I was dropping down a steep, high traction pitch slaloming through some bushes using the rear brake quite a bit when after about 50 yards of this my rear brake lever pulled to the bar. I was going pretty slow so was able to stop with my front. The rear disc was hotter than hell as expected but neither the hose nor the reservoir were even warm.
It doesn't feel like I have any air in the system as the brake works fine elsewhere. In fact, the entire rest of the ride it was trivial as usual to lock up the rear brake. Any ideas why it pretty much failed in the above situation?
In article <[email hidden]>, getnews1 @dslextreme.com says...
Quoted message said:
I was dropping down a steep, high traction pitch slaloming through some bushes using the rear brake quite a bit when after about 50 yards of this my rear brake lever pulled to the bar. I was going pretty slow so was able to stop with my front. The rear disc was hotter than hell as expected but neither the hose nor the reservoir were even warm.
It doesn't feel like I have any air in the system as the brake works fine elsewhere. In fact, the entire rest of the ride it was trivial as usual to lock up the rear brake. Any ideas why it pretty much failed in the above situation?
Greg
Well if it didn't come back then it simply has a leak. If it did come back then you did boil the fluid. What brake are we talking about here. -- _________________________ Chris Phillipo - Cape Breton, Nova Scotia ramsays-ramsays-Open ↗ online.com
In article <[email hidden]>, getnews1 @dslextreme.com says...
Quoted message said:
I was dropping down a steep, high traction pitch slaloming through some bushes using the rear brake quite a bit when after about 50 yards of this my rear brake lever pulled to the bar. I was going pretty slow so was able to stop with my front. The rear disc was hotter than hell as expected but neither the hose nor the reservoir were even warm.
It doesn't feel like I have any air in the system as the brake works fine elsewhere. In fact, the entire rest of the ride it was trivial as usual to lock up the rear brake. Any ideas why it pretty much failed in the above situation?
Greg
Well if it didn't come back then it simply has a leak. If it did come back then you did boil the fluid. What brake are we talking about here.
Avid Juicys. Shouldn't the hose have at least been warm?
In article <[email hidden]>, getnews1 @dslextreme.com says...
Quoted message said:
I was dropping down a steep, high traction pitch slaloming through some bushes using the rear brake quite a bit when after about 50 yards of this my rear brake lever pulled to the bar. I was going pretty slow so was able to stop with my front. The rear disc was hotter than hell as expected but neither the hose nor the reservoir were even warm.
It doesn't feel like I have any air in the system as the brake works fine elsewhere. In fact, the entire rest of the ride it was trivial as usual to lock up the rear brake. Any ideas why it pretty much failed in the above situation?
Greg
Well if it didn't come back then it simply has a leak. If it did come back then you did boil the fluid. What brake are we talking about here.
Avid Juicys. Shouldn't the hose have at least been warm?
Greg
Not sure, but I don't think so. That plastic line isn't a good conductor of heat.
Chris is correct about the lever coming back as the brake cools down. I've had this happed a couple times up at Big Bear with my little 6" rotors. -- Slacker
"G.T." <[email hidden]> wrote in message "]news:[email hidden]...
Quoted message said:
I was dropping down a steep, high traction pitch slaloming through some bushes using the rear brake quite a bit when after about 50 yards of this my rear brake lever pulled to the bar. I was going pretty slow so was
able
Quoted message said:
to stop with my front. The rear disc was hotter than hell as expected but neither the hose nor the reservoir were even warm.
It doesn't feel like I have any air in the system as the brake works fine elsewhere. In fact, the entire rest of the ride it was trivial as usual
to
Quoted message said:
lock up the rear brake. Any ideas why it pretty much failed in the above situation?
Greg
Sounds like you got yer fluid too hot...I hear you can get Motul RBF 600 DOT 4 Fluid that has a crazy high boiling point, higher than your brakes will ever get it. Maybe that'll do it; I don't know, I don't run discs.
In article <[email hidden]>, getnews1 @dslextreme.com says...
> I was dropping down a steep, high traction pitch > slaloming through some bushes using the rear brake > quite a bit when after about 50 yards of this my rear > brake lever pulled to the bar. I was going pretty slow > so was able to stop with my front. The rear disc was > hotter than hell as expected but neither the hose nor > the reservoir were even warm. > > It doesn't feel like I have any air in the system as > the brake works fine elsewhere. In fact, the entire > rest of the ride it was trivial as usual to lock up the > rear brake. Any ideas why it pretty much failed in the > above situation? > > Greg > >
Well if it didn't come back then it simply has a leak. If it did come back then you did boil the fluid. What brake are we talking about here.
Avid Juicys. Shouldn't the hose have at least been warm?
Greg
Not sure, but I don't think so. That plastic line isn't a good conductor of heat.
