Sunday 4 September 2011

Adjusting Ural Twin Leading Shoe Front Brakes

 Notes - Ural twin leading shoes brakes can work acceptably well if correctly adjusted.
There are square adjusters with lock nuts on the end of each brake shoe.
There is also an adjuster on the cable for fine adjustment.
The link rod on the outside of the brake plate that connects the two brake cam levers does NOT have a left hand thread in one end. This means simply turning it will not change the distance between the two brake cam levers.

1         Jack up the front of the bike so it is possible to spin the front wheel.
2        Remove front wheel complete with brake plate (remember the spindle is left hand thread).
3        Remove cable from brake plate.
4        Remove the outer levers from the splines while the shoes are still on the brakes.
(the shoes will automatically pull the brake cams round to their lowest level)
5        Refit the outer levers without turning the splined shafts
6        Mark the top shoe so you can always put them back as they are to start.
7        Remove both shoes and draw lines across them every 10mm using chalk.

8        Refit shoes and refit wheel and brake to bike still with no cable.
9        Spin the front wheel and apply the brakes using the lever on the brake plate until it is just rubbing.
10     Remove the wheel again and take a look at the chalk lines.
11      If one is rubbing and the other is not adjust the square adjuster out slightly on the one which is not rubbing. Repeat the wheel fitting, spinning and rubbing until both are rubbing equally.

12     With the wheel fitted apply the brake and check the rubbing starts BEFORE the outer levers get to right angles with the connecting bar. If it does not, adjust both the square shoe adjusters by exactly the same amount and try again.
13      The end result should be that both shoes contact at the same time and before the levers reach right angles and the mechanical lever advantage is lost.
14     Refit cable and make final adjustments for feel.

Allow plenty of time, all this taking off and refitting the wheel makes this a long and tedious job, but once done the cable will do the adjusting for some time.

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