Results 1 to 35 of 35
  1. #1
    mtbr member
    Reputation:
    Join Date
    Sep 2004
    Posts
    239

    Valvoline Syn. Dot 4 brake fluid

    Has anyone tried using the Valvoline synthetic DOTt 4 brake fluid in their hydo. brake systems? This fluid exceeds the current DOT 3 & 4 federal standards and has a higher boiling point. I am just getting set to bleed my Hayes brakes after installing some Goodridge lines and wanted to see if there was any feedback on this. Thanks in advance.
    Another day in paradise!

  2. #2
    mtbr member
    Reputation: mtnbiker1973's Avatar
    Join Date
    Oct 2004
    Posts
    725
    I've had it in my hopes from day 1 and haven't had any trouble.

  3. #3
    Riding free's the mind
    Reputation:
    Join Date
    Jan 2004
    Posts
    1,006

    No problems

    I put them in my Avid Juicy's and seems to work fine.
    Honestly I bought it because the auto parts stores really don't carry a wide variety and it seemed closest to what Avid requires (dot 4 or 5.1).
    Question to a custom frame builder..."So what makes your bikes climb better?"....his answer, "Uh, your legs?"

  4. #4
    mtbr member
    Reputation:
    Join Date
    Sep 2004
    Posts
    239
    Quote Originally Posted by HTail
    I put them in my Avid Juicy's and seems to work fine.
    Honestly I bought it because the auto parts stores really don't carry a wide variety and it seemed closest to what Avid requires (dot 4 or 5.1).
    Thanks! I didn't see where there would be an issue with it but one never knows.
    Another day in paradise!

  5. #5
    mtbr member
    Reputation: 2xPneu's Avatar
    Join Date
    Jan 2004
    Posts
    916
    Quote Originally Posted by COMMITTED
    Thanks! I didn't see where there would be an issue with it but one never knows.
    Coming in late and I assume the work is already done, but Hope told me the Valvoline 3/4 Synthetic is what they put in their brakes in the US.

  6. #6
    mtbr member
    Reputation: Grumpy's Avatar
    Join Date
    Jan 2005
    Posts
    734
    Quote Originally Posted by 2xPneu
    Coming in late and I assume the work is already done, but Hope told me the Valvoline 3/4 Synthetic is what they put in their brakes in the US.
    Who told you that? US Hope brakes are filled with MOTUL DOT 5.1, Hope specifies that if you are going to use DOT4 that you flush the system and not just top off with DOT4.

    http://www.hopetech.com/technical/im...ns%20small.PDF

    see page 10 for recommended fluid and flushing instructions (if you want to downgrade to DOT4)

  7. #7
    mtbr member
    Reputation:
    Join Date
    Sep 2004
    Posts
    239
    Quote Originally Posted by Grumpy
    Who told you that? US Hope brakes are filled with MOTUL DOT 5.1, Hope specifies that if you are going to use DOT4 that you flush the system and not just top off with DOT4.

    http://www.hopetech.com/technical/im...ns%20small.PDF

    see page 10 for recommended fluid and flushing instructions (if you want to downgrade to DOT4)
    I went ahead and used the Valvoline SynPower Brake Fluid. Absolutely no issues on a 20 mile ride. Don't believe there will be any in the future either. This was for a Hayes HFX-9 system.
    Another day in paradise!

  8. #8
    mtbr member
    Reputation: 2xPneu's Avatar
    Join Date
    Jan 2004
    Posts
    916
    Quote Originally Posted by Grumpy
    Who told you that? US Hope brakes are filled with MOTUL DOT 5.1, Hope specifies that if you are going to use DOT4 that you flush the system and not just top off with DOT4.

    http://www.hopetech.com/technical/im...ns%20small.PDF

    see page 10 for recommended fluid and flushing instructions (if you want to downgrade to DOT4)
    Mr. Hope employee who answered the phone at Hope US in Cherry Valley told me.
    He said they assemble the brakes in the US and fill them with Valvoline SynPower 3/4.

    That's what I bled them with when I put on SS lines this weekend. Works fine.

    Really don't know why it would be necessary to completely flush the system when going from one grade of brake fluid to the next-you can add different motor oil weights together, why not brake fluid? If you mixed 5.1 with 3/4 in equal proportions, it'd be 4.3!

