Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner
1 - 20 of 76 Posts

·
Registered
2005 chevy trailblazer_lt
Joined
·
2,636 Posts
Discussion Starter · #1 ·
Based on what I've found to be true thus far, the following appears to be mathematically sound.

The table works by looking up your front spring part number or tag color on the top line first. Then look up or down the scale to see which spring could give you lift (listed on the left). KEEP IN MIND THIS IS SPRING LIFT, NOT WHEEL LIFT. It will be multiplied by a certain factor based on the lever arm dimensions of the lower control arm. Not sure what those are as of now. But if you chose a new spring that is supposed to give, say 20 mm of lift, don't be surprised if you actually get 25-35 mm of lift at the wheel.

Spring 15125889 will give the most lift possible. It is the stiffest possible spring for the TB. For someone with a stock Lavender spring, they can attain 1.39" of lift by going to the 89 spring.

Sorry, all the calcs were easier to do in metric. I only converted the bottom row to inches for your convenience. The conversion from mm to in is to divide by 25.4.



Hopefully that all makes sense. Feel free to ask if you have questions. I wanted to test this out myself by purchasing a new spring, but I don't forsee the funds for that immediately. So while this is mathematically sound, I have not yet tested this on my own vehicle. I will eventually upgrade, but not immediately.


Also, consider this your disclaimer. Use this information at your own risk. A higher spring number WILL produce a stiffer, rougher ride. If you lift your vehicle too far, you WILL break something. Don't blame me because you didn't do the math yourself to make sure you are within a safe CV angle range. This is based on information that has been handed down between a few sources and I did my best to put it all together and figure out the spring mystery.
 

·
Registered
2005 chevy trailblazer_lt
Joined
·
2,636 Posts
Discussion Starter · #4 ·
I just measured my lower control arm. It's 15.5" from the fulcrum to the ball joint centroid, and 10.5" from the fulcrum to the strut mount.

So in theory, if you are supposed to get, say 20mm of lift based on the chart, divide that by 10.5, then multiply it by 15.5. You get 29.5mm of actual wheel lift. (Or to make it simple, just multiply the chart value by 1.47)
 

·
Registered
2007 chevy trailblazer_ls
Joined
·
480 Posts
Very nice job JD! I just looked up SS frt springs in the susp.section and the part number given is 15853193. I wonder where they would fit in the chart? I will see what I can find out. Maybe we can get some members to post up what kind of Trailvoy they have and the frt spring number on the truck? I will go first. I have an 07 I6 2wd SWB Trailblazer. My 2 springs are 881on the right and 882 on the left. Jay:thumbsup:
 

·
Registered
2005 chevy trailblazer_lt_ext
Joined
·
423 Posts
Very nice job JD! I just looked up SS frt springs in the susp.section and the part number given is 15853193. I wonder where they would fit in the chart? I will see what I can find out. Maybe we can get some members to post up what kind of Trailvoy they have and the frt spring number on the truck? I will go first. I have an 07 I6 2wd SWB Trailblazer. My 2 springs are 881on the right and 882 on the left. Jay:thumbsup:
there is another thread for people to post there springs types that has been going on for a while.

i dont think the ss springs would have any purpose for us trying to get some lift there for would not be added to JD's new list.

but then again this is JD's project, so ill let him chime in on what he thinks is relevant to this list.
 

·
Registered
2005 chevy trailblazer_lt
Joined
·
2,636 Posts
Discussion Starter · #8 ·
I think these particular springs were not used in all years. However, we know that the I6 2wd received mainly lavendar and dark green springs. When you add in the 4x4, the SWB I6 trucks received mainly Grey and pink springs. The LWB 2WD vehicles also received Grey and Pink mainly. Finally, LWB 4x4s mainly received light blue and orange.

Hopefully that lets you know approximately where your vehicle would fall (even if you don't have a spring in the provided part number range).

As for the SSs, your springs may be stiffer, but shorter in the free state to give you the same resting height. If you upgraded to a spring on this list, you may be dissappointed and feel it gives a mushy front end.
 

