Ironhead Better Brakes

[mikethebike61]

Originally Posted by RicThompson

If you find a caliper, disc and cylinder combination you desire it's really not that difficult to cut, fabricate, and weld. I'm running a late model V rod disc brake on my 75 slider. Got a nice big rear disc on my round swingarm too.

I bought a NOS set of LESTER cast wheels for a 78 up FX or 79 up XL...
bought a 79 swingarm and was going to use it but it was easier and less expensive....plus you don't alter the wheelbase...to just have Pete Hill fabricate spacers and weld on a tab for the anchor rod.

I now have 4 piston, fixed calipers at al 3 locations and a bike that stops....more than once....

[RicThompson]

I learned about that 79 swingarm after the fact or I would have went that rout. A little longer wheelbase is not such a bad thing. My bike looks small.

[mikethebike61]

Originally Posted by RicThompson

I learned about that 79 swingarm after the fact or I would have went that rout. A little longer wheelbase is not such a bad thing. My bike looks small.

But you also have to fabricate shock mounting and reinforcement on the square arm.....just not worth it in my opinion. Plus the wheel no longer sits correctly under the fender....so what do you do then..move the fender....

And SPORTSTERS SHOULD look small....because they are..

[RicThompson]

my rear fender and support brackets are custom fab nowhere near stock in appearance.

[mrmom9r]

Originally Posted by bustert

super +1
disk material and pad material must match up.
i have no issues with my 1974 ch front except torque steer on hard braking. the rears are something else. on them i made my own shoes with brake material from draw works, if it can stop a 1,000,000# load, what is a 400# mc.
the only draw back is increased drum wear so i will have to sleeve it eventually.
they are ugly but a non stainless rotor will have better friction. if you notice, autos have gone to powder iron, rust over night but works, and even on these, pad material makes a diff.

Did he say sleeve a brake drum?

[mikethebike61]

Originally Posted by mrmom9r

Did he say sleeve a brake drum?

Yes

It is a "lost art"

[Ferrous Head]

I think he meant to say, "Buy a new one".

Much cheaper option. For those of you who don't like long rambles on things, look away now. I'm going to pass on my observations about brakes.

Please bear in ind I look at things mostly from a road race perspective. I hardly ever ride on the road anymore but when I do. it's like an old man is behind the bars.

On street bikes almost any disc fitted from the factory will be adequate. The big brakes you see on race bikes aren't on there to provide more stopping power. The real difference is in the surface area. A larger surface area allows the brakes to dissipate the energy faster. That is, they will cool more between stops. Again. heat id the enemy.

Well, I say that but really pads work in a heat range. Too cold they don't work well, too hot they don't work well. This is why it's so important to pick the correct pad/shoe material for what your doing and the material the disc/drum is made from.

A correctly set up twin leading drum can help you stop FASTER than a disc.

But they simply do not cool down as fast as a disc does which is why we use discs and twin discs on race bikes.

If the brake does not cool down fast enough between stops the heat range of the brake pads gets exceeded and the brakes "go away" as we say.

Once your brakes ability to slow the progress of the drum/disc exceeds the friction coefficient of your tires contact patch with the road you have an immediate problem.

If this occurs in a turn at high speed and your name is not Cal Rayborn or Barry Sheene you are most likely going to kiss the tarmac.

So, will a correctly set up 8 inch twin leader lock a front wheel at speed ?

Yes, it will.

Drum brakes rely on cables which have some "compression factor". Hydraulic fluid is not really very compressible at all.

What this means for us mere mortals is that drum brakes inherently have more "feel" ie lever movement during the braking process than hydraulic systems.

When people have a mis match with master cylinder bore size and caliper sizes that's exactly what's happening. Their is too little movement between just dragging the pads on the discs and fully gripping them. We say they have a "wooden" feeling.
When people tell you they don't brake well it's just their brain failing to cope with the very small increase in pressure required to lock the front brake. It scares you because you know the brake will lock if you squeeze too hard but it's too hard for your brain to judge that pressure.

Coming back to the heart of the matter is the real limiting factor, your tires. That's why the manufacturers pour so much money into trad designs and compounds.

So I'm presuming here that the go faster crowd here is running something like Avon Ultra Sports in a wet compound ?

