Hub Drum Brakes

For discussions about bikes and equipment.
User avatar
fausto99
Posts: 419
Joined: 19 Sep 2011, 10:06am

Re: Hub Drum Brakes

Postby fausto99 » 2 Aug 2018, 10:13pm

Brucey wrote:the only thing is that chainstays are more nearly -if not actually- parallel-sided, unlike most forks...

Great stuff. Never thought of that. You've clearly been there, seen that and bought the T shirt :lol:

I will have to come up with something though. I'll re-look at the chainstays to see how tapered they are.

User avatar
fausto99
Posts: 419
Joined: 19 Sep 2011, 10:06am

Re: Hub Drum Brakes

Postby fausto99 » 5 Aug 2018, 10:38pm

Have just watched some video overhauls of the Bendix coaster brake hub which appears to be ribbed metal shoes onto a metal drum (inside of the hub body) with high temp grease between. Are the SA drum brake hubs similar or is there a friction material on the shoes with no grease?

User avatar
[XAP]Bob
Posts: 16918
Joined: 26 Sep 2008, 4:12pm

Re: Hub Drum Brakes

Postby [XAP]Bob » 5 Aug 2018, 10:43pm

SA Drums are friction material, no grease.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

Brucey
Posts: 35863
Joined: 4 Jan 2012, 6:25pm

Re: Hub Drum Brakes

Postby Brucey » 5 Aug 2018, 10:59pm

Coaster brakes (all makes) and shimano roller brakes use a greased metal-on-metal friction couple. [ BTW the ribs on a Bendix coaster brake shoe are simply there to help stop the parts that are not meant to rotate against one another from rotating, e.g the expanding cone parts.]

SACHS, SRAM, SA, Arai and other brakes that are usually described as 'drum brakes' use a dry friction material against the inside of a metal drum, using a different mechanism entirely to provide the force. Friction materials in drum brakes are closely related (but not identical) to pad materials used in disc brakes. However there is about x50 more friction material in a drum brake shoe, and that is about how much longer they last, too.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

User avatar
fausto99
Posts: 419
Joined: 19 Sep 2011, 10:06am

Re: Hub Drum Brakes

Postby fausto99 » 2 Sep 2018, 3:06pm

fausto99 wrote:
Brucey wrote:the only thing is that chainstays are more nearly -if not actually- parallel-sided, unlike most forks...

Great stuff. Never thought of that. You've clearly been there, seen that and bought the T shirt :lol:

I will have to come up with something though. I'll re-look at the chainstays to see how tapered they are.


This is what I came up with - a converted seat clamp QR bolt. I had to extend the thread on the screw part and I cut it a bit short :oops: but I think I got away with it.

Image Image Image Image

That should speed up wheel removal, I think.

Brucey
Posts: 35863
Joined: 4 Jan 2012, 6:25pm

Re: Hub Drum Brakes

Postby Brucey » 2 Sep 2018, 8:37pm

that looks pretty good! I wonder if you could make the M6 female thread captive in the P clip? Maybe a meatier P clip with an M6 nutsert in it? I guess the downside might be that the lever can't be 'timed' to the chainstay unless one is free to twiddle the nut....

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

nigelnightmare
Posts: 533
Joined: 19 Sep 2016, 10:33pm

Re: Hub Drum Brakes

Postby nigelnightmare » 2 Sep 2018, 9:11pm

Nice. 8)
Necessity is the mother of all invention.
I never bothered because the hub is not QR compatible But after seeing that I might just copy yours as it's 2 less tools to carry/use to remove the wheel.

As "Brucey" said the brakes take a fair bit to bed in properly but should last for 50,000+ miles before needing new shoes.

If I don't have panniers on I can do stoppies but I've got two braked front wheels (ICE Trike) and they're only 20".
With panniers I can lock both front wheels in the dry if I grab two great big handfuls i.e. full emergency stop.
Mine are 11 years old and the brake shoe are not much thinner than new ones. Approximately 1mm difference.

LuckyLuke
Posts: 224
Joined: 10 Jun 2010, 11:54am

Re: Hub Drum Brakes

Postby LuckyLuke » 3 Sep 2018, 9:58am

Another satisfied drum brake user here. "You can't beat the drum" :D
I found Jagwire Compression less brake cables improved braking on my SA 70mm front dynohub, compared to Shimano outer (?SP41).
Fausto, how are the brakes with drop bar road brake levers? I run them with flat bar levers. Am intrigued to try them with drops.
Best wishes,
Luke

User avatar
fausto99
Posts: 419
Joined: 19 Sep 2011, 10:06am

Re: Hub Drum Brakes

Postby fausto99 » 3 Sep 2018, 2:48pm

Will be riding the bike for real on this Wednesday's club run, which, knowing the destination and leader, I'm guessing will be short and hilly :lol:
I'll report back my impressions after that.

