penske shock

Good day, a fellow has for sale a Penske shock for a Stevio will it fit my GRiSO? he wants $875.00 BTW
thanks Keener

Is is a remote res or fixed to the top. The short answer is yes my stelvio factory shock fits and functions correctly, as does my Matris stelvio shock...now my caveat I would only pay 875 for a triple clicker if used not a double (too close to new cost). The only fit issue you could have is if the res. is too long. if this is the case it can be swapped for the short one from penske for cheap, and cause no problem the still relativly short stroke on the stelvio shock limits how much capacity the res. needs to have for shaft displacement.

The Shock should fit I have talked to Penske and they have told me the ONLY shocks they have built for the modern 8v GRiSO and Stelvio were for Todd. I also know that the first few (according to penske they have built very few) and if memory serves they were all internal res. piggyback style..had some fit issues with the cannister that were resolved and the build sheet is now final.

The wild card is what spring does it have on it? if it is over 750 lbs and a blue hypercoil you likely will have fit issues....but that can be fixed with an ohlins 1091 or 1093 series spring. The fit gets a little tighter as the swing arm angle is greater with the stelvio length shock in place.

ps doing this makes the service stand work less well.

ask what spring rate it has it should be around 750is for about a 200-225 lb load

It is a remote res....
and is the spring to thick ?
thanks
Keener

if it is a remote res. you may also have to change the hose. (I think I used a 13") hose

the max diameter is 84mm od for safe clear I am posting some pics of my build tomorrow...

This may have been built by an independant like mine (mine is from my garage out of a gsxr 1k), The Guys at Penske said they did not have a build sheet on file for a remote res. triple clicker on file back six mths. or so ago for a Stella.

Have them measure the eye to eye len just to verify, and look at the shock len thd.

maybe this pic will work ....PO says its new and spring is for a 190 lb rider looks like a Eibach spring
cheers
Keener


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keenerkeen07 wrote:

maybe this pic will work ....PO says its new and spring is for a 190 lb rider looks like a Eibach spring
cheers
Keener


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ok a few ?s to ask and observations

yep it is an eibach spring, that is a bit odd for penske factory bld but they will use sometimes (hypercoil is usual) that eibach will be big od real big I am wondering if this shock is new and un used cause it did not fit? it should also have 4 spacers with it two about 20mm and 2 about 2-3mm the long ones are for the top and the short ones are for the bottom (penske does not make a factory perch for the bottom that fits the moto guzzi link without spacers) ask if he has all these parts. (I know that a 650lb 2.25"id eibach spring will not fit in a moto guzzi, I have one sitting here and have tried it) this shock may have been built for on a small body and have a 2" id spring not the normal body with a 2.25" spring) They would have been more likely to use an eibach spring in this case

ps it is a double adjustable 8300 series rear shock and the retail from penske is $975usd so it is not much of a bargin (Penske build times are 3 weeks usually)

I would ask if Penske built it or if it was done by an indy builder...the price seems so close to retail I would be cautious as it just looks a bit off...but I am only seeing 2 small pics, that may be not showing all the parts, I would ask if he has the build. sheet this is supplied with new Penske shocks.

for what he is asking I would just want to see pics of all the parts (not all is pictured) and the build sheet. at $500 I would buy because if there was a small bld problem at that I could afford to correct it.

this shock is the equivelent of the Matris KE road. Except it is easier to get serviced, and you can rebuild and re charge for $25 bucks at home

I think i am going to back off on the Penske comes with a little to much baggage and the price is too high and if i go with a Matris / Wilbers i know what i have , i would like to thank you Uzidzit for your guidance very helpful indeed
Keener

I know someone who mounted an RSV mille Ohlins in a GRiSO and was happy. I know there are two types because Aprilia changes ratio's in linkage. These Ohlins are cheap from breakers

A thank you to pauldaytona

I just put in a resprung stock shock. #800 Ohlins spring that I got from a list member. It's an improvement to the limp factory noodle and cost less than $200 for the whole project including a low mile spare shock from the breaker.

I used your suggestion to remove the airbox and take the shock out that way. Any time I saved I used greasing the bearings of the linkage but all is well and it feels good, if stiff. I weighed 270lbs when I got the spring and now weigh 225 so a little stiffness is to be expected.

Pauldaytona- I'm looking for info on the Ohlins shock that will fit, do you have any more info such as from what year Mille or even a part # ? Thank You.

Guys, I can tell you from experience playing with the standard shock will net limited results.
I got a used GRiSO shock from a member here because it was a better option than a stock Bellagio shock. Took it to Scott Heyes in Brisbane, resprung & revalved. Needles so blunt and thread so course that if you turn the compression half the width of a c**t hair it goes from a sponge to a rock.
The rest of the internals leave much to be desired. I could get reasonable compliance but cornering hard would induce rear sag and running wide.

