Rear Shock Change.

Since the engine is out currently pending new clutch being fitted. I wondered if it was a good idea to replace the rear shock.

I've read often that others have fitted a Stelvio shock.

I am 100kg in my gear.

Would be interested in advice on this ... Hagan do a Stelvio shock for £325.00

Cheers,

Angus.

Yes, yes and thrice yes.

I have one on mine, i am 85kg without riding gear and the change is one the best things i have done, the bike is changed completely, rides better handles better, more ground clearance and raises the seat an extra inch (25mm).

If i had not purchased a second hand one, then the next option would be the Hagon.

From what I've read here, the Stelvio shock is good, but if you really want to you could put a Matris on your GRiSO. Last year when Pete did the reno on GRiSO, he put Matris suspension front and rear and it is just so much better than the original equipment. He actually said that mine handled better than his, so now he's put ohlins on his.

I agree with Sidrat (sometimes ) around OEM Stelvio as he has got longer shock with better dynamics & spring and seems to work well.....there is a 2nd hand Stelvio shock on ebay at moment; or you could go for Stelvio replacement.

If you go Matris just check you get the right spring rate as I had to lighten my up quite a bit (& it has significantly shorter spring for some reason).

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Update...

The shock will be replaced.

Spoke to Hagan today as the Stelvio shock is not coming up on a search in their uk site.

Discussed that the Stelvio shock was going into a GRiSO. Their shocks are £299.00 delivered, a few people I know have used them and think they are good.
Gent I spoke to seemed knowledgeable enough (at least to me, who knows little about shocks). He seemed to understand the advantages of the change and why it would improve handling and ride comfort. Discussed the GRiSO shock they have also, advised that the replacement unit they have for the GRiSO adjusted to be stiffed by a couple of turns would be good for my weight also but he did think much less comfortable.

He advised it was important check the figures for the Stelvio shocks and be sure that the replacement shock when fully compressed didn't rise too high. So as not to come into contact with the underside of the bike at the back. I can't imagine if that was to happen the fuckwittery I would be dealing with whilst riding would be pleasant

His figures.
Data.                        GRiSO/Stelvio
Overall length mm        320/333
Travel    mm                  50/65
Spring Rate  kg              90/90 (I think this is the rider weight they come setup for?)
Preload mm?                  22/15

So am I wrong to think that fully compressed the GRiSO overall length is (320-50) 270mm and that the Stelvio shock would be (333-65) 267mm?   I can't imagine that Moto Guzzi wouldn't have built in more than a 3mm clearance?  Have I just misunderstood and/or my math suck?  

Cheers,

Angus.

Hi Angus, not sure about your Maths, but if you can , stretch the budget to getting a shock with a remote hydraulic preload adjuster. Makes it so easy to increase the spring preload when carrying a pilion or travel gear BTW , I fitted a Wilber’s ages ago, brilliant shock with both Hi and Low speed compression damping. Good luck.

I agree with waterbottle, the Stelvio comes with hydraulic spring adjustment, for luggage and an extra person.

This is the link to the one on ebay that Paul was talking about Stelvio Shock

I have just gone out and taken this photo to show you how the hydraulic preload looks when fittted.

I have bottomed and topped out the shock at speed, there is no clearance problems with them.

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Decided to go for the Hagan shock [You must be registered and logged in to see this link.]
Hopeful it's a good choice.

it will be great, what spring rate are you going with?

It comes with a 90kg spring .. at 100kg (me in my gear) the tech at Hagan advised it should be perfect for my weight tightened approx 2mm. I was reading your report about the Stelvio and the additional height. Not really sure I understood what you had done front end to counter this but I will re read and maybe pick your brains in September

Angus, all you have to do with the front is raise the bike back up to compensate. Mine was on the fifth ring, so i raised it up to the 1st ring again.

Looking forward to september

Hi Angus;

Just to check :-)what spring you got ? I have three springs that are 135 N/mm; 115 N/mm & 95 N/mm (currently running the 115 N/mm on Matris at rear)....I am around 78 kgs...

I think your 90kg spring is based on average rider weight of 90 k because 90 kg(per mm) spring would be 882 N/mm. Hagon don't seem to quote spring rates for single suspension units although they say they'll customise spring rates if requested.

He Paul that sounds right, the guy said that the spring was 90kg which roughly equated to 90n/mm.

Said that for a 100kg rider that the idea would be the standard spring with about 2mm further compression from out the box setting.

