Virago 250. Softening suspension?

[Bass]

Am I missing anything?

Sort of. As my limited understanding would have it, you are correct up to a point. However the rising rate linkage affects both the spring compression rate as well as the damper compression rate but a variably wound spring affects the springing only. That's why you usually see linear springs on the back but compounds in the forks. Having the damping rate increase as the suspension compresses is a good idea but you can't put a rising rate link in the forks

[Bass]

In fact, no.
The primary effect - and indeed the most important effect - on your average crappy OEM suspension, is to make the owner feel some small measure of satisfaction that they have improved their suspension by tweaking the preload adjuster doohickey. And this, of course, will make their motorbicycle go faster.

Satanic adjustments now?

[Bass]

Of course.
That's why it goes "Doink!" when you tweak it. And frequently traps and pinches any piece of skin that strays too close.

Sounds like you once owned an RF too

[jrandom]

The primary effect - and indeed the most important effect - on your average crappy OEM suspension, is to make the owner feel some small measure of satisfaction that they have improved their suspension by tweaking the preload adjuster doohickey. And this, of course, will make their motorbicycle go faster.

It's funny because it's true.

Actually, ideally, one would want to minimise applied preload, because one would want to have as much upwards movement available as possible in the suspension, to avoid it topping out - suspension needs to be able to move downwards into ruts as well as upwards over bumps.

Having a whole chunk of one's suspension's travel taken up with a rigid collar instead of being available for the spring to extend upwards into (and for the wheel to therefore stretch downwards from) is not really a good thing.

A bike should always sag down a certain amount when the rider sits on it. If it doesn't sag down enough, you can guarantee that the wheels are going to lose traction in certain types of lumpy surface conditions. They'll 'want' to push downwards onto the road, but will be effectively held up in the air by the permanently-compressed spring.

Preload is only there because most riders can't afford and/or can't be arsed to fit springs to their suspension that are precisely right for their weight.

[Bass]

I'm with you on this Sarge. Please stay out of this one for a while Robert

I'll ignore you too. Go and wash your scrambler in some ford

[crashe]

Just in case you lads aren't aware....... but then you may know this already....
But the Virago 250 has 2 rear shocks....... one on each side of the wheel......

While a sportbike has one....


Ok as you all were..........

[tri boy]

It's ok, I thought there was gunna be a , but you boys kissed and made up.
No point sticking around now.

[Bass]

It's funny because it's true.

Actually, ideally, one would want to minimise applied preload, because one would want to have as much upwards movement available as possible in the suspension, to avoid it topping out - suspension needs to be able to move downwards into ruts as well as upwards over bumps.

Having a whole chunk of one's suspension's travel taken up with a rigid collar instead of being available for the spring to extend upwards into (and for the wheel to therefore stretch downwards from) is not really a good thing.

A bike should always sag down a certain amount when the rider sits on it. If it doesn't sag down enough, you can guarantee that the wheels are going to lose traction in certain types of lumpy surface conditions. They'll 'want' to push downwards onto the road, but will be effectively held up in the air by the permanently-compressed spring.

Preload is only there because most riders can't afford and/or can't be arsed to fit springs to their suspension that are precisely right for their weight.

Ummm..... some good some bad. On a properly designed suspension the preload does not affect the available suspension travel, it's the shock length that does that. And since we have got all amicable, I should come clean and say that a great deal of what I wrote is bullshit. I said that leaving the preload set for pillion loads while riding solo will not affect the ride compliance. If you have a rising rate linkage that's crap
With a RRL the damping rate changes with shock extension. It increases as the shock compresses so conversely it decreases as the shock extends. So leaving your preload wound up with solo loads is likely to SOFTEN the ride if your rear end is RRL

Any guesses on how long before this gets whipped off to another thread.

[sunhuntin]

well that was somewhat amusing... for the record: we stayed in 50/70k zones as i HATE riding where theres no street lights. i have a 500, but am not confident on that riding solo, never mind adding another 95kg to control. the 250 took us both perfectly, except for the bottoming out.

i do recall my mate adjusting the ginny suspension simply by twisting the spring [i think?]

so, i can adjust the suspension so it wont bottom out, and then just leave it once the pillion is off?

[crashe]

so, i can adjust the suspension so it wont bottom out, and then just leave it once the pillion is off?

yep .

[FilthyLuka]

Sorry but you won't. Raising the preload does not stiffen the springs - only changing the springs can do that.
It simply changes the ride height.

Eh? By clicking the preload up, you are effectively compressing the springs. The more the springs are compressed, the more force that is is taken to compress them even more.

