Modern Vespa

Finally got around to taking a picture of the Hot Rod Al drilled front hub.

It is hard to see from this picture, but those holes intersect the surface slightly, about 1/2 wide but very shallow.

That creates a channel to scrape clean dust and mosture from the pad surface and sweep it out the holes.

Combined with the grooved pads I got from Travis and a cam pulley to increase the leverage, the brake should approach a disc in stopping power. It is enough to lock it up from what Al has told me.

The price is $35 I think, you provide the hub to be drilled.

That looks cool.. I bet it'll work great. Does he, can he? do the rear? Same concept or..?

I like the holes... can you send a pic when it's on the bike?

so now you can only ride in a dry clean environment?

Yeah, as Bitsa said, the only part that worries me is riding in the rain.

I like the improved cam and grooved brake pads. I do not like having the brakes that exposed to the elements. Maybe the holes could be smaller? I'm not an engineer though.

Hmm. not sure there would be a problem.

There is not that great of seal on the back of the hub anyway, except up at the spindle.

With the hub spinning about 2600rpm @ 30 mph it would fling any water back out pretty fast.

I remember a mod with debris screens, I actually think that would look cool if I could get some plug inserts and put wire mesh over them after drilling out the cap.

Waste of time.

Thanks for the "input".

Next time, don't waste your electrons.

The TV/SX Disc Brake for Lambretta's had those cut outs.

http://jet200.com/catalog/product_info.php?products_id=763

Yeah. It is a disc brake.

I'm not saying the holes don't perform a function I'm just pointing out that most of the benefits of this type of modification are so incredibly marginal as to be actualy a waste of time doing it all. So much crud will get inside that hub you will be amazed. The best thing to do is to machine a groove on the inside of the hub for debris and the channel your brake pads. I know you spent your hard earned cash on a new piece of kit and you want props for doing it. The yes men on this board will give it to you in spades, but not me. The only thing about that hub is it looks cool. That's it.

Why not drill some holes in the side of the headset to cut down on wind resistance? Would it work? Yeah, probably.

Why do you all just vomit "+1" all over everywhere? Why don't any of you offer critical commentary? Shills.

Looking forward to your feedback on how it performs.. and some pics when it's on Russ.

I had a hamster named Rusty. He ate the rubber coating off his Fun Wheel and died. Who'd have expected that, really?

aren't the grooves going to make the brake pulse and grab?

Wouldn't think they would pulse, they grab over such a large area of the brake pad.

This is not new stuff, it has been around for years, it is just that the 90s and early 2000s were not very good ones for scooters so people forget about these things.

I don't understand this. Please explain how the ratio of the pad surface area (coverage area) and the braking surface area in the drum create a relationship so "pulsing" would not occur.

Or you could not, if you don't want.

You've been watching Gleaming The Cube too much.

SFver, go troll somewhere else.

No, for the same reason they don't on disk brakes, the surface is not warped, it is a groove. The grooving and holing can be pretty radical on disc brakes with no issues.

Why? because the surface of the brake pad to the grove size is small in relationship.

A pad is 5 inches long, and each grove is 7/16. 2 can come in contact with the brake at one time, but they are on opposite ends. Total contact lost contact area is 14/16th of an inch, or 7/8th. Roughly 20 worse case, 10% for most of the rotation. Not very radical.

More is probably lost by the 1/4 groves cut in the surface of the pad itself on the brakes.

They will wear out fast, but hey, they cost next to nothing and since the disc conversions are not available, this is an old school solution.

This is simple stuff compared to say:



or

You are comparing holes in the braking surface to holes in the side of the drum?

No, you are talking about them apparently. Why, I have no idea.

How the hell would holes in the side of the drum cause the brakes to shudder and grab?

Clearly, one would have to be talking about changes to the surface of the drum, if one were being serious about the conversation and wanted to contribute usefully.

Those holes don't do enough to write home to mom about. They just look cool. You can gibber-jabber all you want about braking performance, but the holes don't contribute to much. I'm willing to bet they let in as much crap as they let out.

Normally I tend to agree with Chris and the majority of his posts but unfortunately not this particular one.

Here's my S2 Lambretta hub from Hot Rod Al:







As RG suggests, drilling hubs is nothing new. They've been doing it in the motorcycle world since forever.