BTW here is what I decided to go with, for now, for shifting - the original rapidfire levers!
Image Image
I don't think I need to change gear when I'm braking and I spend most of my time on the tops.

p.s. I know the stem colour doesn't go with the red frame and orange tape :oops: but this is a budget job and the stem is what I had. I may get a new stem and reconsider shifters and compressionless outers when tape renewal time comes.

LuckyLuke
Posts: 224
Joined: 10 Jun 2010, 11:54am

Re: Hub Drum Brakes

Postby LuckyLuke » 3 Sep 2018, 9:17pm

Cheers Fausto. Short & hilly should help with bedding them in :D
I won't grass you up to the Stem Police. My past misdemeanours include fitting purple and blue quill riser stems from 80s & 90s hybrids on road bikes, & quill to aheadset converters...

cycle tramp
Posts: 553
Joined: 5 Aug 2009, 7:22pm

Re: Hub Drum Brakes

Postby cycle tramp » 6 Sep 2018, 7:52pm

fausto99 wrote:Will be riding the bike for real on this Wednesday's club run, which, knowing the destination and leader, I'm guessing will be short and hilly :lol:
I'll report back my impressions after that..


How did Wednesday's ride go? Did the brakes perform ok?

User avatar
fausto99
Posts: 419
Joined: 19 Sep 2011, 10:06am

Re: Hub Drum Brakes

Postby fausto99 » 7 Sep 2018, 12:04pm

It was a very damp, hilly 40+ mile ride on Wednesday. The brakes got better and better and I had to pull up the adjusters at the elevenses stop. I could easily live with them as they are but I'm hoping the "bite" will improve with further use.

BBC weather said no rain after 10 a.m. :roll: :roll: . I'd call it rain or drizzle all day long :cry:. However the brakes did not, at any time, display any lag due to having to wipe water off the rims or rotors - result!

I did get a p*nct*re in the front (very unexpected, as I had brand new Conti Contact 26 x 1.75 tyres), but was pleasantly surprised at how easy it was to remove and replace the wheel. Well done S-A on the reaction arm and cable anchoring design.

cycle tramp
Posts: 553
Joined: 5 Aug 2009, 7:22pm

Re: Hub Drum Brakes

Postby cycle tramp » 7 Sep 2018, 5:51pm

Brilliant! Sounds like a great ride, with the brakes working as well as can be expected, given that they'te just bedding in. Please keep us informed - looking forward to a 6 or 12 month review :-)

User avatar
fausto99
Posts: 419
Joined: 19 Sep 2011, 10:06am

Re: Hub Drum Brakes

Postby fausto99 » 18 Oct 2018, 11:24am

About 200 miles completed and the brakes are improving slowly all the time. There are minor variations, throughout a ride, in the strength of the initial "bite" and the amount of subsequent brake lever effort required in coming to a complete stop. Often it feels like the amount of lever effort must be increased to maintain a constant deceleration rate. Might it be worthwhile having a look inside to see if any cleaning or lubrication is required after the bedding in? Lots of dust maybe?

Anyway, the main point of this post was to ask advice on combined brake lever/shifters for this set up. I don't think I want to persevere with the STX/RC rapidfire shifters as it's all a bit crowded on the drop handlebars. So, the question is, which 8 speed triple shifters can I use with these derailleurs and hub brakes? There doesn't seem to be much choice, new. Are the current Shimano Claris 8 sp https://www.sjscycles.co.uk/gear-shifte ... ti-levers/ compatible with my setup? If not what should I be keeping my eyes open for second hand?

Edit: also found these https://www.bikester.co.uk/shimano-clar ... 03440.html. Is there any difference between ST2403 and ST2400?

Brucey
Posts: 35863
Joined: 4 Jan 2012, 6:25pm

Re: Hub Drum Brakes

Postby Brucey » 18 Oct 2018, 12:06pm

If you want STIs then I would advise you to stick with pre-2008 STIs that don't have the longer NSSLR brake cable pull.

When the brake is used continuously (eg on a downhill) or for more than a few seconds at time the modulation may be affected slightly, due to dust build up and temperature effects etc. Most brakes will do this to some extent.

However once bedded in, the initial bite of the brakes is usually consistent and (IMHO) this is a useful safety benefit in emergency stops.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~