If you have low preload, you push the back end down with your hand (not really, just an example) cause the spring isn't preloaded (see where they get the name?), therefore it requires little force to push down.

wind the preload up to balls, and it takes a metric arse ton of force to compress the springs even more, as the springs are more preloaded.

I think you may have confused two things my friend. When you dial in preload, the distance between the eyes of each individual shock (virago's a dual shock, init?) stays the same.

To lower the ride height you throw in a different (longer/shorter) spring

savvy?

[FilthyLuka]

Ummm..... some good some bad. On a properly designed suspension the preload does not affect the available suspension travel, it's the shock length that does that.

Didn't you say preload alters ride height? If the ride height is altered then you loose/gain travel...

[Disco Dan]

When was the last time you replaced your fork oil?

I have found that to be the biggest improvement in suspension on all the bikes I have owned... replace the fork oil.

Then with FRESH oil, adjust your shocks to suit. That way when things get bumpy again you need to change your oil again!

"superbike" magazine did a very good explanation of suspension settings - blew away a lot of the myths and offer advice on how to set things up right.

not a lot of point spending heaps of $$$ on prof set up unless your doing track days every other weekend... or own a sportsbike

[Bass]

Eh? By clicking the preload up, you are effectively compressing the springs. The more the springs are compressed, the more force that is is taken to compress them even more.

If you have low preload, you push the back end down with your hand (not really, just an example) cause the spring isn't preloaded (see where they get the name?), therefore it requires little force to push down.

wind the preload up to balls, and it takes a metric arse ton of force to compress the springs even more, as the springs are more preloaded.

I think you may have confused two things my friend. When you dial in preload, the distance between the eyes of each individual shock (virago's a dual shock, init?) stays the same.

To lower the ride height you throw in a different (longer/shorter) spring

savvy?

Oh God, here we go again.
Sorry mate but it's just not so.
The virago is actually a good example to use because the rear suspension has what is essentially a constant rate linkage, so we can ignore the complications of all the goodies that a modern sports machine has. Get your tape measure out and you will find that the top shock mount, the bottom shock mount and the swing arm pivot are at the corners of an isosceles triangle. Any other arrangement results in a falling rate linkage which (trust me on this) is a really bad idea.
So it's a simple arrangement and good to use for this example.

Let's put Crashe on her bike so that the shock is somewhere in the middle of its travel range. Let's also imagine for a moment that Crashe is an expert gymnast and can sit there indefinitely balancing the bike with her feet off the ground.
Now we have an equilibrium situation where all the forces are in balance with the weight of Crashe and the bike being taken by the springs. They will compress a certain amount in order to do this.

The next part of this is absolutely key to understanding.
The compression and so the length of the springs can only be changed by changing the load on them, which in this case means changing the load on the bike. We have to add another Crashe or get her to lose some weight to do so. If we don't change the load on the bike, the spring length will remain the same whatever other adjustment we make.
I repeat, that part is the key.

If you don't believe me on this one, go out and try it. It's not hard to do.

Now, with Crashe still carefully balancing her bike, let's start increasing the preload (damned misnomer that is), which basically means that we push the top of the springs down further. Remember we have not increased the total mass that the springs have to carry so their length stays the same.
So what happens?
Well, very simply, the bottom end of the spring moves down the same amount as we pushed the top end down, the shock extends a bit, the swing arm moves down and Voila, the ride height is increased.

I have been accused of being incoherent and I probably was, but I can't think of a simpler way than that, to explain it.

As for preload affecting suspension travel, unless the spring is very badly matched to the load so that it becomes coil-bound under full compression, preload should have no effect on the TOTAL available suspension travel. The only thing that affects TOTAL suspension travel is the shock travel length. Increasing the preload gives more compression length available, but at the expense of extension length. Conversely reducing the preload means that you leave less travel for compression, but more travel for extension.

I really hope that this is a better explanation and clarifies the whole picture.

[Bass]

When was the last time you replaced your fork oil?

I have found that to be the biggest improvement in suspension on all the bikes I have owned... replace the fork oil.

Then with FRESH oil, adjust your shocks to suit. That way when things get bumpy again you need to change your oil again!

"superbike" magazine did a very good explanation of suspension settings - blew away a lot of the myths and offer advice on how to set things up right.

not a lot of point spending heaps of $$$ on prof set up unless your doing track days every other weekend... or own a sportsbike

Triumph specify changing the fork oil in the Sprint, every 20,000km. The guys who do it for me tell me that the colour of the oil coming out indicates that it's a good call.