Some even came from the factory that way. It's primarily for cooling but you'll probably see less debris/dust in there when compared to stock drum of similar mileage.

The real trick is to run some mesh around the holes to keep the big stuff out so they can do their job.

The way that he drills the actual drum surface into smaller sections helps keep the brake cooler, which is extremely important when running one of Al's brake pulleys as that bastard would warp right quick without them.



Outside of that? Shit looks trick as fuck.

See, Rusty? That's how you show someone what's up. Don't get so up in arms. Get engaged and be a part of it. I've got zero problems with being told I'm wrong.



Thanks for the show and tell, P-P.

I know they have been doing it in the car world forever as well, Ferrari and Lotus to name a few were drilled from the factory.

Finding pictures of it on the web is very hard tho, I would be curious to see where you got them, or are they yours?

The logic of why to do this is so patently obvious I don't understand any reason why people think it would be an issue. Look at the NewFren shoes, they have channels cut into them... why? Because it works. Larger brake shoes for cars have holes and groves, because it keeps the drum looking stock but provides greater stopping power.

Absolutely essential if you are going to drive your classic 20s to 50s car around other cars that have superior disc brakes that stop on a dime.




Maybe if Chrissy did not bitch so much and did some research before declaring "it won't work" I might think he knows what he is talking about.

Generally tho, all Chrissy does is make broad sweeping statements about how everyone else is wrong. It is sort of like dealing with Sheldon from Big Bang, but without the charming super intellect behind it.

Hell, if Chrissy came with some basic mechanical descriptions behind his argument rather than claiming we are all "yes men" and reductio ad absurdum suggestions like drilling holes in the headset I might think he had a point.[/i]

The Lambretta hub is mine, the rest are from Google. I have a lot of vintage motorcycle experience so it helps me know where to look.

Any Yamaha TZ drums or 4ls brake drums have to be drilled do to the insane heat and stopping power they generate.

I'm not debating the holes in the "side" of the drum, they might let dirt in that could scar the braking surface but will help cool things.

I was wondering more about the holes where they continue into the braking surface of the drum causing a groove. The brake pads pivot out so there is more surface presure near the tip until they wear down. I was thinking the tip would get into the grooves and grab and/or pulse.

If this works, I'll throw my hub up on the mill as I think the front drum brake on my p200e sux to high heaven. It is just that there is so much shudder in the front under heavy braking as it is, I would't want to introduce more.

Drum brakes aren't as efficient as disc as the surface area of a disk brake is so much more. Also, the holes in the disc aren't large and clear across as the drilled drum. If you look at the slots in the disc above you will see they are angular compared to the rotation axis so they won't grab. Lastly, It is my understanding the holes are drilled to lighten the disc where the grooves are to remove contaminants.

So has anyone tried this out with the holes cutting into the braking surface?

My cutdown has a front drilled hub.

Front braking is night and day, anyone who says differently is talking out of their arse.

It's very important that you drill the side too. Every 3 then skip one

Racers have been doing this since the early 60's.

Cheers

The observation I was putting forth was that the holes would provide results not worth the time and expense of the work. However, I'll recognize my thinking as shallow considering other work will be done to take advantage/magnify the gains.

I'm still not convinced comparing stuff on a Ferrari with a drum on a Vespa is something I'd participate in.


Edit: I'm going to try this on my P just to see.

Do it Chris. I can assure you, you will be less of a twat

In the meantime.......

Trip Trap from 1965

Cheers

Get the pulley to if you can. It's so stupidly simple of an idea, I had to slap myself for and have an aha moment after looking at it.

2 fingered drum brakes? Yep, I'll take those, just not on anything pre-p or an undampened lammy fork as I like my teeth in my mouth.

Hot Rod Al did his magic to my kitted P's front brakes about 15K miles ago and it was magical how well it stops now. I can't believe a disc would be any better!
Drilled hub and cam pully to increase force. I have not needed to change the shoes in that time and have only needed to adjust the pully position once. I have had to adjust the cable ferrel 3 or 4 times during that same time. Because of the pulley you need to have an extra clutch cable for a spare as a longer cable is needed. It is probably good to have extra clutch cables around anyway.