  9. #9
    mtbr member
    Reputation: Grumpy's Avatar
    Join Date
    Jan 2005
    Posts
    734
    Quote Originally Posted by COMMITTED
    I went ahead and used the Valvoline SynPower Brake Fluid. Absolutely no issues on a 20 mile ride. Don't believe there will be any in the future either. This was for a Hayes HFX-9 system.
    Hayes recommends DOT3 or DOT4 fluid, so that would be a match.

  10. #10
    mtbr member
    Reputation: Grumpy's Avatar
    Join Date
    Jan 2005
    Posts
    734
    Quote Originally Posted by 2xPneu
    Mr. Hope employee who answered the phone at Hope US in Cherry Valley told me.
    He said they assemble the brakes in the US and fill them with Valvoline SynPower 3/4.

    That's what I bled them with when I put on SS lines this weekend. Works fine.

    Really don't know why it would be necessary to completely flush the system when going from one grade of brake fluid to the next-you can add different motor oil weights together, why not brake fluid? If you mixed 5.1 with 3/4 in equal proportions, it'd be 4.3!
    Well he must have been mistaken, Brake fluid numbers are specification revisions not a measured property (like viscosity) So no, if you mix two brake fluids you do not get the average (ie 4.3) DOT 5 isn't even glycol base like 3,4 and 5.1 (it's silicone based)

    I am not a chemist nor a brake designer, however HOPE recommends NOT mixing DOT4 into the system. If you are going to use DOT4 they (not me!) recommend that you flush all of the 5.1 out with 4 first.

  11. #11
    mtbr member
    Reputation:
    Join Date
    Jun 2004
    Posts
    422
    I think it is only the UK assembled brakes that come with the DOT 5.1 fluid, it is a lot easier to find this spec in Europe. The US ones are filled with Synpower DOT 4. DOT 3,4 and 5.1 are all compatible with each other, DOT 5 is not.

    Asahi had some ATE brake fluid that is DOT 4 rated but has a very high boiling point. If you are boiling your brakes regularly then it may be advisable to go with a higher quality fluid.

  12. #12
    83 feet less per minute
    Reputation:
    Join Date
    Jun 2004
    Posts
    731
    Then what does the Hope bleed kit come with? Why would they send 5.1 with the bleed kit and you would not be able to bleed with it until you flush all of the original fluid out?
    Want to ride in this life and the next? Ask me how.

  13. #13
    mtbr member
    Reputation: Grumpy's Avatar
    Join Date
    Jan 2005
    Posts
    734
    Quote Originally Posted by Furrner
    I think it is only the UK assembled brakes that come with the DOT 5.1 fluid, it is a lot easier to find this spec in Europe. The US ones are filled with Synpower DOT 4. DOT 3,4 and 5.1 are all compatible with each other, DOT 5 is not.

    Asahi had some ATE brake fluid that is DOT 4 rated but has a very high boiling point. If you are boiling your brakes regularly then it may be advisable to go with a higher quality fluid.
    Most high end motorcycle parts shop and automotive speed shops carry DOT 5.1. (it is use extensively in the US for racing or high performance/extreme conditions applications, MOTUL is the most common brand) Again, I don't know the reason why Hope says not to add in DOT4, but they do. (and they designed and manufactured the brake and specified the fluid) Here is the quote from the service guide:

    This Hope disc brake contains DOT 5.1 hydraulic brake fluid which is available from cycle retailers and motor accessory stores. If you cannot obtain DOT 5.1 then DOT 4 is acceptable but you must flush out all the old DOT 5.1 first.

    I am not dissing Hope US, but it is a sales office (all Hope is designed and manufactured in the UK). Filling the brakes with DOT4 is fine, but I would take the word of those who designed the brake and flush out the existing fluid. Has anyone been told that it is ok to mix 4.0 and 5.1 fluids by someone at hope US?
    BTW anyone trying to figure what spec fluid is in their Hope brakes can use this as a guide; Any brake bought (US or worldwide) that came in the familiar black box (with green writing) would be a UK assembled brake and would contain DOT5.1. Brakes filled in the US come packaged in generic white boxes.
    Last edited by Grumpy; 03-08-2005 at 08:38 AM. Reason: typo

  14. #14
    mtbr member
    Reputation:
    Join Date
    Mar 2004
    Posts
    82

    ... and if we just ... Call Hope its toll free 800 303-6863

    I've been running Hopes for years and the us office told me for the us market they are using Valvoline synthetic because the Dot 5 is hard to find is some areas of the US.