From what you are saying you doubt this is correct?

I can have the spring altered at this stage as the order is only just in.

Cheers,

Angus.

Angus

That sounds too weak to me.

The standard GRiSO spring is 9.6kg/mm which equates to 94N/mm

The standard Stelvio spring is 11kg/mm which equates to 107.8N/mm

I am running the standard 11kg/mm Stevio spring and Paul is running the 115N/mm (11.75kg/mm)

Paul is lighter than me, i am 85kg without bike gear on and i think the 11kg/mm is just about perfect, in that i no longer notice it any more. Also the spring does not have much pre-load.  

I would ask to see what heaver springs are available, you would have thought that they would have the same rate spring as the Stelvio has in stock?

If it's 90 N/mm it is probably too light & pre-load isn't the way to compensate for too light spring. As Keith says I'm running 115 NM and TBH I'd go a bit lighter. I think you should be somewhere in the same range.

Beware suspension vendors claims ! After telling them our weight and riding styles Matris shipped me and Brendan identical shocks with 135NM/mm springs and same adjustments out the box...mine was so harsh it hurt...hence I went down to 115nm and still bought 95 nm just in case

Thanks gents, I will ring them in the morning and have them fit a spring equivalent to the standard Stelvio spring.

sidrat wrote:

Angus

That sounds too weak to me.

The standard GRiSO spring is 9.6kg/mm which equates to 94N/mm

The standard Stelvio spring is 11kg/mm which equates to 107.8N/mm

I am running the standard 11kg/mm Stevio spring and Paul is running the 115N/mm (11.75kg/mm)

Paul is lighter than me, i am 85kg without bike gear on and i think the 11kg/mm is just about perfect, in that i no longer notice it any more. Also the spring does not have much pre-load.  

I would ask to see what heaver springs are available, you would have thought that they would have the same rate spring as the Stelvio has in stock?

This is the way forward, running too light a spring will end with having too much compression damping wound in ( to prevent bottoming out ) which causes a harsh ride. The right spring will work throughout the entire stroke range for a plush ride / feel

On my 850 I left the front where it was when transplanting a Stelvio shock. It made the bike feel much more balanced and the front and rear were more in sinc.

OK gents,

Hagan updated. The springs they could offer were 90,100,120 kg for the bike so I've went for the 100 as I didn't want to go too stiff and have no adjustment.

Hopefully this will still give a great improvement over the standard.

Will let you know results

Thanks again!

Angus. It will be better but i still think that is a little soft, shame they didnt have a 110kg spring.

Not to worry, springs are not too expensive if you want/need to replace.

good luck

After a poor experience with Matris (135 kg spring fitted to my order (100kg rider) and Paul Brice 78kg rider) and having far less patience than Paul Brice I was very pleased to return the shock get a full refund (cant complain about that) and went with Wilbers which was in fact about £200 more expensive than Matris but has completely transformed the bike. I went to Darren at MCT in Stowmarket to set up both the Wilbers shock and front forks - I have had the forks uprated by K-tech although Darren said they were not ideal for road use and he changed the air gap by adding more oil, and generally made the front more compliant. Wilbers has a 115 spring. I am 100kgs and if anything I would say the Wilbers is a tad stiff (only marginally), and definitely a 'sporty' feel on our uneven road surfaces.
I spent quite some time fiddling with the Matris in an effort to get it set up and I followed suspension set up guidance on static sag, rider sag etc etc. Had tie wraps on shock and forks and measured travel etc but eventually returned the Matris and went with Wilbers and came to the conclusion that I should just go to a pro and get it set up properly and at £140 plus VAT to remove the Matris, fit the Wilbers and set up the front and rear the best money I have ever spent on the bike! If you can get to Darren/MCT I think its well worth it.  And 75 mile trip each way down the A303/A34/A272 to and from Goodwood Festival of Speed on Saturday just reminded me how good my GRiSO now is! But I agree 100 kg sounds too light and 110kgs spring might be optimum but I think its inexpensive to just swap out the spring if required.

PS. Watching a pro change the rear shock made it look so easy. Jacked it up with a trolley jack with a rubber pad lifting on the exhaust bracket just ahead of the rear wheel under the bike behind the sump. Long extension into the top mount, then removed the lower mount bolts and wiggled the shock out. Mounted the replacement using the jack to lift or lower to get the distance correct to line up the shock mounts and shock. Took 10 mins to remove and 10 mins to fit replacement!
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