H: Hubs, Wheels and Tyres Brake Shoes and Linings

[nortonrider]

I fitted Ferotec D3920 to my Prince about 30,000 miles ago (replacing AM4). I've since fitted it to every drum brake bike I've owned with much improved braking hot and cold. I haven't noticed any abnormal drum wear. I didn't take before and after measurements so can't be categorical that it's no more than wear with other linings.

If you don't see a ridge after 30,000 miles, that could be proof the D3920 is not really any worse for wear than stock material, despite its high metal content.

 

[nortonrider]

David Tompkins ran in practice today at New Jersey Motorsports and this was the first test of the .61 coefficient of friction brake lining and I also supplied him with two new 7" rear brake shoes with the same lining (he has only one rear brake.)

Just to set the stage, he had initially run the race lining supplied with the 8" brake that Mike Hawthorne is running. He found the squealing to be so annoying it was unsettling. He changed the lining to one used by Patrick Godet which turned out to be much better stopping with no squealing. The linings and shoes I supplied him with, which he tested today, performed the best of all according to Dave. He did race there last year and he took 7 seconds off his lap time during the practice.

We have some more testing to do, but I think this is good news for improving the Vincent brakes. I do have higher friction linings that I can try (and I probably will), but this lining performs quite well cold (.61) and they go up to .63 at 600 degrees F. That type of performance is difficult to find in any lining and I suspect that going higher in friction will require more heat in the brakes, which would not be good for street use.

View attachment 22882
A shot of the rear shoes before arcing and chamfering. The standard Vincent geometry was used for placement of the lining.

David

It would be interesting to learn more on what material Godet uses,
although I am rather committed to D3920 now, having done up a couple sets.
I will phone up their shop tomorrow to learn more.

Are you referring to R4 in your test and the above pic?

I see that Porterfield recommends their Woven version R-4 for mechanical pull applications. Has anyone tried this version?

R-4 Woven Kevlar
Porterfields Woven Kevlar is high friction woven composite material designed for use in mechanically actuated drum brake systems. It has very high friction at ambient and low temperatures for good initial bite and may be bonded to aluminum or steel brake shoe cores. Trusted by top car mechanics to stop the most valuable of vintage vehicles safely, without any unnecessary drum wear. This material is widely used in vintage racing and vintage touring events on vehicles with mechanical drum brakes.

 

[Michael Vane-Hunt]

Timetraveller, what lining material are you using on your modified brake shoes?

 

[davidd]

Patrick had his racing brakes done by Dick Hunt in Surrey. I believe that Dick recommended 3920 for use front and rear, but said that 3920 was often used on the rear with a more aggressive lining used on the front. It is easier to generate a lot of heat upfront on a racer, but street bike fronts run very cold.

As far as I know, Dick used 2520V on his front brakes. He supplied the lining to Vintage Brake for some time before the UK distributor of 2520V closed shop in the UK. I think the tables turned and Vintage Brake supplied Dick Hunt with the lining for a while. Dick preferred to use the grooved 2520V. It ran much cleaner as the brake debris could exit quickly via the grooves. Also, it was less likely to tramline.

When I spoke with Porterfield, they said that RD-4 was their top racing drum brake lining. The coefficient of friction is around .5, which is higher than the .44 of AM4, but the higher the mu, the hotter the lining needs to get to achieve it. The big benefit of RD-4 is that it will not fade. It hangs in much longer than other linings. Linings that have higher coefficients of friction are often unpredictable. They provide very high braking when hot, but if they cool a bit on a straight before a corner, they may not provide much stopping power.

A word of caution on lining names. If the manufacturer uses a name it is fine. If the retailer uses a name, it is probably made up. The retailers do not want you to know who the manufacturer is. Thus, they choose a name to market the product. They may choose to use the same numbers, or they may not. There is usually not a lot of consistency in the name selection. Porterfield's long-time racing drum lining was dubbed R-1. But R-4 is a different lining and R4-1 is also a different lining with a very high coefficient of friction. It is difficult to find a listing of all their linings.

I am not certain that Dick Hunt is still in business. He may not be advertising to keep his workload low.

David

 

[timetraveller]

Regarding MVH's question in #33 above. The answer is I don't know. I did telephone up and asked and all the lady who anwered knew was that they were asbestos free woven linings. I only know that all who have used them have been happy but I do not think that any more information will be provided.

 

[nortonrider]

I can no longer find any website or contact info for Dick Hunt, so I suspect he has closed down.

Interested to see any photos of VB3000 and 2520V materials.
Doubt there are any vendor-published co-effecients on these.

Edit: Found a photo of 2520V on the net as done by Dick Hunt with the grooves and copper rivets:

 

[davidd]

I have this close up of 2520V:

I was able to get a graph of 2520V, but there is no manufacturer's ID:

Currently, this is the only shot I have of 3000B

It is the new Neal Videan shoe at the top. Slight greenish coloring and lots of metal.

This is a copy of the Dick Hunt information I had from years ago.

David

 

[nortonrider]

The above pic of VB3000 with its high metal content looks a lot like the US-version of Ferotec D3920 which has more green in it than the UK version.
I wonder if 2520V is a Kevlar-type material.