I actually have one of Al's cam'ed brake leavers.

Putting a pulley on it gives you more mechanical advantage in exchange for travel.

The cam gives you back some of that lost travel.

Once again, I think your assessment of the benefit of this modification is generous to the point of excess.

(Please hold this space for future insertion of appropriate emoticon.)

You just exceeded my expectations.........

Obviously you spend more time typing than riding. I can't possibly expect a more fruitless reply. No emoticon required.

To the other members who actually ride more than talk bullshit.......

I know some of you know, however, I failed to mention why I have a drilled front end.

Project bastard was built (As a challenge) to race from Camden to the top of Mount washington and back. As I was the only scooter to compete and had a very limited budget ($500) I selected to go with the old school hub mod. The grade is typically 12%, on Mt Washington, it's a crazy road that typically do not allow scooters. I used the front brake almost the entire distance on my descent from the mountain.

I recently removed the front hub to check out the pads. Despite some wear there was no noticeable glaze on the pads. The holes did the job and limited the heat transfer.

http://mtwashingtonautoroad.com/start-your-adventure/faqs/

So, there begs the question, if you need to be on your brakes constantly, then it's a wise move. If your sole purpose is to have something look cool, that's another question.

Between hatching the pads, drilled hub, dog leg levers, stainless cable. My front brake is amazing!

Cheers

You guys didn't answer my question.

1) The hubs I have seen since the OP post have been drilled higher up on the side. It doesn't look like they cut into the braking surface on the hub.

If you cut into or groove the braking surface with a drill bit, end mill, etc, to the same diameter of the hole, it seems to me the brakes will pulse as the edge of the pad dips into the groove. Is this not the case?

2) As to the pully system, where can I get some more info? I can see where the pully would give more power with longer travel, no debate, that's how pulleys work. How would a cam not offset this? I would think that if you use a cam you will take away the travel but the increase in travel is what gave you the added power. So how can this work?

I remember seeing a lever system on a pair of pliers that supposedly multiplied the clamp pressure but again, a lever works by trading distance on one end for power on the other. You can't have both.

So adding a pulley giveth; adding a cam taketh away, no?

Here's some info Jerry:

P200 brakes. Can I make them grab better?

I'm sure you can ask JWilliams for specifics



Jim.. great endorsement... I just e'd Al and I'm going to send him my REAR hub to do... The rear pads on my P seem to glaze quickly.. not sure if it's from Extra heat from my exhaust or what (I don't know if that's even a reasonable thought but... ) Anyway, Al seems to think the rear will benefit from this mod, and I think for 25 bucks I'll give it a try... a rear disc which I have an H-on for is toooooo much bread.

I'm going to look at JWilliams setup and see if there's something to be done for the rear brake in terms of a pulley... have no idea yet.

You don't get both at the same time, what you get is slope, and you end up "better distance" when first applying the brake and then better leverage as you pull the handle in.

Which is exactly what you want, a shorter leaver to bring it in contact, then a longer leaver as you ask for more braking power.

Let me try and verbally explain it.

If you look at the one that jwilliams built, the pulley is off to the right of the brake arm.

Al's is a pulley that is mounted off center to the left, about 3/4 or more of the way to the edge, and has an extra anchor point where you place a standard cable trunnion to keep the pulley from rotating out of position.

You arrange the pulley so it's starting point is below the stock anchor, say 8 o'clock or so, using the brake arm pivot point as the center of the clock and the trunnion slot as the hour hand. So at this point, you get more distance but less leverage, engaging the brake to the surface.

As you pull the brake, it rotates and makes the effective arm longer, giving more leverage and applying more pressure to the shoes.

As for the leading edge question... I am sure that it does contact it differently, but it does not pulse any more than a stock one does. Again, the angular speed is about half the road speed, so those slots are going by at 15mph, or about 22rps, or 110 contacts per second.

It does wear them out faster, much faster. The surface gets scoured and never glazes over.

P.S.

This is not a part Al makes available, if you ask him about it, it is not for for sale.

That's just genius! I'm guessing Al got straight 'A's in geometry.
Thankyou for the nice description & pics.

How did you go with the brake? Is it all set up? Pictures?

I still don't quite get how the cam in the picture works without seeing it in place.