Number of caliper pistons doesn't matter.

[Screwloose]

Adding to Mr S's contribution, drum brakes are less able to dissipate the heat generated and add significantly to unsprung weight.

PS: The fall of the Roman Empire is thought to have been caused by a carelessly discarded Corinthian pillar that they tripped over.

PPS: I see that del is back (#57)

Years ago whilst working in industry people would bring in brake drums (from cars/vans and bikes) to get turned, and the ovality was very severe on some of them. No wonder the footbrake would go up and down whilst braking. When some powerful vehicles used them and heat got to them they just went oval. Good for handbrakes at times, although the combined systems of disks and drums tend to add unsprung mass as above. Never weighed them but changed them over many a time, and cringe when I see the obvious of handbrake turns using drums, the heat just hangs in there and distorts, and wears them.

I tried to make the connection of the Corinthian Pillar with composite material (as in pads/shoes), but then realised we may be moving onto another subject as per Parminio above.

It's definitely an education on this forum!

 

[Parminio]

the ovality was very severe on some of them.

You shouldn't be trying to turn and true a rotary engine.

 

[Screwloose]

You shouldn't be trying to turn and true a rotary engine.

 

[DreamV4]

PPS: I see that del is back (#57)

I know! My wisdom is so important to you, you don't want to lose even one word! Maybe you should start copy/paste my every post?

 

[02GF74]

There are a lot of negative comments about drum brakes. They are not the work of the devil, firstly they are not affected by rain and can be be made to stop just as well as equivalent disc.

The disadvantage is they would be heavier which is the main reason they have been abandoned from modern vehicles.

 

[MaxMidnight]

I know! My wisdom is so important to you, you don't want to lose even one word! Maybe you should start copy/paste my every post?

Your wisdom?.....nope, you've got me there, still waiting to see some.

If you are going to delete posts then perhaps you could ask the Moderators or Admin to remove them?

 

[Fire-medic]

I think the #1 reason for disc brakes is they are better by design. They have superior cooling, they aren't prone-to fade as quickly, there are fewer parts, opposed pistons work better to 'pinch' the rotor than do brake shoes and drums which have to use much heavier construction to withstand the design of pushing out/against the drum.

Not sure where you got the "not-affected by rain" from, when I learned to drive, it was common practice to drag your brakes for a bit if you were fording deep water because the drums weren't for s___ the first time you used them, if you didn't. Very-few cars in the USA manufacturers' line-up used discs in the mid-1960's. Those that did were probably Corvettes, Lincolns, Thunderbirds, and other $$$ cars. Even the early pony cars and muscle cars still used drums.

From my store of trivial knowledge, I recall the Crosley Hotshot was the first production car to use disc brakes. Jaguar was also an early adopter. Crosley engines were also used in a great-many 'specials' i.e., sportscars built by backyard tinkerers, or racers on a budget. They were also used in midget cars for circle track use in the 1950's. Allan Girdler wrote a great volume on American sportscar 'specials' from the 1930's to 1970. I have it in my library. If you have an interest in American racing cars of this era, this makes for a great read.

American Road Race Specials, 1934-70: Glory Days of Homebuilt Racers by Allan Girdler (2014-02-26): Allan Girdler: Amazon.com: Books

 

[MaxMidnight]

There are a lot of negative comments about drum brakes. They are not the work of the devil, firstly they are not affected by rain and can be be made to stop just as well as equivalent disc.

The disadvantage is they would be heavier which is the main reason they have been abandoned from modern vehicles.

...but they do take more maintenance to keep them in optimum condition and the rain issue that affected early Japanese bikes does not seem to be a problem now?

However they do look good!

 

[Fire-medic]

The Japanese bikes used stainless steel for rotors, for appearance-sake. They did not work as-well in the rain as iron rotors, and that was the problem.

 

[Screwloose]

...but they do take more maintenance to keep them in optimum condition and the rain issue that affected early Japanese bikes does not seem to be a problem now?

However they do look good!

Not half. Very nice.

Is it my imagination, but the design looks like the brake shoe may get forced out at each end of the shoe, rather than pushing at one side, and a pivot at the other in older designs.

