DOT4 or DOT5 for my brakes?

Discussion in 'Battle Scooters' started by Cortez, Jan 25, 2013.

  1. Cortez

    Cortez BAZINGA!

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    While this might be better suited to a tech section of the forum
    (and please move the message if needed), it's related to my scoot so..
    :deal

    To make a long story short, my manual and brake fluid reservoir caps
    say "use dot 4 only".

    My mechanic (...) says "You got ABS brakes, you should use DOT 5."

    Should I really?

    I can obviously google the differences, but WHY does he insist on using
    DOT 5, and again, why does the manual stress the importance of using
    DOT 4 ONLY more then once?

    What could happen?
    :huh
    #1
  2. S/W

    S/W Been here awhile

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    The manufacturer is the expert of choice, use Dot 4.
    #2
  3. Cortez

    Cortez BAZINGA!

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    I forgot to mention that I'm, of course, gonna trust the manufacturer on this
    one, but I'm curious to the exact differences and possible issues if going with
    the DOT5.

    Just like with the oil recommendations in the manual, most will use "better"
    oil then the manual calls for (which again might not be a good idea but
    we'll never know for sure).
    #3
  4. ragtoplvr

    ragtoplvr Long timer

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    You need a new mechanic, NOW

    Dot 5 is silicone, and will mess things up. There is a Dot 5.1 that is glycol based like dot 3 and dot 4. It can be used BUT

    it is different
    It does not meet the same specifications.

    If there is silicone Dot 5 in there you need to start to flush it all out NOW

    Rod
    #4
  5. Cortez

    Cortez BAZINGA!

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    I've heard that one before.
    :cry

    I'm the kind of person that'll ask before doing anything, so, there's DOT4
    in the brake lines still.. :evil

    Waiting for EBC HH pads to arrive and will do the fluid at the same time so
    I just wanted to make sure.

    Thanks!
    #5
  6. Cortez

    Cortez BAZINGA!

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    My manual also states that I should use the same tire pressures when
    I'm riding alone, and when with passenger or both + fully loaded up
    which makes no sense to me, so that's why I'm questioning everything.

    :huh
    #6
  7. MotoRandy123

    MotoRandy123 Been here awhile

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    Why the heck did they call it DOT 5 and DOT 5.1? Seems easy to make a mistake.

    Very few vehicles use DOT 5, I think some Harley's do...
    #7
  8. Cortez

    Cortez BAZINGA!

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    That's also a valid WTF.
    Maybe my mechanic meant 5.1.
    :huh
    #8
  9. JerryH

    JerryH Banned

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    Never use DOT 5 in anything it didn't come in. It will mess up the entire braking system. The differences between DOT 3, DOT 4, and Dot 5.1 are the boiling point. They are all interchangeable. Unless you are racing, you are unlikely to ever overheat even DOT 3. I use DOT 3 in my '95 Goldwing, for both the brakes and clutch, and have never had an issue with it, even though Honda recommends DOT 4. DOT 4 is a LOT more expensive than DOT 3, and when I first got the bike it needed some brake work. While doing that I went through about a gallon of DOT 3, and then intended to switch to DOT 4 after I got everything rebuilt, but never did. DOT 4 should be good for any kind of street ridden scooter or motorcycle.
    #9
  10. Cortez

    Cortez BAZINGA!

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    Cool, thanks.

    I'll probably stick with DOT4.

    It's a heavy scooter, I'm heavy, and it has a small single disc up front
    so any kind of help is nice, and I like being able to do a "sporty" ride when
    I feel like it without having to worry about cooking up the brakes.

    Waiting for EBC HH pads to come and I'll do the fluid swap then.

    Thanks everyone!
    #10
  11. JerryH

    JerryH Banned

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    The boiling point for DOT 4 is higher than I can imagine any non racing bike ever reaching. As for the pads, I'm not familiar with "HH" pads, I use EBC organic pads on all my bikes, including the Goldwing. I found out a long time ago that metallic pads will eat rotors like crazy. I don't know what the rotors cost on your scooter, but they are over $300 apiece on my Goldwing.


    As far as the tire pressure thing, all tires have a "max" pressure molded into the sidewall, and I use that pressure under all conditions, no matter what the load. Tire companies are probably the most sued vehicle component manufacturers there are. You can bet they would not recommend something unsafe. There is in fact a fairly large safety margin above that pressure. I have also found tires seem to last longer at the max recommended pressure. There are a couple of dual sport bikes I know about that are known to have weak wheels, mostly due to the materials they are made out of. When you run really low pressures in the tires, it allows the spoked wheels to flex a lot, and they eventually start to come apart. I own one of those bikes, with 30,000+ miles on it, and have never has wheel problems, and I believe there are 2 reasons for that. One, I keep the tires properly inflated, and two, I do not ride it like an MX bike.

    Since I weigh 220 pounds, plus gear and cargo, I always keep the tires on all 3 of my scooters inflated to "max" These are small scooters, with 10" and 12" wheels. Two 125s and a 150. I found the rear tires on my Vino 125, with 24,000 miles on it, last about 6,000 miles, while the fronts last more than twice that. I have heard many much lighter people claim tires lasting less than 4,000 miles in the rear. Just guessing, but I figure they were using the tire pressures listed in the manual rather than on the tire.
    #11
  12. Paul Mihalka

    Paul Mihalka Old Fart

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    "I don't know what the rotors cost on your scooter, but they are over $300 apiece on my Goldwing."

    As I picked up on Ebay a spare rear wheel for my Majesty, I got a brand new EBC rotor to make the wheel complete, for $67 + shipping.
    AS I am coming from the BMW world, I love Yamaha parts prices.
    #12
  13. Cortez

    Cortez BAZINGA!

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    I hope you're not riding aggressively or that might get you into trouble.

    Even 10% more then recommended up front on any of the bikes I owned
    resulted in less grip in corners and braking.

    Bicycle tires for example have a HUGE margin of different pressures that
    can be used, and if you like grip and being safe, you don't go to the max.

    Of course they last longer, you're riding on a tiny section of it.
    #13
  14. Cortez

    Cortez BAZINGA!

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    +1

    There's a bunch of aftermarket rotors out there that usually cost less then
    some bicycle rotors (TSW for example).
    #14