    I have and know at least 10 to 15 bikes using this fluid with Hopes with no problem so anyone with Hopes will be fine.

    J

  15. #15
    mtbr member
    Reputation: Grumpy's Avatar
    Join Date
    Jan 2005
    Posts
    734
    Quote Originally Posted by mtnbkrr
    I've been running Hopes for years and the us office told me for the us market they are using Valvoline synthetic because the Dot 5 is hard to find is some areas of the US.

    I have and know at least 10 to 15 bikes using this fluid with Hopes with no problem so anyone with Hopes will be fine.

    J
    Did anyone here, at any time, say DOT4 would not work in Hope brakes?

    BTW I'm (almost) sure you meant to write DOT5.1 in your post, DOT5 is fairly easy to get but a completely different animal from DOT3, 4, or 5.1 (it is silicone based rather than glycol based) and should not be used.

    Again understand that most of the Hope brakes sold in the US were filled with DOT5.1 (in the black and green box) only brakes delivered in generic white boxes are filled with DOT4.
    Last edited by Grumpy; 03-09-2005 at 06:40 AM.

  16. #16
    mtbr member
    Reputation:
    Join Date
    Jun 2004
    Posts
    422
    So far all of the Hope brakes I have bought/installed/seen while in the US, about 15 brakes, have come in the 'generic white boxes'. Do they sell any UK assembled brakes?

  17. #17
    mtbr member
    Reputation: Grumpy's Avatar
    Join Date
    Jan 2005
    Posts
    734
    Quote Originally Posted by Furrner
    So far all of the Hope brakes I have bought/installed/seen while in the US, about 15 brakes, have come in the 'generic white boxes'. Do they sell any UK assembled brakes?
    Yes, from what I understand most of the Mono brakes that have been sold in the US are UK assembled. It is interesting, I have never seen the generic white box. All the Hopes I have seen to date have been the standard black and green box. And some of those have to be recent revisions as they have the new "through the pin" retaining clips rather then the older clip on type. (a hole through the pin rather than a groove)

  18. #18
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    1,071
    I use Motul RBF 600 in my Hayes brakes. It makes the brakes work noticably better than standard DOT 4 fluid. It is full synthetic, so the Valvoline may be as good, but I can vouch for the RBF 600 being wickedly more powerful and fade-resistant than DOT 4. It's what the LBS puts in all the tough-guys' brakes. Available at moto shops.

    http://www.motul.com/uk/produits/moto/freins/index.html

  19. #19
    player hater
    Reputation: VoltesV's Avatar
    Join Date
    May 2004
    Posts
    143
    Quote Originally Posted by watermoccasin
    I use Motul RBF 600 in my Hayes brakes. It makes the brakes work noticably better than standard DOT 4 fluid. It is full synthetic, so the Valvoline may be as good, but I can vouch for the RBF 600 being wickedly more powerful and fade-resistant than DOT 4. It's what the LBS puts in all the tough-guys' brakes. Available at moto shops.

    http://www.motul.com/uk/produits/moto/freins/index.html
    Wow, that's pretty spendy for brake fluid! But, it is indeed excellent fluid. I use this in my car which sees track duty, but it is pricey and not much different from the ATE Super Blue (neat blue color) or TYP2000 (identical, except for amber color). I happened to have recently bled the brakes on my car, so I had a small amount of Motul left and used it to bleed my Hope Minis. While it works just fine, I cannot tell the difference between DOT 4 and therefore personally cannot justify purchasing it if I didn't already have it. I think it is overkill (or maybe I just don't ride hard enough?). I think Valvoline syn for ~$5 works just fine. YMMV.

    Note on ATE Super Blue and ATE TYP2000: These are identical fluids other than color (blue and amber). This is done to help facilitate a brake fluid change; you'll know when the old fluid is flushed when the color changes. Not a bad idea for bikes, too. Again, this isn't the cheapest stuff, (~$12/liter), but half the cost of Motul (~$12/500mL).

    Anyway...just one man's opinion.

    BTW, Watermoc, I completely agree with the Motul being more fade-resistant; it has excellent boiling characteristics. But, I'm curious as to the 'wickedly more powerful' claim. How do you mean?

