GRiSO Suspension Set-Up

The biggest issue I had with the handling of my GRiSO was that it wouldn't hold a line once on it's side. I could get it over pretty effortlessly but It would take a bit of pressure on the inside/downhill bar to maintain the line and wanted to go wide getting on the throttle mid corner. That coupled with damping that for me wasn't set right made it hard work to ride quickly on a narrow twisty road, not to mention not being in optimum control. Anyway, after lots of trial and error, note taking and on and off the bike with the screwdriver, here's what I ended up with, the biggest improvement coming from getting the geometry right.

Rear: Sag: 38mm Comp: 1/4 T Rebound: 32

Front: Sag: 37mm Comp: 1 T Rebound: 1 1/4 T

Pulled the front forks up through the triple clamps to the 6th ring. Mine came from the factory on the 3rd ring. The measurement from the top of the triple clamp to the top edge of the black fork housing (just below the red cap) is now 24.5 mm. The bike is completely stable and there are no clearance issues with the front fender and header pipe at full fork compression. There is a slight reduction is ground clearance to the extent that when cranked over really good on the left and hitting a bump, I scrape the side stand just a bit which it did before I pulled them up, but I'm going to work on that by grinding off some material on the leading edge of my stand and work on the bump stop for the side stand to see if I can get it to hug up a little closer to the chassis.

This setup works well for me, but will probably not be everyone's cup of tea. If you're not already aware, there's a thread at GT that lists lots of different combinations to try out.

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I found I was getting too much dive on the front forks on braking even at 'optimal settings' so had the front forks rebuilt. He replaced the compression and rebound valves with Racetech valves and new shims, also 5W oil. Transformed the handling and would be the first thing I would do if I was new to the GRiSO (unless you are 65kg soaking wet).

Did the same with the rear shock and put in a much stiffer spring, not as much of a difference as the front but an improvement, especially over potholes. Am looking at a Matris or a Wilbers rear shock now but not sure how much better I am going to get for $1600.

Did it about a year ago and can dig out the details if anyone is interested.

Race tech has a style of cartridge valving I  find a little hash  (their gold valve flow a lot of oil and thus requires a heavty shim stack)  Not bad at all but they tend to work best on pretty smooth roads, or the track, (race tech seems to struggle with sport touring road bikes a little, track good, MX good, adv tour ok, sport touring ok,  They just seem to set up a little firm, and seem to favor pure linear compression curves)  Their are kind of 2 schools of set up  for suspension and they seem to favor one riding style over another.  Race tech seems really good at setting up point and shoot type bikes.  And a little less proficient at setting up high corner speed softer platform bikes.   Sport touring is usually more of a corner speed setup. and typ. a little softer.

 Probably one of the masters of the sachs rear shock is Martin at TD,  It sounds like you are running quite a bit of sag at the rear.  One thing that is odd on the GRiSO is that the rear shock stroke is very short!  and the linkage is pretty high ratio  (not a really good combo for oil control)  The better soloution for the front end is to not drop it, but to raise the back end it has the same effect and actually gains ground clearence.  

Now for the real trick,  If you have a penske built you can get it with a longer stroke.  I built mine from an old gsxr triple clicker I had.  I increased the shock len. 6mm (that is about .900" at the rear end), I did this not with ride ht. adjuster but by making the stroke of the shock about 34mm instead of 27mm.  the bump stop makes the wheel position in upper end of travel at the same place as it was stock, but I picked up ~1.00" of rear wheel travel and more piston stroke (really good for control) and having a real useable ~3.75 4.00" of travel is nice, you really only have about 2.2-2.5" of travel left with 38mm of sag in the rear. and the stock shock len.

There is another problem with the GRiSO (any carc bike really) and that is the shock well is very small in diameter.  Any spring with a rate above 800lbs /in is a problem.  the soloution is to use 1093 series OHLINS springs they are true 57mm id through the full series, Hyperco the id grows with rate above 750lbs, and thus by the time you get to the correct rates for the Guzzi they rub, 84mm od is the magic number. a 971lb Ohlins is 83mm od, a 950lb hyperco is 87mm.

