Drum brake vent holes....A different idea!

[Corsair]

OK guys....

I know we have some aerospace guys on here, and maybe you folks can answer this question......

I plan to drill the rear drum cover on my CB350 Four to vent some of the heat....and I thought about possibly elongating the top of each hole at a rearward angle (50-60 degrees) with the thought that this might help the gases to more easily escape when the bike is in motion.

My question is: Would this make a difference or not?

Thanks!
Robb

 

[kicker]

Possibly but probably not a noticable difference from normal holes.

 

[Tim]

Just remember, holes let water in as much as they let heat out.

 

[hillsy]

Just remember, holes let water in as much as they let heat out.

Bingo......

 

[Corsair]

certainly.

Sent from my Nexus S 4G using Tapatalk 2

 

[mydlyfkryzis]

You would be better with a front and rear facing scoop of some sort on the brake plate...sort of a ram air effect, and would be a little better in keeping water out.

I believe Triumph used to do something like that...always looked functional too...

 

[f22hb]

All road race drums either have or add on a forward facing scoop then something like holes to vent the air from the rear, but ask yourself if you've ever been under repeated hard braking to the point where you notice the brakes fading. Also, is the trade off on a street bike of exposing those drum components to all the elements worth it? I've been over it many times considering it, but I can't justify it. Just keep good pads in there, keep the rotor surface glaze free and the drums perfectly adjusted.

Edit: just realized this is for the rear brake. Which really just enforces my first question even more though. I can't remember the last time I used the rear brake hard on my cb350...

 

[Flugtechnik]

I'm having trouble visualizing what you mean. Do you have a pic of something similar or a sketch?

I have seen people put little scoops on their holes. That would definitely increase airflow.

 

[Corsair]

Flug.....

Here's what I have in mind....Drill the hole, then use a dremal to lengthen the top of the hole.

 

[mydlyfkryzis]

Honestly, I doubt the rear wheel hub gets much air flow externally anyway. It is inline with the tire, so is not really in a moving air stream at all.

I doubt that the holes would make a real difference in braking, as the rears don't do much anyway, and unless you are racing around at 100 mph, the size is more then adequate.

So what I am suggesting the holes don't really matter, nor the size or placement. they are just decorative. So make them how you like, how you wan them to look. Functionally they really won't make a difference in the larger scheme of things.

 

[Corsair]

Re: Re: Drum brake vent holes....A different idea!

Honestly, I doubt the rear wheel hub gets much air flow externally anyway. It is inline with the tire, so is not really in a moving air stream at all.

I doubt that the holes would make a real difference in braking, as the rears don't do much anyway, and unless you are racing around at 100 mph, the size is more then adequate.

So what I am suggesting the holes don't really matter, nor the size or placement. they are just decorative. So make them how you like, how you wan them to look. Functionally they really won't make a difference in the larger scheme of things.

Good points. I' m in the process of re-thinking my plans for both brakes, and you guys have given me some things to consider.

Thanks!!

Sent from my Nexus S 4G using Tapatalk 2

 

[Thump]

Corsair,

My .02, and take it at that much, is the back brake takes very little of the bikes stopping load so heat is probably not much of an issue. With that said though, I love the look of vented hubs such as the CZ front hub. So if your wanting to do it for asthetic reasons then have at it as that is what custom bikes are all about right? It's the little touches like your idea that I think make these bikes "one of a kinds"

Okay, we take you back to your regular programming...

Thump

 

[Corsair]

Here's what I came up with... I had started out drilling a series of gradually decreasing diameter holes in the top rear quadrant of the cover. But it didn't turn out to be what I wanted. so, following the webbing on the interior of the cover, I just hollowed it out and this is what I ended up with. I personally like it.

 

[mydlyfkryzis]

I would put some sort of screening over the slots. You don;t want any large debris, like a stone, getting caught up in there.

 

[ako]

If you are riding fast enough and braking with the rear enough to overheat drums, then how about an upgrade to disc brakes?

Or, if you are doing it to look cool, then just make whatever you think looks cool.

 

[Corsair]

Re: Re: Drum brake vent holes....A different idea!

If you are riding fast enough and braking with the rear enough to overheat drums, then how about an upgrade to disc brakes?

Or, if you are doing it to look cool, then just make whatever you think looks cool.

I did what I thought would...do the job, cost something I could afford, and yes look cool. In that order.

Sent from my Nexus S 4G using Tapatalk 2