  20. #20
    Let's ride
    Reputation: rensho's Avatar
    Join Date
    Mar 2004
    Posts
    7,137
    Quote Originally Posted by VoltesV

    BTW, Watermoc, I completely agree with the Motul being more fade-resistant; it has excellent boiling characteristics. But, I'm curious as to the 'wickedly more powerful' claim. How do you mean?
    I second this question/point as well. Why would 5.1 be anymore powerful? Unless you are routinely hitting the dry boiling point of your brakes, using DOT 4, none of this should come into play. I personally have not measured disc pad/rotor/MC temps after long DH runs, but I don't think they are reaching 400F. Maybe, but i really don't know for sure. Yes they get hot, but 400+? DOT 5.1 is for folks that are worried about hitting 550F+ routinely.
    Maybe if you weighed 300lbs and did the big runs at Whistler...
    What we need is someone with a laser pyrometer living next to a hig DH...

  21. #21
    mtbr member
    Reputation: Grumpy's Avatar
    Join Date
    Jan 2005
    Posts
    734
    Motul is kind of spendy... are you kidding? You only need to change fluid every few years (5.1 has a longer service life than 4.0) You think 10 or 15 bucks every few years is spendy? (if you DH I would flush every year, but that still only 15 bucks a year) I shudder to think what I spend on biking in a year but I bet it runs in the low-to-mid three figure range.

    There is certainly a difference in feel between fluids, anyone involved in motorsport racing can tell you. DOT 5.1 is lower in viscosity (tighter faster, more direct feel) and has lower compressibility so the brakes will feel stronger (firmer.)

  22. #22
    player hater
    Reputation: VoltesV's Avatar
    Join Date
    May 2004
    Posts
    143
    Quote Originally Posted by Grumpy
    Motul is kind of spendy... are you kidding? You only need to change fluid every few years (5.1 has a longer service life than 4.0) You think 10 or 15 bucks every few years is spendy? (if you DH I would flush every year, but that still only 15 bucks a year) I shudder to think what I spend on biking in a year but I bet it runs in the low-to-mid three figure range.
    Nope, not kidding. Yes, I think it is spendy.


    Quote Originally Posted by Grumpy
    There is certainly a difference in feel between fluids, anyone involved in motorsport racing can tell you. DOT 5.1 is lower in viscosity (tighter faster, more direct feel) and has lower compressibility so the brakes will feel stronger (firmer.)
    Interesting. I know a couple of people that would be interested to read about this (myself included); do you have the source for this info? Thanks.

  23. #23
    83 feet less per minute
    Reputation:
    Join Date
    Jun 2004
    Posts
    731
    OK, my Mono Minis came in green and black boxes and have the "R" clip that goes through the retaining pin. I wrote Hope to find out from them what fluid is in the master cylinder and this is what they answered:

    In the U.K. we use Dot 5.1. However in the U.S. they use either Dot4 or
    the other type you mentioned Valvoline Synpower. All depends what they
    can get hold of. As they are all glycol based fluids you can just top up
    your brakes if you wish.

    Ian Jesson

    Hope Technology
    Hope Mill
    Skipton Road
    Barnoldswick
    Lancashire
    BB18 6EN
    Want to ride in this life and the next? Ask me how.

  24. #24
    mtbr member
    Reputation: Grumpy's Avatar
    Join Date
    Jan 2005
    Posts
    734
    Quote Originally Posted by VoltesV
    Nope, not kidding. Yes, I think it is spendy.

    Interesting. I know a couple of people that would be interested to read about this (myself included); do you have the source for this info? Thanks.

    Im sorry but I think being concerned about the difference in spending $5 or $12 every three years is kind of silly.
    (Particularly if the extra $7 gets you better performance and a longer service life)

    I googled compressibility and DOT 5.1 here are the top hits, I'm sure you can get more info if you want to get creative with google. The empirical result is certain however Motul (and other HP 5.1 fluids) has great reputation for "lever feel" (from GP motorcycle racing, but is just as relevant to MTB discs.)

    http://www.rpmnet.com/techart/fluid.shtml
    http://www.southerndownhill.com/2002...ke_fluids.html
    http://www.raceshopper.com/brake_fluid.shtml
    http://www.gs610.com/abc.htm

  25. #25
    mtbr member
    Reputation: Grumpy's Avatar
    Join Date
    Jan 2005
    Posts
    734
    Very interesting and also somewhat confusing. Hope US has told me (numerous times) that in the US ONLY white box brakes are filled with DOT4.

