Ponte Vecchio/Zacconi Spring Rate

October 20th, 2015, 11:48 am

Hi, anyone know? Thanks for any help.

October 24th, 2015, 2:23 pm

So, estimated about 66 lbs based upon dimensions. If that sounds completely wrong please let me know fast cuz I placed an order for some stuff based upon this.

October 24th, 2015, 2:24 pm

Seriously.

#4: Post by **peacecup** » October 24th, 2015, 3:12 pm

Sorry, never saw it posted anywhere. But I understand that estimates based on measurements should be pretty accurate, so I guess you're ok there?

#5: Post by **peacecup** » October 24th, 2015, 3:27 pm

Anyway, I just had some fun estimating the rate using an extra spring for a PV and this online calculator:

http://www.thespringstore.com/spring-ca ... lator.html

in inches:
wd= 0.187
OD = 1,5
Lfree = 3
Number of active coils, na = 6

Spring rate = 129.349 Lbs/In

#6: Post by **peacecup** » October 24th, 2015, 3:34 pm

FWIW I am a little uncertain whether it has 5 or 6 active coils. When I reduce it to 5 I get a higher rate, 157.065 Lbs/In.

I think it's probably 5 active coils.

#7: Post by **peacecup** » October 24th, 2015, 3:37 pm

An image of the spring, from http://www.lamacchinadelcaffe.com/pontevecchio.html

October 24th, 2015, 4:50 pm

So how I did it originally was find a spring with same dimension on Century Spring and got 66 for closest spring rate. When I do your thing, I have

Wire diameter of 5/32" (.15625)
Outer diameter of 1-7/16" (1.4375)
Free length of 2-13/16 (2.8125)
Counting 6.5 coils

and it gives me closest match as 54.222 spring rate. Seems like our springs are different. Hmmm, I dunno.

Other thing is I ordered slighly longer spring of 3 inches since people say their springs shrink over time, so wondering now if that was right thing to do, but it says it will compress to what the spring I have now, but I know you are only supposed to compress so far before it causes issues. The max recommended on all of them is less than what I think it will be.

Big ones:
http://www.centuryspring.com/Store/item ... ber=s-3022
http://www.centuryspring.com/Store/item ... ber=72768S

Little ones:
http://www.centuryspring.com/Store/item ... mber=10119
http://www.centuryspring.com/Store/item ... ber=72461S

We'll see how it goes, thanks for your feedback!

October 24th, 2015, 5:20 pm

It looks like it has all to do with the wire diameter, using your specs except wire diameter of .156 gives spring rate of 60.679, so little bit difference in wire diameter makes a huge difference in the rate. Geez.

#10: Post by **FJ60Cam** » October 25th, 2015, 10:33 am

Are you experimenting with different springs rates or just buying a replacement?