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Question concerning ride height. First what is ride height? And doesn't sag have an effect on it?

Reading the shop manual I note that the ride height is set between the tool and the pit stand and then the chain is adjusted. Adjusting the chain moves the hub eccentric which then would change the position of the axle in the hub which, it seems to me, would alter the already set ride height which seems to me to be a set distance between the frame and the tire contact patch or axle. What am I missing here?

That "tool" is quite a contraption. If I could lay my hands on one for a day I'd make a pattern from it and make my own out of 1/8" 7075 Alu. And for anyone else who wanted it. Anyone want to trust me with theirs? I'll pay the shipping.
 

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Give me numbers :) - I would have thought that following re-tensioning the chain it would not have changed the ride height by even a millimetre - going from a really slack chain to correct tension and the amount of rotation on the eccentric hub seems to be less than 5 degrees rotation - Shock changes I can understand... am I missing something :crazyeyes
 

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Hi Lee,
Very interesting read there. I just read through the process of setting "ride height" in my F4 manual. It is interesting to note that the "tool" provides a reference point from which to make the sag setting adjustment. It is also interesting to note that the point form which you measure to obtain the correct ride height is the top of the factory stand. Differing stand frame tube diameters will produce differing results here. The goal of the ride height adjustment is to put the bike at the factory setting for the distance to the ground for the hard parts of the bike when the suspension is under it's fullest compression (think high speed tight turn on a banked turn while decelerating...the bowl at Louden comes to mind). It also affects the steering angle (rake). Rake changes with rear height changes or fork height changes. So, it will effect the "quickness" or stability of steering input. Once the ride height is set, you set static sag...sans rider...to 22mm for F4 1000S, the S 1+1 and AGO and it's 25mm for the Tambo.

It seems, based on sequence, that the eccentric change to ride height is of little effect.
 

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Check ride height...adjust chain....recheck ride height.

Moving eccentric hub in swing arm changes ride height because the hub center is moving in relation to the swing arm plane. Sag is suspension movement under chassis weight. Ride height can be adjusted independent of sag and affects steering geometry.
 

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If setting ride height determines the distance between the frame and the road and it is an important dimension then why set sag after ride height? Seems to me it should be the other way around as sag will alter ride height but not vice versa.

I am familiar with the effects of rake/trail having built front ends with 45 degrees of rake and having to take out alot of the ensuing trail to make it handle well. When I first looked at superbike front ends my first reaction was "that's got to be the most twitchy unstable thing I've ever seen" after dealing with the long "frieght train" front ends I'd been used to messing with.
 

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I guess the way I look at it is in extremes. If I were to take the bike and lower it to the lowest possible rear height and the lowest possible fork height (by slipping the forks up through the triple clamp), then set the appropriate front and rear sag, hard parts might hit each other...probably front fender to fairing and maybe rear wheel to exhaust. That is an extreme...basically the seat hight goes down as ride height goes down. If you do it equally front and rear then steering ratio remains the same, but the whole bike is lower to the ground. In so dioing,the wheels are closer to the frame parts of the machine.

It is all trigonometry or geometry if you will. Because of where the pivot points are in realtion to the dimension being changed, I'd assume that the sequence in the manual for setting ride height and sag results in the appropriate bike geometry.
View attachment F4 Rear End.pdf
 

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In my opinion the term 'ride height adjustment' is incorrect and has no relevance or reference to the understanding that most owners/riders have of the term. It was probably just a term coined by somebody years ago that has just stuck.

Looking at this tool and considering it's fixing points and points of reference for measurements, I'd suspect the main purpose of this tool is to provide a reference to *roughly* set and maintain the angle of final drive (the angle from horizontal between the rear axle and swingarm pivot point). The value of this angle has an effect on the squat characteristics of the bike.

Decreasing the rear height increases the bike's tendency to squat which in turn relaxes the steering angle and gives the rider the slower turn feeling that they would normally associate with increased rake. Conversely, increasing the ride height decreases the tendency to squat (increases anti-squat) and tightens the steering angle. This is why most riders when they talk about geometry operate on the incorrect understanding that changes in handling from adjusting the rear ride height are due to changes in rake/trail, and almost always completely neglect to mention/consider the squat characteristics.

As it's almost impossible to change one aspect of the geometry without affecting another, there is some change in rake by changes in ride height but, in my opinion the majority of the change in handling from rear ride height adjustment is from the changes in the squat characteristics rather than the small changes in rake.
 