Also, playing with shocks off other brands/models is also fraught with danger. Different bikes have totally different linkage systems, its not just the static ratio, but the rising rate that effects how the bike responds. If you have a shock who's internals function differently, at given points within the stroke, now being used with a linkage system it was NOT designed for, who knows? WTF!

Shock eye to eye length. 8mm difference here may change ride height by 25mm, which alters rake by 1 degree, which increases or decreases trail by .......................... whatever. See Tony Foales Suspension Kinematics. I did all this to my Cali Stone.

Shock stroke, or travel when bottomed out. Most people don't check this one. Stroke x rocker ratio gives you total rear wheel travel. You could end up with short stiff and harsh suspension, or the wheel jamming into the mudguard/seat base.

Spring rates are calculated on wire thickness, inside diameter and number of coils within a given distance. Each spring should have a number which gives an indication of its weight. Fatter doesn't necessarily mean stiffer. Seen too many people fuck up and get hurt.

Best advice, go see a suspension guru like Scott. I thought I knew heaps but keep learning more stuff and then realize how much of a black art this really is. And every time I go the economy route, WOFTAM!

Sorry to keep bangin' on 'ere.
What price satisfaction? But the bitterness of poor quality lingers long, after the sweetness of cheap price. I only say that because Ohlin's have two factories, one in Sweden and the other in China. There are affordable Ohlin's, and high end Ohlin's, and unobtanium Ohlin's for factory race teams. You work it out.

Ducati specialists will tell you bikes suppled with Ohlin's as standard up to 2002, fantastic. After 2002 they were just a pretty gold colour with a blue sticker. Showa were better.

Last I checked Ohlin's didn't do a shock specifically for the late Guzzi's, Matris do, and full fork cartridge kits as well. Scotty says internally they are a work of art.
When you order a shock from Matris, and their third tier race team stuff is available to every one, don't make the mistake of telling them you are Valentino's cousin, OK. (Don't over estimate your ability).

Sage advice...

Uzidzit: Wanted to confirm that stock Sachs or aftermarket Matris shock for Stelvio will fit GRiSO? Understand from your previous narrative that added length and xtra stroke of Stelvio shock is no problem while yielding better geometry.

Entirely my fault due to neglect but need to take action soonest as the bike is scaring me in a straight line for fucks sake! At highway speeds, the rhythmic stutter over concrete panels sometimes makes the bike feel uncontrollable.

Thanks for your help.

The stelvio Matris r I have fit the GRiSO fine but raised the back end about an inch (a good thing, it also is a bit longer stroke, a good thing) I will have to check its length bottomed tomorrow and let you know on that...I just did not have that in my notes for some reason...in the mean time you can lower the fork legs in the triple trees which will make it feel more stable try leaving only 2 rings visable on the forks.

Sorry to butt in, but I have concerns with FreshEggs problem of stability at speed. I have my forks raised so that all 6(?) rings are visible and yet I find the GRiSO not only super stable at speed across any hard surface, but also somewhat slower steering than some bikes I've ridden.

Could there be some other cause for his stability issue?

Steering head bearings, tyre pressures, tyre wear and incorrect tyre sizes can have a dramatic effect on handling.

Incorrect suspension settings, especially too hard can result in your exact instability problem.

You lowered the front by 2 rings, how much is that in mm?
30mm at the front will decrease rake by about 1 degree.

Raising the rear 1" or 25mm on a sports bike will decrease your rake by 1 degree. Guzzi's have a long wheelbase by comparison so rake maybe decreased further.
CAUTION - This measurement is NOT taken of the shock eye to eye length. Measure vertically from the axle to a specific point on the frame. Do this with the suspension fully extended. Due to the rising rate suspension linkages on monoshock bikes, 8mm at the shock could net you 24-32mm at the rear wheel.

GRiSO standard rake is 26.3 degrees. Just because a Buell has 22 degrees rake don't mean a Guzzi will be safe with the same. Wheelbase, CoG and the biggy, trail will all have a bearing on handling.

Remember, alter one setting and in reality you change everything.

Thanks Beetle & Ghezzi. My earlier experience is actually consistent with yours - that the GRiSO is usually very stable in all situations. But somethings has changed recently. The local interstate highway (I-5) in Seattle is constructed of concrete panels where, in addition to the joints, each panel is cupped by truck traffic. The resulting rhythm is giving my bike the fits : every alarm from ass to brain is giving red alert in this situation. Action clearly needed right away.

As to the cause, I'm attributing it to neglect and lack of maintenance on my part: poor damping due to old/low fork oil; bad steering head bearings (but it's not a wobble) or, perhaps,  broken bits in fork or shock. I also crashed the bike lat summer while indulging my inner squid on the backroads of northern California. Maybe I missed something in the fix.