 

[Fire-medic]

SLS vs TLS

I'd heard that the SLS is a better 'hill-holder' than a TLS.

Grimeca and Fontana were high-end drum brakes.



There was a British guy who made drum brakes, Eddie Robinson, which had a good reputation (below). He began his production in the 1950's. This one appears to be a 4-shoe brake, but w/o a pic of the other side, who knows?



Giacomo Agostini, who knows something about high-performance bikes, continued to use TLS/4LS drum brakes after he could have switched to discs.

Then there was the Munch Mammut (Mammoth in English-speaking markets) with its TLS-drum brake, made of a special alloy. Colin Seeley made a 4LS drum brake. As you can see from the chart below, Suzuki also made a 4LS drum brake.

Here's a sheet on drum brakes specs:

Model OD x shoe width Swept area Radius x S.A.

Suzuki drum brakes

(square inches) braking coefficient

GT550/750 4LS (200mm) 7.81" x 1.0" wide (x 2) 49.07 191.6​

T500 (1967) (200mm) 8.00" x 1.6" 40.21 160.8​

T350 (1970) (180mm) 7.12" x 1.12" 25.06 89.21​

X-5 Invader (160mm) 6.25" x 1.09" 21.4 66.87​

Kawasaki drum brakes

H1R 4LS (250mm) 9.87" x .75" (x2) 46.53 229.74​

H1 (1969) (200mm) 7.90" x 1.4" 34.74 137.22​

A7SS (180mm) 7.00" x 1.2" 26.38 92.33​

Yamaha drum brakes

XS-650 (1969) (200mm) 7.80" x 1.3" 31.85 124.2​

YDS-6 (1967) (180mm) 7.02" x 1.17" 25.8 90.3​

TD 3 (260mm) 10.29" x 1.06" (x2) 68.53 352.6​

entire front wheel assy, inc. 19" alloy shoulderless rim (36 spoke), axle and​

TT100 tyre and tube (and valve and cap!) is 18.5 kg.​

Each brake backing plate assy: 2.25kg​

Honda drum brakes

CB350 (1970) (180mm) 7.08" x 1.18" 26.24 92.91​

CB175 (1971) (160mm) 6.20" x 1.18" 22.98 71.24​

CB77/1968 CB450 (200mm) 7.88" x 1.18" 29.21 115.08​

Bridgestone

350 GTR (190mm) 7.40" x 1.2" 27.89 103.20​

175 (160mm) 6.20" x 1.18" 22.98 71.24​

Bultaco drum brakes

250 Metralla (160mm) 6.30" x 1.6" 31.65 99.69​

Ducati drum brakes

250 (180mm) 7.08" x ???​

Bianchi

500 GP (230mm 4LS) 9.5" x 1.25" (2) 74.61 354.41​

BSA

Gold Star (200mm SLS) 8.0" x 1.375" 34.60 138.42​

Moto Morini

350 Sport (Grimeca 230mm Dual-SLS)​

9.05" x 1.16" (2) 65.96 298.47​

Munch

Mammut 2LS 10.0" x 2.0" 62.83 314.1​

​

The Munch Mammut (Mammoth in English markets) was a hand-built ('bespoke' in the hipster tongue) bike designed and built in West Germany. It used a magnesium alloy which was used in aeronautical designs during WW II by the Luftwaffe. The engine was from a West German automobile the 1,000cc NSU TTS. The frame was a copy of the Norton Featherbed. The bikes were hand-built and because you could order it with a variety of options, it's probably safe to claim, "no-two were exactly-alike." I have pics of Friedl Munch at Daytona Bike Week, he came to the USA at the invitation of a Munch enthusiast who lived in so. FL, who was an acquaintance of mine. The front drum brake was Munch's design.​

