Which fork leg should I fit the stronger spring in?

[Mr. Dazzle]

Fitting different springs in each leg sounds less difficult than commissioning custom ones to me, but you pays your money.

I think people are getting way too hung on up on the symmetry thing. As soon as you do anything other than ride in a perfectly straight line on a perfectly flat road the legs are doing/seeing different things. They're built for it. I say that as someone who's worked with one of the big name suspension manufacturers on experimental carbon forks - 'they' expect the legs to be seeing different loads, you're not gonna break anything.

[porter_jamie]

I'm guessing the OP is trying to get a "half" value between two available rates?

Getting custon springs seems more complicated than fitting one of one size and one of the other. The legs are already asymmetric by virtue of the fact one does compression and one does rebound. Its not like you're gonna anger the suspension gods by making the legs different. They're already different.

But yeah, I wouldn't be surprised if the makes have finer steps available than first advertised. Do that if you can.

My point is that if you go to a spring maker you can specify the exact rate you want, to fractions of a kg/mm, lb/inch or N/mm. There is no need to use different rates in each leg to try and arrive at a median setting. It really is just making life diffficult and being imprecise when you don't need to be.


And the damping in both legs of the fork (be they compression or rebound) is predicated on the assumption that the spring rate is the same in each leg. OK, it's not going to be a mile out doing it the way the OP is thinking of, but it's not ideal.

how?

says who? and how can the bike or anyone tell when he is riding along?

i would put the higher rate spring in the rebound side

[Demannu]

Do you know how much Faulkner charge for 1 off springs?
And the forks have assymetrical damping so not an issue re 'imbalance'.
Providing the springs are pretty close, not a 1kg/mm in one and 10 in the other then it's a simple and cheap way to get a proper sag set up

[Mr. Dazzle]

And the forks have assymetrical damping so not an issue re 'imbalance'.

Well yeah, that's all the proof you need really innit? The manufacturers themselves see fit to put compression in one and rebound in the other, hence each leg is pretty much always gonna be doing something differenet to the other. They don't see it as a problem, so why should we?

P.S. I don't thikn it really matters which side you put it in BTW

[Yorick]

The suspension guys who did my bikes on track never bothered setting the sag. Always seemed OK but I'm a thicko when it comes to sussies

[mangocrazy]

Do you know how much Faulkner charge for 1 off springs?

Perhaps you should go to the people who make Faulkner's springs for them. They're called Springcoil and they're based in Sheffield. I had a set of custom fork springs made by them for my Duke 690 R last year, cost £60 for the pair if I recall correctly. No more than that anyway.

How much are you paying for a pair of 1.0 kg/mm fork springs?

[mangocrazy]

And the forks have assymetrical damping so not an issue re 'imbalance'.

Well yeah, that's all the proof you need really innit? The manufacturers themselves see fit to put compression in one and rebound in the other, hence each leg is pretty much always gonna be doing something differenet to the other. They don't see it as a problem, so why should we?

P.S. I don't thikn it really matters which side you put it in BTW

Point me to a manufacturer who deliberately fits springs of different rates in their fork legs and I'll agree.

Or is it more a case of arguing for the sake of it?

[weeksy]

And the forks have assymetrical damping so not an issue re 'imbalance'.

Well yeah, that's all the proof you need really innit? The manufacturers themselves see fit to put compression in one and rebound in the other, hence each leg is pretty much always gonna be doing something differenet to the other. They don't see it as a problem, so why should we?

P.S. I don't thikn it really matters which side you put it in BTW

Point me to a manufacturer who deliberately fits springs of different rates in their fork legs and I'll agree.

Or is it more a case of arguing for the sake of it?

I do wonder if you'd get some twisting in terms of one of them trying to return fractionally quicker.... i mean it may be fractions, but if a fork on a road moves 20 times per second, then even just a tiny fraction of difference between the return/compression rates may make a big difference ?

[Mr. Dazzle]

And the forks have assymetrical damping so not an issue re 'imbalance'.

Well yeah, that's all the proof you need really innit? The manufacturers themselves see fit to put compression in one and rebound in the other, hence each leg is pretty much always gonna be doing something differenet to the other. They don't see it as a problem, so why should we?

P.S. I don't thikn it really matters which side you put it in BTW

Point me to a manufacturer who deliberately fits springs of different rates in their fork legs and I'll agree.

Or is it more a case of arguing for the sake of it?

What's your point here fella? I've already said you could do it either way. I just don't think it's something to overly worry about - if the OP has the springs to hand then by all means fit different ones. Or don't. Whatever you fancy really, I don't think it's something to sweat about much at the levels he's talking.

I do wonder if you'd get some twisting in terms of one of them trying to return fractionally quicker.... i mean it may be fractions, but if a fork on a road moves 20 times per second, then even just a tiny fraction of difference between the return/compression rates may make a big difference ?

