Is Dot 4 Synthetic a Dot 5?

[Degreaser]

I went to Canadian Tire auto store and they had STP Dot 4 Synthetic, the guy at the counter said the synthetic is ok to use in my '05 Kawasaki Vulcan 800, so I went to NAPA store and they had the non-synthetic NAPA brand Dot 4 regular and he told me that the synthetic STP Dot 4 is actually a Dot 5 brake fluid, and my bike calls for Dot 4 only, so is the STP synthetic bottle a Dot 5 brake fluid?

 

[JMJNet]

All brake fluid are synthetic in a sense that there is no dino oil component in it.

 

[Dave Sherman]

NO. Dot 5 is silicone. Dot 4 is not, and they do not mix. Dot 5 is only used in some specific applications, like some motorcycles and antique cars.

 

[Vuflanovsky]

I would think that what you're asking just falls under the mixability of the fluids as there are two different DOT 5 fluids and if STP DOT4 "that's actually a DOT5" is glycol-based then you can use it. If it's silicone-based as in the DOT5 spec then you wouldn't or couldn't. You'd assume that the parts guy is referencing that you can mix with DOT3, DOT4, and DOT 5.1 fluid so in his mind "it's also a DOT5" ( not correct terminology without the .1 if that's what he means ) but someone could decipher this better than me.

 

[ragtoplvr]

Dot 5.1 is glycol based. Dot 5 is silicone DO NOT MIX

 

[Degreaser]

after reading comments from you guys, I have come to conclude that the word 'synthetic' on that STP bottle was for me confusion #1 which caused me to ask the Canadian Tire store parts guy about it, and confusion #2 was the parts guy saying it's actually a DOT 5 brake fluid, and you're right, he was not correct and he probably meant to say its a DOT 5.1 fluid, either he did say 5.1 or I didn't hear him say the point 1, so I solved my confusion by returning that bottle of STP DOT 4 Synthetic to Canadian Tire store and went to the NAPA store and bought their DOT 4 bottle that didn't say synthetic on the bottle, oh wait, I got that wrong, now I confused myself, actually it was the NAPA parts guy who said that STP bottle was a Dot 5 fluid, so it was the NAPA guy who confused me and that Canadian Tire parts guy was right all along in saying that the STP Dot 4 synthetic can be used in my bike. Long story conclusion is, I'm glad that I only have to buy bike brake fluid when the Moon shines at Noon on a rainy day in March when it's snowing and the Sun is shining at the same time, ie: hardly ever ha

 

[blupupher]

DOT 4 and DOT 4 "Synthetic" are the same thing. The "synthetic" may have a little better heat range or could just be a marketing term because "synthetic" is "better", but they can be easily mixed with each other (or with DOT 3 or DOT 5.1).
I have also seen bottles labeled as "DOT 3/4", which does not exist, but make it easier to market to those that don't understand compatibility.

For me, I just use the cheapest DOT 4 I can find (usually the Walmart Supertech), since I change my brake fluid on a semi regular basis (annually in my bike, every 2-3 years in my other vehicles).