Author Topic: V85 beware  (Read 2088 times)

Offline tris

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Re: V85 beware
« Reply #30 on: September 20, 2021, 08:47:35 AM »
I find the whole spring rate/pre load/ ride height conundrum most frustrating

Just as I think I have my head around it it drifts off - just out of reach again  :cry: :cry:
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Online LowRyter

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Re: V85 beware
« Reply #31 on: September 20, 2021, 10:13:32 AM »
I had a weave on my V11 Sport when I had saddlebags on it.  Unlike yours, my bike would straighten up when I backed off the gas.  The bottomline to all this, I needed a stiffer rear and softer front.  I got the shock re-sprung with a stiffer spring and rebuilt the adjuster, also run the front softer when I carry a load.   The stiffer spring helps because it can be adjusted in the "sweet spot" for heavier loads.

Since your bike wheelied, I'd guess you're still loaded too far back.  But you might try to stiffen the rear substantially and soften the front to some degree.  Actually, for my Sport, I got more benefit from softening the front than stiffening the rear- not with preload but with the adjusters, just to make the fork more compliant. 
« Last Edit: September 20, 2021, 10:13:56 AM by LowRyter »
John L 
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Online Moto Vita

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Re: V85 beware
« Reply #32 on: September 20, 2021, 10:42:51 AM »
Don't worry , just remember the forces are directed downward . Einstein kinda proved that  :grin:

 TS

 Are you thinking of Newton?

Offline rudyr

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Re: V85 beware
« Reply #33 on: September 20, 2021, 12:50:34 PM »
Men I have looked bike over can’t finder anything.  I just was west of a town with fresh asphalt (2 wk.) flat slightly down grade, wind?  My is reg.Cot, 4 man tent, sleeping bag, chair 3 legged stole, & one change of clothes exter socks & sweater,coat.  Est. Weight passed back of axel is half seat load, 20 lbs. from saddle baggies. Told it was a Give top case but it’s Hepco/Becker I think it’s 33L I really don’t think over 10 lbs.  l Am load the spring a little tighter and take the little rubber bumper off the under side of the seat3/16” lower and go a little slower(the hard part) that ride yesterday was for real young men not old men.amen Rudy

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Re: V85 beware
« Reply #33 on: September 20, 2021, 12:50:34 PM »

Offline Vagrant

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Re: V85 beware
« Reply #34 on: September 20, 2021, 03:00:26 PM »
I hate to admit I'm 240# but I've had all 3 bags fully loaded and hit 90 maybe once with no issues. I do have the front dropped 3 lines on the fork tubes (about 1/2") so you might do that.
how did you do a wheelie without the TC kicking in and shutting it down?
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Online Huzo

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Re: V85 beware
« Reply #35 on: September 20, 2021, 04:12:19 PM »
I find the whole spring rate/pre load/ ride height conundrum most frustrating

Just as I think I have my head around it it drifts off - just out of reach again  :cry: :cry:
It’s because people muddy the waters with poor analogies and repeating back what was said to them innacurately.

Online Huzo

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Re: V85 beware
« Reply #36 on: September 20, 2021, 04:13:46 PM »
Don't worry , just remember the forces are directed downward . Einstein kinda proved that  :grin:

 TS
And Newton said there was an equal one in the opposite direction. :grin:

Online Huzo

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Re: V85 beware
« Reply #37 on: September 20, 2021, 04:16:17 PM »
Actually, for my Sport, I got more benefit from softening the front than stiffening the rear- not with preload but with the adjusters, just to make the fork more compliant.
Which adjusters...? :popcorn:

Online Huzo

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Re: V85 beware
« Reply #38 on: September 20, 2021, 04:25:45 PM »
Well , one of those guys  :laugh:

 Was actually thinking of the theory of relativity , which as explained by a physicist bud states that "gravity pushes down"  :grin:

 When thinking of a spring it helps to see them as a lever over a fulcrum , pushing down on one end causes the other end to go up , right ?

 Dusty
Einstein was referring to that concept when he stated..
“Give me a place to set my foot and I will move the Earth...”
If you release a basketball from 2 metres, the Earth attracts the ball and the ball also moves the Earth “upwards”, by an incomprehensibly tiny, but calculable amount.