    As far as just topping up DOT 5.1 filled brakes with DOT 4. The service manual specifically addresses it as a no no (you are directed to purge the remaining DOT4 with 5.1) This had to be put in for a reason (it 's not like an omission which sometimes slip by in tech pubs) Someone (assumably the engineer in charge of service specifications) specifically put those flush instructions in the manual.

    It isn't much money (a few dollars worth of fluid), and if you have the system open it isn't much trouble (no difference at all if you have the bottom up bleed system) so why would you want to go against what is written in the service manual? If you are unsure about the fluid in the system I would always suggest flushing it when adding new fluid.

    The long and short is on DOT fluid is: 5.1 is better fluid. (it is by definition a higher specification) it is lower in viscosity than DOT 4 (better lever feel) lasts longer (better service life) and holds up to abuse better (higher stable operating temperatures) and only costs a couple bucks more. Again unless you simply can't find it locally (and don't want to order it) why would you want to use anything else?

  26. #26
    player hater
    Reputation: VoltesV's Avatar
    Join Date
    May 2004
    Posts
    143
    Quote Originally Posted by Grumpy
    Im sorry but I think being concerned about the difference in spending $5 or $12 every three years is kind of silly.
    (Particularly if the extra $7 gets you better performance and a longer service life)

    I googled compressibility and DOT 5.1 here are the top hits, I'm sure you can get more info if you want to get creative with google. The empirical result is certain however Motul (and other HP 5.1 fluids) has great reputation for "lever feel" (from GP motorcycle racing, but is just as relevant to MTB discs.)

    http://www.rpmnet.com/techart/fluid.shtml
    http://www.southerndownhill.com/2002...ke_fluids.html
    http://www.raceshopper.com/brake_fluid.shtml
    http://www.gs610.com/abc.htm
    Hmmm...the only thing I found about a specific viscosity figure was in the last link you posted which states:

    Viscosity – Here’s a really interesting specification. One where the DOT 3 spec could be perceived as actually being better for the micro passages of an ABS system than the DOT 4 spec. Webster’s defines “viscosity” as, “Physics, the resistance of a fluid to flowing freely, caused by friction of its molecules.” As you may recall from motor oil, the higher the viscosity number, the slower the flow of the oil. Well the same applies for brake fluid although the actual measurement technique is different. The DOT 3 specification for viscosity at -40°F is 1500 mm2/s and the specification for DOT 4 at -40°F is 1800 mm2/s. Yep, that’s right, the DOT 3 fluid flows better at the testing temperature than the DOT 4. It should be noted the specification at 212°F for all DOT specifications is 1.5 mm2/s.


    I looked for a bit, but I haven't been able to find this empirical result of which you speak.

  27. #27
    mtbr member
    Reputation: Grumpy's Avatar
    Join Date
    Jan 2005
    Posts
    734
    Quote Originally Posted by VoltesV
    Hmmm...the only thing I found about a specific viscosity figure was in the last link you posted which states:

    [/font]

    I looked for a bit, but I haven't been able to find this empirical result of which you speak.
    Motul has a reputation of having superior lever feel. This is from field (or empirical) GP racing experience (ie the riders and mechanics say they get improved lever feel)
    5.1 is far lower viscosity than 4 that is why 5.1 is recommended in Antilock systems where low viscosity is critical to operation.

    Why are you being obstinate? If you want to run weasel piss in your brakes, by all means be my guest.

  28. #28
    player hater
    Reputation: VoltesV's Avatar
    Join Date
    May 2004
    Posts
    143
    Quote Originally Posted by Grumpy
    Motul has a reputation of having superior lever feel. This is from field (or empirical) GP racing experience (ie the riders and mechanics say they get improved lever feel)
    5.1 is far lower viscosity than 4 that is why 5.1 is recommended in Antilock systems where low viscosity is critical to operation.

    Why are you being obstinate? If you want to run weasel piss in your brakes, by all means be my guest.
    Obstinate? I'm just looking for the facts to back up your claims. Believe it or not, I'm trying to learn something while you prefer name calling (first silly, then obstinate). If I'm missing something about brake fluid, I'm opening minded to learning and hearing opinions of others.

    Reason I mention this is because I regularly hear that Motul 600 has great wet/dry boiling points, but is relatively more hygroscopic and a better 'short-term' fluid. From http://www.shotimes.com/SHO3brakefluid.html:

    Motul Racing 600 is a very exotic and expensive synthetic fluid with high wet and dry boiling points. I use this exclusively in my race cars. Too expensive for the street and requires frequent changing due to its hygroscopic nature. Sold in plastic bottles. It is not suitable for the street because it absorbs moisture quickly.
    That is a quote from Dave Zeckhausen (www.zeckhausen.com) that sells hi-perf brake systems.

