Adjusting rod brakes




Following on from my previous post where I was fiddling with the rod brakes on my Raleigh Superbe and inadvertently broke them, I ordered and received a NOS Raleigh front stirrup brake assembly from eBay.  It arrived today and I learnt a bit about how to setup rod brakes and their fiddly idiosyncrasies.  The unit I got was identical the the original broken unit, the only marking was the Raleigh logo and some patent numbers stamped on the pads.  The pads themselves were a little different because they had what appeared to be a leather insert on the braking face, I'd heard these were meant to be a bit better in wet weather than the normal rubber blocks.


Rod brakes - note that the pads are actually
facing the wrong way; see below

 Rod brakes are mostly found on old roadsters and are different to calliper brakes because they use steel linkages to pull the stirrup holding the pads to the inside face of the rim for a braking surface.  This means a few things, wheels are more difficult to remove and the brakes are not self-centering.  Rod brakes have a tendency to judder when braking hard which can cause the tyre to skid; this is due to an out of round wheel.  Calliper brakes don't have this problem because they depend mostly on lateral true of the wheel, any minor lateral wobbles can be tracked by the caliper which still allows you to stop smoothly and with control. Rod brakes when setup properly only really give moderate braking at best, good caliper brakes are superior in this aspect.  The only saving grace of rod brakes is their low maintenance, simplicity and ruggedness, they are still very popular in the developing world on utility bicycles.


There are a few steps to adjusting rod brakes, they are a little fiddly but not really much more work than setting up calliper or cantilever brakes.  The adjustment only really requires an adjustable wrench for the bolts as well as bending, very simple.

A:  Keep a 2-3mm gap between the rim braking surface and the pad, use the adjustment nut at the top of the stirrup where the rod enters it to do this.  Because the pads are both fixed to the stirrup, they are not self-centering.  This means that squeezing the lever can result in one pad hitting the rim before the other.  Ideally they should hit the rim at the same time, you can move the pad itself up and down a few millimetres in the holder to get it right, if it's really off you may have to bend the stirrup itself.  Spin the front wheel to see if there are any high spots which rub.

B: Try to get the outside face of the pad flush with the outside face of the rim, this will ensure that the pad will get full contact with the braking surface

C: Don't get the pads too far in however as they can rub on the valve and spoke nipples as the wheel rotates, this could be quite bad if you were going down a hill and braked hard causing the pads to get thrown into the spinning wheel.

D: Get the height of the guides so that when A is adjusted correctly and the brake is squeezed on, the stirrup posts stay in the guides.  If the height is too low, the stirrup posts could be pulled out accidentally when the brake is squeezed on hard which could be potentially dangerous.  The guides can be rotated to help get the lateral adjustment (B & C) correct.  You can also bend the part of the stirrup where the pads bolt on to get adjustment.

This is the correct orientation of the pads

Once this is done both the pads should hit the rim evenly and squarely without dragging on the rim or hitting the valves or spoke nipples.  The NOS leather faced pads I fitted give a little bit more braking power than the crusty old pads that they replaced, haven't tried it in the wet yet, however just having them properly adjusted improves them greatly.

Please note that on later Raleigh models they introduced anti-vibration plates which offsets the brake pads from the stirrups, they are meant to face towards the rear of the bike so they sit inside the fork.  This is how they were oriented when I first got the bike however I incorrectly faced them towards the front initially as they allowed better access to the bolts.  Apparently they stop vibration during braking but I have not noticed any real difference either way.

Happy adjusting and thanks for reading.

2 comments:

  1. HELP!


    It's the rear brake I'm strugling with. I've just done a 'revamp' of an old raleigh 1935 i think, for my wife. Now i cant see how i can allign the pad with the rim on the rear stryup.

    Any ideas?

    Andy

    ReplyDelete
  2. Hey there Andy,
    The rear is basically the same principle as the front I've shown, the key is to get both pads to hit the rim more or less simultaneously straight on. Although this assumes your rear wheel is in radial true and that the linkages are all in reasonable condition.

    Realistically though, I found on my Raleigh that the rear brake was barely able to stop the bike anyway, even with proper adjustment. This is even more true on an older bike, let alone one from 1935! Good luck

    ReplyDelete