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In my opinion the term 'ride height adjustment' is incorrect and has no relevance or reference to the understanding that most owners/riders have of the term. It was probably just a term coined by somebody years ago that has just stuck.
Nope it's the correct term as you are directly altering the ride height of the bike. When you lower or raise a car what are doing? you are lowereing the ride height of the vehicles main weight in respect to it's axles. Same for the bike. Everything above the shocks/forks is sprung weight and it's position has a direct effect on a massive amount of things, turning ability, braking, flicking from left to right, wheelies and overall handling characteristics.

Looking at this tool and considering it's fixing points and points of reference for measurements, I'd suspect the main purpose of this tool is to provide a reference to *roughly* set and maintain the angle of final drive (the angle from horizontal between the rear axle and swingarm pivot point). The value of this angle has an effect on the squat characteristics of the bike.
Not quite, when you alter the rear ride height you are pivoting the weight of the bike forwards or backwards . This will alter the weight on the tyre and provide more or less grip (which in some terms is used as a definition of squat) but if your overall geometry is right then squat (traditional squat of the rear being puched into the track) is nothing but a by product of good overall set up. It will very slightly alter the ratio between the wheel spindle and swingarm pivot. Unless you are making big changes you are likley to notice more of an effect on wheelbase. the effect on squat with a fixed swingarm pivot however is likley to be more influenced by suspension setting and sag settings than ride height.

To influence Squat you move the swingarm pivot either above or below the output shaft. Doing this alters how the swingarm behaves when load is put through the chain. The swing arm will rotate and if the changes are enough it will change direction as the chain pulls it from either the top or bottom of the sprocket, each of these directions is known as squat and anit squat and does just what it says on the tin. From my experience being inline or below the swing arm pivot point provides more squat and greater grip but slows the steering down..........the bike does feel smoother, we tried raising the ride height to get more weight over the front but the lap times were still lower. 3mm higher and the bike turns faster, flicks from left to right better but provides less confidence through the tyre, this can be cured with fine tuning suspension........the difference from memory between each setting was roughly 2secs a lap at a 1m10s track (snetterton).

Decreasing the rear height increases the bike's tendency to squat which in turn relaxes the steering angle and gives the rider the slower turn feeling that they would normally associate with increased rake. Conversely, increasing the ride height decreases the tendency to squat (increases anti-squat) and tightens the steering angle. This is why most riders when they talk about geometry operate on the incorrect understanding that changes in handling from adjusting the rear ride height are due to changes in rake/trail, and almost always completely neglect to mention/consider the squat characteristics.
Decreasing the rear has nothign to do with promoting squat, you are moving the weight bias and as such pushing the front out causing the bike to convertitself into a chopper mid turn. You could take all the sag out and max the suspension out to remove almost any movement in the rear shock and the fact that you have lowered the rear will still have a greater effect on handling basics than anything else. Ideal geometry is arse up nose down, trying to keep this mid turn is the job of the shock and fork settings, having this geometry to start with is the job of the bikes front and rear ride height.

As i have said earlier, my understandings of the science of squat or anti squat is a swingarm pivot, output shaft matter and not a ride height rake and trail matter.

You are right that ride height alters rake and trail, but consider this.

Of these two examples which will provide more "squat" and whicjh will actually handle better.

That standard settigns for this fictious bike are:
Rear ride height = 220mm
Front ride eight (forks through yokes)= 1mm

Bike A has a low rear ride height of 205mm but a perfectly set up rear shock. the front ride height has the forks raised 15mm through the yokes

Bike B has standard front and rear ride heights but a badly set up shock with way too much rear sag.

In those examples which is being affected more? squat or weight bias and rake and trail?

As it's almost impossible to change one aspect of the geometry without affecting another, there is some change in rake by changes in ride height but, in my opinion the majority of the change in handling from rear ride height adjustment is from the changes in the squat characteristics rather than the small changes in rake.
Or could it be weight bias on/off of the rear tyre which would be a direct result of rear/front ride height adjustment and a change in geometry or rake and trail.
 

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Nope it's the correct term as you are directly altering the ride height of the bike. When you lower or raise a car what are doing? you are lowereing the ride height of the vehicles main weight in respect to it's axles. Same for the bike. Everything above the shocks/forks is sprung weight and it's position has a direct effect on a massive amount of things, turning ability, braking, flicking from left to right, wheelies and overall handling characteristics.
What exactly is your definition of 'ride height' when applied to a bike?

When applied to a car I equate ride height to essentially the same thing as ground clearance, with ground clearance being defined as the vertical distance from the ground to the lowest part of the chassis. I'd imagine that different car manufacturers have different ways of expressing and measuring ride height so I suppose a general definition of ride height for cars might be the vertical distance from the ground to a known fixed point on the sprung mass of the vehicle, yes/no?