I have both shocks (on different bikes, Matris and wilbers) as well as Penske , Mupo , and ohlins.  The Matris R shock is very very well done,  Wilbers are also very good (have them on 3 bikes).  they are very different though and what you tell them about how you ride is key....be very very honest.  I do a lot of suspension work and know most folks over estimate their level of aggression and underestimate the roughness of their roads.  You probably want to tell either company "sport touring" as your riding style.  Wilbers will be just a little firmer in low speed damping, and softer in high speed damping (compression ), Than Matris.  Matris has more linear adjustments, and much less crosstalk between high and low speed compression than wilbers.  The matris shocks and most Italian shocks I have used are generally 1 rate softer than you would use with say a penske but they work.  You will be happy with either,  Wilbers tends to go a little light on their shock springs on bikes with a high ratio linkage, (honda vfr 800, triumph street)  so if you get wilbers say you weigh about 10-13% more than you do.  On bikes with more modest linkage ratios (vstrom, gsxr, r1 they do better)  The matris has better rebound range than the Wilbers,  Wilbers tends to over damp on re-bound a little,  they do this so the ride is a little more plush.  Both need to be rebuilt every 10-20kmi depending on how hard you work them.  (rebuilds are not too bad)   JUST KEEP A SHOCK SOCK on any shock, this will keep the seal head intact, and not leaking.  The Matris has a little more of a velocity VDP type of compression curve, and the Wilbers has a little bit of a more regressive curve to its damping (at least mine do)  I always ask for sport as the riding style  usually 80% sport and 20% touring.

Do not discount Penske, they make the most tunable of the bunch, is it as good as the Matris R, not quite, but you can re-build it easily at home and Penske has 5-6 valves you can try, and are super nice folks(not to mention any body doing suspension service in the us knows penske shocks),   they are about the most tunable shock out there,  pick your response curve and they have a piston for it.  They do tend to crosstalk a lot in their adjustments but if they are doing it badly your base valving is not right.  They do have a reputation of leaking a little,  they really do not but their seal head is prone to leaving a tiny weep on the shaft,  this is not a problem.  (penske shocks do require more frequent rebuilds ~7-10kmi of road use)  but they cost ~$80 to re-build at the house, then take to a shop and have charged. BTW most of the time Penske will re-configure a shock, so if you sell your bike and get a different one keep the shock and send it to them to re-configure (this is usually 20-50% the cost of a new one)

How much better than the re-built Sachs stocker, quite a bit if you are picky.  Penske is the only one that you could easily get them to build with the extra length in the stroke. and they are just$1300.  The thing you can change is the piston in the sachs, and re-valve and it will be really really good, but if you are not doing yourself, at $150-250 each time you get to the cost of a top flight shock quick.  The thing is decide if you need high speed compression adjustment.  if not then stick with the rebuilt Sachs,  you can do VDP valving to some extent with the sachs with a two stage crossover stack.  It would just take a try or three to get it right most likely.   Those sharp edged high velocity hits are what the high speed compression adjuster will really help tame when set right. (as would a VDP piston, or two stage stack with crossover.

I really liked my Sachs after it was revalved and sprung,  It was equal really to a penske twin clicker, or so close it did not natter(the response curve is not as tuneable though)....Ps the Sachs is hell for durable  they very rarely leak.

I was lookin at your settings and I would tend to think your rate on the shock is off a little 1/4 turn compression is not open enough,  you need more compression damping in the stack on the piston, and your rebound at 32 clicks is pretty much wide open and doing almost nothing(so the rebound bleed is probably small)  The fornt looks in the ballpark for the adjusters to be in a good spot in their range.      What spring rate did they install in the shock?   Too much spring rate and a little bit underdamped in compression is better than too much compression damping (usually) reason is even if you do not have enough pre-load to hit the linear part of the spring curve (at correct sag)  you are still ok as far as bottoming and the like the only real difference is that the chasis will move under you a little more before it "sets" in the curve, not out of control just move a little more, in the vertical direction. If the rate is right it will displace a little less in the same corner at the same speed.  This is usually better than being hammered when the compression is in a poor flowing spot in the adjustment.

It really looks like you do not have enough spring in the rear. and are compensating with compression damping.  Raising the rate in the rear will make you close the rebound adjuster and that would be a good thing.  (do you know how much pre-load, you have?  much over 12-13mm means it is probably light, if the free sag is less than ~5mm)

Sorry for the length of the post  it is the first place to improve, nothing makes you go better than suspension
Maybe it is just where I live, If it dosen't handle here you got a problem.

I haven't done much with mine.
I didn't trust my front end much at first.
Tried setting the front damping to the owners manual sport/track settings.
tightened up the rear spring to increase rear ride height.
I increased damping on the rear. The manual did NOT show me if it was compression or rebound but it the only adjuster that I could adjust and it helped a lot with my wife on the back over very sharp bumps.
Lowered the front one notch on the forks.
THEN I topped up my front tire pressure (it dropped to 29psi) and Bingo! Happpiness.
I did have some harsh pogoing in my front on concrete freeway joints so I dialed both front damping adjusters all the way out (soft) and I can NOT tell any difference blitzing apexes in the mountains so I left the front that way.