    You state that DOT5.1 has a 'far lower viscosity' than DOT4. Earlier, it was stated that Motul was 'wickedly more powerful'. You'll recall that this is what prompted my initial response. If someone can show me this is the case, I'm all for it. But, maybe I need a little more empirical evidence than this. Grumpy, if my desire for clarification to what you (or others) are saying, and my request for a source for your info upsets you or hurts your feelings, that was not my intent. No hard feelings.

    BTW, you should try Castrol SRF. It is THE brake fluid of choice among my track buds, but I haven't yet tried it. At about ~$80/liter, I think the price is a bit "silly".

  29. #29
    Hoops - Big and Small
    Reputation: Crash_Burn's Avatar
    Join Date
    Oct 2004
    Posts
    1,087

    Lever Feel V.S. Boiling Point

    Is'nt lever feel and boiling point the two ends of the continuum?

    Is there a fluid that performs both of these functions?

    I personally use shimano stuff (xt 755, mineral oil) I boil my oil 2% of the time - Do I wish I had 100% no boil? you bet! I do like my lever feel though.

    Good luck with the weasel piss, these guys are hard to round up.
    Attached Images Attached Images
    Last edited by Crash_Burn; 03-10-2005 at 10:18 AM. Reason: typo

  30. #30
    player hater
    Reputation: VoltesV's Avatar
    Join Date
    May 2004
    Posts
    143
    Quote Originally Posted by Crash_Burn
    Good luck with the weasel piss, these guys are hard to round up.
    You ain't kidding. But if you think rounding them up is hard, try getting them to piss in the master cylinder...now THERE is a challenge.

  31. #31
    mtbr member
    Reputation: Grumpy's Avatar
    Join Date
    Jan 2005
    Posts
    734
    Quote Originally Posted by VoltesV
    Obstinate?
    When I asked if you were kidding that $10 every 3 years on brake fluid was "spendy" you replied
    "Nope, not kidding. Yes, I think it is spendy"
    So the answer is; Yes you are an obstinate little troll spoiling for a fight.

    That should have clued me then and I shouldn't have spent any (more) time on your trolls. (BTW I happend to be out in the barn and checked, the last 1/2 liter bottle of Motul DOT 5.1 that I bought at my local cycle shop (retail) cost me $6.95)

    So you and your "track buds" can run $80 weasel piss if you want, but i'll say now what I should have said to your earlier post

    Talk to the hand...
    Last edited by Grumpy; 03-10-2005 at 03:13 PM.

  32. #32
    83 feet less per minute
    Reputation:
    Join Date
    Jun 2004
    Posts
    731
    I personally don't mind the difference in cost. I would just like to know for sure what is already in my master cylinders. Sure I would have to mail order 5.1, but what if I do and the master cylinder really has DOT 4 in it? Seems like the only safe thing to do is buy something and flush all the old out when any is added. Am I wrong?
    Also how full should the master cylinder be filled on a Hope? Some brands say overfill and then put lid on. Is this the procedure for Hope?
    Want to ride in this life and the next? Ask me how.

  33. #33
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    1,071
    Quote Originally Posted by VoltesV
    BTW, Watermoc, I completely agree with the Motul being more fade-resistant; it has excellent boiling characteristics. But, I'm curious as to the 'wickedly more powerful' claim. How do you mean?
    The lever feel is a bit more firm and positive when the brakes are cool, as mentioned by others, and much more firm and positive when they are hot. I have a season pass at the Whistler bike park, weigh 210 lbs, and like to ride really fast and jump a lot and generally beat the crap out of my bike. On a good weekend I'll do over 2000 jumps (49 per run on my favorite loop), bottoming my 8" bike with extra-stiff springs several times per run. Under these conditions, the Motul RBF is worth the extra few $$ for the reduced arm-pump alone. I didn't keep track, but probably went through around 6 sets of Hayes full metallic brake pads last season on my Mags, and didn't have to bleed the brakes once.

    Not sure why it's cheaper here, but the local moto shops sell RBF for $7-8 a bottle. I gotta try that weasel-piss, sounds like good stuff. Also haven't had any problems with getting water in my brakes, including some really wet riding that seized BBs and pivot bearings.