Current plan is to follow Uzzidit's lead:
(1) Rebuild / Revalve forks with stiffer spring. Farm this out. Dying to tear into it myself but just don't have the time right now...and need to recognize expertise of pros.
(2) Rebuild / Revalve stock Stelvio Shock with stiffer spring. Farm this one out for sure as I'm intimidated by the notion of charging shock with nitrogen.

Stock Stelvio shock is cheap on EBay! $160.

Question: 2009 Stelvio shock is Sachs unit, right? Quality enough to justify small investment in rebuild? If the resulting geometry works out, I'm graduating to a Matris R.

Thanks again for all the useful info, all.

FreshEgg wrote:

As to the cause, I'm attributing it to neglect and lack of maintenance on my part: poor damping due to old/low fork oil; bad steering head bearings (but it's not a wobble) or, perhaps,  broken bits in fork or shock. I also crashed the bike lat summer while indulging my inner squid on the backroads of northern California. Maybe I missed something in the fix.

Alarm bells ringing! Could the accident have caused some misalignment? Slightly skewed forks, triple calmps or steering head? How does it ride on other roads?

+1 what Beetle said!

egghead said "If the resulting geometry works out, I'm graduating to a Matris R."

The Matris R is height adjustable, meaning you can increase its length eye-to-eye to increase rear ride height.

My personal experience in modifying the standard Sachs is minimal benefit with some aspects still totally unacceptable. If you can afford the Matris R just buy it now! You won't look back.
When you have it dialled in at standard ride height, start increasing it slowly for a faster turn in.

If you are in the states, I would go Penske for rough roads...only because every suspension guy can set them up, and you have a great VDP option,

That said I love my Matris R, on the Stelvio, but the Penske Triple clicker I built for the GRiSO is one of the best rear shocks I have ever had. It is valved VDP compression/ Linear Re-bound

The stock sachs is really a very very good shock, but you have to know how to re-valve them and few in the us know them. Martin at Traxxion Dynamics is very good with sachs shocks

Dan Kyle is down in Ca. I do not really care for Race techs work for the street they just flat set up too stiff for every day bikes.

The GRiSO sachs is better than the Stelvio unit as it has slow speed compression adj. you just can not change the height with it

Beetle: "Steers" pretty good otherwise. I'm semi sure it is a damping issue - feel is analagous to a vertical tank slapper, if that makes any sense. Tire is definitely losing contact with road as the suspension is overwhelmed by washboard surface. Will know for sure when I get the shop to turn the forks over on V-blocks with a dial gauge.

Only other odd thing i've noticed with the GRiSO, even from the 5000 mile mark, when I first got it, is a tendency to displace laterally when it hits long irregularities in the road, which is odd for a 600LB bike.  But that may have more to do with tires. Will also check swingarm bearings.

Ghezzi; Uzidzit: Thanks for the info. Adjustable length of Matris, I had forgotten about. That changes the equation. This all adds some clarity: Sounds like Stelvio Sachs is a waste of time.

Some final dumb questions, then:
- So how much does traxxion charge for revalve GRiSO Sachs so I can understand the delta?
- Can a decade-old Penske, off my mothballed SV650 racebike, be reworked for GRiSO? They're modular right?
- Anyone have the number for roller steering head bearing ? I'm a little leery of the chinese-made AllsBalls stuff (Yeah, yeah. So I'm a race traitor...)

Again, Want to express my gratitude for all your contributions of advice. This community is the best.

I've got the number for steering head tapered rollers to replace the shitty ball and cone set-up from the factory but I'm down the beach this weekend. Nag me Tuesday and I'll dig 'em out. (Its a long weekend in Oz this weekend.)

Pete

Pete Roper wrote:

I've got the number for steering head tapered rollers to replace the shitty ball and cone set-up from the factory but I'm down the beach this weekend. Nag me Tuesday and I'll dig 'em out. (Its a long weekend in Oz this weekend.)

Pete

How's the suntan going there Pete ?  

Dude, you are bottoming the shock. or have the compression so hard you are getting the same effect, and have the re-bound set sloooooooooow. It aint the alignment by your description... Traxxion charges about $240-270 with a spring (remind Martin to use a ohlins 1091) spring for the od issue. May have to add a spacer and I would add a adjuster bearing wich are about $25

And yes that sv-650 Penske could be a GRiSO shock Penske will re-configure for probably 1/3 the price of new. That shock may be very very close to right and just need a new hose, spring ,and re-valve. The penske is also adjustable for length if you want

but I know what is happening you are totally out of suspension travel and down to using your tires as the only elastic element...every joint is acting like a little jump and you are not set up for the landing