Commando High Speed Stability

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acotrel said:
Phil, you must be much more sensitive than I am. I crashed a lot of times before I could see it coming. Main problem was drum front brakes, however I rode my Triton for years with exhausting heavy handling after I fitted 18 inch wheels to it to get decent rubber. It is never really that obvious where the problems come from. I just thought the Triton was nice and stable, even though it always ran wide a bit in corners. The Seeley Commando is a much better thing - much easier on the nerves.
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I doubt I am more sensitive than you acotrel. Out on the race track pushing the limits, of course you've fallen off many times. When I was young and reckless, I took a couple of nasty spills pushing the limits on 70's tyres and going too fast around corners, way too fast. I don't take those risks anymore. Too worried about seriously scratching my beloved Norton Commandos. I'm not a special rider by any means but I can sense subtle handling issues. I've been riding Nortons since I was 16, along with a long string of different bikes as well, especially Beemers. I don't like the 18" rear wheel on my Fastback. I didn't like it on my hand built hybrid combat last owned either. It seemed like a good idea at the time but I now think it is a mistake to fit. Once it is gone from my Fastback I can look harder at the high speed stability issue, should it still exist. I appreciate your comments on the subject as obviously you have done a lot of experimenting at the skinny and dangerous end of the envelope. I don't plan on crashing to learn what works and doesn't work, you have. I'm too cautious these days to push the matter to the end of handling limits. But I'll get this subtle issue sorted and will report my findings if it interests anyone.

Phil
 
phil yates said:
But everything should be okay with everything on the bike having been replaced to virtually make it better than new.

Phil
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If you have the old headsteady not better than new. A good quality headsteady like the one suggested could make a big difference in handling.
 
dennisgb said:
phil yates said:
But everything should be okay with everything on the bike having been replaced to virtually make it better than new.

Phil
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If you have the old headsteady not better than new. A good quality headsteady like the one suggested could make a big difference in handling.
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Then I guess I'd better buy two from Jim. Maybe three, the BMW might need one.
But yes den, sounds like the way to go. Jim can send them back with the Fullauto when he's finished.

Phil
 
The factory head steady Lord mounts can part from their base like they tend to do on muffler mounts and easy to check. i've switched from 19" and 18" in same afternoon on both tri-linked Peel and factory Trixie d/t a flat to get back to work and did not notice any unsteadyness on either of the. Back then hardly ever got below the [pavement] ton on Peel except where leaning far enough over for the turns would put my head too close to oncoming free flyers in blinds. I always hang turns close to outside paint line. When I left head steady off Trixie I did get some slight weaving sense at 65-ish until I let us cross double yellow at legal 55 to short cut a 35 mph marked S chicane [no traffic] and THE Hinge hit dramatically so on the way home I tested Trixie a bit towards 80 in the opens to get uncomfortable front wundering that seemed from wind eddies as road was perfect surfaced so slowed back down to legalish and used great care till putting steady back on. After head steady back on crossing paint lines such as to pass didn't bother Trixie nor did 115 [about topped out] in opens but would get crazy if I tried nice long sweepers at about 45' lean towards 80 mph on setting THE Hinge to point I'd have to let up, straighten up and open up radius into next lane before settling down to keep in my mind isolactics are likely worlds worse dangerous handling cycles ever conceived as at least the worser cycles would not even tempt ya to go over sight seeing handling rates.
There is only ~1/2" height difference betwix the 18 & 19" tires we can fit in there.
Besides switching tires on the 850's could also switch their steadies to learn something useful to us all.
 
hobot said:
The factory head steady Lord mounts can part from their base like they tend to do on muffler mounts and easy to check. i've switched from 19" and 18" in same afternoon on both tri-linked Peel and factory Trixie d/t a flat to get back to work and did not notice any unsteadyness on either of the. Back then hardly ever got below the [pavement] ton on Peel except where leaning far enough over for the turns would put my head too close to oncoming free flyers in blinds. I always hang turns close to outside paint line. When I left head steady off Trixie I did get some slight weaving sense at 65-ish until I let us cross double yellow at legal 55 to short cut a 35 mph marked S chicane [no traffic] and THE Hinge hit dramatically so on the way home I tested Trixie a bit towards 80 in the opens to get uncomfortable front wundering that seemed from wind eddies as road was perfect surfaced so slowed back down to legalish and used great care till putting steady back on. After head steady back on crossing paint lines such as to pass didn't bother Trixie nor did 115 [about topped out] in opens but would get crazy if I tried nice long sweepers at about 45' lean towards 80 mph on setting THE Hinge to point I'd have to let up, straighten up and open up radius into next lane before settling down to keep in my mind isolactics are likely worlds worse dangerous handling cycles ever conceived as at least the worser cycles would not even tempt ya to go over sight seeing handling rates.
There is only ~1/2" height difference betwix the 18 & 19" tires we can fit in there.
Besides switching tires on the 850's could also switch their steadies to learn something useful to us all.
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I said I'd switch wheels hobot, when I get a moment free from bathroom reno's. I'm getting used to 0300hr visits to the Port-o-loo positioned in the backyard guarded by the vicious Norton Guard Dog. The MkIII head steady is different from earlier ones as you probably know, and not prone to breaking. What I dislike about the 18" rear wheel is the greater tendency (being lower) to scrape one's helmet on the road during very sharp lean angles around corners. The radius difference between an 18" wheel and a 19" is a complicated mathematical formula that even Time Warp is still working on. I will report further.

