How Much Better are Dual Front Discs vs. Single?

Mis-matched parts will cause you greif in your front brake system. Using a single disc master cylinder on a dual disc front end will not provide the correct ratio needed to brake efficiently and vise versa.
Single disc or dual disc, it really comes down to the small patch of tire that you have on the road. If your brake system continuosly lock up the wheel and has no modulation(its either on or off), then reguardless of if it is a single or dual disc, it doesnt "really" work at all. If your brakes easily overpower the tiny tire patch in contact with the road, it does you no good at all.
I've used both the single and dual on my KZ 900 and they both worked fine, but the added weight of the 2nd disc and caliper just made the front end feel heavy. I did like the symetrical look of the dual disc though.
Most newer sport bike master cylinders have an adjustable lever on them. With the adjustablity of the lever you can often place the braking action of the calipers to be in a comfortable reach for your fingers (on the lever), giving a better feel and more confident braking.

Heres a link where the stock Honda 11/16 master cylinder is replaced with a 5/8 newer style master cylinder to improve the braking action and feel of this dual disc brake.

randakks.com/Brake%20Parts.htm

There is also a link in there for "Vintage Brake Ratio Chart". The info on the chart should be used as a guideline and not taken as "set in stone" as there is no chart for "Personal Preference".

The quickest, easiest way to "improve" your brakes is to replace your stock rubber lines with a set of braided brake lines. Getting rid of the flex in the lines will give a better feel at the lever and in turn better braking.
JMO

I'll guarantee I can stop much faster without the "aid" of ABS in my Ford trucks. Like I said, they only have 2 wheel ABS. Assuming the brakes are strong enough to lock all 4 wheels in a panic stop, so I'm driving along at 40mph and come up on a loose dog staring at me in the middle of the road. Without ABS I jam on the brakes, lock up all 4 wheels, have no contol and hope for the best unless I choose to use some skills. With the wonderful Ford ABS I jam on the brakes, instantly the ABS kicks in and disables the rear brakes, so I slide with locked up fronts and no rear brakes out of control. Either way I don't have a lot going for me, but I can always stop faster with 4 wheels brakes than only 2, I know that much. I'm sure the new cars modulate the brakes 55 times every second, whatever. My ford does not modulate, it simply turns off the brakes on the rear and not for a split second, they'll be off for several seconds before the ABS is dead sure the wheels are not locked. Seeing as they recall vehicals for anything, they should have recalled these brakes. Several guys on the Ford diesel newsgroup have been in accidents solely from the ABS system Ford used. So I've been ruined for life on ABS, I'd be thinking of this every second I rode a motorcycle and it would take quite a while to build up my trust in them.

Z1109R Fin wrote:

bountyhunter wrote:
The point made was that the stock brakes (single disc) have a proportional amount of braking for a given pressure. A light pull gives a light brake and a hard pull puts my face in the windshield. There is no advantage to having a brake system that locks the wheel with a light pull, it effectively moves system operation towards digital (on/off) instead of an analog one (proportional). I'd rather have the brake work like it does now. I have enough brake power to lock the wheel, I can't use any more than that.

As for panic stops..... practice them all you want, but if there is a truly life threatening situation, 99.999% of people will yank hard on the brake. That's why ABS systems were developed, I wish they had them on bikes. I don't want a hair trigger front brake.

Pheww, so you are saying that modern bikes have more or less on/off -brakes?

No, I was clearly saying the obvious: my single brake is designed with a usable range of braking force corresponding to brake lever force. Light pull = light brake, hard pull = heavy brake force. That is called an analog or linear system with a usable range. If I have a system where a very light pull results in hard braking, THAT IS AN ON OFF BRAKE SYSTEM. Light pull = front wheel locks. Medium pull = front wheel locks. hard pull = front wheel locks. Reducing the rider's the usable range of lever force does not make it easier to use safely, it makes it harder.

Read back through the posts and you will find more than one post referring to the reduction in lever force when the second disc was hung onto a bike designed to run one.

