Ideal GRiSO shock length? Less than 330mm, but more than stock...

I know 330mm is the Stelvio length which some people have installed, but would something just a bit less tall, maybe 325mm be the best compromise? Have any of you Matris owners dialed down the shock length?
Thanks!

The 330mm Stelvio shock length makes the GRiSO feel better planted up front.

I bought a Wilbers Shock. Triple adjustment.
The custom length is 326 mm.
I asked for the 330mm and was talked out of it. (Wilbers also offer adjustable length.)
Happy with the result.
My forks are lowered thru the fork yokes by 4 rings. But the fork spring rate was also increased so sag height (less) is a little higher than stock. So ride height is a little higher but not noticeably.

If I had my time again. I would put a Matris shock which comes with an Eibach spring that is closer to required spec than the Wilbers. Wilbers was grossly under sprung to my quoted weight for a custom shock.

I have Matris and Stelvio shocks. I've tried Matris at standard length 319mm and maximum 328mm and it's 100% better at the longest option. I didn't get on with the Stelvio compared to Matris - it felt less compliant and steering bit too much 'drop-in' on corners....but I didn't play around much with preload or front set up to correct (I'm running standard fork position in yolk). I think Matris is overall just a better shock & I'd defo go for max length at 328 mm (with front forks at 'std')

I've got my Matris maxed out too.

wardest wrote:

I bought a Wilbers Shock. Triple adjustment.
The custom length is 326 mm.
I asked for the 330mm and was talked out of it.  (Wilbers also offer adjustable length.)
Happy with the result.
My forks are lowered thru the fork yokes by 4 rings. But the fork spring rate was also increased so sag height (less) is a little higher than stock.  So ride height is a little higher but not noticeably.

If I had my time again. I would put a Matris shock which comes with an Eibach spring that is closer to required spec than the Wilbers.  Wilbers was grossly under sprung to my quoted weight for a custom shock.

No idea Wilbers offered an adjustable length shock when I ordered mine. I must have whatever the "standard" length shock is (?). Wardest, out of interest, what spring rate did Wilbers put in for you, and did you end up changing it?

Quote :

No idea Wilbers offered an adjustable length shock when I ordered mine. I must have whatever the "standard" length shock is (?). Wardest, out of interest, what spring rate did Wilbers put in for you, and did you end up changing it?      

As far as I know the the length supplied is same as stock unless stated otherwise.

Spring rates.  
We took the shock out 3 times on the day of fitting.
The original (Sachs) spring was around 77 kg/10mm

The Spring supplied with Wilbers for a 100kg rider was around 88kgs.  With this spring we were unable to get rider sag / static sag

Next step was remove the Wilbers spring and fit an Eibach spring . The Eibach spring fitted was approx 100kg/10mm
The rider sag and static sag figures were attained but the preload wound on was around 30 mm.
The mantra from my suspension specialist was to minimise the preload.

The shock was removed again and a Eibach spring 110Kg was fitted.
This achieved the Rider sag of 33 mm and static sag of approx 12mm .
There is the minimum preload on the spring.

Note:- I have recently removed just over a third of a turn on the preload to soften the ride.

The spring rates listed above were measured in the shop rather than specs on the spring.

The Wilbers spring supplied was labelled 59/59 - 95 - 130
As far as i can tell the 59 refers to the internal diameter of the spring at each end, the 130 refers to length.
The 95 figure may be kg/10mm but it was grossly overstated when measured as the other 2 springs measured on the day were within 1KG/10mm of their stated rate as a control.

I am still working on the adjustment high/low speed rebound fine tuning.

Thanks. I believe the reference to 95 is "newtons" as such. I recall my Wilbers spring is also a 95-130 and I'm about 83kgs in battle gear, and I even think the 95 is a bit light, so little wonder you had issues with yours.

I tried sub-100NM/mm 6 inch long spring on the Matris (also tried 100NM/mm 7 inch long spring on Stelvio shock) and agree that's too light even for my 75 kgs weight. Currently running 115NM/mm which is a bit firm but OK....Ideally a bit less would be optimal but close enough now.

Paulbrice, interesting you mention that, as I am planning to ask my suspension shop to get me a 105 or 110nm spring to replace the 95Nm, but my only fear was that it was too little of a change to warrant the cost and inconvenience. Pointless to get a spring too stiff though, as I’d be substituting one problem for another.

Springs are only about £25 each and it's free and quick to change (using underneath method and not even removing wheel)......the 'too-light' sub-100 nm/mm doesn't bottom out but it defo starts to feel more wallowy on fast slow dips & corners so I'm tending for firm side of optimum.

Interesting the way bike is balanced the spring rate Vs Rider weight .