If your definition of ride height when applied to a bike is similar to that above then how can this tool measure actual ride height without referencing the ground, without providng a means to factor in tyre wear, without providing a means to factor in tyre pressures, without providing a means to factor in differing profile heights across differing tyres?

I can't help but think that if the purpose of this measuring was (as many suggest) to maintain rake/trail they would provide a tool that directly measures rake/trail?

I can't imagine there would be many that would buy into the statement that "that's how it works on a car therefore that's how it works on a bike".

Not quite, when you alter the rear ride height you are pivoting the weight of the bike forwards or backwards . This will alter the weight on the tyre and provide more or less grip (which in some terms is used as a definition of squat) but if your overall geometry is right then squat (traditional squat of the rear being puched into the track) is nothing but a by product of good overall set up. It will very slightly alter the ratio between the wheel spindle and swingarm pivot. Unless you are making big changes you are likley to notice more of an effect on wheelbase. the effect on squat with a fixed swingarm pivot however is likley to be more influenced by suspension setting and sag settings than ride height.

To influence Squat you move the swingarm pivot either above or below the output shaft. Doing this alters how the swingarm behaves when load is put through the chain. The swing arm will rotate and if the changes are enough it will change direction as the chain pulls it from either the top or bottom of the sprocket, each of these directions is known as squat and anit squat and does just what it says on the tin. From my experience being inline or below the swing arm pivot point provides more squat and greater grip but slows the steering down..........the bike does feel smoother, we tried raising the ride height to get more weight over the front but the lap times were still lower. 3mm higher and the bike turns faster, flicks from left to right better but provides less confidence through the tyre, this can be cured with fine tuning suspension........the difference from memory between each setting was roughly 2secs a lap at a 1m10s track (snetterton).



Decreasing the rear has nothign to do with promoting squat, you are moving the weight bias and as such pushing the front out causing the bike to convertitself into a chopper mid turn. You could take all the sag out and max the suspension out to remove almost any movement in the rear shock and the fact that you have lowered the rear will still have a greater effect on handling basics than anything else. Ideal geometry is arse up nose down, trying to keep this mid turn is the job of the shock and fork settings, having this geometry to start with is the job of the bikes front and rear ride height.

As i have said earlier, my understandings of the science of squat or anti squat is a swingarm pivot, output shaft matter and not a ride height rake and trail matter.
Squat or net squat is normally presented as a percentage of anti-squat it isn't a guessing game, it can be accurately calculated from a few key measurements, care to tell me where those measurements are taken from?
 

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The tool references the ground by using a fixed position on the swingarm stand. The relation between the fixed point on the stand and the ground is constant, therefore it is in relation to the ground.
 

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The tool references the ground by using a fixed position on the swingarm stand. The relation between the fixed point on the stand and the ground is constant, therefore it is in relation to the ground.
And how does that account for tyre wear, pressure and/or profile height?
 

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And how does that account for tyre wear, pressure and/or profile height?

To that extent it won't however tyres have nothign to do with setting the ride height as it is done on a paddock stand

The tool hooks into the frame and as such you are moving the swingarm up or down underneath it. the paddock stand is a set size and will never change (on an individuals bike). As such the distance between the paddocks stand and measuring point of the tool will always be within 0.5mm i would say. If someone has a different paddocks stand then this could throw a variable in but only 2 or maybe 3 mm at worst.

When you use the tool you are measuring the distance of the axle to a set point (measuring tool). You can set the ride height on an MV without a rear wheel in so tures, wear or whatever have nothign to do with what measurment you get.

The figures thrown around for rear ride height are for guide only, the rest is narrowed down by riding and feedback.

I would never ever just set a bike up to a bunch of figures and assume it is right. However if someone rings me up from 10,000 miles away and wants to discuss handling issues then figurees obtained by using this tool will instantly enable me to get a clear picture of where they are at with their bike set up and what possible provblems they may be facing.

The measuring tool is Just that..a tool by which to measure things and provide data that is more easily understood by a wider audience. It's just a reference. Why do shocks or forks have clicks on their adjusters?.........so that you have a point to go back to and can ring someone up if you get stuck with info rather than just saying "well i screwed it in about oooooooooooh so much and then backed it out a tad and it felt weird so i wiggled the thingy half a smidge and it still feels weird, what should i do"

As to your other reply, ride height to me is the height that the main weight of the vehicle is riding at. Higher ride height = higher distance of mass weight to the ground, lower ride height = lower mass of weight to the ground.

Each position has it's advantages and disadvantages but they have to be explored by the individual rider.

