My first experience with "The Weave"

I'd read a few of the threads on this, hadnt experienced it yet until last night. I know this has been talked probably to death, but i'm just starting this so i can post (hopefully) my results. Last night i went to the Miami vintage bike night and it was the first time i took my fastback. I'd previously only ridden it around town no faster than 55. Well, at a little over 60 i definitely figured out what the weave was all about. Smooths out when you scoot your butt backwards or when you apply some throttle and power through it. I had it up to 80. Kind of nerve wracking. Anywho after reading a bunch of threads i did some nosing around and swingarm/iso's/wheel squaredness and tire pressure are all fine. I'm kinda thinking rear shocks. As far as i know they are original to the bike and don't seem to have a lot of damping. They definitely bounce a bit when you push down and let go...moreso than on my Atlas. Seems to make sense that if you lack good damping a bump could cause some oscillations that could escalate into a dreaded tank-slapper. I'm going to get some new ones and report back!

Hehe aka THE Hinge. Anything and everything splashes its influence to upset isolastics. Tires top the list and certainly sloppy shocks can. At least you now know its always lurking. If you can power around a turn so bike tends to squat and also unloads the forks then can zing around a faster but if whole turns not as smooth or wind free as entry can end up beyond recovery by let off or power on. Play with tire air front/back for a bit more tamning or bit more wildness education.

The rod links front top and rear help a lot tamming weave and in my case with
front and top links kind of compliant I find Cdo the best handling cycle ever made.

MIami has lots of freeway curls to enjoy if no pavement seams encounted diagonally.

tires can cause it too if there getting up there in age and/or miles - last time happened to me a new set cured it (the old tires were about 3 years old )

Hi,
It sounds like you have the same problem I have with my 1968 model. What year is your bike? The early bikes have less rake and trail than the later bikes, especially the 850s. This seems to make them less stable but quicker steering. The latest mod. to mine is 70lb rear springs to replace 90lb springs. No difference whatsoever.
The biggest improvement has been to fit a 100/90/19" Avon Roadrider to match the front 90/90/19". This has greatly reduced the weave which like yours seems to start over 70 mph. In the spring I will fit a hydraulic steering damper. You may get a few more ideas if you search ....Weave at speed on a '68.
Hope you find the solution.
Regards,
Martyn.

TYRE choice can have a vast inflance .

tho ' . :lol: stock shit el cheapo shocks were disposables .Getting Good Second hand ones were almost as trying as finding good S/H Amals . :lol: :lol: :lol:

Most were shot . leaking at seals ? shafts scoured ? Bent ? operate without binding with springs off ? ANYWAY the Gas Girling two way damped with 110Lb springs , kept the rear well up . stopping draging ( pipes not stoplights ) . Front was stiffish too .

The Nervousness & camber sensitivity , & contour following were nasty at the odd time ( not paying attention ) with the triangular type race tyre front .
On the low profile Oval Avons ( the old road runners ) the manners weremuch improved. In respect you could RELAX rideing it . Had good neutral characteristics
with the 3:60 F , 4:10 R .

THOUGH that Swing Arm Mount , in my opinion , unless that pin is pressed in Very Securely ( Tight ) it isnt ' LOCATED ' . If youve riden tTriumphs (real ones)
you can pick it . Any before 67 weaved . On occasion . Not necessarilly relateing to Load / Speed . More road conture / throttle .

Those Swing Arm Spindle mount clamps arnt a bad idea . As is Iso's 2 1/2 to 4 1/2 clearace . The Bich was there by 5 on mine . Schnick / schnick .

Load Related , upright & leant . IF you could pick it . Kepping the Throttle On stops it . & a firm grip .

mikegray660 said:

tires can cause it too if there getting up there in age and/or miles - last time happened to me a new set cured it (the old tires were about 3 years old )

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+1 on the above comment. Not sure what tyres you've got or what condition they're in, but consider them when looking for a cause.
I'd been chasing a rear end weave for a couple months, which I thought odd as it disappeared in the corners but was present only on the straights. I went through the Iso's, bushes, tyre pressures, even bought the Kegler clamps off a member here. I was just about to fit them when I noticed how much my rear Dunlop K81 TT100 had worn out since I checked it last. I'd forgotten how quick they go, it's been about 10 years since I'd had them on a bike. I put a new one on a couple weeks ago, gone for a few rides since and no weave!
Sometimes, the simplest explanation is the right one.

