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Discussion Starter #1
Never having been on a track, brake fade hasn't been an issue for me. Do brakes fade because of heat in the pads & rotor, or because of heat in the caliper & fluid?
 

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Both and you can feel the difference. One feels like a new pair of pads, the feel is good, but the stopping power isnt there. The other is spongy.
 

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upgrading the pads as well as swapping out the brake fluis (front and rear) to a better/higher quality brake fluid should/will help resolve brake fade under extreme braking coonditions.
 

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On the brake fluids, I picked up a tip from a sports car forum for easing the "know" about when to stop with brake fluid changes. Use two different colored brake fluids to alternate. One is Super Blue, which is blue, and the other is.... Spectro Gold, maybe
 

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kanwisch said:
On the brake fluids, I picked up a tip from a sports car forum for easing the "know" about when to stop with brake fluid changes. Use two different colored brake fluids to alternate. One is Super Blue, which is blue, and the other is.... Spectro Gold, maybe
yes sir, only ate super blue brake fluid in my bike (previous bikes), and all my cars. they also have a ate super blue brake fluid that is red.
 

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Discussion Starter #6
So have the new high-boiling point fluids eliminated fluid boiling as a cause of fading?
 

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Rundog said:
So have the new high-boiling point fluids eliminated fluid boiling as a cause of fading?
I dont think its something you can eliminate, just postpone
 

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Yeah, you can't avoid it completely when you are breaking hard and a lot. Remember, those drag cars use carbon pads and get red after slowing down from 300+mph in just a few seconds. That's got to be a couple thousand degrees to do that...
 

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Rundog said:
If the brake fluid & calipers were cooled, would it make a difference?
If you look at some race bikes, they have a scoop that collects and channels air to the brakes. Its even more prevalent in cars, where brake loads are much higher.

Cooling fluid would most certainly help, but all the extra piping involved would take away from the feedback, so it would be a double edged sword. However, it occured to me the other day, that the same effect can be done with some one way valves and an extra line, if you could force the brake fluid to return from tha caliper down a different line than it came in (some modification to the master cylinder may be required). Basically the idea is to return the fluid from the very bottom of the caliper to the top of the reseruor during brake release. This way, instead of holding the same fluid in the caliper and letting it boil, you flush some of the fluid away, to return to the reservour where it can cool, and replacing it with cold fluid from the same source.

I might just try to build something like that.
 

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what about some brake lines made out of some sorta heat conducting material? copper or something? or do they already do that? and or is it not practical?
 

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Meat_Shield said:
what about some brake lines made out of some sorta heat conducting material? copper or something? or do they already do that? and or is it not practical?
Lines have to be flexible to take the movement of the suspension
 

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Discussion Starter #14 (Edited)
Vash said:
If you look at some race bikes, they have a scoop that collects and channels air to the brakes. Its even more prevalent in cars, where brake loads are much higher.

Cooling fluid would most certainly help, but all the extra piping involved would take away from the feedback, so it would be a double edged sword. However, it occured to me the other day, that the same effect can be done with some one way valves and an extra line, if you could force the brake fluid to return from tha caliper down a different line than it came in (some modification to the master cylinder may be required). Basically the idea is to return the fluid from the very bottom of the caliper to the top of the reseruor during brake release. This way, instead of holding the same fluid in the caliper and letting it boil, you flush some of the fluid away, to return to the reservour where it can cool, and replacing it with cold fluid from the same source.

I might just try to build something like that.
Picture this, V.....a six piston caliper with two bleeder valves. Now picture a short, U-shaped piece of steel tubing connecting the two bleeder ports. Because the pressure is the same at both ends of the tube, there would be no flow, and because we're talking about a short, steel tube the would be very little added fluid volume and very little change in feel.

Make sense so far?

