18 replies to this topic

[MartyD]

Std brake shoes are 138mm o/d x 25 width
Does anyone do a set of 140mmo/d x 25 mm shoes
The i/d of the hub is slightly below 140mm(139.8)
The brake is very vague and spongy so i thought a larger dia set would be better
Any advice??
Marty D

[B40RT]

Can you not just pack out the cam / pivot ?

[Racey]

There are a number of various thicknesses of lining that you could have rebonded onto your old shoes, which would solve your problem.

Also there are particular linings better suited trials bikes. pm me if you need further help

Edited by Racey, 06 September 2009 - 08:08 PM.

[charlie prescott]

Hi Guy's

Now some time back I bought a set of shoes from "TrickyMicky" which were thick enough to skim,along with the brake drum, and made a super stopper. I dont know if he still sells these but I could do with another set for the next project.

Regard's Charlie.

[Alan_nc]

You are probably already doing this but I "bed" the brakes to the hub. I chalk the mounted shoes and with the wheel off the bike rotate the hub in the wheel applying the brakes with the lever. Sand down the parts where the chalk is missing. Usually repeat the process 4 or 5 times before I am getting pretty much full contact between the shoe and the hub.

Also take a dremel tool and grind 3 grooves in each shoe to move water away.

Hate to do it but also remove the wheel and brakes, clean and replace, if I ride in a muddy or wet trial.

Alan

[MartyD]

I think that by spacing the cams/pivots out the diameter is possibly wrong??
Have taken the hubs to a engineering shop and hes going to sleve the hub to 138mm id
think that if this is done the brake shoes will be (Off the shelf) fit
The easest way was just to find a set of 140mm O/D shoes but i cant find them
Thanks for all your help
Marty D

[DAVETOM]

Hi,
looks like too late now but I`ve just used "Classic Brake Services" for my Bsa A65. The drums had already been skimmed as they`d gone oval, so Classic Brake fit oversize grippy linings and skim them to the hub diameter. The change was unbelievable, the front was only a single leader but it`s as good as many twin leaders i`ve ridden. Probably overkill for a trials bike but certainly an improvement, apparently a lot of the road-racing crowd use him. Cost me £65 each end inc post

[B40RT]

MartyD, on Sep 7 2009, 08:23 PM, said:

I think that by spacing the cams/pivots out the diameter is possibly wrong??

Wrong but works !

[Stickinthemud]

Mick Ash alias prideandclarke formerly trickmicky should be able to help.
Failing that, contact Saftek at Cleckheaton, West Yorks 01274 862666. They will reline your shoes to any thickness you want.

Trick then is to find someone with a lathe and turn the shoes to the diameter of your old drum.
Straighten the brake plate to get the shoes in line with no twist first. Then lock the shoes open on the brake plate until they are just over the right diameter and mount it on a loose wheel spindle in the lathe. Turn off the friction material slowly until it fits the hub perfectly. You will need to sharpen the tool several times as it blunts very quickly.
The new shoe castings that are being sold are very poor and out of alignment in height and diameter so this exercise is well worth doing with any new shoes.
Spacing the cam is ok for the rear but the front needs to be spot onto be effective.

Hope this helps.

Edited by Stickinthemud, 07 September 2009 - 09:55 PM.

[TRICKYMICKY]

Stickinthemud, on Sep 7 2009, 10:54 PM, said:

Mick Ash alias prideandclarke formerly trickmicky should be able to help.
Failing that, contact Saftek at Cleckheaton, West Yorks 01274 862666. They will reline your shoes to any thickness you want.

Trick then is to find someone with a lathe and turn the shoes to the diameter of your old drum.
Straighten the brake plate to get the shoes in line with no twist first. Then lock the shoes open on the brake plate until they are just over the right diameter and mount it on a loose wheel spindle in the lathe. Turn off the friction material slowly until it fits the hub perfectly. You will need to sharpen the tool several times as it blunts very quickly.
The new shoe castings that are being sold are very poor and out of alignment in height and diameter so this exercise is well worth doing with any new shoes.
Spacing the cam is ok for the rear but the front needs to be spot onto be effective.

Hope this helps.

As there's been a couple of posts about my oversize Cub shoes, i ought to mention i dont have any at the moment, i've been waiting for a fresh batch. stickinthemud is right with the procedure though, although i just press the brake plate onto a mandrel in the lathe.
Often,Cub hubs are so worn/oversize that 1/16" oversize shoes fit straight in. If they do, its still important to check the contact area,or the brake will still be poor. For anyone without access to a lathe,Alan Whitton mentioned alsewhere will usually oblige .

[charlie prescott]

Hi Guy's

Hi Mick and Steve.

Mick perhaps you will let me know when your new batch arrives,Thanks. The rest has now been said.

Regard's Charlie.

[Brumbie59]

I like the advice re skimming shoes, I hadn't thought of the problem from that direction before.

But, if you go for skimming an oval drum does this need to be done to a laced up drum to stop it being pulled out of 'true' when wheel is re laced?.

[MartyD]

Will hope to ahve the hub back from the machine shop by the weekend
think that all the adviceso far is great
A lot of different ideas to give the right end result
The frint hub was 140mm I/D and the rear 142mm
Obviously the rear badly worn
As im (new) to this mad world of Classic \Trials im not sure on a lot of things ( Have a 4rt as well)
What else does Tricky Micky do??
Marty D

[MartyD]

Got the hubs back into the bike to night after getting them back from the machine shop
And what do you know,even with .75mm clearence still SPONGY!!
Anyone tried very small discs inside the hubs?????
i hope that when bedded in for longer they improve
Marty D
P.S what oil do i use in the B40 and what quantity?

[charlie prescott]

Hi Guy's
Hi Marty,

Still spongy? Are you sure the hub was skimmed and the shoes were skimmed fitted to the back plate, and centralised, if they were, it sounds to me that you have play in the pivot and, or, operating arm or both. Another trick I have tried in the past is to elongate the pivot point on the shoes. this helps them centralise themselves. And file a lead on both ends of the linings. or they may grab. Getting them right is a bit of a Art?
Regards Charlie.