Dommy brake shoes

I would think twice about the RGM brake shoes. I bought some for my ES2, which has the full width front hub, and they were like granite. I broke them in for several hundred miles and the trailing shoe had a contact area about an inch long and the braking effect was very poor. I gave up on them and had some shoes redone by Villiers Services. You can tell them what you use the bike for and they will use appropriate material for the linings. I've done a couple of hundred miles on the one's they supplied and the brake is much better already.

https://villiersservices.co.uk

There are instruction on their website as to what measurements they need.

Ian

I'm another satisfied customer of Villiers services.

Ian, did you contact RGM, about the problem? Obviously, they buy in the brake shoes, and sell them in good faith. If no one reports a problem, they have no reason to assume they are unsuitable. RGM are one of, possibly the best, suppliers of Norton parts, who?s speedy, and helpful, service cannot be beaten.

Previously John Shorter wrote:

Ian, did you contact RGM, about the problem? Obviously, they buy in the brake shoes, and sell them in good faith. If no one reports a problem, they have no reason to assume they are unsuitable. RGM are one of, possibly the best, suppliers of Norton parts, who?s speedy, and helpful, service cannot be beaten.

No I didn't bother contacting RGM, just put it down to experience. I've bought plenty of stuff off RGM and will continue to use them. The brake shoes are one of the few things I've had off them that I was disappointed with.

Robert,

This is most interesting. I've had my Mercury for about 20yrs now and have always been disappointed with the stopping power of the rear brake. I've noticed that earlier Domi's have the rear brake lever pointing downwards, whereas the Mercury has it pointing upwards.

I've looked at changing my set up for the earlier arrangement, but there doesn't seem to be room to pass the brake rod past the silencer. Please let us know if the high friction linings give an improvement.

Philip

Previously robert_tuck wrote:

Hi Phil, If the lever arrangement is part of the problem, I would consider fitting a small bore siamese exhaust . Likely to be noisy though. Braking these old bikes is beginning to be a real issue ,car brakes have improved so much and some drivers habitually leave braking very late .

Hi Robert - An interesting thought provoking thread. I have noted over the years of running Dommies that there are various lengths of lever for the downward types of levers whereas the upward ones all seem to be the same with the brake-rod positioned further from the brake cam. Could this have a bearing on your results ? In experiments I have done over the years with SLS front brakes I have indeed noted differences with forward and rearward facing brake-plate levers. Gold Star 8 inch plates seem to work better forward facing as do Seeley 8 inch. It is difficult to position the lever forwards on the Dommie 8 inch front but I shall do it sometime and compare. Cheers and good luck, Howard

Hello Robert - The early Commando sprocket / brake drum has the same dimensions as the late Atlas/650SS but has UNF threads on the QD wheel studs for the sleeve nuts. I have interchanged Mercury drums with Commando and seen no differences whatsoever. The later Commando with the extra wheel bearing and cush-drive is quite different however. Cheers, Howard

Previously Philip Ham wrote:

Robert,

This is most interesting. I've had my Mercury for about 20yrs now and have always been disappointed with the stopping power of the rear brake. I've noticed that earlier Domi's have the rear brake lever pointing downwards, whereas the Mercury has it pointing upwards.

I've looked at changing my set up for the earlier arrangement, but there doesn't seem to be room to pass the brake rod past the silencer. Please let us know if the high friction linings give an improvement.

Philip

Hello again Phillip - have you thought about using a cable a la Commando? It's a simple enough job to fit an outer cable stop to the brake-plate and there are a lot out there at jumbles with the job done already (from cafe racers no doubt). The cable stop at the front is a bit trickier but certainly not beyond your expertise. I have also noticed on some of the late Atlas's, 650SS's and Mercuries that I have owned that there are different lengths of brake-rod pull levers on the foot pedal. Some of them were also at a shallower angle. I suspect that AMC knew about the problem of a poor rear brake and were experimenting with different set-ups. If there is any wear in the bush on the brake-plate because of the action of force on the upward brake-plate lever being further away from the cam it is translated into a bigger movement of the cam towards the action of the force - which is bad. So I think it's better to have the downward acting lever if there is significant wear between the cam and bush because it is closer to the cam. I wouldn't bother with a siamese pipe for the downdraught head. They are awkward to fit correctly and that nut on the rhs can't be replaced. Cheers, Howard

The early Commando sprocket / brake drum has the same dimensions as the late Atlas/650SS but has UNF threads on the QD wheel studs for the sleeve nuts. I have interchanged Mercury drums with Commando and seen no differences whatsoever.

Check out the attachment, which shows that the Commando rear brake/sprocket had 42 teeth. The Atlas had a 43 rear sprocket.

Not sure what the Mercury had. My guess would be 43. Bacon's Restoration Book says they were 43T but that would suggest Cycle sleeve nuts.

Attachments
bike-specs-page-7-bmp