Also your physicist bud might be better to say gravity “pulls down”, because the two masses are “drawn towards” each other.
Just sayin’.

Online LowRyter

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Re: V85 beware
« Reply #39 on: September 20, 2021, 05:08:18 PM »
Which adjusters...? :popcorn:

meaning compression and rebound.  For the V11 Sport, I soften both fork adjusters when I load the saddle bags on.  I usually leave the rear shock alone I got it dialed with a heavier rear spring. 

« Last Edit: September 20, 2021, 05:10:34 PM by LowRyter »
John L 
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Online Huzo

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Re: V85 beware
« Reply #40 on: September 20, 2021, 05:20:06 PM »
I'll let you argue that with him .

 TS
Ok Dusty.
My # is +61437 070946

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Re: V85 beware
« Reply #41 on: September 20, 2021, 05:41:22 PM »
The only  thing that makes sense here is the part about passing the car. The wake can upset and impart some sort of steering input through the wind force and the arms and torso or maybe the high front fender. The steering geometry’s influence from having excessive rear sag is debatable as is the effect of the rider’s steering inputs.

I researched this last year after a friend gave up riding when his KLR did the Hong Kong Wobble and landed him in the hospital for 9 days. He passed a tractor trailer on a two lane 55 mph highway. I also previously watched him remove a lowering link for the rear. The fork tubes were slid up to compensate, and I told him he should change that back too, but he blew it off….. Made sense that the steeper steering head and the truck’s wake caused this. There’s a-lot of good videos on this topic and it will always be as clear as mud….

Another friend related his story of his Guzzi that he crashed from a wobble. His Telefix fork brace snapped and must’ve had energy stored in it. He said it slid and caught on fire.

Online Huzo

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Re: V85 beware
« Reply #42 on: September 20, 2021, 06:26:23 PM »
Trust me on this , Brandon can and will tie your mind in knots W/O even breaking a sweat , having a PHD in physics means he actually knows of which he speaks . Then there was his GF who worked in a field of theoretical physics so esoteric she could tie his mind in knots . Once looked at the math she was generating , that was years ago and I still get a headache thinking about it . Him and Kirby both responded with the same answer as to what the ToR really means , gravity pushes down . An oversimplification , well yeah , but in real world terms it is close enough .

 TS
Doubtless your Physics mate could tie my brain in knots.
But I was happy with it the way it was and yes we should all listen to Kirby because he’s clever...
Now that we’ve paid our dues.
As for your Physics mate regarding wiping the floor with me, I’m reminded of the words of the great man A Einstein..
He did a little bit of Physics too..
“If you can’t explain something simply, you don’t understand it well enough..”


Couldn’t agree more Frankenstein.
BTW..
I’d love to talk to what’s his name...
Not to try to match him, but to have my misunderstandings put to rights. But for now I’m stuck down here on the ground with the average bloke.
« Last Edit: September 20, 2021, 06:32:50 PM by Huzo »

Offline Texas Turnip

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Re: V85 beware
« Reply #43 on: September 20, 2021, 06:48:50 PM »
I hate to admit I'm 240# e .


In my circle of friends 240# is called puny. Come to Texas and I'll buy you a chicken fried steak. :grin:

Tex

Online Huzo

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Re: V85 beware
« Reply #44 on: September 20, 2021, 06:51:16 PM »
Peter , no one was arguing with you , most of us understand how preload actually works , no idea why you are worked up over this mate . What we were doing was infecting some humor , Rudy is a real world friend , he knows that .



 TS
Actually you were injecting humour, although you were sort of correct ... :wink:
The new thread I posted is to try convey some stuff to Tris and to the others that are not in the “most of us” bracket.
If you took a poll two years ago and asked the membership what preload does, you would have gotten a different average response to what you’d get today.
PM sent..

Online Huzo

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Re: V85 beware
« Reply #45 on: September 20, 2021, 07:09:30 PM »
Maybe , although I doubt that . Most of figured that out 30 years back , buncha old guys here , remember .

 Dusty
Anyway, I’m glad Rudy’s bike didn’t get too out of control so as to hurt him.
Will be interested to see if the probable cause raises it’s head.

