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+--- Thread: uncoupled brake balancing - old forum thread (/showthread.php?tid=718)
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uncoupled brake balancing - old forum thread - JonE - 20-01-2018
Trying to interrogate the old forum is difficult as there are some gems, but the images are now often missing. Rob Beck posted this in a discussion about coupled and uncoupled brakes in 2012. If Rob still tunes in or if others have adopted, please would you post a picture of give a better description of what is done please? It seemed to attract brownie points in the thread.
http://pub25.bravenet.com/forum/static/show.php?usernum=2099944454&frmid=5&msgid=936030&cmd=show
quote was...
"split brakes
Here is a mod i am pleased with... Balanced rear brakes achieved by using a single cable passing through the cross shaft. You cant do this to the later cross shafts with concentric tubes."
RE: uncoupled brake balancing - old forum thread - Tony Press - 20-01-2018
(20-01-2018, 10:56 PM)JonE Wrote: Trying to interrogate the old forum is difficult as there are some gems, but the images are now often missing. Rob Beck posted this in a discussion about coupled and uncoupled brakes in 2012. If Rob still tunes in or if others have adopted, please would you post a picture of give a better description of what is done please? It seemed to attract brownie points in the thread.
http://pub25.bravenet.com/forum/static/show.php?usernum=2099944454&frmid=5&msgid=936030&cmd=show
quote was...
"split brakes
Here is a mod i am pleased with... Balanced rear brakes achieved by using a single cable passing through the cross shaft. You cant do this to the later cross shafts with concentric tubes."
I believe this would need a special long rear cable a bit like the front cable . This would be taken from the rear brake lever forward through the eye of the cross shaft lever, down to and through the cross tube, back up the opposite side through the eye and back to the opposite rear brake lever.
I don't know how the ends would be fixed on and I wouldn't think that any side to side adjustment could work with six right angle cable bends.
I may have it completely wrong though !
Cheers, Tony.
RE: uncoupled brake balancing - old forum thread - Ruairidh Dunford - 20-01-2018
Rob’s modification used one long brake cable which went through the centre of the cross shaft, exiting through smooth brass cups then up over a wheel on an arm, from memory.
RE: uncoupled brake balancing - old forum thread - Ruairidh Dunford - 20-01-2018
Found the picture Jon,
RE: uncoupled brake balancing - old forum thread - Tony Press - 21-01-2018
(20-01-2018, 11:40 PM)Ruairidh Dunford Wrote: Found the picture Jon,
That looks better- and presumably the cable end would fit through the tube.
Cheers,Tony.
RE: uncoupled brake balancing - old forum thread - squeak - 21-01-2018
An elegant solution. I presume the previously " hard feel" of the foot brake pedal as the drivers side wheel locked up, would be replaced by a "spongy pedal feel" as both rear wheels locked up and the cross shaft flexed in torsion. russell
RE: uncoupled brake balancing - old forum thread - JonE - 21-01-2018
Thanks all. I think it was Ruairidh's use of something like 'elegant' in reading/considering such in the first place, and it clearly has other supporters. (I've found another project - more in due course - hence the theoretical search...)
RE: uncoupled brake balancing - old forum thread - Steve kay - 21-01-2018
I have been considering the opposite action, that is uncoupling.
When I was young and athletic, uncoupled brakes on an Ulster were vital for trialling, it allowed safe steering when coming backwards down slippery and rutted sections.
Competition is now gentle nav rallying and autosoloing in the Ruby. It might just be me, but there are widespread refernces to a degree of front brake binding when on full lock, part of the attempt to compensate for the axle movement when vigorously braking in a straight line. Day to day one doesn't
notice this, trying to wiggle-woggle as quickly as possible round the bollards it becomes intrusive. Bowdenex front brakes avoid the binding, but are difficult to find on ebay, and not offered by cherished suppliers. So I am wondering if merely uncoupling front and rear might be helpful. Any thuoghts?
RE: uncoupled brake balancing - old forum thread - JonE - 21-01-2018
Steve - this thread IS about improving uncoupled brakes! Someone mentioned to me yesterday about Morris 1000 handbrake bowden cables as being suitable/good even for replacing cables. But don't quote me.
RE: uncoupled brake balancing - old forum thread - squeak - 22-01-2018
(21-01-2018, 06:55 PM)Steve kay Wrote: I have been considering the opposite action, that is uncoupling.Steve I rather like uncoupled brakes in the chummy, one can alternate down a very steep hill to cool them, and using rear only are adequate for most stops. On the Apex prototype however, it being also uncoupled, I would consider the continuous rear cable modification.
When I was young and athletic, uncoupled brakes on an Ulster were vital for trialling, it allowed safe steering when coming backwards down slippery and rutted sections.
Competition is now gentle nav rallying and autosoloing in the Ruby. It might just be me, but there are widespread refernces to a degree of front brake binding when on full lock, part of the attempt to compensate for the axle movement when vigorously braking in a straight line. Day to day one doesn't
notice this, trying to wiggle-woggle as quickly as possible round the bollards it becomes intrusive. Bowdenex front brakes avoid the binding, but are difficult to find on ebay, and not offered by cherished suppliers. So I am wondering if merely uncoupling front and rear might be helpful. Any thuoghts?
The 38 ruby has full girling coupled rod brakes and are the best I have experienced. If your ruby has the girling type fronts, you too can have good brakes. Bowden cable quick fix is no substitute for the radius cups, king pins, shackles, etc being in top condition.
My friend and I raced a sports last year with the above brake gear in good nick, and the brakes were RUBBISH. I put this down to the internal friction in the bowden cables.
Pay particular attention to the angle of the front brake levers being JUST forward of vertical, the balls being UNDER the king pin and a slight slack in the cable. cheers Russell