Chris is correct about the lever coming back as the brake cools down. I've had this happed a couple times up at Big Bear with my little 6" rotors.
That's disappointing as this was just a short pitch, although I was using my rear brake more than usual because the traction was incredible. I sent an email to Goodridge to see if they're working on hose kits for the Avids.
Chris is correct about the lever coming back as the brake cools down. I've had this happed a couple times up at Big Bear with my little 6" rotors.
That's disappointing as this was just a short pitch, although I was using my rear brake more than usual because the traction was incredible. I sent an email to Goodridge to see if they're working on hose kits for the Avids.
Greg
While the Goodridges are very nice, I don't think they'll help heat induced lever fade.
There are a few other things you might want to look into.
Larger rotors will dissipate heat much better than smaller ones.
Not all brake fluids are created equal - look for higher boiling points. I've seen them range from around 300F to 600F for racing (not DOT approved) fluid, which is what I'm using for the Turner. The downside is the racing fluid is 7x the cost.
Also, maybe try a different brake pad compound if they're available?
"Slacker" <[email hidden]> wrote in message "]news:[email hidden]...
Quoted message said:
G.T. said:
Slacker said:
Chris is correct about the lever coming back as the brake cools down. I've had this happed a couple times up at Big Bear with my little 6" rotors.
That's disappointing as this was just a short pitch, although I was using my rear brake more than usual because the traction was incredible. I sent an email to Goodridge to see if they're working on hose kits for the Avids.
Greg
While the Goodridges are very nice, I don't think they'll help heat induced lever fade.
There are a few other things you might want to look into.
Larger rotors will dissipate heat much better than smaller ones.
Not all brake fluids are created equal - look for higher boiling points. I've seen them range from around 300F to 600F for racing (not DOT approved) fluid, which is what I'm using for the Turner. The downside is the racing fluid is 7x the cost.
Also, maybe try a different brake pad compound if they're available?
None of that is relevant even if correct - his problem is, he didn't fit Hopes.
Shaun aRe - I have Hopes. WTF is 'brake fade' ',;~}~
Well if it didn't come back then it simply has a leak. If it did come back then you did boil the fluid. What brake are we talking about here.
Avid Juicys. Shouldn't the hose have at least been warm?
Greg
Only the caliper has to be to cause a problem. I'm surprised you've been having trouble with those the engineering in them really impressed me, I'm going to get a set my self. -- _________________________ Chris Phillipo - Cape Breton, Nova Scotia ramsays-ramsays-Open ↗ online.com
Not sure, but I don't think so. That plastic line isn't a good conductor of heat.
Chris is correct about the lever coming back as the brake cools down. I've had this happed a couple times up at Big Bear with my little 6" rotors.
That's disappointing as this was just a short pitch, although I was using my rear brake more than usual because the traction was incredible. I sent an email to Goodridge to see if they're working on hose kits for the Avids.
Greg
There's always the possibility that the wrong fluid is in there. -- _________________________ Chris Phillipo - Cape Breton, Nova Scotia ramsays-ramsays-Open ↗ online.com
I was dropping down a steep, high traction pitch slaloming through some bushes using the rear brake quite a bit when after about 50 yards of this my rear brake lever pulled to the bar. I was going pretty slow so was able to stop with my front. The rear disc was hotter than hell as expected but neither the hose nor the reservoir were even warm.
It doesn't feel like I have any air in the system as the brake works fine elsewhere. In fact, the entire rest of the ride it was trivial as usual to lock up the rear brake. Any ideas why it pretty much failed in the above situation?
Possibility: Brake fluid can absorb water from the air. That's why the car stuff says "Always close tightly" or something like that on the label. That water can boil long before the fluid. Steam brakes don't work well. :-) Can't really see how water can get into the system otherwise, unless you hit a really deep stream crossing while descending. the sudden cooling could conceivably decrease the pressure in the system sucking water into it (Idoubt it though-just avoiding what I need to do right now :-) ). Although this can allegedly happen with hubs and BBs (but that's air contracting not fluid). I'd put in better fluid and bleed well.
"Shawn Curry" <[email hidden]> wrote in message news:lvW9c.122577$1p.1726610@attbi_s54...
Quoted message said:
G.T. said:
I was dropping down a steep, high traction pitch slaloming through some bushes using the rear brake quite a bit when after about 50 yards of this my rear brake lever pulled to the bar. I was going pretty slow so was able to stop with my front. The rear disc was hotter than hell as expected but neither the hose nor the reservoir were even warm.
It doesn't feel like I have any air in the system as the brake works fine elsewhere. In fact, the entire rest of the ride it was trivial as usual to lock up the rear brake. Any ideas why it pretty much failed in the above situation?
