Fox suspension settings

[marcusjames]

I'd like to harden the suspension for road or track. Unfortunately I wasn't paying the appropriate attention when I collected the car and can't remember the process (whoops!). Is there a simple way to reduce lean without the need for a full geo set-up?

Thanks

[Karl V]

What do you mean by 'reduce lean' Marcus?

The owner's manual outlines the factory settings and which knobs control which settings (High Speed, Low Speed and Rebound) - did you get an owner's manual?

[John Scherrer]

Does he mean reduce roll perhaps?

[marcusjames]

Yes, I mean roll.

The factory mentioned they had set the car for road. I was wondering if I can easily adjust it for potential track use.

[Karl V]

Yes, you can firm up the compression and rebound settings on the dampers to do this.

The high and low compression adjusters are on the remote reservoir and the rebound adjuster is at the bottom of the shock itself (almost inside the wheel).

Do you have any specific questions? I'm sure we'll try to help out...

[HenryJS]

Marcus,

Yes there is - Jack the car up, and you will see two lockrings inside the springs.

Unlock them from each other, wind them down so they eliminate the 'top' spring from working, then lock them together again.

This will make the car stiffer and reduce the 'roll' you experience.

It wont be properly stiff though as the FOX dampers have a heavy off road bias.

Fitting a more suitable tyre will help as well - the 15" 50/50 All terrains roll ALOT. The 18" 65/35 All terrains roll much less - and a set of Yokohama A052's fitted up to your 18"s will roll very little.

[John Scherrer]

Bear in mind that playing around with the roll stiffness between the front and rear can influence understeer/oversteer behaviour.

Generally, increasing roll stiffness at the front leads to more understeer and increasing it at the rear leads to more oversteer.
Playing around with the ratios front to rear may help adjust the handling balance.

If you're really out to reduce the roll as much as you can, then you may need to eliminate the top springs both ends as Henry suggests and alter the balance by tyre pressures, ride height, shock absorber bump/rebound etc.

[Karl V]

The gap is only around 5mm between the floating seat and the factory's position of the locking rings, but yes - best to treat front and rear the same.

As it happens, I went in the opposite direction with the locking rings to smooth out suspension travel, but again - treating front and rear the same.

[marcusjames]

Thanks everyone for the replies. I'll have a play at the weekend.

Henry, apologies for not paying enough attention when you explained that in person. I was like that at school! In my defence, I did ask the friend I was with to listen to you while I admired the car......he let me down

[HenryJS]

No Problem at all - its always best to ask! If ever in doubt - you can always ring me at the factory and ask for advice. Its why we are here!

[Mutley]

Having just moved to Fox at my last service I am going to have to learn how to adjust my shox too. I was delighted with the ride home from the factory so I guess they were set up for the road.

Is it necessary to jack the car to unlock the lock-rings ? That's a slight PITA.

I don't have a manual. Is that something that can be found online?

Thx.

[Karl V]

If you want to 'unwind' the locking rings to benefit from full suspension travel (as I did), you don't have to jack the car up because there is no load on the locking rings. You're really just moving them out of the way so that they don't hinder suspension travel.

If you want to 'tighten it up' though, I suspect you would need to get some of the load off the springs to position the rings to fit snuggly when the car is at rest.

Although how far 'down' to set the rings, I'm not sure. It makes sense to me to have them so that they are retarding the top spring movement when the car is at rest. Any further down will probably start to affect ride height; but this is based on my assumption.

Maybe someone else has more professional advice ;-)

[Mutley]

OK have to admit I’m puzzled. I downloaded what I assume is the user manual from here: https://www.ridefox.com/fox_tech_center ... 7_RevA.pdf

As far as I can see the twin lock rings position is determined by a formula based on shock travel spring rate etc. The way it’s described it seems that this is a one-off setting. As Karl points out the Ariel factory setting allows a surprisingly small 5mm of travel of the tender spring.

Although Fox say that the crossover point is ‘tunable’, the percentage rate spread they describe suggest this would be only over a very narrow range.

Based on a pretty basic knowledge of setting up dirt bikes, the first thing I would want to do to make a bike more suitable for off-road would be to reduce the spring pre-load – or in other words soften the spring.