Concur - Tires (or Tyres).

My 850 did that badly with the tires the PO had on there - widest 18" wheels/tires that would fit on the bike without rubbing (rear did a tiny bit anyway). Put the stock size 19" Avons and weave gone; bike tracks great at all speeds to max (about 115 indicated) Also no longer needed the POs steering damper so that's gone as well.

my bike is a 68, fairly new tires on it but not the correct sizes ....it has 4.10-19 front and rear.

Those really aren't the "wrong size" as many run 19" 4.10s on the front/back - if a tire issue is causing the weave its almost always back tire related

usefulidiot said:

my bike is a 68, fairly new tires on it but not the correct sizes ....it has 4.10-19 front and rear.

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I run mine on Dunlop TT 100's 4:10 / 19 front and rear and the handling is fine, I've yet to experience "The Weave" hopefully I won't.

My opinion - the most practical cost effective and best over all brake and corner traction and wear life, [and heavy load carrying] is 110 front and 120 rear. 120 is a bit of a fiight to get mounted tire into the swing arm though, but chain clears ok. 120 rear feels a bit slugissh like running in boots but not noticed if just operating in sane legal zone, only when trying to really kick up heels and you're still imprinted on the lighter throttle and fling response of 100 or 110 rear. 120 rear for me definitely feels more secure crossing loose stuff as don't tend to surprise unintended fish tailing - as easy. As my factory Combat [un-tri-linked tammed] tires wear the hands off stability degrades, to point its dangerous to let go of bars below 50 mph to diddle helmet bugs or jacket vents, but not too bad on worn tires hands off if I shift way back on seat first. I can nurse out like 6000 miles on 120 rear, IF I use some discipline to only thrust up mcuh when leaning and not use engine braking and weave zig zags in lazy arcs on long straights and get close to fouling limits in turns as often as I can [w/o pressing speed or traction risking], or ~4000 miles center cords show up too soon - again.

In my exploring handling upsets I asked Wes to let me try his '71 about 7 yrs ago when It had over 1/4" side loose gap at front isolastic, easy 3/8"+ side side and twisting of rear tire in swing arm and clutch wobble jerking on primary chain to jostle the power unit - rear patch obliquely in relation to frame/front stem/tire and forks worn out noisy and likely low in fluid. It allowed nice fast zig zags going around turns leaned pretty far on pretty good throttle and tracked straight ahead just fine- The Only Thing I noticed was a short instance of twitch going side/side as the slack taken up. I could not induce THE Hinge or Weave+Wobble - UNTIL I tried to hold stable lean in some sweepers at constant speed - Then the oscillations had time to build up on the slackness so backed off down to legal posted speed, instead of 20+ mph over.

Personally I don't think a regular Cdo handles worth a shit compared to rigid sports bikes nor rigid sports bikes handle worth a shit compared to tri-linked compliant isolastics, so just don't press luck on super duper racers or sloppy Cdo's no mo. Everything I did following normal-orginary handling Cdo improvements, new tires, re-newed isolastics and swing arm collars and fork brace, definitely upped the threshold before THE HInge, but then when THE HInge hit - it onset at such harder and faster frequency surprise I could barely recover it in time. This is exactly how them fat tired rigid sports bikes behave too, all is fine right up to Terror Zone fork slap or tire break loose into low or hi sides. I think the absolute best power handling cycle lurks in the ingenious isolastics on fairly skinny tires, once set up to allow secondary dampered chassis suspension to function to take up tire vector conflicts.

I've just balanced the front wheel, and no waves anymore
Fritz

Some of the early commandos had almost racing steering geometry due to input from Peter Williams. A few inexperienced riders got chucked up the r oad in the UK, after hitting the 'cats eyes' in the centre of their roads. Apparently an experienced rider would have just ridden through the incident. A combination of sensitive steering geometry and those stupid isolatics are simply an accident waiting to happen. If I owned a standard commando I would modify the frame to pick up the ends of the swing arm spindle, or I would simply keep the speeds down to a sane level. You haven't lived until you've gone into a tank slapper, had the handle bars disappear into a blur and been chucked down the road with your bike turning into a bunch of screeching metal beside you.