Phil
 

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Phil's new toilet
Commando High Speed Stability


Phil is that an 18 inch or a 19 inch you're using on the rear!
 
auldblue said:
Phil's new toilet
Commando High Speed Stability


Phil is that an 18 inch or a 19 inch you're using on the rear!
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I have a 19 incher at front!!
Terrifies the girls when it gets the wobbles up and starts weaving like a snake.

Phil
 
My Dominator 99 never used to suffer ANY handling issues. That featherbed frame was as solid as a rock. It was a tough act to follow for the Commando but I reckon Norton got it right. At least when brand new a Commando's handling was generally impeccable. Okay, the odd frame broke and you could bend it like a banana two up in a dip corner, but who cared? It got better over the years. Considering the weight saving and the remarkable achievement of isolating vibration, the space frame was unbelievably innovative. But with it came some quirks we are still trying to deal with, which is quite amazing really. It seems that nearly every Commando is subtly different. Back in the "good ole days" we didn't scrape helmets on the road around corners because we didn't even wear helmets. But you could throw a Dominator hard into a corner with complete confidence until you fell off, I did a couple of times, pretending to be Agostini. Is he still alive??

Phil
 

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auldblue said:
Phil's new toilet
Commando High Speed Stability
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Please tell me that isn't yours! :shock: That's something I'd expect from an American (Texan in particular). That, or Hyacinth Bucket (it's "Bouquet")

Phil, I'm running Avon's 100/90-18 on the back and 90/90-19 on the front and it corners like it's on rails. High-speed stability seems to be dead-on, but I don't have the advantage/hindrance of another Norton that can be used for back-to-back comparison. I'm very anxious to hear the results of the rear-wheel swap; makes me think I should go back to the 19" rear, if only for the ability to run the same tires on both ends.
 
When the bike's handling depends on the head steady, you have a real problem.
 
Nater_Potater said:
auldblue said:
Phil's new toilet
Commando High Speed Stability
Click to expand...
Please tell me that isn't yours! :shock: That's something I'd expect from an American (Texan in particular). That, or Hyacinth Bucket (it's "Bouquet")

Phil, I'm running Avon's 100/90-18 on the back and 90/90-19 on the front and it corners like it's on rails. High-speed stability seems to be dead-on, but I don't have the advantage/hindrance of another Norton that can be used for back-to-back comparison. I'm very anxious to hear the results of the rear-wheel swap; makes me think I should go back to the 19" rear, if only for the ability to run the same tires on both ends.
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I'm losing confidence now. I'm thinking I'm completely wrong about this rear 18" wheel thing. But I'm going to fit a 19" regardless, for looks if nothing else. An 18" rear on a Commando just doesn't look right to me. If your bike is stable at high speed, I wouldn't go following my rectifying antics. If it ain't broke, don't fix it.

Here is my current indoor toilet. Believe me, lowering a 19 incher into that when it's wobbling and weaving takes a lot of practise. Then there is the fear of what might be in that hole with very sharp teeth, and very hungry!!

Phil
 

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acotrel said:
When the bike's handling depends on the head steady, you have a real problem.
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But apparently it is so acotrel. I've heard terrible stories of what happens to you and your Commando if that head steady lets go. And effects the head steady can have on handling. Not something to be dismissed though I don't know what can be done if it's serviceable. Just replace rubbers I guess. I never have on any Commando I've owned.

