The Commando Weave

rpatton said:

Do you think that the crisp steering is from the rake and offset combination that Herb uses?

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Yes, most definitely. Herb also tweaked the geometery on my 500 Seeley and both the 500 and 750 Commando of Herb's literally dropped into a turn. For me, initially it was shocking but stable as a rock and predictable.

rpatton said:

Are you using the teflon pad sets?

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No. I was using a Norvil head steady with a stock front end geometery, Commando Mk3 frame, 18" alloy wheels and Avon super Venom race compound tires. When I first got on that bike I was dismayed with the heavy feel to it; the term "heavy pig" came to mind when compared to a street Commando. I attributed it to the much wider tire profiles I was running. The Commando has sat since the end of season 1999 or 2000. I just resurrected it a week ago and have some plans of what I will be doing with it; mostly weight reduction, handling enhancements and a new motor. The teflon puck head steady was always on my things to do list and only recently realized that Herb had developed an under cradle teflon puck system.

Swash plate head steady was tested by Gerry Bristow in '01 or '02 on his 850 in Greece to feel too much vibes and no significant delay of the weave onset or landings of side ways leaps he did on a special cresting turn he found. Ms Peel will re-purpose them for swing arm flex. Here's a view with wear marks that reveal the top motion.

The plate tabs shown above just don't look like they are stiff enough to do much good.

Ah contare dear sir, this ain't hobot handy work its by the late great Oil Man, Gerry Bristow- Plates are 1/4" steel plate and rather heavy to heff. Gerry died before I tired it as head steady but as he's the only other Cdo rider that that would blast right through weave and know that meant air time sideways for chassis-fork testing landings on power, I took his word that the only thing his upgraded *stiffer* head staeady did was buzz him to remove it. The only compliance in his headsteady would be the boxed head mount, under brace tube and cylinder head fasteners. One puck is thicker than the other d/t power unit offset. Peel has slab sided swing arm so these will double up backing up swing arm/shock mount strains and luggage rack strut mount - prefect asymmetrical spacers I needed in Z plates to s-arm gap. That'd make 4 links points on Peel, 3 fairly compliant by a few silly mm's Max. Bob calculated at least 350 lb side loads he can apply. I can exceed that on Peel or she'd not hang so tight nor fly up so far or hi when I release the loads to get the most extreme whiplash G's I ever get short of animal smacks. Have you a tale of blasting through THE Hinge in crisis tearing one out on a factory Commando? Ugh please Lord never again.

I too was even more mis-guided than yoose guys in '99 to '03 learning to ride for the first time in my life on cycles that leaned much to turn, pure dragsters only, are too low to lean, so must steer in town like ATV's with Posi-Track locked differentials > kick rear out enough so it can aim thrust to straight steer to avoid the wide slides out of line or trip downs. i was 1st forced then forced myself to find handling limits, both in chassis upset and traction loss. In very good conditions its pretty hard to upset un-tamed Cdo's before traction loss. Rider Patton has a severe chronic nerve/R shoulder>wrist injury and smarter seasoned than me, so may not have pressed his testing like I have. Dances you are a mystery I pay attention too plus Drouin handling experience I don't have, so don't understand why you are not nearly as afraid as me of Commando THE HInge, THE Slap, THE Weavey Wobbles Fish Flop.

If a cycle/rider can't enjoy tarmac so harshly its as loose as THE Gravel > into MX bike straight steering-rear locked in a deep rut-no let off- sharper acceleration *Into Apexes*- its not anything that I'm interested in or can learn from. I always get a chuckle reading how powerful and on rails the elites are, *coming up out of Apexes*. Pashaw Peel snapped em up & split out by before apexes *while they were still on Brakes!!* After apex is pure relaxation relief to Peel too and where she can most use extra power.

At the energy I'm into its very hard to keep both tires in traction or planted but not like ya see in TT/IOM weaving off crests in vertical wheelies, but side way wheelies that relieve the peg noise or trips out to peg noise in low sides that wind up chassis for orgasmic releases > into hi side sling shots. We have seen one example so far of a elite rider that can/will do what I learned to do on similar steeds, phase 4 leap up just as the weave hits to settle out in air plus twisting some to smack down on nailed higher throttle right into the next fling. Everyone here was ohhing and Ahing on the next more "dramatic looking" air time mostly straight upright . Other races would not do the needed half crash set up but one that attempted it & crashed. I fully recognized this gem of handling prowess it took to set up the second higher leap - so backed up till I saw what he did that no other rider would or could, let bike jerk itself up in controlled crash that snaps forks faster than humans can, with *air under both tires*. So if you ain't going at it so harsh to need straight steer or crash, then you ain't got enough energy build up to charge into a new phase of solid state condensed matter physics.

Remain in the too flexy or too stiff zones, but be careful, I've left that behind on Peel. Keep in mind my world ain't divided up into vintage skinny vs modern balloon, It divides by rally car-Kart like power steering vs everything else. I just returned from 120 miles of Ozarks delights, about 20 of that in constant state of THE Weaving Hinging WOT Combat nuisance zone, d/t special conditions and state of mind, finally maxed out life on a factory Commando = its not hardly worth it for the little extra speed gained over staying just below Its Evil s.

