IGHs, drums and discs....

qwerkus

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Jul 22, 2017
Messages
785
Hello,

I'm working on a new conversion, based on an aluminium frame with no rear disc mount and only 130mm dropout width. The motor will be a mid drive, and I am considering IGH options. The final round is going to be between sunrace / sturmey archer and shimano, the main question beeing the braking system. Shimano would require to machine some custom disc mount adapters, and "tweak" the hub to fit into 130mm. Sunrace would fit directly, but I have no experience with drum brakes, as I always thought they'd be too heavy. What do you guys think?
Anyone tried the gorgeous x-rd8 hub? Is it as strong as the newest shimano alfine 8?

Edit: just saw they now make a 5 speed havy duty hub with a nicely set 3rd 1 to 1 ratio gear, probably with ebikes in mind. Anyone tried it?

Thank you for your time
 
Back when I was using Sachs and SRAM gearhubs, I found the drum brake versions weighed almost exactly the same as the non-brake versions. The difference was far less than the weight of the lightest possible alternative brakes.

Sturmey Archer drum hubs are good. The brakes are capable but not amazing; if you want strong braking in the rear wheel (which is not always a good thing), then use a 90mm drum version rather than the more traditional 70mm.

My friend Aaron Goss in Seattle (http://rideyourbike.com) can convert a Sturmey Archer drum brake to dual-leading-shoe configuration for maximum drum brake performance.

Shimano IM70, 80, and 81 Rollerbrakes are nicely powerful. They do add a significant amount of weight to the hub.
 
Chalo said:
Back when I was using Sachs and SRAM gearhubs, I found the drum brake versions weighed almost exactly the same as the non-brake versions. The difference was far less than the weight of the lightest possible alternative brakes.

Sturmey Archer drum hubs are good. The brakes are capable but not amazing; if you want strong braking in the rear wheel (which is not always a good thing), then use a 90mm drum version rather than the more traditional 70mm.

My friend Aaron Goss in Seattle (http://rideyourbike.com) can convert a Sturmey Archer drum brake to dual-leading-shoe configuration for maximum drum brake performance.

Shimano IM70, 80, and 81 Rollerbrakes are nicely powerful. They do add a significant amount of weight to the hub.

Thank you for your reply. I thought dual-shoe on bike drum brakes = overheating ?
 
qwerkus said:
I thought dual-shoe on bike drum brakes = overheating ?

All traditional drum brakes feature dual shoes, but one leads its pivot and the other trails. Friction force on the leading shoe has a self-servo effect, while on the trailing shoe the effect is opposite. In switching the shoes' pivots to both leading, you get an increase in braking force in the forward direction and a decrease of braking force in reverse.

It's not easy to overheat and fade the bigger drum brakes these days; however if you convert to a dual leading shoe configuration, the increased braking power will allow the drum to overheat more quickly when pushed to the limit.
 
Chalo said:
All traditional drum brakes feature dual shoes, but one leads its pivot and the other trails. Friction force on the leading shoe has a self-servo effect, while on the trailing shoe the effect is opposite. In switching the shoes' pivots to both leading, you get an increase in braking force in the forward direction and a decrease of braking force in reverse.

It's not easy to overheat and fade the bigger drum brakes these days; however if you convert to a dual leading shoe configuration, the increased braking power will allow the drum to overheat more quickly when pushed to the limit.

Thank for the explanations; I think I finally understood the fuss about dual leading brake shoes.
 
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