Grimeca compared to Laverda front drum brake?

1200ts

1200ts

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USA - Riverside CA
This morning out riding a twin with Grineca brakes, I almost crashed in to a car as I could not stop! The brakes always work fine until the front gets hot and the lever comes all the way back to the handlebar. It has new linings that were arced to the drum and everything is in perfect condition. It works better than with the original linings but has never been a good brake in the 30 years I have owned the bike and have tried everything to improve it. Although better than British bike drums of the era it would be more appropriate on a 350cc bike.

So am considering fitting a Laverda drum brake in its place but as I have never ridden a bike with these brakes, are they really any better?
 
I'm a heretic, but there's a reason front drum brakes are longer used. I realize it's a "period correct" thing w/ purists. You can try different pads or drum brake but it will never be as good as a Brembo disk system, not to mention the added weight.
 
I am stuck with drum brakes on this bike unless I replace the forks. Years a go I rode a Rickman Triumph with Ceriani four leading shoe brakes and it would definitely stop the bike from any speed. So I know there are drum brakes out there that do work.

How much better is the Laverda brake compared to Grimeca?
 
Conic hub Triumph brakes improve with slightly longer levers connected to the shoes, more mechanical advantage and either cooling holes or big scoops that channel more cooling air in. Are you sure you have the best possible material for the shoes? Asbestos-free made a big change in performance, but it did kill fewer Mechanics.
 
Drum brake linings have gone backwards in quality since losing asbestos.
No production incentive now to keep development going.

Ferodo do a non asbestos lining which supposedly replaces AM4 race lining.
It's not bad but can still be made to fade on a heavy bike.

Guy I know has a Grimeca double sided single leading shoe brake on the front of his Manx Norton.
Even with the good lining, it's fading after 4 laps of a fairly short circuit.
 
😁 progress then 😳 reminds me of the old Jap discs in the rain - I can remember coming down a motorway slip road onto a roundabout during rain and sailing straight into the traffic luckily avoiding everything with no brakes whatsoever - RD400 Yamaha
 
1200ts said:
I am stuck with drum brakes on this bike unless I replace the forks. Years a go I rode a Rickman Triumph with Ceriani four leading shoe brakes and it would definitely stop the bike from any speed. So I know there are drum brakes out there that do work.

How much better is the Laverda brake compared to Grimeca?
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From my experience with Grimeca 2LS on a GT, Grimeca 4LS on S, first series Laverda drum on SF, second series on GTL, disks on SF2 and with Zane' models disks, there is only a marginal improvement from the Grimeca to the Laverda types and all of these are heart-stoppers in traffic compared to the twin disks on the SF2 which are absolutely nothing like the effortless stoppie achievable with more current disks. For me there's a totally different defensive mentality and planning ahead needed when out in traffic on the old bikes.

All the drums need very careful setup of simultaneous shoe contact - I've scared myself numerous times on the GTL and spend time adjusting the linking pullrod which is time consuming but essential for best performance. I'd thought back then that, having got it set, it would stay set but it doesn't seem to be the case and is a maintenance item.

My understanding of the change from Grimeca to Laverda drums is that it was partially driven by the desire to avoid the slow release of cam type shoe actuation which may not retract as quickly as the lever action of the Laverda TLS. Apparently too the case with the first series Laverda drum where we see pictures of springs and rubber bands to pull back the opposing rods to try to make brake release quicker as was addressed by the spring in the link rod mechanism of the second series Laverda drum.

While the Laverda drums were sought after by vintage racers as one of the biggest and best TLS, I'm not sure the Laverda drum will provide much greater peace-of-mind over the Grimeca unless there's constant care taken to keep it adjusted for simultaneous shoe contact.
 
My GT has the “S” type brake with the tea strainer vents- I asked for soft linings for a heavy old bike that’s not going racing.
Mine are fine in normal use - only a couple of times I’ve had to hit them hard and the front is super grabby and could lock the wheel but the rear is crap, a retarder more than an effective brake. I ride pretty slow and rarely use the brakes, so my experience is from cold drums in a cold country- if you’ve been hooning around in a hot country they may well fade and terrify. I have spent along time setting them up and made my own adjuster rod to get them spot on, my feeling is your linings are too hard. I seem to remember someone using forklift linings ( really soft ) on a trials bike and they were fantastic.
 
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