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Discussion Starter · #1 ·
So after about a month of rolling around with Bilstein HDs in the back, i finally got around to putting in the Z71 shocks for comparison purposes...

side by side, the ava shocks are about 1" longer than the HDs, they are significantly harder to push down than the HDs

i drove it around for a little, and some places where the back of the truck had somewhat "jumped" when hitting a particular bump, it was very smooth... very very very little bouncing...

i must say, I LOVE how the truck rides now... its damn near perfection...

on that note, anyone want to buy a almost brand new set of rear Bilstein HDs???? :thumbsup:
 

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That's actually a surprise to me. I thought the Avalanche shocks were smaller diameter than the Bilsteins, but I only bought some Z71 springs, so I never experimented.
 

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I did the same and installed only the Avalanche shocks. I had the Bilstien HD's and when I put the Avalanche shocks in I noticed a big improvement over the HD's. I wont be going back at all. Now if anyone wants my set of the Avalanche springs and a fairly new set of HD's let me know. :thumbsup:
 

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I too replaced my Bilsteins with the Avalanche shocks. My Bilsteins were originals, and with 148k were totally shot. I am very pleased with the Avalanche units. The only annoyance was the need to shim the lower mount. You can see the difference in the spacer length in the photo. Grade 8 washers work fine.

When I compared the lengths of both shocks, they were identical. I should have taken a photo. Interesting to see that the Bilstein HD's are a tad shorter than the Avalanche shocks, and presumably the stock Bilstein shocks.

I have purchased Bilstein HD's for the front, they'll be here today, and I'll be installing them Saturday. I'll be interested to see how the new combination works. Right now the front is very floaty.

Mark
 

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question

Would one of you fellas be kind enough to provide a part number? And will they work with my bds lift?
:hail:
 

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Would one of you fellas be kind enough to provide a part number?
:hail:
Were you looking for the Avalanche part number perchance? I don't have that here. It is a GM part number, as the shocks I bought were "take-offs" from an Avalanche.

I'll try and dig it out tonight unless somebody else has it handy and can provide it sooner.

Mark
 

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Just curious why you would put on Avalanche shocks?
They usually come for free when you're buying the takeoffs from Tahoe/Avalanche owners who are going lowered. The Ebay sales are usually for a set of two Z71 springs and two shocks. Cheap. :cool:
 

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i have avalanche springs too... and look above... a bit more articulation, not much, but some. and so far, a MUCH better ride (for my tastes, at least)
Oh ok, so it's more for lift/off road then?

Aren't the factory Avalanche shocks made by Bilstein?

They usually come for free when you're buying the takeoffs from Tahoe/Avalanche owners who are going lowered. The Ebay sales are usually for a set of two Z71 springs and two shocks. Cheap. :cool:
Interesting. I didn't realize any full size parts worked on our TVs. If you switch to Ava rear springs/shocks, does it give you lift or more load capacity?

BTW, I finally installed my S Maxx spacers in the front on Saturday. They've only been sitting on my work bench since last fall. lol
 

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i drove it around for a little, and some places where the back of the truck had somewhat "jumped" when hitting a particular bump, it was very smooth... very very very little bouncing...
After thinking about this more, it make sense.

Even though the Bilsteins are HD shocks, they are designed around two main factors, our springrate, and the gross axle weight rating (what the max weight on that axis would be).

By changing to a Ava spring, you are changing a major player in the equation. A higher spring rate has a higher frequency for the same spring-mass setup, it would thus require a higher damping rate to reach a critical damping system.

The Ava also has a higher GVWR (i assume) which would also require greater damping. So, all in all, I guess it makes sense. I bet bilsteins for the Ava would be an even better ride...
 

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Discussion Starter · #14 ·
Oh ok, so it's more for lift/off road then?

Aren't the factory Avalanche shocks made by Bilstein?

Interesting. I didn't realize any full size parts worked on our TVs. If you switch to Ava rear springs/shocks, does it give you lift or more load capacity?
Yes... this is for lift/off road, hence the subforum that this was posted in... :dielaugh:

Not sure who makes factory avalanche shocks

and Yes, you get anywhere from 1.5-2" of lift over stock TB height with the Ava Springs...

I bet bilsteins for the Ava would be an even better ride...
i would agree... once these are in need of replacing, best believe i will be looking into Bilsteins for a 07 Ava z71...
 

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After thinking about this more, it make sense.

Even though the Bilsteins are HD shocks, they are designed around two main factors, our springrate, and the gross axle weight rating (what the max weight on that axis would be).

By changing to a Ava spring, you are changing a major player in the equation. A higher spring rate has a higher frequency for the same spring-mass setup, it would thus require a higher damping rate to reach a critical damping system.

The Ava also has a higher GVWR (i assume) which would also require greater damping. So, all in all, I guess it makes sense. I bet bilsteins for the Ava would be an even better ride...
With what you just said the HD should not be a firmer ride than the Ava shocks if they are set up for the TrailBlazer. I know in most applications the HD's provide 15-30% more dampaning than most OEM shocks.
 