  34. #34
    player hater
    Reputation: VoltesV's Avatar
    Join Date
    May 2004
    Posts
    143
    Quote Originally Posted by watermoccasin
    The lever feel is a bit more firm and positive when the brakes are cool, as mentioned by others, and much more firm and positive when they are hot. I have a season pass at the Whistler bike park, weigh 210 lbs, and like to ride really fast and jump a lot and generally beat the crap out of my bike. On a good weekend I'll do over 2000 jumps (49 per run on my favorite loop), bottoming my 8" bike with extra-stiff springs several times per run. Under these conditions, the Motul RBF is worth the extra few $$ for the reduced arm-pump alone. I didn't keep track, but probably went through around 6 sets of Hayes full metallic brake pads last season on my Mags, and didn't have to bleed the brakes once.

    Not sure why it's cheaper here, but the local moto shops sell RBF for $7-8 a bottle. I gotta try that weasel-piss, sounds like good stuff. Also haven't had any problems with getting water in my brakes, including some really wet riding that seized BBs and pivot bearings.
    Good to know...thanks for your input. No doubt that Motul RBF600 is the shizzle. Just for clarification (not necessarily to you, Watermoc, but to others following the thread), there might have been a bit on confusion between Motul RBF600 and Motul 5.1; RBF is DOT4 and 5.1 is (obviously) 5.1. RBF600 actually has higher boiling points (wet and dry) than 5.1...the difference is viscosity (I just learned this today). So, RBF600 would be a better choice for higher boiling points and 5.1 if you're looking for better viscosity (for things like ABS). Knowing this, it makes perfect sense that you're feeling a more solid lever considering the riding that you do (I'm jealous), due to the RBFs ability to absorb more heat.

    Check out this link I found for more info...http://www.evilplastic.com/bfluid.htm

    paddlefoot64...In general, you can mix DOT 4 and DOT 5.1 fluid (even though the Hope manual says not to) since they are both glycol based. Just understand that you'll compromise the better specs of 5.1 by mixing. It's a good idea to completely flush the system (as is often recommended) just to get all new fluid in there.

    Grumpy, settle down. If my honest answers to your questions (kidding? and spendy?) offend you and come across as obstinate, like I've already said, that's not my intent...I didn't realize you were so sensitive, especially in light of your abrasive replies. But as to the third name (troll) that you've called me in the same thread...GFY.

  35. #35
    mtbr member
    Reputation: Grumpy's Avatar
    Join Date
    Jan 2005
    Posts
    734
    Quote Originally Posted by paddlefoot64
    I personally don't mind the difference in cost. I would just like to know for sure what is already in my master cylinders. Sure I would have to mail order 5.1, but what if I do and the master cylinder really has DOT 4 in it? Seems like the only safe thing to do is buy something and flush all the old out when any is added. Am I wrong?
    Also how full should the master cylinder be filled on a Hope? Some brands say overfill and then put lid on. Is this the procedure for Hope?
    Yes fill to rim and then try to trap as little air under the seal as you can, same as other brakes.
    The thing about what fluid is in the brake and wether you need to purge it if you change spec is confused. Here is my take; although 3, 4 and 5.1 are chemically similar the Hope service manual says don't mix. Who knows for sure why that was put in, or what any given system was filled with to begin with (there seems to be some confusion on that as well). BUT my take is why worry? Purge the system with the new fluid it's only a couple dollars worth of fluid and then you will be correct no matter what. (just my theory that ANYTHING I can do to make the bike more trouble-free is worth doing).

Similar Threads

  1. Dot brake fluid and mineral oil differences?
    By rjpstoked in forum Brake Time
    Replies: 7
    Last Post: 06-20-2012, 02:46 PM
  2. DOT brake fluid vs.Mineral oil.
    By Big JuJu in forum Brake Time
    Replies: 8
    Last Post: 09-19-2004, 07:29 PM
  3. Bled with wrong brake fluid. Now what?
    By Freshies in forum Brake Time
    Replies: 3
    Last Post: 08-27-2004, 01:30 PM
  4. brake fluids?
    By r1Gel in forum Brake Time
    Replies: 5
    Last Post: 08-10-2004, 07:39 AM
  5. Hayes fluid same as Dot 3 or 4 auto?
    By Ironbar in forum Brake Time
    Replies: 1
    Last Post: 06-09-2004, 11:02 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •