front brake upgrades

[coldrider]

Now 8" and twin leading shoe brakes have been round for a while, I'd be interested in hearing some feedback from users prior to upgrading my own brakes. Any info/ advice would be much appreciated.

 

[Albervin]

Now 8" and twin leading shoe brakes have been round for a while, I'd be interested in hearing some feedback from users prior to upgrading my own brakes. Any info/ advice would be much appreciated.

Me too, especially now 8" brakes are available for Brampton forks.

 

[Mark Fisher]

I have the new brakes fitted to my '52 shadow and have covered about 2-3000 miles with them. My original brakes were alarmingly bad, but they were not in good condition, I did fit new shoes etc which improved matters but I still didn't have a lot of confidence so I took the plunge. The first effect after fitting was the replacement of the sponginess and "lever back to the bar" effect with a solid but somewhat wooden feel and a slight improvement in braking performance. Over time however the woodeness has gone and the brakes have plenty of feel, the braking performance has improved significantly and the nice part is that they are very progressive. These brakes are not incredible in terms of power but they are good and the behave very predictably and are a big improvement over the originals. The other observation I have made is that because the forks don't dive it actually fools you into thinking that the brakes are less powerful, I guess because I rde my egli a lot I'm used to the dive effect on braking so you get more of dramatic brake feedback, but on the shadow it is simply a lack of drama...the brakes work well.
The other thing to remember is that there is no room for the wheel nuts, you have to shim everything. Make sure the new drums have a groove machined into the back wall, otherwise the shoe pivots will touch the drum. A friend of mine had these grooves in his already but mine didn't so I had them machined in. You can't do it all with shims because you'll be splaying the fork blades and believe me, they don't want to be splayed and will fight you all the way! All in all though a really good modification with the added bonus that they are beautifully made and look great, yet still "period".
FAB!
thanks
mark

 

[Albervin]

The last thing I want to do after spending £1,000 is to machine the brake drums! As far as I am concerned that is not what I would term "beautifully made". Also, was the hollow axle & other necessary parts (shims, cable) included in the "kit"? I guess my "B" Rapide brakes OK in most circumstances but it is the unexpected emergency that concerns me.

 

[Mark Fisher]

Maybe I was unlucky because Davids kit already had the grooves machined in, it only cost me $20 to get them grooved, far less than the cost of returning them to the UK, not to mention the delay. Like I said, not a big deal. No shims came with the kit, but I had plenty of spare wheel bearing shims in the shed or "nerd-cave" as my 12 year old calls it! The original hollow axle is retained, the original cables were a bit tight, and the club supplied a set of slightly longer cables, which, with hindsight should have come with the kit.
Albervin is right, it is the unexpected emergency that will prove the value of the new brakes and I have already been there....money well spent.
thanks
mark

 

[Albervin]

I was reading that the VOCS recommend using a "Lightning" hollow axle that is not threaded at the ends. Good to know a standard one still works OK. I am leaning towards purchasing them now. Thanks for the input.

 

[Tom Gaynor]

"Sponge" is in direct relationship to mechanical advantage. The greater the MA (leverage) the greater the sponge. If the shoes have to move 10 thou to go from first kiss to full on, and the MA is 100:1, the lever has to move an inch. Reduce the MA, the "sponge" decreases. But now one has to squeeze a bloody sight harder to get the same braking force. Might even feel "wooden". Go figure what a standard Vincent MA is...
I had a race bike with a single disc, Lockheed caliper and master cylinder. It stopped, but took so much effort that after five laps I had a forearm like Popeye's. The solution was to change to a Marzocchi master cylinder probably intended for twin discs, and therefore with more MA. (OK, really HA, hydraulic advantage) Sponge increased noticeably - but I could now nail it with two fingers and retain forearms like a ballet-dancer's. Sylph-like? Damn right...
This isn't to say that one shouldn't eliminate all the slack one can, but ultimately there's a trade off.
For comparison / callibration, my PV 2ls brakes have something like 1/2" - 3/4" of "sponge" as defined above, with a Magura twin-pull lever (no balance bar), and they stop like a bitch, with two fingers. My 9" (210 mm) Menani four-shoe race brake is about the same in terms of sponge, and in terms of stopping, as good as the single disc was, if not exactly as predictable. (It heats up and the drum expands: the extra shoe travel, multiplied by MA, shows up as sponge, and has to be compensated for. When the lever hits the bar, sunshine, you're intercoursed, or into previously unexplored levels of corner entry speed. ) But that's racing: for road use, unless you plan frequent crash stops from 100+ mph, it wouldn't matter.

I think all later supplied kits should be OK. The clearance problem was actually due to the variation in the distance of the fork blades, and the later kits should now cater for the variations in our 'standard' Vincents.

My kit was modified by the manufacture, who is a friend on mine. You do need longer brake cables as the actuating arms are further away!

I am surprised by the earlier comments on wooden feel/sponginess. My longer brake cables are heavy duty ones, and I have a balance beam support bridge. My old set up was very spongy, whereas the new set up does not feel spongy or wooden in operation.

For minor speed adjustments I now can use just two fingers. I think it was money well spent as I no longer have to worry so much about emergency stops.

 

[Robert Watson]

I installed a set of Speet brakes about 3 years ago. They replaced nice thick alloy plates with green linings all trued up etc, which worked quite well, however with two up and full luggage, I just wanted more stop. I have to say that despite a few naysayers going on about how any 2LS brakes are just killers etc etc, these brakes have worked very well indeed. For a demo one day I grabbed a handfull at 60 MPH and locked up the front wheel. They were not cold, but not what one would describe as"racing temperature" either, and I was solo, and as I mostly ride two up with luggage on that bike, the suspension is quite stiff. There is no sponge, after contact the handlebar lever hardly travels any further, and these are no new either, as I have put around 15,000 miles on them now.

I was out with the local"modern" sportbike club last weekend and with them and all their 4 and 6 pot floating this and that, I found I was riding (mostly) with just two fingers on the brake, and when getting rather spirited with them (Picture me leading a 1050 Sprint. a VFR800, and Aprillia Tuono, a 650 V strom, and a couple of others through some local - well known to me - twisty bits) took to all four fingers. Ya, so it won't pull a wheelie for several 100 yards, but you guys really need to learn how to keep up corner speed -- but I digress.

Bottom line is at my time and place the Speet brakes work great for ME!!

Someone needs to do a more scientific test on which ones work the best, and how much each weighs etc etc.

 

[bmetcalf]

Maybe I can get you to ride my bike in June to compare. I have steel plates with gussets, a balance beam outrigger and the thick cables. Seems pretty good to me, but it is hard to separate out the habits of compensating for what our brakes are now days. If you survive, I'll buy you a beer, Canadian, of course.

 

[Tom Gaynor]

Weights of various wheels / brakes

Of course, Robert, your being such a little guy would be an advantage....

I agree entirely: no one has fitted single leading shoe drum brakes to British bikes (except lightweights) since about 1970. 2LS dangerous? Bullshit: an old wives tale. I think the PV 4LS brakes are a perfect combination of looks and function. And they look as though Vincent made them: no one notices - except when you outstop them by a factor of two.

Science: a bit rough and ready, on my precision bathroom scales, but my front wheels, weighed c/w with tyre and tube are as follows, and the comments on function are subjective. The Manx brake comments are the least subjective, because all have been compared on the same circuits over many laps.

Menani electron 210mm 4ls 18" ally rim (now on the Manx) 11 kg - stop a Manx from 145 mph without fade, as good as the disc, below
Kawasaki ally 250 mm 4ls 18" rim (formerly on the Manx) 14 kg - not as good as the Menani, and faded very quickly. Looked good though...
Ceriani ally 250 mm 4ls 19" rim (from an MV) 16 kg - sold on, untried
Laverda ally 250 mm 2ls 19" rim (from a Laverda SF = super freni = Italian for "super brakes") 16.5 kg - intended for the 600cc Comet, untried.
Lockeed 210 mm iron single disc, 18" ally rim (originally on the Manx) 11 kg - stand a Manx on its nose
Vincent 20" wheel with Shadow drums and ally Lightning plates 15 kg - would easily outstop an aircraft carrier
Vincent wheel as above, Lighning plates replaced with PV (Speet) 4ls brakes 15.5 kg - see above. Not in the same league as discs, but infinitely better than what went before. And took 45 minutes to fit to my existing (Magura) lever set up.
(The only differences between modern Menani and Fontana replicas are cosmetic. Patrick Godet uses (or at least has used, because I looked) Menani 250 mm 4ls on his Eglis. Menani and Fontana were business partners back when. They're probably made from the same drawings.)


Tom

I installed a set of Speet brakes about 3 years ago. They replaced nice thick alloy plates with green linings all trued up etc, which worked quite well, however with two up and full luggage, I just wanted more stop. I have to say that despite a few naysayers going on about how any 2LS brakes are just killers etc etc, these brakes have worked very well indeed. For a demo one day I grabbed a handfull at 60 MPH and locked up the front wheel. They were not cold, but not what one would describe as"racing temperature" either, and I was solo, and as I mostly ride two up with luggage on that bike, the suspension is quite stiff. There is no sponge, after contact the handlebar lever hardly travels any further, and these are no new either, as I have put around 15,000 miles on them now.

I was out with the local"modern" sportbike club last weekend and with them and all their 4 and 6 pot floating this and that, I found I was riding (mostly) with just two fingers on the brake, and when getting rather spirited with them (Picture me leading a 1050 Sprint. a VFR800, and Aprillia Tuono, a 650 V strom, and a couple of others through some local - well known to me - twisty bits) took to all four fingers. Ya, so it won't pull a wheelie for several 100 yards, but you guys really need to learn how to keep up corner speed -- but I digress.

Bottom line is at my time and place the Speet brakes work great for ME!!

Someone needs to do a more scientific test on which ones work the best, and how much each weighs etc etc.