There is a Goldie Locks solution nothing else can touch lurking in isolastic Commandos.

hobot said:

Ah contare dear sir, this ain't hobot handy work its by the late great Oil Man, Gerry Bristow- Plates are 1/4" steel plate and rather heavy to heff.

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Read my post again hobot. No reference whatsoever as to ownership of concept or design.

I could care less if they were 1" thick plates, the way they are fastened is the obvious flexy point. I direct your attention to Doug McRae's post of the Herb Becker isolation thingies.

Sorry chap, two thin cantilever plates just don't cut it; I thought you would know that.

Gerry Bristow RIP, wish he were around for a good informed oil thread.

Dances with Shrapnel said:

rpatton said:

Do you think that the crisp steering is from the rake and offset combination that Herb uses?

Click to expand...

Yes, most definitely. Herb also tweaked the geometery on my 500 Seeley and both the 500 and 750 Commando of Herb's literally dropped into a turn. For me, initially it was shocking but stable as a rock and predictable.

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I don't know what the level of difficulty it would be to fabricate the offset inserts to go to 26 degrees of rake from 28deg on my '73 850. I got a front end from an RF600 about ten years ago. They're 41mm non-cartridge conventional forks. I rebuilt them and got Gold Valve Emulators for them. They aren't great, but they are adjustable and they sort of look like Roadholders, with full gaitors it would be hard to tell. I had a set triple trees made for the forks that reduced the offset from the stock 70mm(?) to 50mm. I didn't do anything further with it because I thought the only way to get the rake down was surgery on the frame. If I could get those inserts made then it would be more than half the way to completed.

26deg sounds wicked steep. But it's all about trail I guess. :?:

Framecrafters makes alloy triple clamps with eccentric collars for adjustable rake angle. I don't see why you could not order them to your offset specification.

What I learned from Gerry was swash plates transmit buzz.. What I learned on my own- was long rod link up there did not vibe but Peel's head link is not as robust as the flexy parts its attached too. I said it before and sticking to my path, don't make em too rigid like moderns nor too sloppy like Commandos.

If ya want tighter handling *sensations*, which is totally different than actually handling the easier tighter sensations of turn in-fall downs, put the dang forks almost vertical. To get more actual handling of sharper turning, shorten the wheel base by chopping a bit of cradle out. This is path Ken Augustine did for his racers. Ken A did the Worlds Straightest Commando build so knows a bit about their geometry.

While contemplating mostly dead end unless modern features, what I ran into was what makes em turn in- lean down with least effort or fight back, does exactly opposite trying to get them to fling back up in time, they fly into weave that can lift tires and toss rider. I can/have induced weave in various bikes trying tip down under power and also trying to rise back up. Both take athletics and neither any fun for thrills. We may have some confusion reading my stuff as what is sharp to you'all may not be very sharp switch backs in my book.
At speed if it takes .33 sec to get down or back up that my end up 3 ft into bluff face or 3 ft over railing by time it happens. Takes a lot of force to do this and nothing seems to enjoy it like a tamed Cdo that's not in a straight jacket.

After ya get it on a really Neutral smoooth handler and can't lean more or turn forks more to sharpen a power turn, pilot can just skip rear out to pivot on front or both tires on bike/pilot CoG. Do it with counter street to slide wide or straight steer to hook sharper. There are incremental improvements and there are transforming ones. Just staying in smooth lines ain't enough to test pilot or handling of Karts or Rally cars, bikes either.

http://www.bayarearidersforum.com/forum ... 60882.html

Certainly there have been tube frames were the engine was not a stressed member (Norton Commandos come immediately to mind, but I'm sure there are others), and there are cast/formed frames where it is a stressed member (e.g. oilhead BMWs). I know of no reason why your claim would have to be true.

That's exactly right Flyin Hun. Another example like the Norton Commando...Buell.

Mine had the frame made of straight tubes (like a Ducati frame) and the engine sat in rubber mounts and in the movement directions confines of Heim Joints. That was Erik Buells contribution to Harley back before he set out on his own (the first time) when he designed the FXR frame.

As to overkill in stiffness, Honda ran into a related issue a few years back where they had gotten to a point with design and technology where they had made the frame so stiff, they had problems with it. Not like real serious issues, but to the extend that it was harming rideability so they went back and designed the frame to be less stiff, within certain parameters of course and called it something like "tuned flex". Where they added limited flex in certain places in certain directions. And they saw an improvement in rideability fo the bike. I want to say it was their race teams RC51 or the superhawk where this happened, but I am not totally sure on that part.