I can not believe that geometry that works well on race tracks don't work even better on the street obstacles. Something else going on Alan and would appreciate some back up on you conclusions with references to the changes factory made to both hinder race handling as well as stifle street handling speeds to point it made Norton "safer". Does not compute to me unless somehow made bikes too scary to ride normally which should cause more crashing not less. Ugh. Simple question Alan, do you think your neutral handling self steering racer would be a risk to ride on streets compared to factory Commando -at less than tire traction risking rates?
I think not. My surprise in Peel was lifting front ~2" and softening rear for more throttle sag and increased effective trail made a better off roader and even better pavement holder. Putting me feet on fork sliders on both Cdo and SV650 revealed I could not tip into any corner w/o the forks extending, even just sightseeing speed and no throttle. I never trail brake but if so slow don't really need to brake to get around or if too fast its a crisis to try to save, but never ever for on purpose getting around faster.

My Seeley wouldn't be a problem to r ide on public roads. I don't usually ride on the street, but when I first moved here I had an RD250LC which was very skitterish on one of our roads in particular. There was a depression running longitudinally for long distances in two places where heavy trucks had bee n running for years. The most dangerous roads for a motorcycle are ones that have been 'grooved'. You can get flicked off anything with light steering very easily. Most of the guys who do historic racing here use modified street bike s with normal production geometry, so ride around their handling problems. My Seeley is different to ride compared w ith many other bikes, it oversteers if gassed when cranked over. It won't grab you by the throat, but unless you are aware it will do that, you can't use it t o advantage. It is quite a pronounced effect. If you were building commandos for sale to kids, they would have to be very stable and neutral. That early commando could be good for competent riders , but if I had one I would stabilise the isolastics so there would be no hinge in the middle of the bike. If it goes wrong, it can grab you very quickly even if you are very experienced.
You have to be very careful when changing steering geometry, fortunately that doesn't happen very often for most of us. When I first raced my Seeley, it mishandled very badly. Both my mate and myself also nearly crashed due to it . Under brakes it would stand up and turn away from the direction in w hich it was laid over. When that happened to me, I decided to crash the bike on the grass beside the bitumen. As I turned it on again to get there it laid down again and I was able to recover. I wasn't even taking metoprolol then.

Acotrel, what you describe implies to me that all other cycles but one are all compromises and I'm so spoiled on Ms Peel half sloppy triple links I have no worrys about any conditions encountered because I've charged head long full tilt across washborads and frost heaved and truck pounded broken pavement chiances in complete awe till point of boredoom until catching air side ways to sharpen up even more with no let offs just extra throttle spike to make it more thrilling.
I well know about the powered over steering and seek out or make every turn a fast decreasing radii while staying in 9 ft wide lane with rock face or rail drop offs bordering and not even needing any athletics but breath control force to keep from backing out to focus on next aim point. Best place I've found to practice this in on snow covered grass to keep upping power and fork straight steering till screwed down spiral into snow angels. Must be levelish or another factor comes in that almost no pilot but me and some sand dune runner realize, loose rear will weather vane down hill no matter the bike speed and aim of front. Once past the mental and cycle limits of counter steering on front patch, several new worlds of handling open up and none of them depend on front tire traction. I have tried to practice Peels lines on other cycles to point of sliding front tire and low sides and hi side and tank slappers on other bikes. I gave up very quickly so don't know if your Seely or any other type cycle is up to what I have in Peel.

But Peel is just a dream right now so I"m in constant avoidance of recovery from weave on my regular Combat that suffers everything know from tire wear to innate isolastic spring backs, even going slowly w/o a thought of speed handling to suddenly hit sections that set off the Hinging, but going slow enough its easy to back off of in time to carry on with a lingering disdain for the dangers innate in all other cycles but my oneinarow. Either I'm full of it or ya don't yet know what rest of the world is missing out on.

Is that a napping reindeer ? At x-mas ? Does Santa's sleigh weave with all the weight of presents then lessen as they are dropped off to the boys n' girls ?

I would not run 4.10 on the front of early bikes.

bad_friday said:

I've just balanced the front wheel, and no waves anymore
Fritz

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I had balanced the front wheel with my ancient "Dangle" wheel balancing rig, took a LOT of weight on one side. Anyone else connect balancing/lack of with the weave?

Unbalanced wheels, on anything, is asking for trouble...