Wildgoose Chase Moto Guzzi

General Category => General Discussion => Topic started by: jevincen on December 30, 2014, 04:56:52 PM

Title: 2013 V7 Stone Shock Spring Rate?
Post by: jevincen on December 30, 2014, 04:56:52 PM
Does anyone know the spring rate for the rear factory spring used with the default shocks on a v7 stone?
Title: Re: 2013 V7 Stone Shock Spring Rate?
Post by: neverquit on December 30, 2014, 08:00:26 PM
I measured the Sachs shocks on my small block and calculated the spring rate to be 145 lbs/inch when the spring is mostly extended.  It is progressively wound and after about an inch or two of compression 3 of the 11 coils are bottomed out and then the rate calculates to be about 195 lbs/in.  Don't take my word for it, measure your spring OD, length, wire diameter and count the number of coils and then use a calculator.  Several are online.  Here's one.

http://www.thespringstore.com/spring-calculator/spring-rate-calculator.html (I think the best match for material is the oil tempered steel.)

 The ride is very harsh in my opinion. I replaced the Sachs with Hagons with a spring rate of 135 lbs and 3/8 inch of pre-load, they still seem a little harsh to me.  I'm thinking of trying springs with a 120 lb/inch starting rate. I weigh about 175 pounds with gear.  I used an engineering text book to get the formulas and they were a little more involved but the results are almost the same as the online calculators.

I would like to know what you come up with for the rate and what you plan to do with them.
Title: Re: 2013 V7 Stone Shock Spring Rate?
Post by: pyoungbl on December 30, 2014, 09:18:25 PM
     Thanks for the spring rate calculator.  That will be very useful in the future.  Like you, I found the stock shocks to be very harsh even with reduced preload.  Lacking that tool I bought Racetech shocks for my '13 V7 in hopes of making the rear more compliant.  It took multiple tries to get the RT shocks to work.  There were problems with the shock body hitting my rear rack and their initial settings were still too harsh.  We finally found a reasonable combination of spring and valving, then mounted the shocks upside down for more clearance.  The end result was pretty good.  Lesson learned was next time I would go directly to a RT certified shop, someone who specializes in suspension.  I found that I was actually going through a middleman and my problems were not being translated correctly to the RT tech.  When I finally talked directly to the tech I was able to get some satisfaction.  The final setup is (per the RT invoice): Spring 2.2, Spring preload 8mm, rebound adjuster 40 clicks out.
     I'm afraid you are going to find that even if you get the correct spring rate you will be stuck with a poorly valved shock body.  The stiff springs mask the poor dampening qualities of the OEM shock.  If you could pull the shock apart and improve the valving you would have the key to improving the suspension for all of us.

Peter Y.
Title: Re: 2013 V7 Stone Shock Spring Rate?
Post by: neverquit on December 31, 2014, 06:20:33 AM
Thanks pyoungbl.  I am assuming that the specs on your Racetech shocks are metric.  So your 2.2 springs convert to (if I did it right) 123 lbs/inch. which is close to the 120 lbs I've been considering for my basic Hagon shocks.  I think you are right in that only more sophisticated shocks with adjustable damping will do the job correctly.  I get two free spring swaps with my Hagons so I will try lighter springs next.  Your pre-load, 8mm, isn't much so a slightly lower spring rate might be OK.  Thanks for the input, the actual rates and settings are helpful for anyone trying to achieve a better ride.
Title: Re:
Post by: vGuzzi63 on January 01, 2015, 09:30:22 PM
Thanks all.  I am having a suspension specialist work on my stone and he is questioning the original spring rate on the rear shocks