Possibility: Brake fluid can absorb water from the air. That's why the car stuff says "Always close tightly" or something like that on the label. That water can boil long before the fluid. Steam brakes don't work well. :-) Can't really see how water can get into the system otherwise, unless you hit a really deep stream crossing while descending. the sudden cooling could conceivably decrease the pressure in the system sucking water into it (Idoubt it though-just avoiding what I need to do right now :-) ). Although this can allegedly happen with hubs and BBs (but that's air contracting not fluid). I'd put in better fluid and bleed well.
I'm going to look into different fluid. The fluid that's in there is what came with the Avid bleed kit so I'd think it should be ok. And I haven't ridden any stream crossings yet this year.
"Chris Phillipo" <[email hidden]> wrote in message "]news:[email hidden]...
Quoted message said:
Quoted message said:
Quoted message said:
>situation? > >Greg > >
Well if it didn't come back then it simply has a leak. If it did come back then you did boil the fluid. What brake are we talking about
here.
Quoted message said:
Quoted message said:
Avid Juicys. Shouldn't the hose have at least been warm?
Greg
Only the caliper has to be to cause a problem. I'm surprised you've been having trouble with those the engineering in them really impressed me, I'm going to get a set my self.
"Slacker" <[email hidden]> wrote in message "]news:[email hidden]...
Quoted message said:
G.T. said:
Slacker said:
Chris is correct about the lever coming back as the brake cools down. I've had this happed a couple times up at Big Bear with my little 6" rotors.
That's disappointing as this was just a short pitch, although I was using my rear brake more than usual because the traction was incredible. I sent an email to Goodridge to see if they're working on hose kits for the Avids.
Greg
While the Goodridges are very nice, I don't think they'll help heat induced lever fade.
There are a few other things you might want to look into.
Larger rotors will dissipate heat much better than smaller ones.
Not all brake fluids are created equal - look for higher boiling points. I've seen them range from around 300F to 600F for racing (not DOT approved) fluid, which is what I'm using for the Turner. The downside is the racing fluid is 7x the cost.
Also, maybe try a different brake pad compound if they're available?
Thanks for the tips, I'll look into racing fluids. Even if they're not DOT approved I assume they're safe?
In article <[email hidden]>, [email hidden] says...
Quoted message said:
Quoted message said:
contracting not fluid). I'd put in better fluid and bleed well.
I'm going to look into different fluid. The fluid that's in there is what came with the Avid bleed kit so I'd think it should be ok. And I haven't ridden any stream crossings yet this year.
Greg
The water in the fluid would come from the air. It's usualy recommended that you don't save the remaining portion of Dot 4 brake fluid unless you can seal the bottle up again 100% air tight. -- _________________________ Chris Phillipo - Cape Breton, Nova Scotia ramsays-ramsays-Open ↗ online.com
Only the caliper has to be to cause a problem. I'm surprised you've been having trouble with those the engineering in them really impressed me, I'm going to get a set my self.
Well, Google for my other issues with them.
Greg
I saw those too, this could be a one thing led to another sort of situation. -- _________________________ Chris Phillipo - Cape Breton, Nova Scotia ramsays-ramsays-Open ↗ online.com
Thanks for the tips, I'll look into racing fluids. Even if they're not DOT approved I assume they're safe?
Is this stuff the same as car brake fluid? Why not just hold of some DOT 5.1 fluid. It's not astoundingly expensive, doesn't eat seals and will stand very high temperatures. IME of disk braked cars is that unless there's something very wrong with the fluid (ie, old water contaminated fluid, or it's already been boiled), it's always the pads overheating and not gripping properly. With most car pads you can tell because they start stinking and plumes of white smoke sometimes appear from behind your wheels. I've no experience of bike pads, but I'd expect basic ones to have similar problems as temps rise.
Chris is correct about the lever coming back as the brake cools down. I've had this happed a couple times up at Big Bear with my little 6" rotors.
Is that to say that any hydraulic disk brake can effectively fail from too much heat?
I'm thinking stupid-long-steep hills (like coasting down the Mt Washington access road or the road from Hale Akala observatory)... Could *both* brakes fail in this manner?
If so, does the failure mode involve something specific to hydraulics? -- PeteCresswell
I'm going to look into different fluid. The fluid that's in there is what came with the Avid bleed kit so I'd think it should be ok.
I've got Hope C2's on my FS and Avid mechs on my hardtail.
I'm thinking of swapping them around so I have a Hope C2 on the front wheel of each bike and an Avid mech on the rear of each.
Reasons-up-until-now: 1) The mechs are cheaper/lighter and I don't perceive any significant performance diff between the mech and the Hope when used on the rear wheel.
2) The mech is a little grabby/unpredictable on the front wheel (180 mm rotors). Probably a pad composition issue but but the Hope is sooooo much more controllable/predictable...
Now maybe there's third rationale:
3) The mech isn't prone to any hydraulic-specific failure, so there's an ace in the hole in whatever situation provokes same. -- PeteCresswell