[RicThompson]

I run Pirelli MT66 Route 66 tires. 19 up front, 18 on the rear. So far I have no complaints. Not sure how they measure up compound wise to an Avon.

[mikethebike61]

Originally Posted by Ferrous Head

I think he meant to say, "Buy a new one".

Much cheaper option. For those of you who don't like long rambles on things, look away now. I'm going to pass on my observations about brakes.

Please bear in ind I look at things mostly from a road race perspective. I hardly ever ride on the road anymore but when I do. it's like an old man is behind the bars.

On street bikes almost any disc fitted from the factory will be adequate. The big brakes you see on race bikes aren't on there to provide more stopping power. The real difference is in the surface area. A larger surface area allows the brakes to dissipate the energy faster. That is, they will cool more between stops. Again. heat id the enemy.

Well, I say that but really pads work in a heat range. Too cold they don't work well, too hot they don't work well. This is why it's so important to pick the correct pad/shoe material for what your doing and the material the disc/drum is made from.

A correctly set up twin leading drum can help you stop FASTER than a disc.

But they simply do not cool down as fast as a disc does which is why we use discs and twin discs on race bikes.

If the brake does not cool down fast enough between stops the heat range of the brake pads gets exceeded and the brakes "go away" as we say.

Once your brakes ability to slow the progress of the drum/disc exceeds the friction coefficient of your tires contact patch with the road you have an immediate problem.

If this occurs in a turn at high speed and your name is not Cal Rayborn or Barry Sheene you are most likely going to kiss the tarmac.

So, will a correctly set up 8 inch twin leader lock a front wheel at speed ?

Yes, it will.

Drum brakes rely on cables which have some "compression factor". Hydraulic fluid is not really very compressible at all.

What this means for us mere mortals is that drum brakes inherently have more "feel" ie lever movement during the braking process than hydraulic systems.

When people have a mis match with master cylinder bore size and caliper sizes that's exactly what's happening. Their is too little movement between just dragging the pads on the discs and fully gripping them. We say they have a "wooden" feeling.
When people tell you they don't brake well it's just their brain failing to cope with the very small increase in pressure required to lock the front brake. It scares you because you know the brake will lock if you squeeze too hard but it's too hard for your brain to judge that pressure.

Coming back to the heart of the matter is the real limiting factor, your tires. That's why the manufacturers pour so much money into trad designs and compounds.

So I'm presuming here that the go faster crowd here is running something like Avon Ultra Sports in a wet compound ?

The ability to LOCK the front wheel, or any wheel for that matter, is not the true measure of a good brake system...hell, my 1970 and 1973 Sportsters would lock the rear wheel.....what you want is CONTROL....think 1977 Sportster vs 2020 1198 DUCATI.....the Sporty has a front brake that is damned near impossible to modulate...pretty much pull on it and how it's enough but not TOO much....whereas the Ducati gives you feedback and a degree of control not available in a single disc anything that I've ever ridden.

That includes 73 Sporty, 75 NORTON, 77 Sporty, 77 Superglide, 350 Honda, 450 Honda, 750 Honda, 1000 Z-1, Triumph Bonneville and Tiger.

No comparison to a dual/rear mounted caliper set up

[Ferrous Head]

Which is my point about why drum brakes can be more effective. You get more "feel" with cables than hydraulics. With a mismatched or poorly designed disc setup you don't get enough lever travel to have precise control.
And why I stressed that tires are of such importance.

Notice also that I prefaced that my comments are mostly based around racing.

At a walking pace any braking system will be fine.

As you increase your speeds it starts getting more critical. At race pace it's the difference between the Mick Doohan's (substitute your favorite fast rider here)of this world and the rest of us.

A lot depends on the how and how fast you ride thing.

If you have really hard or "race" compound pads/drums on they don't work very well when cold. So if you use those compounds on the street they might not reach operating temperature for you and you'll notice much higher pressures are needed.

"Softer" pads/drums provide more bite at lower te,peratures and are ood for street use.

Pad material also really depends on disc/drum material as has been said.

Brembo have been making some of the best braking systems in the world for many years. It's why the Italian companies adopted them so early on.

The Italians are very passionate about racing motorcycles. They built race bikes for the road, not road bikes that could be raced.

In the last 50+ years I've ridden every bike I could get my hands on.

And I can say I once worked on the brakes on Wayne Gardner's Kawasaki Superbike.