​

Munchs were at-first carbureted, and as they grew in displacement, they also were fuel injected. As-massive as they appear, they were actually light in weight, especially compared to a Harley-Davidson of similar or larger displacement. NSU besides the TTS air-cooled engine used in cars and motorcycles, was also the first European manufacturer to sell a rotary automobile, the RO 80. Another West German manufacturer, Hercules, was the first manufacturer to sell a Wankel-engined motorcycle (W2000). It was a single-rotor air-cooled design, with a bit of a resemblance in the engine to a jet airplane, due-to the cooling air intake. Then Suzuki released a much-larger displacement water-cooled 1-rotor rotary-engined motorcycle, the RE-5. Styling was courtesy of Giugiaro, who had and would continue to have success with automobiles, but his design for Suzuki was well, weird. An unusual list of components got styled to remind owners and observers that this engine didn't use pistons! Later models were more conventionally-styled. It lasted only two years.​

​

​

​

Here's a pic of a Moto Morini which has an unusual design, it has two narrow, parallel SLS brake shoes instead of one wide one. The giveaway is the actuator arm on both sides of the drum. This is the famous 3-1/2 model which uses the Heron combustion chamber in the piston crown design, like the Jaguar XK-12 engine. One of my friends has one of these. He bought it from one of my co-workers, who bought it new.

 

[CaptainKyle]

Still trying to determine if John H and Eagle Pi had a kid together. Lmao

 

[Screwloose]

SLS vs TLS

I'd heard that the SLS is a better 'hill-holder' than a TLS.

Grimeca and Fontana were high-end drum brakes. There was a British guy who made drum brakes, Eddie Robinson, which had a good reputation. Giacomo Agostini, who knows something about high-performance bikes, continued to use TLS/4LS drum brakes after he could have switched to discs.

Then there was the Munch Mammut (Mammoth in English-speaking markets) with its TLS-drum brake, made of a special alloy. Colin Seeley made a 4LS drum brake. As you can see from the chart below, Suzuki also made a 4LS drum brake.

Some bizarre looking figures in there. Bianchi S.A. 354.41? Dont get me wrong, It's my miniscule brain that cannot understand why.

It is clear that SS (stainless steel) rotors (as you mention above) do not work as well as iron in the rain, and motorcycle front rotors are exposed to the elements.

Going back to the question; Agostini was the best, he may not have wanted high pressure breaking, but more of a feel, he may not have had the same feel with pads; so they may not have been better for his requirements.

Maybe the SLS by mechanical play, takes a bite into the opposite material by it;s own mechanism (increasing a force at a point). Where TLS may have been trying to distribute forces and bite over an area. It could be leading edge bite V's trailing edge bite when trying to put force on an object.

Did I put that across correctly, as I'm trying to say that the mechanism and play would naturally force itself to dig into an object on it's leading edge, and maybe this is why SLS V's TLS.

 

[VMAXXIMUM]

Still trying to determine if John H and Eagle Pi had a kid together. Lmao

That is hilarious Kyle. You should work up a piece of commemorative art in their name. I for one would love to see what you come up with.

 

[Parminio]

Comment removed by Fire-medic

You mean proving you wrong with essentially every single post you've ever made?

Yeah. OK. Tell yourself whatever you need to tell yourself to get through the night.

 

[Fire-medic]

Insults and demeaning comments will be removed.

 

[DreamV4]

Amazonas 1600cc had rotor brakes.
https://www.odd-bike.com/2012/12/amazonas-1600-beetle-powered-brazilian.html

 

[CaptainKyle]

That is hilarious Kyle. You should work up a piece of commemorative art in their name. I for one would love to see what you come up with.

I already have enough of the blind followers pissed off at me for ragging on him & they are listening to him which I could care less about. I don't feel like going back all the years and digging up all the facts on him I really don't think most would listen ! I have been getting more carburetor work than normal following behind him so it ai'nt all bad.LMAO

 

[MaxMidnight]

Not half. Very nice.

Is it my imagination, but the design looks like the brake shoe may get forced out at each end of the shoe, rather than pushing at one side, and a pivot at the other in older designs.

No they are eight leading shoe, four shoes on each side of the hub.

 

[Screwloose]

No they are eight leading shoe, four shoes on each side of the hub.

Aha, that would make sense then for improvement over the old system, as the diameter of the large shoe never perfectly fitted the drum, so make more of them, and getting the benefits of keeping them dry in wet weather.