Twin leading shoe brake queries.

Singles, twins and fours.
allan.walker
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Re: Twin leading shoe brake queries.

Postby allan.walker » Wed Nov 13, 2019 12:10 pm

john.whiting wrote:...was at the medicos today to get flu and pneumonia shot, he clocked the helmet ,and informed me that if I break a bone at my age,I have only a 25% chance of surviving.....


In that case, I hope that he was referring you for tests/treatment for osteoporosis......or is that asking too much of the NHS? :x

allan.walker
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Re: Twin leading shoe brake queries.

Postby allan.walker » Wed Nov 13, 2019 12:15 pm

john.whiting wrote:Looks quite well done,not yer average bodge....or are the bodgers getting scientific....


I agree, it does seem to have been carried out well (notwithstanding my concerns....)

Does anyone recognise this? I wonder if it is a one-off, or a limited-production job by someone in the club. I've tried the Cheval search and I've only found a tls converted BSA single-sided hub, so I've no idea what other alloy hub tls conversions look like.

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paul.jameson
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Re: Twin leading shoe brake queries.

Postby paul.jameson » Wed Nov 13, 2019 7:20 pm

I'm pretty sure its a one-off. The ones produced by the Club in the past didn't use the original shoes. These are original shoes, modified. My advice would be to bin it, or use the plate as the basis for a Lew Wallwork hydraulic conversion which features a steel plate to carry the shoes, leaving the alloy original plate as little more than decoration.
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Re: Twin leading shoe brake queries.

Postby roger.fellows » Wed Nov 13, 2019 10:31 pm

Is it meant to have different sized washers under the cam nuts? I wouldn't like it to wear to the point at which the washer at the top of the third picture interfered with shoe movement.

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Re: Twin leading shoe brake queries.

Postby roger.fellows » Wed Nov 13, 2019 10:33 pm

allan.walker wrote:
john.whiting wrote:...was at the medicos today to get flu and pneumonia shot, he clocked the helmet ,and informed me that if I break a bone at my age,I have only a 25% chance of surviving.....


In that case, I hope that he was referring you for tests/treatment for osteoporosis......or is that asking too much of the NHS? :x


I think John W lives down under - it was probably the flying doctor :)

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Re: Twin leading shoe brake queries.

Postby john.whiting » Thu Nov 14, 2019 12:38 am

Nope ,he s Russian,and somewhat incompetent,but he does bulk bill......Meanwhile ,back at the station,have a look at Jap tls front brakes,a lot are around the 7" dia ,and can likely be fitted to an Ariel.........the other one worth a look is the smaller BSA /Tri TLS fitted to the 500s ........not the bigger one ,which is 8"..........but the 8" one from the late 60s BSA /tri 650s is a fantastic brake ,if you can find one........I found one a while back in a junk pile ,filled with dirt ......but all there and OK except for a small bit broken from the ally.

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Re: Twin leading shoe brake queries.

Postby john.whiting » Thu Nov 14, 2019 12:43 am

On the subject of medicos ,he did inform me there is a vaccination for shingles,which is a nasty ailment likely to strike anyone who s had chickenpox as a child....Worth considering.

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Re: Twin leading shoe brake queries.

Postby david.anderson » Thu Nov 14, 2019 3:36 am

The twin leader brake plate as shown is not like any conversion that I have seen as both ends of the shoe will be moved out simultaneously. When a twin leader conversion is done where both shoes rest on the cam it is normal for the cam to be non-symmetrical. The trailing edge of one shoe normally fits against a cam that is a full radius so as not to operate the shoe when the cam turns while the other side of the cam is normally flat or with a minimal arc to operate the leading shoe.
The question is how effective will that conversion be?
While the original FWH had a reputation for grabbing, that was only in the wet. I have 3 FWH bikes and all 3 when fitted with the same new VB3000 linings gave different results. All hubs were turned true and linings turned to fit the hub. In the wet one bike was extreme grabby, one just a little untrustworthy and the other was normal. In the dry they were all satisfactory but the most grabby wheel was also the most effective stopper in the dry. So I made a pattern and had some brake plates cast for twin leading shoe conversion. I fabricated new shoes cams etc and completed the twin leader brake plates. Over size linings were fitted and turned to size. The result was a better brake, however the same problem in the wet. And the same hub is the grabby one. I have used a dial gauge to check the hubs however there is no out of round due to spoke tension. The material (iron/steel) used to line the hub did however turn a little differently on the grabby hub in that the turnings were smaller. So I tend to believe that Ariel may have used a different grade of iron or steel in some of the hubs and the friction material is more effective/grabby in that case.
Strangley enough I have never had a problem with a grabby FWH rear brake, wet or dry and have never heard of anyone else having a grabby rear brake.
David

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Re: Twin leading shoe brake queries.

Postby Bruce Saunders » Thu Nov 14, 2019 8:24 am

My 54 Modified NH350 (500) with Guzzi TLS
Great brake, 18" rim, still intending to fit 18"
matching rear rim
20160520_173232.jpg

allan.walker
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Re: Twin leading shoe brake queries.

Postby allan.walker » Thu Nov 14, 2019 9:21 am

Thanks for the replies, gentlemen, and particular thanks for the description you gave, David.

From all of the reports about the alloy fwh brake I've read/heard, this covers everything succinctly. Probably most importantly, it is first-hand experience - excellent. The variability of material used in the brake drums of these wheels leads me to think that trying to make a good reliable brake out of the Ariel alloy fwh is flogging a dead (iron?) horse....

This variability of the braking surface does make me wonder if the hydraulic conversion would be a total solution, Paul. Has anyone experienced the dreaded damp-morning grab with one of these conversions, I wonder...

One point regarding this brake. At first I thought that both cams opened both shoes together, but they do not. The cams are 'single-sided,' if that makes sense. There is a lobe on one side only. Therefore the 'plain' part opposite to the lobe acts as a stop for the shoe to 'float' against. So, by definition, it is a twin leading shoe.

As a one-off, there has been a degree of engineering applied to it. The machined, wedge-shaped pieces on the ends of the shoes seem quite complex. Not sure about those washers, Roger. I'll have a closer look.
Ultimately, though, I do feel that it has been a lot of work which may not produce the desired result

However, I am tending towards trying it on the bike, which is a Square Four-engined Huntmaster, which should give the brake a decent workout, I suppose.....

Regarding binning it, this is still a consideration. The inherent weakness of the alloy plate is a concern. I've looked at BSA/Triumph 7" and 8" brakes, John. It would seem that a pair of fork legs (or just the sliders?) with bolt-on end caps would be necessary for the spindle - or have people who have used these brakes made a spindle which passes-through, like the original Ariel one? If so, what about the torque stay?
Apart from the work involved fitting one of these brakes/hubs, there is the fact the these things, generally, are now silly money. Also, I'm not keen on how these brakes look. The large peripheral flange which protrudes beyond the diameter of the hub looks like someone has fitted the wrong brake plate.....(I understand that this flange gives rigidity to the plate, so it's something you have to live with.)

I've read somewhere that an Ariel owner fitted a tls drum front wheel from an 'airhead' BMW. Does anyone have any information about this? (I think that my delicate sensitivities may be less offended by a German brake than a Japanese one......I have even considered an Indian Enfield tls. The problem of these is that, it seems, no two brake plates are machined alike at the factory and they are even more problematic than the Ariel brake....)


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