H: Hubs, Wheels and Tyres Drum Brake and Shoe Tuning - Race Tech

[vibrac]

I use safetek now for my linings but a thin coating of epoxy followed by rivets was how we did it when am4 was available in the sixties mind you aradite was different then much better I remember a guy built up his aerial arrow crankcase into twin carbs with a great lump of it and it worked! You could not do it with the rats poo it is now

 

[Vincent Brake]

i recommend a very maximal runout of 0,15, if you do 0,25 you start to notice when braking.
(continental mm of course...)
When turning, wrap a rubber inner tire tube very firm arround the drum, avoiding/limiting vibration, and use a sharp TC cissel radius of about 0,2 max 0,4 mm, ( always grind them sharp on the top only by a 1200 mesh diamond stone creating also a bit negative swarf relieve corner, (or how does one put this in english))

 

[greg brillus]

Geeze Vincent

 

[greg brillus]

Sorry, about that.........Your description sounds impressive ........Way better than my method with the "Angle Grinder"............

 

[chankly bore]

Sorry, folks. That clause in Greg's post "most old plates have bent pins" If they bend once, they'll do it again, and more easily every time you bend them back. As an old Yorky mate of mine would say, "think on." The only answer is a bridge across the tops of the pivot pins, after reducing the width of the shoe eyes. Mind you my engineering knowledge ended with e.e.cummings and started with Geoffrey Chaucer.

 

[Cyborg]

Most brake linings we use have normal working temps of up to 800 degrees F - that's around 430 degrees C.

Since epoxies are thermosetting resins, they have a softening point called the glass transition temperature (Tg). Heating above the Tg , generally around 200 C, will soften the material causing it to loose its grip. Most epoxies will decompose and turn to carbon ash at temperatures of 400°C and above. By heating the unit above the degradation temperature, the epoxy adhesive simply burns away.

Don't use epoxy on brake linings - get the professions to do the bonding for you using the correct type of adhesive material. Or keep your medical and ambulance insurance up to date

I appreciate the feedback and your concern. The layer of epoxy is extremely thin so if it does fail for any reason, the rivets will still hold the lining tight to the shoe.

 

[Tom Walker]

Machining the drums off the wheels is a waste of time. Find someone with a suitable lathe - you may need to remove the tyres first

Martyn I dont understand your reasoning here. Which part of the wheel do you hold in the lathe?
The wheel hub and axle are the bits which need to be concentric with the drum surface.
The wheel rim can be miles out cant it?

 

[Robert Watson]

I think he means you need to remove the tyres so you can swing it in the lathe! swing an 19" rim is easier than a 26" tyre. I don't think he is suggesting you dial up on the rim!

 

[Martyn Goodwin]

I think he means you need to remove the tyres so you can swing it in the lathe! swing an 19" rim is easier than a 26" tyre. I don't think he is suggesting you dial up on the rim!

Exactly Removing the tyre is to make it easier to hold. In the lathe you need to centre it around the wheel axle

 

[Tom Walker]

Ah sorry it was a bit late!