Z1109R Fin wrote:

bountyhunter wrote:
The point made was that the stock brakes (single disc) have a proportional amount of braking for a given pressure. A light pull gives a light brake and a hard pull puts my face in the windshield. There is no advantage to having a brake system that locks the wheel with a light pull, it effectively moves system operation towards digital (on/off) instead of an analog one (proportional). I'd rather have the brake work like it does now. I have enough brake power to lock the wheel, I can't use any more than that.

As for panic stops..... practice them all you want, but if there is a truly life threatening situation, 99.999% of people will yank hard on the brake. That's why ABS systems were developed, I wish they had them on bikes. I don't want a hair trigger front brake.

Sorry Bountyhunter, I really don´t buy your arguments on this.

Fine with me.

Z1109R Fin wrote:


So did you try to make a panic stop with rear wheel up?

Here is some advice from somebody with 45 years on two wheels with motor: real world panic stops are not like the ones you do playing around. First of all, you will be trying to move laterally to avoid hitting whats in your path. Do you know how much steering you have with the back wheel in the air? NONE You will also not want the bike in the air if it comes down to having to lay it down on it's side to use for protection to keep from going under what is in front of you. One wheel stops look great on magazine covers. beyond that, not worth much.

To sum it all up:

1) Do I need dual disc up front?
-Not really unless racing, your milleage may vary.

2) Is it hard to convert to dual?
-No, just make sure things are symetrical. Same fork legs, rotors, etc.

3) Does it matter what master cylinder I use?
-Yes, find one that works for dual disc setups. Mine is off of a newer sportbike, others have used OEM masters from other bikes that were dual disc from the factory.

4) Where can I find parts?
-Ebay, Z1, salvage yards, etc...

5) What now?
-Order parts and go ride until they show up.

eddiem wrote:

Four

As someone who has to deal with ice six months of the year, Five!

bountyhunter wrote:

Z1109R Fin wrote:

bountyhunter wrote:
The point made was that the stock brakes (single disc) have a proportional amount of braking for a given pressure. A light pull gives a light brake and a hard pull puts my face in the windshield. There is no advantage to having a brake system that locks the wheel with a light pull, it effectively moves system operation towards digital (on/off) instead of an analog one (proportional). I'd rather have the brake work like it does now. I have enough brake power to lock the wheel, I can't use any more than that.

As for panic stops..... practice them all you want, but if there is a truly life threatening situation, 99.999% of people will yank hard on the brake. That's why ABS systems were developed, I wish they had them on bikes. I don't want a hair trigger front brake.

Sorry Bountyhunter, I really don´t buy your arguments on this.

Fine with me.

Z1109R Fin wrote:


So did you try to make a panic stop with rear wheel up?

Here is some advice from somebody with 45 years on two wheels with motor: real world panic stops are not like the ones you do playing around. First of all, you will be trying to move laterally to avoid hitting whats in your path. Do you know how much steering you have with the back wheel in the air? NONE You will also not want the bike in the air if it comes down to having to lay it down on it's side to use for protection to keep from going under what is in front of you. One wheel stops look great on magazine covers. beyond that, not worth much.

This is true, I´m not arguing with this statement. Only on braking power being on/off as you mentioned earlier. Seems that you are saying that more power means automatically "digital" or "on/off" -brakes which is not true. You will have more control on braking if you don´t have to yank it with everything you got. Check MotoGP. Those guys are braking so hard that their rear wheel is slighly up and they still have perfect control. And no, I´m not referring to my ability to ride being anywhere near that but simply saying that more power means more control. Not less control or digital or what ever!

Bluemeanie wrote:

I have to stick up for the single disc. I've ridden both and IMO my larger single disc stops as hard as the smaller duals. Just my .02

what do you polish those rims with i want to polish mine those are awesome

Ted

My question is...When installing a different 18" wheel with duels on a forks that had a larger single, the mounting holes for the calipers are different by about 1 cm. And since the duel rotors are smaller there is not as much pad surface in contact. Should you swap the forks as well or call it good?