Online Ncdan

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Re: V85 beware
« Reply #46 on: September 20, 2021, 07:44:35 PM »
I know absolutely nothings about the Physics involving the forks or rear shocks but I did have an incident when I got my 02 Stone last year, that I will share.

The guy I got it  from was a big guy, 300lb.
He told me that he had cranked the shock preload down quite a bit to keep it from bottoming out on bumps.
Therefore when I got it home the first thing I was to turn the adjustment nut up towards the top to release the spring pressure, thus getting a softer ride.

I took it on a test ride and around 75-80 mph the the bike started going into a wobble. Experience told me that if I didn’t back off at that point that things would get serious.

I went home and called a buddy, that’s actually involved in this conversation now, and gave him the scenario which had taken place.
He advised me to tighten the spring back down, making the spring stiffer, about mid way between the setting it was and the setting I had moved it to.

I took the Stone back down the same 4 lane highway and after letting the traffic get ahead and out of sight, ran the bike up to 90+ mph and it was totally stable.

The Stone is equipped with the large shield and Givi large bags, empty.

I admit I have no idea as the the Physics behind the shock spring changes but the difference was made.

« Last Edit: September 20, 2021, 08:29:01 PM by Ncdan »

Offline vibr8r

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Re: V85 beware
« Reply #47 on: September 20, 2021, 08:12:51 PM »
On my EVT there is a sticker on the tank recommending I not exceed 130kph (80mph) due to aerodynamic wind loads.  In addition, there is a crude friction type steering damper between the lower triple clamp and the frame.  Perhaps an aftermarket  steering damper would help. 

Offline Bulldog9

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Re: V85 beware
« Reply #48 on: September 20, 2021, 08:40:23 PM »
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Online Huzo

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Re: V85 beware
« Reply #49 on: September 21, 2021, 02:07:19 AM »
I was to turn the adjustment nut up towards the top to release the spring pressure, thus getting a softer ride.

He advised me to tighten the spring back down, making the spring stiffer,


:popcorn:

Offline egschade

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Re: V85 beware
« Reply #50 on: September 21, 2021, 07:35:00 AM »
An Oldie but a goodie..... https://www.youtube.com/watch?v=z3OQTU-kE2s

Here's another one https://www.youtube.com/watch?v=fvsDIq3WwVA Wobble & weave starts at the 4:30 mark. Emphasis was given to weight distribution AND tire condition/pressure.

Also mentions that wide loads (panniers) can contribute. Perhaps it's not the amount of weight so much as how it's distributed AND what profile it presents to the oncoming air. If the load it particularly wide OR if it's uneven it could create a high level or uneven drag that could unweight the front end or introduce a weave/wobble.
« Last Edit: September 21, 2021, 08:03:06 AM by egschade »
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Online Sye

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Re: V85 beware
« Reply #51 on: September 21, 2021, 07:58:13 AM »
Preload is your friend when adding any weight to the bike. The further back, the bigger effect it has on the front end. 30lbs behind and above the rear wheel has a similar effect as 100lbs on the pillion seat.
Keep top boxes as small as you can and distribute additional weight as low and centrally as possible.
Remember the 30% sag rule, it works. Adjust preload to give the correct amount of sag with rider and luggage every time. This ensures that rake and trail remain constant.
Your arse sliding down the road, your choice.

Online LowRyter

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Re: V85 beware
« Reply #52 on: September 21, 2021, 10:10:17 AM »
Here's another one https://www.youtube.com/watch?v=fvsDIq3WwVA Wobble & weave starts at the 4:30 mark. Emphasis was given to weight distribution AND tire condition/pressure.

Also mentions that wide loads (panniers) can contribute. Perhaps it's not the amount of weight so much as how it's distributed AND what profile it presents to the oncoming air. If the load it particularly wide OR if it's uneven it could create a high level or uneven drag that could unweight the front end or introduce a weave/wobble.