Now that I got my front feeling good I am back to spirited diving around mountain twisties and my front feels fine. No shaking ever.

DM

Moved this topic to the GRiSO Tech forum as I think it's better suited here.

 

Nothing to do today, so I decided to fiddle with the suspension settings on my new GRiSO -14. Now, I am really no expert but I've been lucky with adjusting bikes before, so I was surprised with what I found: in order to make the bike behave similiarly at both ends I had to soften the front and stiffen the rear. Quite not what I've seen in other threads.

This is what I found, measured with rider weight 86 kg with gear (all figures reflect turns/klicks out from fully in, in orher words anti-clockwise from hardest):

STOCK
Front sag: 39 mm
Front comp: 1 turn
Front rebound: 1,5 turns
Rear sag: 35 mm
Rear comp: 1,5 turns
Rear rebound: 14 clicks

With these settings the bike moved much more at the rear, especially on the compression stroke (tested seated on the bike by pushing on the pegs and bars). I figured that the sag front/rear was quite ok, so I concentrated on the comp and rebound. The best balance I could get was with the following settings:

Front comp: 2,5 turns (max out)
Front rebound: 2,25 turns (almost max out)
Rear comp: 0 turns (max in)
Rear rebound: 30 clicks (of 44 possible)

With this the bike still moves more at the rear, but much more in balance with the front. Jowever, not nearly as balanced as my wife's stock non-adjustable basement spec Ducati Monster 696. Very annoying.

Any thoughts?

//Olof

Uzi, those spring rates you listed I assume are for two-up + luggage.
At 92kg + riding gear I had settled on a 600lb (10.5kg) spring for solo only riding.
Having increased the stroke length of my Matris R by 10mm (skock eye length now 330mm), meant the starting ratio of the rocker set up would now be higher than the original 2.6:1. So initial compression was softer and needed too much pre-load to set sag. Installed a 650lb (11.4kg) spring now and all is much sweeter. Overall it is now firm but compliant with a good progressive action.

For those of you complaining about running wide coming off corners, more low speed compression and stiffer spring is needed. Stock spring is only 9.6kg. 11kg spring is minimum requirement for solo rider 90-100kg.

What Uzi said about being honest with your abilities, riding style, terrain etc rings true. Even my suspension guru is mainly involved with SBK set-up for national championships. Race tracks are very smooth by comparison to our roads. I don't corner at lean angles around 55°, I don't push 200HP thru slicks and my bike won't do 325kph. Therefore I cannot load the chassis and suspension to the same degree. I tour at 120kph, I ride as hard as I can through tight and twisty sections, but these are bumpy roads. My max lean angle would be <45°, my av. corner speed is probably <70kph (not 170kph), my sport touring tyres won't set lap records, my lard arse and Guzzi are 50kg+ heavier than any racer and his bike.

My Matris R came set up for the race track, Scotty revalved and resprung it softer, probably for the IOM TT, still too hard. Once I showed him a photo of the 'Melon Patch', he cottoned on,
"You need a Motard set up" he said.

THE MELON PATCH
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Trust me when I say, this is more like a motorcross track with a tar coating, yet it is my favourite road. Just did it on New Years Day with my carbon fibre wheels, what an improvement for ride quality and control, its like the bumps have been smoothed out.

I'm not afraid of that kind of road but I surely do not gravitate to them!

That looks like pretty much every road near Chicago/northern Illinois!

I'd love to see some more info on this. I'm a big rider at 220lbs plus gear and my wife is at 125lbs and rides every so often. So I'm looking for a good solution to balance the two. I bottom out on the rear occasionally regardless of settings.

Thanks!

Yes, yes you do. Time to do what I need to do - replace the rear spring with something strong enough to do a good job.

DM...

I'm tempted to just go in and get the Matris R. Interesting that I can legnthen the stroke a bit. I have a crap ton of preload on the rear to get it to 32mm sag.

Just used "DD's Fat Gizzer" settings and the front was pretty harsh. Took it for a spin and she really wanted to not hold a line and run a bit wide on sweepers. That and I could be rusty for having 5 months off the bike in winter.

These were the settings I used.

All settings are from fully wound in, hardest settings.
Front.
Sag 30mm
Comp 2 turns
Rebound 3/4 turn
Tyre Pressure 33lb

Rear
Sag 32mm
Comp 3 Turns
Rebound 17 clicks. When 2 up, 11 clicks
Tyre Pressure 36lb

I guess to I try a 600lb spring first? I'm thinking I'd just be wasting time and money in the end.