Okay, so I don't think Spring ID has ever been discussed in here. What are the advantages and dis advantages to different spring ID's(Inside Diameter)? is it merely weight or are the deflection(or other) advantages to be weighted

Peace
Schu

 

I'm pretty sure it's just what size your adjustable coilovers are made to use. I know Ground Controls use 2.5" ID springs for Honda applications. I'm pretty sure they can't use anything else, at least not safely anyway. Some other coilover sleeves and full coilovers out there use 2.25" ID springs. Again, you couldn't really use anything else, either for physical or safety reasons.

 

well... they do sell adapters, and this is what made me wonder. My 2812's are 2" OD but they came with what they call a 2.5" OD adapter, they are more like 2.25". Why did they do this? are larger springs more prone to deflection?

 

If you want an answer that sounds technical, go post in the road race/autocross forum, and maybe Jonny Mac will say something smart sounding.

Option two, is you go to Eibach's web site, and using two browsing windows side by side (this may require a wide screen monitor, or a purchase of a second monitor), bring up the specs for a 2.25" and 2.5" spring with the same rate. You will see that the large ID spring is heavier, but in general has more travel before coil bind.

Option three is go to google books search, turn on full or limited preview, and type in a few search terms like spring twist coil diameter torsion, etc, and eventually you'll find a chapter that calculates all this out for you.

PS: Your adapter looks flimsy

 

only a matter of weight.

the adapter looks fine. is it an off the shelf item?

my racing buddy uses 2.25" because thats what he was told was the best. i have a lot of 2.5" that id like to be able to use. i could machine my own, but it'd be easier to buy of course.

 

I haven't seen any reasons discussed other than weight. High end dampers like the 2812 are typically used on sports racers and open wheel formula cars, where you'll want smaller & lighter components due to packaging and weight restrictions. You'll almost always see 2.25" ID springs on 2812s, where its more common to see 2.5" ID springs on production cars with lower end dampers like 8041s.

 

I think for Koni, it is an off the shelf item... to adapt the 3011's and 2812's to 2.5" ID, which is what I have now. I dont like the extra weight or the way it sits on the perch, so I am going to switch to 2/2.25 I think

thanks Schu

 

For the record;
2.25" ID springs are lighter. +
2.25" ID leaves a little more room for ducting, less wasted space, etc. +
2.25" ID sets me apart from the "cool kids" +
2.25" ID springs only suck for trading.... -
2.25" ID springs were suggested and are run by two MUCH faster drivers whom I go to for racing help and advice (one is a NASA nat'l champ and the other one is a lead tech at American Honda) +
2.25" ID springs are less likely to be borrowed +

Looks like the plusses outweigh the minuses for me....
my $0.02.....
good luck

P.S. BTW, I just got off the phone with Crx Lee. I ordered the 2.25" to 2.5" plastic adapter for $1.76 each. Koni part number 15.29.04.003.0.