That is true for my V11 Sport.  I usually got the weave on the loaded bike in semi wake at about 80mph.
John L 
When life gets you down remember it's one down and the rest are up.  (1-N-23456)

Offline Vagrant

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Re: V85 beware
« Reply #53 on: September 21, 2021, 10:18:29 AM »
In my circle of friends 240# is called puny. Come to Texas and I'll buy you a chicken fried steak. :grin:

Tex

That's one of the reasons I got this way! Pass the gravy.
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Offline bulwnkl

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Re: V85 beware
« Reply #54 on: September 24, 2021, 07:57:42 PM »
Quote
Don't worry , just remember the forces are directed downward . Einstein kinda proved that  :grin:

 TS
And Newton said there was an equal one in the opposite direction. :grin:

Gravity is NOT a force, no matter what Newton said.  General relativity shows us this.
https://youtu.be/XRr1kaXKBsU

 :grin:

Online Huzo

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Re: V85 beware
« Reply #55 on: September 24, 2021, 09:53:12 PM »
And Newton said there was an equal one in the opposite direction. :grin:


Gravity is NOT a force, no matter what Newton said.  General relativity shows us this.
https://youtu.be/XRr1kaXKBsU

 :grin:
Well said Bulwnkl.
That’s intrinsically true. F=m.a
But can you imagine the rabbit hole that we’d end up going down before we got back on point if we thrashed that one out...(assuming we could).
The thread would be more contaminated than the Nile and would be nuked mid stream.
But I love that stuff on the video.
Physics does not lie or become confused.
« Last Edit: September 24, 2021, 09:54:09 PM by Huzo »

Online Huzo

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Re: V85 beware
« Reply #56 on: September 24, 2021, 10:36:55 PM »
Sure it does , witness the spin 1/2 and spin 2 particles , or string cheese theory , even Albert himself couldn't explain the latter .

 TS
The truth is being told by the Physics, but Alby couldn’t speak the language.
How d’you reckon he’d go with today’s super computers and electron microscopy techniques ?

Online Huzo

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Re: V85 beware
« Reply #57 on: September 25, 2021, 12:29:45 AM »
The real thinking and problem solving at the edge of theoretical physics is still done by the human brain , so Albert would likely still be at the cutting edge . Remember , he did his best work before he became famous , and now all these years later there are hundreds of physicists around the planet trying to disprove a lot of what he theorized , and failing mightily . W/O Einstein we might still be stuck with Newtonian physics .

 My PHD buddy who found Mark Knopfler and Einstein at about the same time commented once that Einstein was the Mark Knopfler of physics , so brilliant some folks didn't appreciate how great a talent he was .

 TS
I think I’ll enlarge that post and have it framed on my wall Dusty.
For once we totally agree..

Offline egschade

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Re: V85 beware
« Reply #58 on: September 26, 2021, 06:03:09 AM »
But back to the question about bike instability...

I had the occasion to strap a larger parcel on the back of the bike yesterday. Not heavy at 14 lbs (about 6 kg) but large presenting an area 34" x 8" to the wind. At 40 mph the V85 started to feel the effect with a vague feeling front end feel. Not a weave or tank slapper by any means, but it might have been worse at a higher speed.

To me this means that one need to be mindful of the load cross-section as much as the weight. Putting that large an item across the back seat certainly had an impact on the bike's handling. Could drag, especially away from the center line of the bike, be part of the cause of his wobble?
The elder Eric in NJ
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Breva 1100
EV Touring

Offline rudyr

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Re: V85 beware
« Reply #59 on: September 26, 2021, 02:26:45 PM »
Just got back off 140 mile exploring for primitive camp grounds (40+ miles gravel & steep mt. roads).  found two good ones had to stop and get gas.  Got on freeway coming home going 75 mph, truck got on my back end, I passed 3 truck trailer windy the front end stated to wable( 92mph) as I tuned back into lane it stops back to 75mph. A lot of wind from trucks, I think it was starting into a high speed wable but turning into the other lane just before it got started stoped it I think. Nothing but me and coat on back case.  During my ride up Hy. 123 really curvy ( hairpin) going up the mt. stopped and picked up a guy with fun helmet and a skateboard no pads.  2miles or so let him off.  He said he was going up and down the curve mt. road.  with cars on road.  Question is theirs some kind of skateboard raceing?  I don’t know about.Rudy

 

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