Shock spring issue

[tatters]

I just received a replacement spring for my hyperpro shock but it shorter in length and is a thinner gauge than the current spring. The current spring is a 1216 and after contacting hyperpro with rider and luggage weight l was told l needed a stiffer spring a 1220 which the replacement spring is marked with.

Am l right to believe that a replacement stiffer spring would be the same length but just a thicker gauge wire?


https://cdn.bikechatforums.com/files/20130511_170209.jpg
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Past:NRG50,AF1125(x2),NSR125RR,ZZR250,CX500,VFR400,KR1S,ZZR600(x2),CB400N,YZF1000(x2),KH125,Z200,FX400R,CBR954RR(x2)GPZ500S,GT550,VFR750F(x2),RD350N,XR650R,CBR600F,CB250,KDX250,YZF750R,CRM250,400EXC,KLR650,TTR600RE,DR350S,R100GSPD,RGV250,VMAX1200,DL650,KZ750 Present:G650XC,C12,CRF450X,1190ADV

[Aff]

Shortening a spring makes it stiffer.

Think of it like a torsion bar (which is effectively what a spring is), much easier to bend a 4m bar than a 1m bar.

:edit: Just saw you said it was a different gauge, this would only be comparable if you could guarantee it was made from the exact same material. It all depends on the Shear Modulus of the metal used.
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Current Bikes:Honda 929RR Fireblade, Honda CD200 Benly (Project), Stomp Z2 140
Electric Bike Project

[tatters]

I understand about preloading/shorting the spring would make it stiffer but it also reduces the length of travel. Ohlins springs l had for my R100GSPD and XR650R were always the same length just a thicker gauge wire.
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Past:NRG50,AF1125(x2),NSR125RR,ZZR250,CX500,VFR400,KR1S,ZZR600(x2),CB400N,YZF1000(x2),KH125,Z200,FX400R,CBR954RR(x2)GPZ500S,GT550,VFR750F(x2),RD350N,XR650R,CBR600F,CB250,KDX250,YZF750R,CRM250,400EXC,KLR650,TTR600RE,DR350S,R100GSPD,RGV250,VMAX1200,DL650,KZ750 Present:G650XC,C12,CRF450X,1190ADV

[stinkwheel]

After talking to an engineer friend, nobody really fully understands what's going on with springs.

He did say that most of what's going on is on the surface of the spring, the middle of it is just to hold the surface of the metal away from itself but doesn't contribute much to the springiness.

So. Surface area probably has more to do with it than thickness or length of spring.

A thinner guage spring will have a higher surface area to volume ratio. It's entirely possible it's a stronger spring. The only real way to find out would be to see how much it compresses when you apply foprce to it, external dimensions aren't necessarily going to tell you a lot.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.