Telix fork brace how too?

[Chuey]

Now this relates to the two percent comment and to the need for bling. (Note to spellcheck: I know I spelled bling correctly!) Anyway, this is related but it is specifically about bicycles, not motorcycles. When people admire Bride of Chuey's bicycles, she tells them that "By God, I'm slow, but I make up for it by having a really cool bike!"

Feel free to use her line 98%ers.

Chuey

[RDG]

Both my Airheads are running Telefix' and they're sweet! Installing is easy once you have done the homework of straight forks, no stickchen, etc. It helps if you loosen the fender mount bolts just some, to allow the proper spacing after the brace is pulled tight.

Take care the brace is seated fully on the bottom flange. Start the bolts to a finger tight torque. Bounce the forks up and down by holding the brake. Further tighten the bolts. Do this several times, tightening bolts in sequence as you go...Eventually, the brace will be tight and the suspension will be free.

[vanzen]

The primary function of a fork brace is to reduce or eliminate slider misalignment
introduced by lateral forces acting upon the motorcycle in a curve.
These forces use the tire, wheel, and axle as a kind of a lever
that will force the slider closest to the inside of the curve
to compress ever so slightly more than the other.
This dynamic misalignment CAUSES STICTION
that no amount of static "forks-alignment procedure" can eliminate !!!

What ? You say BMW forks are immune to dynamic flex ?
Start with perfectly aligned forks, and try this simple experiment,
an easy one for the 98% :
Block the front wheel in a lift vice, sit on the bike, turn the handlebars –
and watch the front fender move laterally across the front tire.

And for the "2%"ers :
While hard into a curve, look down and notice
that the front tire is no longer centered under the fender.
Hard braking will actually stuff the tire backwards towards the frame.
In a controlled situation and with a little presence of mind, you can actually watch it happen.

So, you don't need a fork brace ?
For me, motorcycling is not the nostalgic memory of an activity relegated to bygone years,
nor is riding always so sedate ...
But, apparently even the BMW factory would disagree with the premise.
Larger diameter stanchions and a fork brace were stock issue on the Type-247 in 1984.

It is simplistic to say that only "2%" of riders will "notice the difference",
and although speed will certainly accentuate inherent weaknesses,
the statement does not present the entire picture ...
A (better) design will function strictly according to the laws of physics –
regardless of the rider's appreciation or ability to notice !
What might be an essential improvement for those riding at speed
might also serve to make riding and handling EASIER and more enjoyable –
at any rate of travel.
I'm talking about less rider input, less effort needed, a less tiring day on the road,
to affect any and all of the required responses that we expect and need from a motorcycle.

In spite of our chosen preference and fondness for the old airheads,
one only needs to ride a contemporary motorcycle
that has addressed these antiquated chassis technology issues
to appreciate the difference !

/5 through post /7 BMW telescopic forks,
(like many forks systems on the market in those times)
are best described as al dente spaghetti -

If you are happy with all that –
enjoy it with marinara !

[ME 109]

The primary function of a fork brace is to reduce or eliminate slider misalignment
introduced by lateral forces acting upon the motorcycle in a curve.
These forces use the tire, wheel, and axle as a kind of a lever
that will force the slider closest to the inside of the curve
to compress ever so slightly more than the other.
This dynamic misalignment CAUSES STICTION
that no amount of static "forks-alignment procedure" can eliminate !!!

Right, well there's an action on the forks I didn't consider, one fork compressing more. That puts a new light on what a fork brace.........braces.
A curved brace like my oe pie plate would not offer a lot of opposition to said action.
In this context I can see where a telefix would offer support.


What ? You say BMW forks are immune to dynamic flex ?
Start with perfectly aligned forks, and try this simple experiment,
an easy one for the 98% :
Block the front wheel in a lift vice, sit on the bike, turn the handlebars –
and watch the front fender move laterally across the front tire.

This is the walking flex I thought to be more of an issue....
Another test is to wobble the handlebars side to side on a fully loaded for touring, two upped bike when sitting still. Nauseating to say the least.


And for the "2%"ers :
While hard into a curve, look down and notice
that the front tire is no longer centered under the fender.
Hard braking will actually stuff the tire backwards towards the frame.
In a controlled situation and with a little presence of mind, you can actually watch it happen.

So, you don't need a fork brace ?
For me, motorcycling is not the nostalgic memory of an activity relegated to bygone years,
nor is riding always so sedate ...
But, apparently even the BMW factory would disagree with the premise.
Larger diameter stanchions and a fork brace were stock issue on the Type-247 in 1984.

I don't know if I need a fork brace, I've never tried one. I've never needed to try one.
Mind you when an old farmer finally buys a new tractor.....

It is simplistic to say that only "2%" of riders will "notice the difference",
and although speed will certainly accentuate inherent weaknesses,
the statement does not present the entire picture ...
A (better) design will function strictly according to the laws of physics –
regardless of the rider's appreciation or ability to notice !
What might be an essential improvement for those riding at speed
might also serve to make riding and handling EASIER and more enjoyable –
at any rate of travel.
I'm talking about less rider input, less effort needed, a less tiring day on the road,
to affect any and all of the required responses that we expect and need from a motorcycle.

In spite of our chosen preference and fondness for the old airheads,
one only needs to ride a contemporary motorcycle
that has addressed these antiquated chassis technology issues
to appreciate the difference !

Never!


