowledge for race bikes. For my limited budget, I go with cheaper stuff and replace it twice a year. Maybe I should upgrade to a better fluid, but I am slow so it does not matter.
here is what i learned from my 7 minutes reading this thread: $70 minus $4 equals $63 for beer! so if i use cheap brake fluid i can justifiably spend more money on beer. thanks guys!:up:
