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 Suspension fore and aft

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Lenz9753
Tanabuso
Tanabuso


Posts : 87
Join date : 2015-06-16

PostSubject: Re: Suspension fore and aft   Tue Jun 30, 2015 2:23 am

I've now done the front and rear sag measurement with completely unexpected results. With all spring preload set at zero / lowest possible, for my ~ 97kg - 98kg the front suspension shows 27% total static sag (front spring rate too high / hard) and the rear suspension shows 77.4% total static sag (rear spring rate much too low / soft).

My assessment is the front springs need to be reduced in deflection rate by 21% - 25% with revalving to match and the rear shock binned because it's just too far from acceptable specs - undersprung with inadequate damping adjustment.

I didn't expect to find the rear undersprung and deficient in working suspension travel - I expected a grossly oversprung rear shock based on the front.

So now the games begin sourcing replacement gear for the GRiSO in OZ plus a suspension guy experienced with GRiSO's on the EAST Coast of OZ that will respring and revalve the front suspension - suggestions Gentlemen ????
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ghezzi
Fra Cristoforo
Fra Cristoforo


Posts : 1692
Join date : 2014-05-22
Age : 59

PostSubject: Re: Suspension fore and aft   Tue Jun 30, 2015 3:03 am

Well, your in luck as most of us fat arsed ol' grey beards down under, average 100kg in battle dress.
Many are the bikes that come from the factory with front springs to suit an 85kg rider, and a rear spring to support 75kg or less, go figure.

You will need a rear spring in the 10.5 to 11kg range, stock is 9.6kg.
I have a Matris R, but Penske can build you one as well as Walter Preisig from YSS/Hyperpro in South Australia. I only suggest this as a way of cheap freight in case you need follow up service considering your remote location.

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I would respectfully suggest you do not need lighter front springs;
1. I have never heard of stock springs being too heavy for a 98kg rider.
2. Static (stationary) is one situation, forward weight transfer when braking is another.
3. With a stiffer rear spring and better damping, on any given bump the front will appear to travel a lot further than previous, and it will feel softer.
4. My Bellagio is now close to 200kg wet (300 incl my fat arse), has stiffer than stock front springs (9.5kg from memory) yet feels very compliant.

I know the shit roads you ride on, I ride to Biloela once a year.

If you want to deal face to face with a great suspension tech in Brisbane, contact Scotty Heyes at Edge Competition on 0431 109 675
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Lenz9753
Tanabuso
Tanabuso


Posts : 87
Join date : 2015-06-16

PostSubject: Re: Suspension fore and aft   Tue Jun 30, 2015 4:21 am

ghezzi wrote:
Well, your in luck as most of us fat arsed ol' grey beards down under, average 100kg in battle dress.
Many are the bikes that come from the factory with front springs to suit an 85kg rider, and a rear spring to support 75kg or less, go figure.

You will need a rear spring in the 10.5 to 11kg range, stock is 9.6kg.
I have a Matris R, but Penske can build you one as well as Walter Preisig from YSS/Hyperpro in South Australia. I only suggest this as a way of cheap freight in case you need follow up service considering your remote location.

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

I would respectfully suggest you do not need lighter front springs;
1. I have never heard of stock springs being too heavy for a 98kg rider.
2. Static (stationary) is one situation, forward weight transfer when braking is another.
3. With a stiffer rear spring and better damping, on any given bump the front will appear to travel a lot further than previous, and it will feel softer.
4. My Bellagio is now close to 200kg wet (300 incl my fat arse), has stiffer than stock front springs (9.5kg from memory) yet feels very compliant.

I know the shit roads you ride on, I ride to Biloela once a year.

If you want to deal face to face with a great suspension tech in Brisbane, contact Scotty Heyes at Edge Competition on 0431 109 675

Thank you for your input my friend.