Given everything I have to hand on the Fox shox this is where I get lost straight away.

I think I get the dual spring set up on the Bilsteins. The tender spring is the small square section spring designed be nearly fully compressed at a standstill to prevent the suspension constantly topping out over rises and jumps. It doesn’t really seem to work that way – but that’s another matter!

Whereas – the Fox suspension is to me – a mystery. The ‘tender’ spring is heavier gauge and more tightly wound. i. e. a stiffer spring. And then there is the crossover lock. I would love to see the shock in action to see how the springs interact. But as I can’t this is what I think must happen:

The lower (lighter) lower spring compresses until it begins to move the bottom of the upper spring. It moves this – for 5mm... until the spring couple hits the crossover lock. Surely this is therefore nothing more than a springy bump-stop? Maybe that is what you want for road-use? But then how does winding the crossover ring all the way up make the suspension more suitable for off-road use? (and remember Fox actually only allow you a few mm to play with according to the manual?)

Surely what you want is softer springs? In which case, as well as releasing more travel by raising the crossover ring you ought to wind up the top pre-load ring (as you would on a dirt bike?)

I would be quite happy to experiment to find out – except you would spend so much time fiddling that none of your weekend would be left for driving.

I’m not worried about the damping settings – they are easy to change and all quite conventional. I just want to know – what do I need to do to my spring settings to switch between road and off road – and why?!

[Karl V]

I think I get the dual spring set up on the Bilsteins. The tender spring is the small square section spring designed be nearly fully compressed at a standstill to prevent the suspension constantly topping out over rises and jumps. It doesn’t really seem to work that way – but that’s another matter!

Yeah, that or a helper spring, which is designed more to expand during decompression to stop the main spring from falling out of the seat; and little to do with absorbing compression.

But then how does winding the crossover ring all the way up make the suspension more suitable for off-road use? (and remember Fox actually only allow you a few mm to play with according to the manual?)

My understanding here is that by 'getting rid' of the locking rings, you are allowing both springs to compress along the length of the shock, rather than just the bottom spring + 5mm. As you say, 5mm of travel for the top spring really just makes it a 5mm spring - or pseudo bump stop. Allowing both springs to travel as a single unit should - in my mind - make for longer travel and therefore better absorption of bigger bumps.

Have you had a chance to play yet Chris?

[Mutley]

Hi Karl,

Thanks for that. Have to admit I did some more research and had a bit of a 'Doh' moment. :-)

I had incorreclty become convinced that the tender spring was heavier gauge. Strangely it does look a bit that way, but reading up on Fox shox setups, I realised that it can't be. As such, it clearly comes into play first as the shock compresses. So with the factory road settings the helper spring barely comes into play (I at least got this bit right!)

What was interesting is how disparaging the US off-roading 'buggy' community (who are clearly THE market for these kind of set-ups) were of any dual spring set-up that doesn't use the crossover ring set-up the Fox shocks has. The received wisdom appears to be that two differntly springs not separated by a cross-over ring just add up to the equivalent of the combined total. The only use of the helper in that situation is to help the shock from clatttering as it tops out (didn't seem to work very well with the Bilstein dual spring set-up in my view!).

Terrible weather has kept me off the road (or is that off the off-road?). Knowing how the dual spring/crossover set-up works now I can see how adding a few inches of soft spring travel by raising the cross-over ring should wok perfectly off-road (even if it seems quite an extreme change to the road settings?). It ought to work better than the much cruder approach of decreasing pre-load at the top of the shock (crude because it would also lower ride height - not great for off-road).

I also don't really see why it should be necessary to jack the car up to change the crossover ring either up or down - but I guess I'll find out.

When I finally get a chance to play around, my goal with the settings will be this: Find a spring/damper/tyre pressure setting that seems optimised for off-road, so that I can make the changes as quickly as possible to go off-road and vice versa. Given how much better the Foxes seem on-road, I think that getting the two settings spot-on could release a massive amount of latent potential from the Nomad. I feel even more confident about the Fox shocks now I know how much different they are to the 2 spring Bilsteins.