Weight of Commando front forks

I'm curious as to how Commando forks compare to lightweight forks such as those made by Metal Profiles, Ceriani/Maxtons etc. Anyone know the weight of bare Commando forks, no triple clamps?
Hoping to build a lightweight Norton Special someday and there is no time like the present to start gathering parts!

Glen

An interesting question this Glen!

I've thought about this before, and concluded that the heaviest parts of any tele fork are the stanchions and sliders. And, in order to prevent flex etc, these would seem to need to be thick walled and made from good materials. So, any meaningful weight saved here would, in my opinion, be quite false economy.

The damping internals are not generally very heavy, but nevertheless, some weight could be saved here by using lighter materials, especially with Roadholders as all of the stock damping internals can be replaced with alloy. But then again, I can't understand why anyone would do this as one would surely replace them with some alternative (Lansdowne, Maxton, etc) that actually work properly!

With Roadholders, changing from the stock full length spring to a short external spring might be the biggest saving?

If I was building a ground up special, I'd buy the Maxton Ceriani replicas, available new and custom built to your requirements.

big diameter and small wall thickness is the norm these days .
I dont have a standard inner spring on hand to weigh but I just weighed an external spring from some of the external spring kits I was making a while ago
it weighs 332grams so if someone would like to weigh a standard internal spring to compare.

I happen to have a pair of forks ready to bolt up to my Stock Bike. The forks themselves don't feel any heavier than other fork legs I've lifted. But the heaviest part, by a long shot, is the disc brake caliper. & I'm sure a lot of weight could be saved there.

not to mention the disc. any other disc would be lighter. what is the caliper weight?
hope we are not going off track here.

worntorn said:

I'm curious as to how Commando forks compare to lightweight forks such as those made by Metal Profiles, Ceriani/Maxtons etc. Anyone know the weight of bare Commando forks, no triple clamps?
Hoping to build a lightweight Norton Special someday and there is no time like the present to start gathering parts!

Glen

Click to expand...

Glen - I can't give you a figure for the forks complete but I can say that a Commando bare stanchion weighs 1750g. An early 1970s 35mm Ceriani stanchion weighs 1325g, a significant sprung weight saving from the stanchions alone.

If you keep the Roadholders, you could get RGM alloy damper units to replace the steel originals or you get cartridge dampers. If someone here can supply the weight of an original Commando damper, you can compare that to the weight of a Showa cartridge damper: 350g. John Bould will tell you the weight of his cartridges.

Unsprung weight savings could come from a drilled steel disc and alloy caliper, assuming you will start with alloy rims, and a lighter front tyre. I have a Bridgestone BT45 on another classic and it is significantly lighter than an equivalent Avon or Continental (and lighter in the right place). If you keep the Roadholders, you might also consider a high-spec alloy wheel bearing spacer, alloy fork top nuts and alloy seal retaining rings.

I would say that Cerianis or Maxton replicas would be a big improvement. But then you would need different triple clamps and steering stem. Knowing your machining skills, you could make a set! A bit off topic, but the Maxton rear shocks I have on my Seeley feel as light as a paper cup, and I am guessing they could be close to half the weight of the equivalent Konis/Ikons.

Dave

edit

Hi.
4400g brake leg.
3360g t'other.
Residual oil in both.
Ta.

I had Maxtons front & rear on my first Triumph Street Triple, & it was the sweetest ride I've ever had; like a magic carpet ride! It was better even than my 2nd Street Triple, which was an R, with the Ohlins rear shock upgrade. & that was a very nice bike But if/when I buy another Street Triple (love them bikes) it'll either have Maxtons fitted already, or I'll buy one with stuffed suspension & stick Maxtons underneath it.

I am in the process of upgrading my brakes.
I just weighed my disc and caliper. Disc is 5 lbs 3 ounces, caliper is 2 lbs 12 ounces! Ridiculous.
Jaydee

My scale shows the stock disc at 5 lbs 8 ounces and the Madass disc at 4 lbs 9 ounces. Jaydee, has your stock disc been ground?
This is less difference than I expected, however while the Madass disc is just under a pound lighter, it is also much bigger in diameter. So bigger braking and lighter weight is a pretty good combo.
Not sure about the Madass caliper, I did not weigh it during installation but it felt very light compared to the stock Lockheed. Once again, six pistons and big pads vs two pistons and small pads but the two piston small pad setup is the heavier of the two, maybe by a pound.
The weights which Needing has given for the forks seem to say the Commando forks are not overly heavy compared to some others. His numbers convert to about 17 lbs for the two legs. Metal Profiles claims 18 pounds for their lightweight fork which could replace the Commando fork. The Metal Profiles number includes the lower triple clamp and stem, so it is perhaps a pound or two lighter than the Roadholder. Not the difference I expected.
Perhaps the best way to go truly light weight on the forks is to go modern, thin wall big diameter. Once again, this type of fork gives you the best of both worlds, stronger forks combined with lower weight.
I believe the GSXR 600 forks I used on my Vincent Special were only 14 lbs including both triple clamps and stem.

Glen

Excellent question, as I am in the exact same process as you, i.e. building light from scratch.

From a price point of view, the original forks seem the cheapest (compared to ceriani or maxton) , but what about japanese xj 650 forks ? Have seen these once on a commando but have no clue about their efficiency, weight, etc...

regarding brakes , comparing my 6piston caliper and 320mm disc for Norton against the standard Norton bits
320mm disc 4 Lbs 9 oz
Norton disc 5 Lbs 8 Oz

6 piston caliper 2 Lbs 3 oz
Norton caliper 2 Lbs 12 oz

so there is a saving of 1-1/2 Lbs
My disc is not that light in comparison to other 320mm discs and I'm sure there are other lighter calipers also
so obviously at least 2 lbs or more could be saved by using lighter brake components

The CNW Brembo kit I have, the disc weighs 1600g/3 lbs 8 oz, and the caliper is 1050g/2lbs 5oz.

a good saving even over mine, my disc carrier (center) is stainless, hence being heavier.
My disc is fully floating and if the carrier was alloy then it would wear fairly rapidly at the rivets, like some well known floating discs from the UK where
users have had their discs wear out in low mileage.
anyway back to lightweight forks...........