Now, we make the U-shaped steel tube about 8 inches long, we bend it into a compact 'wave' form, and we add cooling fins so what we end up with is a very small radiator. Of course, we still have no flow, but we have a circuit which starts and ends at the caliper, and which adds no more extra fluid volume than a standard 3-line system vs. a two-line setup.

So how to move the fluid without affecting brake feel, and without adding complexity or a lot of unsprung weight?

This is what I thought - a small pump attached to the leg lower, connected by a thin rod to the upper. Suspension action provides a source of reciprocating action. a piston driven by the thin rod and incorporating a one-way valve in its crown would pump fluid from one port, through the radiator, and back through the other port every time the suspension compressed.

When the brakes are applied, there would be no effect on braking action because pressure on both sides of the circuit would be the same.

What do you think?
 

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Interesting idea, thats for damn sure. I like the radiator idea, but the pump sounds abit scary. Is it located inside or outside the caliper?

Either way the rod has to enter thru some seal, which I dont entirely trust. especially considering the side loads on the thin long rod will be transfered to the seals.

Of course the simplest solution might be to put the radiator fins on the caliper body, and thin out the walls where possible.
 

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Discussion Starter #16 (Edited)
Vash said:
Interesting idea, thats for damn sure. I like the radiator idea, but the pump sounds abit scary. Is it located inside or outside the caliper?

Either way the rod has to enter thru some seal, which I dont entirely trust. especially considering the side loads on the thin long rod will be transfered to the seals.

Of course the simplest solution might be to put the radiator fins on the caliper body, and thin out the walls where possible.
The pump would be mounted to the leg lower and driven by a lever, since we would only want the piston to move a maximum of 1", not the full distance of suspension travel. The side loads and travel limits could be dealt with mechanically, on the rod side of the lever,so the reciprocating force delivered on the pump side would be straight up and down, and the pump would work like this - Say you had a bucket with a trapdoor bottom that would flip up when pressure was applied to the outside. When the bucket was lowered into a well, the water pressure would
push the bottom up, allowing water to flow into the bucket from the bottom. when you started raising the bucket, the weight of the water would force the bottom of the bucket to close, trapping the water in the bucket. In the pump, the piston would be the bucket, and the rod, working through a lever, would provide the force to raise & lower the bucket in the 'well', which would be the pump body.

The sealing of the pump where the drive rod entered wouldn't be impossible. The diameter of the rod that actually enters the pump body could be increased to the point where a rubber seal could be used, similar to the seals around your brake pistons.

Of course, the devil is in the details but I think the basic scheme is doable. Tell you what, V. You build the prototype, we'll sell it to Galfer, and we'll both retire!
 

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If you really think you can get the sale done, I can get a prototype built
 

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Vash said:
Lines have to be flexible to take the movement of the suspension
dont they make braided metal lines already? just change the material?

or just make a bizillion dollars off galfer:D
 

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Meat_Shield said:
dont they make braided metal lines already? just change the material?

or just make a bizillion dollars off galfer:D

The braided lines you see today are a teflon inner sleeve that holds the fluid, with a steel braid over the sleeve to reduce expension, and protect the line, with an outer plastic sleeve to protect against abraision. In order to conduct heat, you will have to have metal contacting the brake fluid, resulting in a line that isnt flexible.
 

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Discussion Starter #20
What up, Meat? Without fluid circulation, cooling the fluid in the lines wouldn't be effective. Vash, forget about the suspension drive for the pump. With the size and weight of electric motors available today, there is no need to drive the pump using suspension action. That would simplify the design. I like the internal pump design, because it would not be affected by the pressure changes of braking, but it may be a rotary design would be better. Any thoughts?
This design has no street application, but could conceivably give a racer an advantage. I never conceived of it as a money-making idea, just a mental problem-solving exercise, but if good answers are found for the most obvious problems I would present the idea. There have been significant advances in brake materials, but little change in brake mechanics for many years, other than radial m/cs' and caliper mounts.

PM me with a design , and we'll see if we can develop a marketable prototype.
 
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