Rear Nitron Shock respring opinion

Sgt.Cupid

Sgt.Cupid

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I have a Nitron rear shock on my old Hexhead that has the correct weight spring for me solo but majority of road riding is done 2 up. Both of us are around 100kg in our riding gear
On a recent trip, 2 up fully loaded with luggage, the centre stand would touch down over fast sudden undulation in the road.
This was with the preload to max and the fast and slow damping set to mid way. Don't recall what the rebound was set to though.
Also, I occasionally take the bike off road, but nothing too challenging.

So I'm thinking of changing the spring to one rated for 150 - 160 kg to try and stop the centre stand grounding when fully loaded...does this sound like a sensible idea or should I go for a heavier spring?

Thanks in advance.
 
Depends upon where the bike sits in its travel and how the damping is adjusted. As you have full preload dialed in then Increasing compression damping may slow how the bike blows through its travel. Make certain you don't have too much rebound damping as that may cause it to pack down.
If you have too much dynamic sag, then a heavier spring may be needed... But that might make it a bit harsh when you are solo.
A dual rate (or non linear) spring may help, but you'll never get a nice damping set up.
Always a compromise!

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Maybe check the suspension sag 2up with luggage before deciding on the Spring rate you need?
 
Damping wont make any difference to how far it drops when loaded up (static sag)

A stronger spring will restore the correct sag but will need the damping turned up to control it's movement.

Measure how far it sags one up and again two up. Then talk to Nitron about the spring you need.

Bear in mind if the spring is too stiff, the bike will skip about when one-up.
 
"Damping wont make any difference to how far it drops when loaded up (static sag)"

If we mean 'loaded up" to include rider and pillion, then that is dynamic sag.
My suggestion was that this may be correct (or good enough), but if there isn't enough compression damping, then it will go through the travel too quickly... Thus it may ground out when hitting bumps or holes whilst also under increased g-force caused by cornering :-)
The damping settings are mid-point, so scope for adjustment there.
You can test if it needs servicing (new oil!) by bouncing the bike and observing the rebound control. Best done when the shock is warmed up.

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Thanks for replies. I did call Nitron but they didn't really give any opinion other than we can fit any spring you want.
The shock copes ok 2 up with luggage until we go over a sudden dip/undulation in the road. This causes the shock to compress quickly and ground the centre stand.



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It sounds like the compression damping could be increased but a too light spring does the same. Take those sag measurements and go back to Nitron. They probably work better with specific questions.
 
Sudden dip?
Dial a load more high-speed compression damping in. If it then feels "crashy" over potholes, back it off a bit.

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If it is undulations in the road, then increase the slow speed damping, by two and rebound by one and analysis what difference it makes.

If it is sudden bumps/holes then high speed compression up one along with rebound.

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From what's been described, I really don't think increasingly rebound damping will help.
You may already have too much!
If it's sudden compressions causing a problem look at high-speed damping; if it's "roller coaster" type dips causing it then look at low speed damping.
If it boings you in there air AFTER a compression, then look at rebound.

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It may be worth asking Nitron for more detail about the intended weight ranges of their springs - if the one you have fitted has an upper range limit significantly below your actual fully loaded weight, the handling will always be compromised no matter what you do with the damping (the shock will effectively be sitting towards the bottom of its range, setting the compression to prevent it bottoming out will mean the damping is too much for the majority of the time).

The question will be whether there is a spring that has sufficient range to enable a setup when riding solo as well, it may well be that you have to chose a spring which does not work at its best in either scenario (i.e. sits in the middle of what is ideal for each of solo and fully loaded touring), but offers a better all round compromise and may be sufficient to prevent the bottoming out you are experiencing.

As others have already mentioned getting sag set correctly to start with is key to fixing this...
 
Stock Spring Rates.
2011 GSA White power 135
2012 GS White Power 130
I am about the same weights 2 up as the op and on a 2012 GS use a 170 x 185 springs on 30mm lowered Wilbers but with an extra 5mm preload spacer.
Static sag 22mm and dynamic sag 48mm with a static seat height in the one helmet position of 805mm.
can flatfoot the bike in one and 2 helmet position and the bike does not bottom out 2 up with luggage as with stock shocks.
 
Just be aware, not all spring manufacturers use the same "weight" rating (stand up Ohlins). So beware when comparing weights between different brands.
I "think" that WP and Tractive are fairly standard.
The second figure is always its uncompressed length through!

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I appreciate different manufacturers use different units of measurement Lbs/in, N/mm, Kg/cm etc.but if they quote say a rate of 150 kg cm that is what it should be.
Should have put the second figure ( length in for the stock shocks or left it off my wilbers)
Just for the record stock spring rates.
2011 GSA White power 135 x 222
2012 GS White power 130 x 215
 
Mistacat said:
Stock Spring Rates.
2011 GSA White power 135
2012 GS White Power 130
I am about the same weights 2 up as the op and on a 2012 GS use a 170 x 185 springs on 30mm lowered Wilbers but with an extra 5mm preload spacer.
Static sag 22mm and dynamic sag 48mm with a static seat height in the one helmet position of 805mm.
can flatfoot the bike in one and 2 helmet position and the bike does not bottom out 2 up with luggage as with stock shocks.
Click to expand...
How do you find the bike solo? Is it harsh and bouncy or can you compensate for stiffer spring with damping settings?
Olly at Nitron has recommended I swap to a 170 on the rear which is for a 130kg solo rider then use preload and fast/slow damping to suit.

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Sorry, yeah, that's what I meant...
So you can't compare (for instance) an Ohlins 130 with a WP 130.... One uses N/mm, the other kg/mm

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Sgt.Cupid said:
How do you find the bike solo? Is it harsh and bouncy or can you compensate for stiffer spring with damping settings?
Olly at Nitron has recommended I swap to a 170 on the rear which is for a 130kg solo rider then use preload and fast/slow damping to suit.

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Click to expand...

It is always a compromise.
The Wilbers were originally ordered for the specified rider and pillion weights + damping to match spring rate.
I find the solo + ESA normal slightly firmer than stock but it feels very planted.
With Pillion ESA two helmets + Normal or Comfort rebound damping depending on road conditions is softer but with plenty of feel.
Regards rebound damping the bike Solo now feels in Normal as it did previously in Sport.
The Wilbers WESA only have the same features as the stock shock ie. Adjustable Pre-load and adjustable rebound damping.
Would be nice to have adjustable high and low speed compression and rebound damping, but would probably spend more time trying to get it right !! rather than riding it.
 
Mistacat said:
It is always a compromise...................
Would be nice to have adjustable high and low speed compression and rebound damping, but would probably spend more time trying to get it right !! rather than riding it.
Click to expand...

I had the same problem on my Hexhead, two up with luggage in the south of France it was grounding the stand occasionally in bends, so I changed to Ohlins which was better, but still suffered the same to some degree. So I took them to Reactive Suspension in York who fitted uprated HyperPro springs. I asked for them to be set up for two up touring, gave them our weights and left it to them. I haven't altered any settings since, they were spot on. Bike is just on the firm side with just me on it, but not so as to ruin the ride.
 
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