·
Registered
2005 chevy trailblazer_lt_ext
Joined
·
49 Posts
Hi, James,

I wasn't able to get the part number or code from the spring tag but the right spring has an orange tag.

TB is a 2005 EXT 5.3l 4x4

RPO codes are
6HF
7HF
8HM
9HM

The RPO codes indicate at least the the front and rear springs are in pairs - the front right being Orange should have the part number 15125886.

I'll try and have someone who is a little more agile read the spring tags tomorrow.

Bill French
 

·
Registered
2005 chevy trailblazer_lt
Joined
·
2,636 Posts
Discussion Starter · #10 · (Edited)
...we know that the I6 2wd received mainly lavendar and dark green springs. When you add in the 4x4, the SWB I6 trucks received mainly Grey and pink springs. The LWB 2WD vehicles also received Grey and Pink mainly. Finally, LWB 4x4s mainly received light blue and orange.
It's ok, I no longer need codes. I only had spring specs for the springs listed in the chart anyways, so any others out there are going to have to assume their installed spring based on their vehicle package... based on my post above. However you did reinforce the last statement, found in bold.
 

·
Registered
2003 chevy trailblazer_ls
Joined
·
1,031 Posts
Thank you for the work up on the available information. Now the search begins as I will not doubt that buying new springs over the counter through a dealer will be quite pricey. And being the "new, leaner, greener GM" I am sure that they are not going to want to give any discounts. We will see though, a quote never hurts.
 

·
Registered
2005 chevy trailblazer_lt
Joined
·
2,636 Posts
Discussion Starter · #13 ·
6## = Left front spring
7## = Right front spring

## = the letters below:

5125881 - FH, HM, HU, FZ, JC
5125882 - HN, HW
5125883 - HP, HX
5125884 - FL, HY, JL, HC
5125885 - FM, HD
5125886 - HT, JA, JR, JT, HF, JC
5125887 - None
5125888 - None
5125889 - HK, HL
 

·
Basic Vendor- Skid Plates
2007 chevy trailblazer_ls
Joined
·
3,700 Posts
So, has anybody actually done this, and measured the difference compared to how they are calculated?

I have the grey tag, and am looking at going to the dark blue tag (15125887) to get ~1" - 1.25" in front, and want to get some idea that it's going to be close to that before I order the springs...

Thanks,
Mike
 

·
Registered
2006
Joined
·
4,126 Posts
I could really use another 1/2 to 1 inch in the front for clearance. I had heard it was hard to find the springs for sale even if you did find some you thought you wanted.
 

·
Basic Vendor- Skid Plates
2007 chevy trailblazer_ls
Joined
·
3,700 Posts
Mike, I'll be doing it in a few weeks... until then the only people that have done it have upgraded to junkyard EXT springs.

You may also want to post in the thread on ORTB.
It will be after that, for me... Just would like to do it sometime this summer...

I had completely forgotten that there was a copy of this post/spreadsheet on ORTB...

Thanks,
Mike
 

·
Registered
2005 chevy trailblazer_lt
Joined
·
2,636 Posts
Discussion Starter · #18 ·
I could really use another 1/2 to 1 inch in the front for clearance. I had heard it was hard to find the springs for sale even if you did find some you thought you wanted.
Pop the part numbers into the GM parts websites, they're there!
 

·
Registered
2006
Joined
·
4,126 Posts
Est. price??? I guess it was rock auto that only had a couple of the parts.

I ned to figure out which ones I have and step up.
 

·
Basic Vendor- Skid Plates
2007 chevy trailblazer_ls
Joined
·
3,700 Posts
Est. price??? I guess it was rock auto that only had a couple of the parts.

I ned to figure out which ones I have and step up.

www.gmpartsdirect.com and enter the part number you want from the graph above... Put that GM part number into the search on the website, and it'll come right up... They're like $43 per spring...

Mike
 
1 - 20 of 76 Posts
Top