Front Disc Brake Modification

Poke out the rubber restrictor hole to get more brake than traction below 50 mph which don't change ratio but sure does allow hand grip force to get to tire patch. I tease thee not. Put on RGM race lever and get about as much ease as the 12 mm bore which gives about 21:1 ratio compared to 17:1 of factory. My SV has like 25:1 and it don't stop any faster but is a whole whole lot more dangerous when panic control needed, I tease thee not. I have almost the strongest grip I've test in clinic over 130 bl and good days 140, via digital instrument and for the life of me could not get Trixie to squeal an old hard tire and barely on THE Gravel but now must use caution below 60 and will put on 110 instead of 100 next time for more whoa of sudden hazards.

I'll have to try your mod Ludwig on my factory Combat brake out of curiosity but will be pissed as hell if I can't control it down hill on THE Gravel or wet grass and leaves. Not everyone has a shop at home or nearby and you've only recently revealed it so not yet common awareness to act on it. I saved your reference to try but I don't understand its hydraulic principle to alter pad pressure bias by just removing some of the rim on the pressure side. Peel might do it on her SS pucks to save mass. I didn't think just poking out the restrictor 'valve' would be so reassuring either. I'm brake skidish of too easy a grip, hair triggers are for snipers not fast draws in a hurry.

Ludwig,

I don't anyone disagrees that this mod can improve the stock brakes. Thanks for posting the info.

Dennis

Relax I am not contesting the mod don't work Ludwig, glad you'd showed us something new to do. I just have not yet understood how it works to put more pressure on on trailing or leading surface of friction pads. Only thing I can think of is the rim trim allows some rocking of the pucks in the bores. I will look up famous brand references you left but my concerns are generally opposite of every one else and one of them is having too easy/too much leverage or self energizing or non linear friction development per grip application. I am over my last crash 2 mo's ago trying to slow on 30' loose steep from 30 mph d/t 3 big dogs out to impress each other on chasing something while on SV650 and kept the front from locking while making some rough rock rolling noise over some dozens of yds but either my subconscious or the character of the rear disc dragging friction locked as dog crossed right in front of me SPLATT @ 15ish mph. Some times at legal pavement speed have to trail brake like the racers technique I abhor so brake power ain't my concern nearly as much as staying short of lock up in loose traction states. If it'd of been a logging truck&trailer or a log across path I'm fear practiced enough now to lock both brakes and toss down sideways off the path to avoid the impact or under the wheels. SuVee is still down for the count - again. I see some the spectacular dangerous places you take you C'do as similar to me so expect I'll be pleased by the control the mod provides, just don't know till I try it and wonder if other motorcycles have used it.

Ugh, I had the pucks oriented installed the wrong in my mind so now see its the puck contact that is unblalanced. I can see the logic of arranging for more trailing edge pressure on regular rotor surfaces but might not work out on my wave rotors that claim its benefits are due to more edge to edge encounters and need pretty tough pad material to last a while.

Hello All,

Sorry to post on this thread again, not wanting to hi-jack it!!, just wanted to say thank you to worntorn, al-otment, hobot and ludwig, and all the other interesting and informative posts on here!.

I do have a couple more questions, but had better start my own thread.....

Thanks all,

John

Norton Dave said:

I thought this is the reason for multiple pistons ??? •Differential bore calipers -- As the surface of the rotor heats up, the clamping force of the pistons has to be increased to avoid brake fade. If the caliper has multiple pistons (or multiple pairs of pistons), the brake rotor surface is initially heated by the pistons pushing against the brake pad at the leading edge of the caliper, making the rotor surface hotter when it rotates back to the pistons closer to the trailing edge of the caliper. Therefore it helps if the pistons closer to the rear edge of the caliper are larger. Differential-bore calipers use smaller pistons up front, larger pistons toward the back.

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A load of technical jargon that is a load of b/s.
The smaller diameter pistons should always be the leading pistons according to disc rotation
i.e. On the Left hand side of the front wheel, with the calliper mounted behind the fork leg, they are at the bottom , the larger pistons at the top.
The true reason of why four pot calipers were invented was because AP Lockeed / Girling were always having the disc pads wear at a taper on twin pot opposed piston calipers, they found that if you fit a 4 pot and have the leading pistons smaller ( about .750 smaller) the wear in pad taper was not so pronounced.

Huh, didn't know about the unequal pad wear-size issues on multi pad brakes. What references state is main reason for multi small pads was the rotor friction band was made narrower so needed more pads to make up the lost surface area. The main reason for narrower rotor friction band was the difference in speed between inner and outer parts of the contact patch, so outer parts got hotter than inner parts which caused rotor thermal distortion.

Bernhard said:

...The smaller diameter pistons should always be the leading pistons according to disc rotation ...... with the leading pistons smaller ( about .750 smaller) the wear in pad taper was not so pronounced.

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thanks .....didn't know that!! just another reason I love these threads :^)

hobot said:

Huh, didn't know about the unequal pad wear-size issues on multi pad brakes. What references state is main reason for multi small pads was the rotor friction band was made narrower so needed more pads to make up the lost surface area. The main reason for narrower rotor friction band was the difference in speed between inner and outer parts of the contact patch, so outer parts got hotter than inner parts which caused rotor thermal distortion.

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Re; “

hobot said:

Huh, didn't know about the unequal pad wear-size issues on multi pad brakes.”
Should not be a problem in multi 4 pot calipers.
When Lockheed invented and patented it, (the owned the patents for both 2 & 4 pot opposed pistons calipers) they took it over to show it to the big four bike makers in Japan, but because the Japs hate paying anybody royalty fees, there were no takers, however, within one month of their visit, 2 piston calipers on sliders came out on their bikes- they were still wrong because both the pistons were of the same diameter, so the pad still wore at a slight taper :?:
Those little men from Nippon are not so smart :shock:

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