Author Topic: Rear brake update  (Read 1840 times)

Smudger462

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Rear brake update
« on: August 19, 2013, 10:26:58 AM »
Just dug our old Thorn Adventure tandem out of the shed with a view to getting out at the weekends again. The brake set up is cantilever Suntour SE xc on both front with 26" Suntour CR18 rims (48 spokes at the rear). Previous rides in the hills showed the braking was inadequate on some of the descents therefore we would like to upgrade to a drum or disc brakes. Is this the way to go and what are our options? Any information would be appreciated. Thanks Ian

Danneaux

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Re: Rear brake update
« Reply #1 on: August 19, 2013, 04:50:17 PM »
Hi Smudger, and welcome to the Thorn Cycling Forum!

As it happens, I recently made a couple posts on setting-up SE brakes for maximum stopping power. They can be seen as responses in this thread: http://www.thorncycles.co.uk/forums/index.php?topic=3032.0

As for hill braking, my tandem uses SE cantilevers (SunTour rear, Scott/Pedersen front) with an Arai drum brake serving as a drag brake at the rear (actuated by a bar-end shifter...pull it up a few clicks, and it keeps the brake partly on). This has worked really nicely. Without the drag brake, downhill speeds exceeded 63mph/101kph. With it, it is easy to keep speeds to 42mph/68kph or less (pretty much any speed desired) and then it is an easy task for the cantilevers to diminish speed further.

Drum brakes can soak up and dissipate tremendous amounts of heat and still provide solid braking. A disc can warp and fade in the same kind of use. For many years, the Arai has been the drum brake of choice for tandem use because it was relatively inexpensive, worked very well, and had a ready supply of replacement parts available.

Unfortunately, the Arai drag brake is now a thing of the past...and so are the inexpensive double-threaded freewheel hubs needed to mount them. It is still possible to use an Arai or Arai-compatible drum brake using the (more expensive) specialty tandem cassette hubs currently on the market. For example, Phil Wood have a left-threaded tandem cassette hub that will mount an Arai (photo here: http://www.peterwhitecycles.com/images/products/hubs/philta~1.jpg ), Shimano make the HF07 tandem cassette hub (photo here: http://www.peterwhitecycles.com/images/products/hubs/Shimtandemrear.jpg ), and Hope have a cassette tandem hub with threads on the left to mount an Arai-compatible drum as well.

There are rumors of a worthy replacement for the Arai drum brake from my neck of the woods, and it appears to now be in production: http://tandemgeek.wordpress.com/2010/11/14/next-generation-drag-brake/
Followup here: http://tandemgeek.wordpress.com/2013/07/10/next-generation-drag-brake-now-available/

Sadly, drum brakes are only available for derailleur hubs with threads on the left side; Rohloff hubs are limited to disc brakes.

If you wish to go for a disc or v-brakes, Andy Blance discusses the dis/advantages of each in the latest Raven Twin brochure: http://www.sjscycles.com/thornpdf/ThornRavenTwinBroHiRes.pdf , page 10

Hopes this helps.

Best,

Dan. (...still beating the drum for Arai drum drag-brakes on touring tandems)
« Last Edit: August 19, 2013, 04:57:11 PM by Danneaux »