/5 through post /7 BMW telescopic forks,
(like many forks systems on the market in those times)
are best described as al dente spaghetti -

If you are happy with all that –
enjoy it with marinara !

I thought it said something else for a second and I was gonna say I do!

I always learn sumpin from you Vanzen.

[Major Softie]

The primary function of a fork brace is to reduce or eliminate slider misalignment
introduced by lateral forces acting upon the motorcycle in a curve.
These forces use the tire, wheel, and axle as a kind of a lever
that will force the slider closest to the inside of the curve
to compress ever so slightly more than the other.
This dynamic misalignment CAUSES STICTION
that no amount of static "forks-alignment procedure" can eliminate !!!

What ? You say BMW forks are immune to dynamic flex ?
Start with perfectly aligned forks, and try this simple experiment,
an easy one for the 98% :
Block the front wheel in a lift vice, sit on the bike, turn the handlebars –
and watch the front fender move laterally across the front tire.

And for the "2%"ers :
While hard into a curve, look down and notice
that the front tire is no longer centered under the fender.
Hard braking will actually stuff the tire backwards towards the frame.
In a controlled situation and with a little presence of mind, you can actually watch it happen.

So, you don't need a fork brace ?
For me, motorcycling is not the nostalgic memory of an activity relegated to bygone years,
nor is riding always so sedate ...
But, apparently even the BMW factory would disagree with the premise.
Larger diameter stanchions and a fork brace were stock issue on the Type-247 in 1984.

It is simplistic to say that only "2%" of riders will "notice the difference",
and although speed will certainly accentuate inherent weaknesses,
the statement does not present the entire picture ...
A (better) design will function strictly according to the laws of physics –
regardless of the rider's appreciation or ability to notice !
What might be an essential improvement for those riding at speed
might also serve to make riding and handling EASIER and more enjoyable –
at any rate of travel.
I'm talking about less rider input, less effort needed, a less tiring day on the road,
to affect any and all of the required responses that we expect and need from a motorcycle.

In spite of our chosen preference and fondness for the old airheads,
one only needs to ride a contemporary motorcycle
that has addressed these antiquated chassis technology issues
to appreciate the difference !

/5 through post /7 BMW telescopic forks,
(like many forks systems on the market in those times)
are best described as al dente spaghetti -

If you are happy with all that –
enjoy it with marinara !

You just don't get this whole "Rubber Cow" thing, do you?

[Rev Light]

I have had a tarozzi on my R65 for ages with not issue.

However they are non adjustable, unlike the telefix.

Just lucky I guess.

Cheers

[Rob Frankham]

The primary function of a fork brace is to reduce or eliminate slider misalignment
introduced by lateral forces acting upon the motorcycle in a curve.
These forces use the tire, wheel, and axle as a kind of a lever
that will force the slider closest to the inside of the curve
to compress ever so slightly more than the other.

Sorry, I think I need that justified...

My understanding is that, when a bike is in a bend, and assuming that it is properly balanced in the bend with the load (rider, panniers, pillion etc.) balanced, then the net force will be vertical to the axis of the machine and the load would be equal (or more or less equal) on both stanchions. If this were not the case, the bike would either fall into or out of the bend. Assuming that this is correct, I see no reason why one suspension unit should be compressed any more than the other. Of course, I acknowledge that transient loads, such as uneveness of the road surface, or transition loads entering and exiting the curve, might place side pressure on the wheel but there is no reason to assume that this would be on one side in particular. It can also happen when the bike is travelling in a straight line.. although I would accept that these forces will tend to be less in these circumstances.

Regards

Rob

[vanzen]

Well stated, Rob, and yet, the fact that sliders can move independently of one another
and that stanchions will flex with load remain as primary causes
of lateral displacement of the front tire contact patch from the motorcycle's axis
and an inherent flaw of telescopic forks design.
Lateral displacement of the front contact patch will be the #1 cause of motorcycle chassis instability.
Larger diameter stanchions, larger diameter spindles, and robust fork braces are attempts to control this displacement.
"Transient load" just might be an integral part of motorcycle dynamics.

[Major Softie]

Yes, Rob, if that vertical axis force, which certainly does exist, is followed down through to where it leaves the bike, you will see that, in a corner, that axis must travel through the air to reach the ground. That vertical axis force is being resisted by the contact patch, which is not aligned with the force axis, and that resistance is not perpendicular to the force axis. The torquing of the forks that vanzen is talking about is the result of your axis of force, and his contact patch, not being in alignment. Thus, the force is trying to bend the fork out of alignment.

On a banked turn, if the banking and speed are such that the axis you spoke of is perpendicular to the "ground" of the banking, then no such torquing of the fork would occur, as the contact patch would be perfectly centered on that axis.

[Ken in Oklahoma]

Yes, Rob, if that vertical axis force, which certainly does exist, is followed down through to where it leaves the bike, you will see that, in a corner, that axis must travel through the air to reach the ground. That vertical axis force is being resisted by the contact patch, which is not aligned with the force axis, and that resistance is not perpendicular to the force axis. The torquing of the forks that vanzen is talking about is the result of your axis of force, and his contact patch, not being in alignment. Thus, the force is trying to bend the fork out of alignment.

On a banked turn, if the banking and speed are such that the axis you spoke of is perpendicular to the "ground" of the banking, then no such torquing of the fork would occur, as the contact patch would be perfectly centered on that axis.

Nice succinct explanation Major.


Ken