[rav400]

So, I need to bleed brakes on my DH bike. I have Formula the Ones MY10. They are labeled DOT 4, however, the closest I could find is a brake fluid labeled for DOT 3 and DOT 4 brake systems. I emailed emailed Formula and they told me to use the best DOT 4 fluid I could find and absolutely not to use DOT 5, DOT 5.1 or mineral oil. So is the stuff I have ok to use?

 

[IH8Rice]

So, I need to bleed brakes on my DH bike. I have Formula the Ones MY10. They are labeled DOT 4, however, the closest I could find is a brake fluid labeled for DOT 3 and DOT 4 brake systems. I emailed emailed Formula and they told me to use the best DOT 4 fluid I could find and absolutely not to use DOT 5, DOT 5.1 or mineral oil. So is the stuff I have ok to use?

does your LBS have any avid brake fluid?
and why wouldnt you be able to use 5.1 in the system? its essentially the same as 3 and 4

 

[Juddos]

Further to this,

Is there any aftermarket lever options for the ones..?

I know twenty 6 made them for 09 but thats it!

 

[rav400]

I have some avid fluid that is labeled DOT 5.1. Formula recommended staying away from that.

 

[IH8Rice]

I have some avid fluid that is labeled DOT 5.1. Formula recommended staying away from that.

they should maybe change their site then. 5.1 will work fine

What type of fluid do my Formula brakes use and where can I get it?
Formula Brakes come stock with a High Performance DOT 4 fluid. We strongly recommend using DOT 4 when bleeding you brakes. DOT fluid is available from your local auto parts store, but if you want a better selection of High Performance fluids you may be better off checking out a Motorcycle store. Formula Brakes are compatible with any glycol based DOT fluid, which includes DOT 3, DOT 4 and DOT 5.1. DO NOT use DOT 5!! It is silicone based and not compatible with the seals in your brake.

http://formulabrakeusa.com/faq/

 

[jonKranked]

I bleed all my brakes with Olde English 800

 

[canadmos]

On this subject, does anyone have a suggestion as to where I can find DOT 5.1 that isn't at a bike store that will charge an obnoxious price for a tiny bottle?

I can't find the stuff anywhere here.

 

[jonKranked]

autozone, napa, etc.

 

[rav400]

they should maybe change their site then. 5.1 will work fine

http://formulabrakeusa.com/faq/

D'oh. I don't know how I missed that while checking their site. Thanks, man

 

[gemini2k]

dot 3, 4, and 5.1 are all compatible. Dot 5 is the only...odd ball.

 

[canadmos]

autozone, napa, etc.

I thought that too, but apparently not around here...

 

[Udi]

A lot of motorbike / motocross stores will carry DOT 5.1. Motul makes some.

 

[Optimax150]

dot 3, 4, and 5.1 are all compatible. Dot 5 is the only...odd ball.

If they are all compatible what's the difference between them then? Why they called different numbers?

 

[Udi]

If they are all compatible what's the difference between them then? Why they called different numbers?

They are different standards, which have different requirements for boiling point and viscosity. For example (if my memory serves me right) DOT3 has a lower boiling point requirement than DOT4, but also a lower viscosity requirement. DOT5.1 is designed for ABS systems and has a higher boiling point requirement than DOT3 but is also required to be very low viscosity to flow through the small ABS channels.

This is why the highest boiling point fluids (eg. Motul RBF series) are DOT4 fluids, as they don't meet the viscosity cutoff for DOT5.1.

I don't think it matters hugely what you use in bicycles as long as the bleed is good and there is no air present. Perhaps if you ride in the Alps or very steep and long trails, a high boiling point would be beneficial.

 

[IH8Rice]

I thought that too, but apparently not around here...

yeah, theres no major autostore around here that sells 5.1 or even a motorcycle store.
i asked a few for it and they told me theres no such thing.

 

[brownie1664]

If they are all compatible what's the difference between them then? Why they called different numbers?

DOT 4 glycol based fluid has a higher boiling point (446F) than DOT 3 (401F), and both fluids will exhibit a reduced boiling point as water content increases. Viscosity of DOT 4 is more than DOT 3. Since DOT 4 fluids were developed, it was recognized that borate ester based fluids offered the potential for boiling points beyond the 446F requirement, thus came the Super DOT 4 fluids - some covered by the DOT 5.1 designation - which exhibit a minimum dry boiling point of 500F (same as silicone, but different chemistry).



When you've just replaced your brake fluid and the system has been properly bled, you are working at the Dry boiling temperature. Over time, water works its way into the system through age, heat cycling, through the hoses, etc. You are then working at your Wet boiling point for the fluid.


DOT 5 is completely different and is silicone based, it is not compatible with DOT 3 and 4 systems