My assessments of the front suspension being a little over sprung are based on the total static sag being around 20% less than the "recommended" 33% of total suspension travel for road usage - the goat tracks that pass for roads in Central QLD just punish anything that resembles "sport" suspension. Also with the compression damping set at 2.25 turns out ie near enough to fuck all compression damping (2.5 is max ) an aggressive ride with some heavy braking on rough road still left 30.7mm of total 122mm front suspension travel unused.

The end result of all this %ing, is a little softer on the spring rate and more give in the valving to utilise the full suspension range ????

I think this process is gonna have to be carried out in stages. The rear shock setup is seriously WRONG and is the highest priority - then we'll re-assess on the front maybe.

I've read a bit of how you've deal progressively with springs first etc. From my observations, your experience and the experience of other hardy souls, playing with the std rear shock is likely to be similar to putting lipstick on a pig - it might end up being a very purty pig but it's still a PIG (there may be some here who take issue with my lack of enthusiasm for cross-species "attractions" ...... )

I'll have a chat to Mr Heyes and do some more research on the Matris K / R

There's some great mountain road between Gladstone and Monto that I used to ride several lifetimes ago on my 1969 650 Bonnie - the GRiSO needs to go there - so many goat tracks so little time ....

Many thanks again for your input
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Lenz9753
Tanabuso
Tanabuso


Posts : 87
Join date : 2015-06-16

PostSubject: Re: Suspension fore and aft   Mon Oct 26, 2015 3:52 am

I've had a look around at rear shocks recently and have gone for a German made Wilbers with high and low speed damping, hydraulic pre-load adjustment and their 5 year warranty backup.

If I wanted a race bike I would have bought one - the highest priority for me is compliant, maximum wheel travel suspension so my re-engineered but 2 disc short / fused spine can actually deal with a spirited ride on the 1200 8V over "low scrutiny" back roads.

I have had to park the GRiSO due to the shit original suspension proving to be totally inadequate. Now that I'm facing the reality (again) of a hot Central Queensland summer with extended periods of days reaching 40C and higher, the other project (boat rebuild) is only possible for a few hours in the mornings so motorcycles are "back on the menu boys".

Always had good service from German made equipment - we shall see ......
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ScottMellor
Carlotto
Carlotto


Posts : 43
Join date : 2014-05-02
Age : 59

PostSubject: Re: Suspension fore and aft   Mon Oct 26, 2015 12:05 pm

Can anyone recommend a Guru in Southern California?
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Steak
L'Innominato
L'Innominato


Posts : 1904
Join date : 2013-05-28
Age : 51

PostSubject: Re: Suspension fore and aft   Mon Oct 26, 2015 1:51 pm

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So Cal is chock full of 'em...

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2012 MOTO GUZZI GRiSO 1200SE

2013 MOTO GUZZI STELVIO 1200NTX - Orange Blossom Special
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ScottMellor
Carlotto
Carlotto


Posts : 43
Join date : 2014-05-02
Age : 59

PostSubject: Re: Suspension fore and aft   Mon Oct 26, 2015 2:18 pm

D'oh!
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89millegt
Montanarolo
Montanarolo


Posts : 18
Join date : 2013-06-22

PostSubject: Re: Suspension fore and aft   Tue Oct 27, 2015 9:10 pm

guzziownr wrote:
I managed to change the rear shock without shedding too much blood.  I winkled it out the top after removing the airbox and battery tray.  Here is what I replaced it with, a low miles used shock and an Ohlins 800 lb spring:
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Now that is settled I turn my attention to the front:
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Spring preloading is nut 3?  The more it "protrudes"  the more preload, yes?

TIA, DW

guzziownr,
How has that spring worked out for you on the stock shock? I have the same spec spring sitting on the shelf and was planning to swap the stock spring for it.
Is it too stiff for 1-up riding?
What did you settle on for damping settings?

Thanks in advance. Seeing you already did this swap, any feedback would be great.
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PostSubject: Re: Suspension fore and aft   Today at 8:34 pm

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