You'll get loads of things trying to twist the forks out of 'true', mismatched springs would just be one of those things. That's part of why you want forks that are stiff and hence why MotoGP bikes have big drainpipe sized things.

On the flip side you might also want them to bend sometimes too, the most obvious example is when you're leant over. That's why were looking into composite fork legs BTW - carbon fibre lets you make them have different stiffnesses in different directions more easily than you could with metal.

[Yorick]

If one leg is doing compression damping and the other rebound damping, there'll be a lot more twisting force exerted by those 2 than a teeny bit of difference in spring rate

[Mr. Dazzle]

If one leg is doing compression damping and the other rebound damping, there'll be a lot more twisting force exerted by those 2 than a teeny bit of difference in spring rate

Yeah exactly.

Bumps in the road, cornering forces, braking forces, gyroscopic forces from steering - they're all yanking about on the wheel more than a slight difference in spring rate would.

OEMs aren't going to do it from scratch 'cause that would indeed be a bit weird. You'd need to buy two different types of spring for a start. But I wouldnt' worry about it overly. Personally I doubt I CBA commissioning new springs if it were me.

[mangocrazy]

If the OP already has the stronger spring ready to pop in, then use that. If he doesn't and he has to buy a set of stiffer springs, then why not buy a matched pair at the exact rate he wants? That's my point. I can even give him a contact name and telephone number if he wants.

[porter_jamie]

If the OP already has the stronger spring ready to pop in, then use that. If he doesn't and he has to buy a set of stiffer springs, then why not buy a matched pair at the exact rate he wants? That's my point. I can even give him a contact name and telephone number if he wants.

can't fault your logic here

[Demannu]

Do you know how much Faulkner charge for 1 off springs?

Perhaps you should go to the people who make Faulkner's springs for them. They're called Springcoil and they're based in Sheffield. I had a set of custom fork springs made by them for my Duke 690 R last year, cost £60 for the pair if I recall correctly. No more than that anyway.

How much are you paying for a pair of 1.0 kg/mm fork springs?

£40 delivered
The reason manufacturers fit paired springs is because they're a compromise. Rarely if ever manufacturers provide the correct springs because it's not cost effective. Your KTM is proof of that.
Manufacturers also fit progressive springs, which are the work of Satan, but they still fit them

[mangocrazy]

Do you know how much Faulkner charge for 1 off springs?

Perhaps you should go to the people who make Faulkner's springs for them. They're called Springcoil and they're based in Sheffield. I had a set of custom fork springs made by them for my Duke 690 R last year, cost £60 for the pair if I recall correctly. No more than that anyway.

How much are you paying for a pair of 1.0 kg/mm fork springs?

£40 delivered

That's a good price. Where from?

The reason manufacturers fit paired springs is because they're a compromise. Rarely if ever manufacturers provide the correct springs because it's not cost effective. Your KTM is proof of that.

The reason they fit paired springs is because it's cheaper and there's less stock to keep track of. All manufacturer's spring rates are a compromise as they have to cater for such a wide range of rider weights and applications. As you have found out.

Manufacturers also fit progressive springs, which are the work of Satan, but they still fit them

That's your opinion, which you're welcome to. Personally for road use I can understand the rationale. For track use, probably not.

[Demannu]

Huge self righteous thread tangent

But what leg should I fit the odd spring in?

[weeksy]

Huge self righteous thread tangent

But what leg should I fit the odd spring in?

techincally they're both odd

[mangocrazy]

Huge self righteous thread tangent

But what leg should I fit the odd spring in?

The tangential one.

[Demannu]

Dog with a fucking bone

Just FYI.
I've got some Andreani springs here lurking around.
One's 4mm taller than the other.
Brand new never used.
I bought some springs for my old Fazer from ktech, different number of coils in each spring, didn't notice til I sold them on and they wouldn't go together.
If fork suspension had to be symmetrical, then why did Yamaha supply damping only in 1 leg.
Take your blinkers off and use your imagination

[mangocrazy]

Dog with a fucking bone

Just FYI.
I've got some Andreani springs here lurking around.
One's 4mm taller than the other.
Brand new never used.
I bought some springs for my old Fazer from ktech, different number of coils in each spring, didn't notice til I sold them on and they wouldn't go together.
If fork suspension had to be symmetrical, then why did Yamaha supply damping only in 1 leg.
Take your blinkers off and use your imagination

I think you need to take a chill pill, mate.

If you don't want suggestions, don't ask for comments - it's simple. I've said my piece, you don't agree with it, and that's fine. Not quite sure why it's boiling your p1ss to the extent that you keep substituting snidey comments for mine, but it's your pig.

And the reason why manufacturers have started using asymmetrical damping is purely down to them saving the cost of 1 compression and 1 rebound valve and shim stack, and also simplifying the fork internals. It's a win-win for them and the vast majority of punters won't notice the difference.

But then I'm sure you already knew that.