I am 88kgs plus riding gear = 100kgs (with the stock 12kg muffler)
I am running the 6 inch 110nm or the 11.2kg/mm Eibach spring . (Measured in the shop)
The spring is a little firm for riding around town commute but does feel sure footed (better) in spirited riding around back roads but i can still fell it squat under acceleration out of a turn but is a huge improvement over the stock.

Paul is 75kgs and riding on a heavier spring so I suspect he has a much more aggressive style of riding .

Just shooting from the hip
Has anyone put the bike on scales to see fore and aft balance ? The spring rate Vs rider weight seems to indicate that there is already plenty of weight on the back spring (shock) before the rider gets on ?
Wilbers got the spring rate so wrong when I ordered my leg I suspect there is a little guessing going on or I was just unlucky.

Springs in Australia are a little more expensive than 25 quid but worth getting right and you only have to buy one.

Is there a separate thread/instruction on how to remove the rear spring via the "underneath" method? My suspension shop did have a bit of a whinge at the time about how fiddly it was to do the rear shock when I had my Wilbers put in. I don't want to spend $100 on a spring and then $300 in labour to have it fitted!

I can help
Remove the seat.
Fashion a beam above the seat frame . (I used a 2 in 1 ladder) Saw horse on milk crates etc

[You must be registered and logged in to see this image.]

I used 2 cheap 1 inch wide ratchet straps around each side of the seat support frame to raise the rear wheel off the ground about an inch or the thickness of a floor board which ever is handy. For reassembly.

Once supported (for beginners ) Right hand side - release the front end of the rear plastic fairing that wraps the brake/tail light.
This gives you access to the rear brake switch connector (yellow with green and green from memory) Release the connector.

Remove the right hand pork chop , leave the rear brake assembly on and support the pork chop out of the way while maintaining it vertical and not kinking the brake line. Now that the brake light switch wire is disconnected you will be able to feed it out from under the fairing to give you access that you need.

To remove the shock I used a uni and socket  for the upper bolt and the lower is easy access once you bend down that far.

Once the bolts are removed a light jiggle and perhaps lifting or lowering of the swing arm will see the shock come out the right side.

To install . I use the piece of wood for a spacer to raise the rear wheel the correct height for the bolts to line up if you are doing the job alone, or an extra pair of hands is great if you have them available.

Lube everything upon reassembly .

Hope this helps

I take shock out on the left hand side (gear side) using std centre stand which now has bit bigger wheels for extra lift (replaced as one broke) ....I used to take the wheel and exhaust off to facilitate but now defo don't take wheel off but think I still take exhaust off - rest is just dog-arm bolt then lower shock bolt then top shock bolt using ratchet-swivel closed end spanner (specially selected to get in and fit) - then just drop shock and remove top end first with jiggle and swearing - Stelvio comes out same way but needs more swearing and harder jiggle as it's really tight due to extra length.

Thanks gents. Great info.

I swapped the original Sachs for a Matris. Despite suppliers sales ad that the shock would be 'bespoke' to my weight and riding style, I ended up with the same spring rate as Paul Brice - I am 100kgs but naked so probably about 105/107kgs in my kit, and Paul is 75kgs. I still found the Matris unbearably hard, (so Paul must have found it even more uncompliant) and despite professional suspension set up on damping and rebound adj. in an effort to optimize it. Swapped to a Wilbers which has frankly transformed the bike. Had it fitted by MCT in Stowmarket UK, and Darren there removed the Matris but said he would not work on a Matris anyway, and was reluctant to expand on that but clearly did not rate them. I have posted previously on my Wilbers and spring rate but I think its the 95 - 130 as mentioned by Brent S. I find it a tad firm, but not uncomfortably or abruptly so. Probably ideal on smooth blacktop, track surfaces, but a little bit hard on the country lanes with pretty rumbly surfaces that I am usually on. When I took the bike for a test after fitting the Wilbers I went about 6 miles out from MCT and then back. Felt superb by comparison to the Matris, and a much more 'creamy' ride. And although I rarely take a passenger I did take Mrs BBB to the isle of Wight a few weeks ago, and found it slightly too soft 2 up. Not wallowy but slightly less assured. So if I was ordering again I would pay the extra for the remote preload adjuster.......overall though I have found the Wilbers to be excellent.........at a price!

BBB888

Glad you like your Wilbers .
How much preload on the spring do you have and how much rider “sag” and static sag do you have.
For the sake of learning.
I tried the same 95 - 130mm Wilbers spring and after winding a huge amount of preload on, we had a rider sag figure of 45 mm.

That’s when the shock was removed twice more to fit a different spring.

[You must be registered and logged in to see this image.]

See set up sheet attached.
Spring is in fact 110 - 130 (not 95 - 130)
No sag recorded on sheet but it was circa 40mm from memory.

PS. Rider sag circa 40mm (with me on board).