Touring vs Standard Dampers for Lowering Springs

Hello all,

If you've followed any of my posts you know I've been pulling my hair out for 2 weeks trying to figure out if any lowering springs will fit my Prius Touring suspension. B&G claims it has lowering springs designed for the Touring and standard Prius, but I still have my doubts since a) the size of the dampers are supposedly different b) Nobody who owns a Touring has actually said they installed them.

Today I took my investigation to a new level. I crawled under my Touring and a standard Prius (a family member's -- I'm not that creepy) to investigate the rear suspension and I took a few pictures, however it's really hard to tell if there are actually any differences. Therefore, I'm asking for your help, opinions, etc etc ANYTHING.

1. My first test was the visual inspection:

Here are the Touring springs. The part I circled is the part that concerns me. You see how the bottom coil rests on the base of the damper? Now you'll have to look at the second picture to see what I'm getting at.

Now look at the standard Prius. Can you see that the bottom coil is smaller on the standard than the Touring. We know this is true from B&G:
Standard Prius bottom coil
Outer Diameter 3.03" (76.96mm)
Inner Diam. 2.16" (54.86mm)

Touring Prius bottom coil
OD 3.34" (84.84mm)
ID 2.44" (61.98mm)

This makes me believe that the base of the damper base is smaller too, then. If this is the case, won't the standard or aftermarket spring be too tight around the Touring damper? Well yes, according to Eibach springs, this part is larger on the Touring, so their spring made for the standard Prius won't fit around it. B&G seems to claim otherwise. However, if Eibach is right, I don't know how its possible that B&G has bypassed this physical disparity.

2. My 2nd test was a Ribbon test. I measured the circumferences of the damper bases for the standard and Touring, where the bottom coil rests (I have no pictures). The result, they both met at the same point in the ribbon! Now I'm getting confused...

3. My 3rd test was literally measuring the diameter of the base of the shocks with a ruler. Touring:
Standard:

There are 2 issues I see here. First, can you see that the is Touring is about 5mm longer in diameter? Even accounting for photographic error, this seems to be a significant variance. More astonishingly, it puts Toyota's/B&G's dimensions that I listed above completely out of spec - I measured about 65mm vs. 77mm for the standard, and I got 70mm vs. 85mm for the Touring. Is this confusing me? You bet.

My question is simple: So based on what I've provided, do you think either the B&G lowering springs or Eibach lowering springs will fit the Touring? B&G says it will, Eibach says it won't.

I apologize for the long post. There is a lot to explain and I really hope someone can help me out. I posted this here because I consider it a technical problem now and you are the gurus. Thank you so much!

Matt

 

Thanks XS. Yes, as my pictures show, the white/pink stripes denote the Touring suspenstion, and blue/pink stripes denote the standard suspension. However, if I understand you correctly, the fact that they're interchangeable isn't irrelevant to me since I'm not looking to replace the dampers - I only want to replace my Touring springs with lowering springs.

Hey, guess what - I just measured the mark on my ribbon and the circumference was 241cm. Pi*77mm (Toyota's outer diameter of the bottom coil) = 242 mm. Coincidence? I think I'll take another measurement before I get my hopes up...

 

I just remeasured both cars with my ribbon - I was wrong, they each have a different circumference! The Touring measures in at ~265mm which is almost exactly the same as the theoretical 266mm (pi*85mm), and I remeasured the standard Prius shocks at 241 mm, which is very close to the theoretical 242mm (pi*77mm). So, I now have hard evidence that these parts are different sizes. ARGHH!!! We're back to square-1. How does B&G make the same lowering spring for both the Touring and standard Prius!?!?! I emailed them this weekend, I hope they get back to me sooooon!!!

In the meantime I really appreciate more input...