Phil
 
The effect of slight changes to steering geometry can be very deceptive and dangerous. Before I corrected my Seeley, I rode it in a race and as I backed off on a high speed sweeper, it stood up, turned and threw me off-balance and nearly crashed me. It came from nowhere - one split second it was stable and felt great, the next it was grabbing me by the throat. It came out of it's death dive when I turned it on again trying to get it onto the grass at the edge of the circuit. It wasn't my good riding that saved me , it was 'arse beats class'.
 
Phil, some of the fellas on this forum have become upset when I've made disparaging remarks about isolastics. I don't blame them, I've never owned a standard commando. However I know the trouble we always had in the old days trying to get a rigid connection between the steering head and the pivot. The slightest movement can destroy confidence, especially if you are using the old crap tyres we raced on back then. All you have to do is have a look where featherbed frames crack and you can get some idea of the stresses involved when you push a bike hard.
 
acotrel said:
The effect of slight changes to steering geometry can be very deceptive and dangerous. Before I corrected my Seeley, I rode it in a race and as I backed off on a high speed sweeper, it stood up, turned and threw me off-balance and nearly crashed me. It came from nowhere - one split second it was stable and felt great, the next it was grabbing me by the throat. It came out of it's death dive when I turned it on again trying to get it onto the grass at the edge of the circuit. It wasn't my good riding that saved me , it was 'arse beats class'.
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I was coming home one night many years ago in a little Alfa Sprint I owned with a can of beer in one hand. The Alpha handled beautifully but suddenly on one corner it just let go and did a complete 360 without hitting a thing! I just watched my fate unfold whilst sipping my beer!! Nothing else I could do, then continued driving home wondering how the hell did that happen, and why??

I've never had a Norton do a dirty on me with a wild mood change in a corner. My spills have all been my fault. This geometry thing has got me very interested and soon I'll see if the 18" rear has anything much to contribute to instability.

Phil
 
acotrel said:
Phil, some of the fellas on this forum have become upset when I've made disparaging remarks about isolastics. I don't blame them, I've never owned a standard commando. However I know the trouble we always had in the old days trying to get a rigid connection between the steering head and the pivot. The slightest movement can destroy confidence, especially if you are using the old crap tyres we raced on back then. All you have to do is have a look where featherbed frames crack and you can get some idea of the stresses involved when you push a bike hard.
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Some of the fellas on this forum have become upset when I've made disparaging remarks about them. I've never said a bad thing about isolastics. Hmm, I can imagine the issues when racing. But Len Atlee didn't seem to have problems racing a combat Interstate in the Castrol Six Hour, until he fell off. Maybe his head steady broke!! Certainly steering head can cause all sorts of stability issues, worn bearings for example. I've always assumed Featherbed frames were too strong to crack though I can imagine an Atlas would test it severely. If you screw a Commando's isolastics up tight, I reckon the space frame would have the life span of a wombat in the middle of the road at night.

Phil
 
Well it took all bloody night but I finally got the bastard fitted. No more front end instability issues. I welded the steering head fixed straight as the front end is no longer needed. It's never on the road. Bike is, but front end is usually 2 feet in the air!!

Phil
 

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years ago i had an 850 mk2a with the box type headsteady i had a handling problem with it that i eventually traced to the headsteady both threads were ripped out of the frame on the rubbers and both triangular plates were bent outwards!! on the 750 i have now i have an extra isolastic mount under the gearbox i can run the bike without a headsteady fitted it really isnt needed it makes no difference to the handling i believe the kenny dreer commandos had no headsteady fitted at all,,,,,,,,,,,baz
 
baz said:
years ago i had an 850 mk2a with the box type headsteady i had a handling problem with it that i eventually traced to the headsteady both threads were ripped out of the frame on the rubbers and both triangular plates were bent outwards!! on the 750 i have now i have an extra isolastic mount under the gearbox i can run the bike without a headsteady fitted it really isnt needed it makes no difference to the handling i believe the kenny dreer commandos had no headsteady fitted at all,,,,,,,,,,,baz
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What handling problem did you have? Like what effect did the dud head steady have?
It's not an issue with my Fastback head steady but I'm interested.

Phil
 
basicly i was 20 years old the the throttle had 1 position and my mates had jap bikes i always had the advantage in the bends until one night i was hard over on a left hander on a dual carriageway there was a ridge of tar that went across the road i knew it was there and had become used to it but this night the whole bike whipped and stepped out sideways i ended up in the outside lane my mate was right behind and saw my bike get out of shape the next day i was was pulling the back wheel around and noticed the engine moving side to side so i removed the tank and found the problem,i was so green back then i had never had the tank off before never knew it had a headsteady never adjusted tappets/isolastics or changed the oil !!! ,,,,baz
 
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