:)
 

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And how does that account for tyre wear, pressure and/or profile height?
Or a 16.5 rear as used in SB,

I suspect all bikes are set with it at the factory, my 1000R with a 190/55 rear was certainly 10mm or so higher at the rear than my 1000S. ( the first thing I do with any new bike is measure heights etc, MV rear springs are pretty crap quality losing height with age and use)

My take on the factory height tool would only be as a quick reference when making adjustments, maybe with the early 750 bikes with the same rear tyre etc it would have been relevant, but with different makes and sizes of rear tyre UNLESS the w/shop manual gives heights for all combinations it could only be used as a quick reference or checking device.
 

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To that extent it won't however tyres have nothign to do with setting the ride height as it is done on a paddock stand
As to your other reply, ride height to me is the height that the main weight of the vehicle is riding at. Higher ride height = higher distance of mass weight to the ground, lower ride height = lower mass of weight to the ground.
So by your own definition of ride height, are you trying to tell me that tyre (and or wheel as Mike points out) dimensions don't matter or won't affect ride height, or do you only ride your bike on the paddock stand? :p

My take on the factory height tool would only be as a quick reference when making adjustments, maybe with the early 750 bikes with the same rear tyre etc it would have been relevant, but with different makes and sizes of rear tyre UNLESS the w/shop manual gives heights for all combinations it could only be used as a quick reference or checking device.
I'd largely agree with that, my take is that it's an expensive tool of questionable accuracy and dubious usability.
 

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So by your own definition of ride height, are you trying to tell me that tyre (and or wheel as Mike points out) dimensions don't matter or won't affect ride height, or do you only ride your bike on the paddock stand? :p
they will effect it, i've never said they won't, however they do not have any effect when it comes to measuring the rear ride height on an MV Agusta which is what we are discussing here.

Try reading an understanding what i have written andthen commenting rather than jumping the gun. Maybe read the bit where i mention paddock stands a few times or no wheel being needed to be fittted to set the ride height.

You refer to wheels and tyres altering ride height well clearly you have little idea what the MV ride height tool actually is, ifyou di you would know tha not one of those aspects comes into play.


:)
 

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So by your own definition of ride height, are you trying to tell me that tyre (and or wheel as Mike points out) dimensions don't matter or won't affect ride height, or do you only ride your bike on the paddock stand? :p



I'd largely agree with that, my take is that it's an expensive tool of questionable accuracy and dubious usability.

Tell me something; you refer to the measuring of ride height and the potential flaws as though these figures were cast in stone and unable to be adjusted.

Why?

The figures are for reference only and the fact that the adjuster is there in the first place is due to the hub arrangement. And by using the same tool many many people will be able to share data.

You can measure your own ride height any way you like mate but the figures will only make sense to you. the tool simply provides a way for eole to reference figures.
 

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they will effect it, i've never said they won't, however they do not have any effect when it comes to measuring the rear ride height on an MV Agusta which is what we are discussing here.

Try reading an understanding what i have written andthen commenting rather than jumping the gun. Maybe read the bit where i mention paddock stands a few times or no wheel being needed to be fittted to set the ride height.

You refer to wheels and tyres altering ride height well clearly you have little idea what the MV ride height tool actually is, ifyou di you would know tha not one of those aspects comes into play.


:)
My point is if I have a tool called a 'ride height measuring tool' I expect it to accurately measure ride height, quite simply this tool doesn't do what it says on the tin.

MV's are nothing spectacular in terms of their physics behind their geometry, they are exactly the same principles as are applied to the majority of other current sportsbikes on the market and in that sense ride height is ride height and ride height is affected by tyre dimensions MV or not. What makes MV so special that the normal definition of ride height doesn't apply, and tyre dimensions are irrelevant?
 

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And how does that account for tyre wear, pressure and/or profile height?
You forgot to mention the effect of the rear hub eccentric which will change the geaometry more than tire size wear and even changing the rear to a 16.5" wheel. The tool is simply a reference to set the bike to a certain position which can be repeated. Think of it as a rosetta stone which will allow two people to communicate where exactly the ride height is, repeatably. Otherwise two people could measure the same bike at different points and have different numbers (or the same numbers but different set-ups).
 

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Tell me something; you refer to the measuring of ride height and the potential flaws as though these figures were cast in stone and unable to be adjusted.

Why?
Ride height affects various aspects of geometry. If I gave your 2 F4s one fitted with a 190/50 tyre and the other fitted with a 190/55 and asked you to set the ride height to factory spec +5mm those two bikes would roll out your shop sitting at two different heights. Call me old fashioned, but that doesn't seem right.
 
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