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Interesting. I didn't realize any full size parts worked on our TVs. If you switch to Ava rear springs/shocks, does it give you lift or more load capacity?
AlekG is using Tahoe lift springs (not made by GM) in his rear, getting 4". No BDS or SuspensionMAXX spacers at all. I tried a set of Tahoe Z71 takeoffs (only 2007+ work because of the spring perch) and found they worked, and got me 2-2.5" of lift just by being stiffer. Also more load capacity, I assume, given the limitations of the axle and control arm design. And then I told everybody about Ebay auctions of takeoffs and tried to make sure everybody got iin on the bargains. http://forums.trailvoy.com/showthread.php?t=42449
BTW, I finally installed my S Maxx spacers in the front on Saturday. They've only been sitting on my work bench since last fall. lol
Hey, now you're lifted, you need to keep up with what we're discovering here in the Offroad forum, although I know it's not your thing. :dielaugh:

 

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Yes... this is for lift/off road, hence the subforum that this was posted in... :dielaugh:
Well yeah ok!

AlekG is using Tahoe lift springs (not made by GM) in his rear, getting 4". No BDS or SuspensionMAXX spacers at all. I tried a set of Tahoe Z71 takeoffs (only 2007+ work because of the spring perch) and found they worked, and got me 2-2.5" of lift just by being stiffer. Also more load capacity, I assume, given the limitations of the axle and control arm design. And then I told everybody about Ebay auctions of takeoffs and tried to make sure everybody got iin on the bargains. http://forums.trailvoy.com/showthread.php?t=42449Hey, now you're lifted, you need to keep up with what we're discovering here in the Offroad forum, although I know it's not your thing. :dielaugh:
Well, I learned something new today. I really don't have any need to lift the rear end but this is good info, thanks.

I had to lift the front end because my Westin bar kept getting caught on the curbs in the mall parking lot. :laugh: I think lifted with big tires looks cool but it doesn't mesh well with the highway driving I do!
 

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Generally speaking, according to a Firestone Tire and Rubber engineer in Akron, OH, aftermarket shocks are typically about 20% stiffer than stock. He says that in his experience the aftermarket companies make their shocks firmer than OEM not because that is needed or "good", but rather because the public tends to equate stiffer shocks with better shocks, something which he adamantly insists is not the case.

So, it is not surprising to hear that Bilstein HD shocks are up to 30% stiffer than OEM shocks for our vehicles.

Since a heavier vehicle requires greater damping to control ride motions, shocks from that heavier vehicle will be like heavy duty shocks if installed on our vehicles. Put an Avalanche shock on a Trailvoy, and you will have a much stiffer suspension, a harsher ride, and the wheels will tend to skip and chatter more over washboard surfaces. Too much of a good thing is sometimes bad is a gentle way to put it.

Given the foregoing, it seems to shake out like this in terms of stiffness, from stiffest to softest:

HD Bilstein aftermarkets for the Avalanche
OEM Avalanche shocks mounted on a Trailvoy
HD Bilsteins for the Trailvoy
TBSS shocks
OEM shocks for the Trailvoy

I have Avalanche shocks on the back (only because I got a FANTASTIC deal on them), and am installing the Bilstein HD shocks on the front(because they were cheaper than the TBSS shocks)--got the RF done this weekend, the LF will have to await next weekend as I see that I need the axle seal and didn't have it, so I changed the oil instead.

Just a couple of notes on what I encountered. Most folks recommend a Pittman Arm puller. I happened to have a pickle fork that was just the right width/opening and it worked easier and faster than my Pittman Arm puller would have, especially as I would have had to do some grinding to get it to the point where I could hammer it in.

Second, my shock was rusted into the arm support (don't know what it is called), and I had to "separate" the clamp portion to release it. It wasn't immediately obvious to me that the shock is held in place not only by the clamping force, but that it is also located by and retained in part by the bolt. If, as I did, you have the "clamp" portion spread to remove the old shock, be sure to install the bolt before allowing it to alligator the shock, otherwise you may be spreading it again to move the shock upward to get the bolt in. Ask me how I know. :)

Finally, once I got the bolt in, the shock was a bit loose, so I had clearly pushed it down too far the first time. Now is not the time to align the top with the bottom and tighten the clamp bolt. Ask me how I know this also. :) :) Leave it loose so the top can be rotated and the bottom can be slipped over the spindle mount. Once the two top bolts and the bottom bolt are secure, THEN go ahead and tighten the bolt to firmly clamp the shock in place.

Mark
 

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...wheels will tend to skip and chatter more over washboard surfaces. ...
Airing down to 15-18 PSI allows the tire sidewalls to soak up the washboards and the ride is FABULOUS! The shocks aren't even called upon to deal with the high frequency components. I've been able to do 25-30 MPH on washboards that kept me below 5 MPH (or above 50, which isn't safe) when at 40 PSI. Admittedly, this is only useful if you're not going to be on pavement much in the middle of a trail ride.
 
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