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Here's another misconception of race bike designers - that only my flexy tamed iso Peel revealed to me. A really Neutral cycle essentially takes all the lumps-bumps of road inline-through its normal suspension vectors, not through the chassis twist sideways. The faster ya go around leaning the more its like normal road suspension action on bumpy surfaces. The chassis compliance is needed to take up the *tire conflicts*. Tire conflicts are not felt coming from the tires on other bikes, but shows up as too ringing or too floppy chassis-weave. Frame twist up does not come from road texture but the loads pilot puts on it by throttle and forks. My disdain for moderns is how unpredictable they react at limits, at least un-tammed Cdo give ya fair warning. This chassis compliance must be progressive and w/o cycling-ringing on releases. All others think*feel the fork stem should be fixed-rigid in relation to swing arm spindle, not me, make mine articulated thank you very much.

When the motorycycle is leaned way over, the suspension has little compliance in the vertical plane for bumps. So a little bit of flexibility in the frame in that direction helps keep the tires on the ground doing their job. Of course, it has to flex in a predictable way, so the swingarm/steering head relationship isn't altered detrimentally and oscillations don't occur.

This is just my speculation, but when Ducati came out with their carbon fiber frame, it occurred to me that they were trying to build in some flex for this purpose, since a CF structure can have different properties in different directions.

FWIW, I've read that at least in WSBK that the Ducati trellis frame is known for being kinda flexy. That is one of the reasons - along with the motor - that it's known for accelerating well while still on the side of the tire.

Dan, you are spot on. I have been wondering if the Ducati CF head piece is maybe too short for them to get the right "frequency" of flex that they need. This is totally speculation on my part but it seems like a possibility. Given Honda's massive engineering effort to understand the lateral flex issue, perhaps Ducati doesn't have the resources for a similar effort with the CF frame.

Colin Edwards on the RC51 comes to mind. He had a bolt removed to allow for more frame flex.

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I'd be a little careful about that generalization. Certainly there have been tube frames were the engine was not a stressed member (Norton Commandos come immediately to mind, but I'm sure there are others), and there are cast/formed frames where it is a stressed member (e.g. oilhead BMWs). I know of no reason why your claim would have to be true.

The only tube frame (or for that matter, ANY frame) design from England (prior to the advent of Hinkley Triumphs) that used the engine as a stressed member was Royal Enfield.
Triumph, BSA, AJS/Matchless, Ariel, HRD/Vincent, Brough Superior, Norton, James, Excelsior, Rudge...
All had full-cradle frames that just held the engine, without relying on it to add ridgidity to the frame.

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When all the influences on handling upset are completely isolated or removed, its so plain what's really happening even a kook like me gets it. Otherwise everyone is looking at the muzzle blast and missing the triggers.

Btw Ken Canaga warned me off less rake, told me he made one with less fork rake, 26' IIRC and the rider/racer liked its sharper turning ease til it dumped him pressing it for permanent injuries. This also hurt Ken knowing his experiment did it.

hobot said:

All others think*feel the fork stem should be fixed-rigid in relation to swing arm spindle, not me, make mine articulated thank you very much.

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"All others", really. I am happy for you that you sorted this out all by yourself. You must hurry out and publish! :roll:

This brings to mind everyone extoling the virtues of the 1970's Kawasaki 750 Triples handling attributes; yes, they must have perfected "the hinge".

hobot said:

When all the influences on handling upset are completely isolated or removed, its so plain what's really happening even a kook like me gets it. Otherwise everyone is looking at the muzzle blast and missing the triggers.

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You against the world. More like everyone is pulling the trigger.

Sorry hobot but you have taken all sorts of phenomena and experiences by others, mixed them together, thrown them up against the wall and cherry picked (taken out of context) in order to fit your assertions and opinions.

hobot said:

swash plates transmit buzz.

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Truely the Baghdad Bob of all things Norton.

Junk posts.

Doug McRae swears by the Herb Becker teflon pucks and their smoothness. I ran Herb's other Commando at Grattan Michigan (with the teflon puck head steady) and it was probably one of the smoothest and confidence inspiring Commando rides ever, enough so that I am now resurrecting my Commando racer with the enhancements.

1. Even slight Buzz bothers me, so a qualitative opinion till objectively measured as I plan to do.
2. Swash plates placed similar to rod links prove its in right places to bring isolastic handling up to the current bench mark of solid mounted Nortons, rather more comfortably.
3. Still leaves question if swash plates allow as much tire conflict oscillating load handling as more compliant links.
4. The road irregularities don't directly upset chassis as normal suspension handles that when leaned and the G vector is aimed same as tire angle and into tire patch, but the irregularities do casue the front and rear to instantly road follow a few mm's, which tugs the front and rear of chassis in random/opposite angles. if this frequency of oscillation is only taken up by the give in stiff forks/stem or in swing arm their pendulum length levers and torsion bar length rates can't resonate at lower controllable frequencies the irregularities arrive at. At some point these conflicting resonances splash together to snatch forks or chirp a patch right out.
6. A novice hick can't be believed or even understood so for others to contemplate that don't know no better either. Something has to give just like the shocks/fork suspension, but best not be at the tire patch supporters suspension components. .

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