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6x5.5 conversion attempt!

25K views 12 replies 8 participants last post by  Rgulia 
#1 ·
-So I wanted to see if it was possible to do a 6x5.5 conversion on the Trailblazer. I've read a lot of post of people wondering if it is possible but no one has attempted it. I am planning on doing the conversion next spring but I needed to know is it even possible so I did a ton of research and this is what I have found.
The front and rear rotors are almost identical to a 99-06 Silverado and 00-06 Tahoe. The rear is a perfect match and the front is 4mm deeper than stock but is ok once you read about the hub. This is a side by side comparison to see for yourself.

Now the front bearing hub was the big question would it fit. I found pictures but no dimensions.

So I needed to get one to test fit it. I went to a junk yard and pulled a hub from a 2000 Silverado.

The front hubs are identical for Silverado's and Tahoe's for 99-06 for the exception some 2003-06 Tahoe's can have a different hub but I'm not sure why. So I test fit the hub on the Trailblazer and the hub opening on the Trailblazer spindle is to small. The Silverado hub almost fits but you need to grind 5/16" off the opening on the spindle. The Silverado hub is 3 7/8" in diameter and the Trailblazer is spindle hub opening is 3 9/16".
Next the bolt holes on the spindle to mount the hub are too small. The Silverado uses slightly larger bolts so they would have to be drilled out slightly bigger. I'm not sure how much more but it is very minimal.

So far not what I was hoping. I tried to connect the ABS plug to the Trailblazer and the plugs don't match so the stock plug would have to be soldered on.
Here are the two side by side and you can see how much larger the Silverado hub is.


I measured the hub from where it contacts the spindle to the face plate that mounts to the wheel and the Trailblazer is 1 7/8" and the Silverado is 1 15/16". The Silverado hub sticks out a little more which is needed due to the rotor being a little deeper than the Trailblazer. It looks like it would fit the brake caliper with no issue but I'm not 100% since I can't bolt the hub and rotor on yet. The Silverado rotor is 4mm deeper that the Trailblazer which is between 1/8 and 3/16" and the hub sticks out 1/16" more that the Trailblazer so the Silverado rotor with be 1/8" deeper that the stock set up.
Ok, I know its a lot of info so far but now this is the rear set up.
So Trailblazer has an 8.0" 10 bolt rear end with the left axle shaft 846mm long and 28 spline. The right side is 798mm long and 28 spline. The only 28 spline made is for the Colorado's and Canyon's but they are several inches to short. I searched for days but could not find anything that fits. Silverado's and Tahoe's have a 30 spline rear axle. So they only option for the rear is to have a machine shop weld up your bolt holes on your rear axle shafts and redrill the 6x5.5 lug pattern. The good news is that the rear rotors from the Silverado are a perfect match and do not need any modification.
So is the 6x5.5 conversion possible. Yes, but you need to do the following:
Have a machine shop drill out your spindle hub opening to 3 7/8" or slightly larger to ensure it fits,
Have a machine shop drill out the bolt hole opening on the spindle to the diameter of the Silverado bolts,
Connect the Trailblazer ABS sensor plug to the Silverado hub,
and have a machine shop weld up the rear axle shafts and redrill the 6x5.5 bolt pattern.
Everything else should bolt up.
I am not attempting this yet because I am not getting my Sierra replica wheels until next spring and I don't have Silverado wheels to put on. But hopefully this encourages someone to try it. On paper it looks like it should work. What do you all think?
 
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#5 ·
I finally got the 22" Sierra wheels but I decided try wheel spacers because of how much work would be involved with the front suspension. I picked up a set of 1.25" wheel spacers and tried the wheels before putting the tires on.



After test fitting the wheels I found that it would not work because the wheels stuck out 1 3/4" past the fender well. I decided to try the 6x5.5 conversion again and see if I could make it work.



I knew that the Silverado and Tahoe hubs would not work so I tried the 2003-05 Chevy Astro hubs. Chevy changed from a 5 bolt to 6 bolt hub in 03 and it might be smaller to fit the trailblazer. I also found that the Chevy Traverse and GMC Acadia front hubs are very similar to the Trailblazer's. The Travers/Acadia is a 6x132 lug pattern, but if it could fit the spindle then it could be redrilled to 6x139.7 lug pattern. The rear I was planning on having the rear axle and rotor redrilled to 6x139.7 and there did not appear to be any clearance issues.
I took measurements of the Trailblazer hub and spindle and then went to the auto parts store and they let me get some measurements from the Astro and Acadia hubs. The Astro hub is the same as the Silverado and there is no way it would fit. The Acadia hub is very close to ours. All of the measurements were within mm of the Trailblazer except for the plate that the studs are mounted. The Trailblazer is 5 3/4" and the Acadia is 6 1/2". The Trailblazer rotor is only 6" in diameter on the inside that mounts to the hub so it would not fit. I looked in to a Silverado or similar rotor to mount but realized that the brake caliper bracket is designed to fit very close to the rotor and the Trailblazer rotor slopes to a 45 degree angle. A brake bracket would not allow the Silverado rotor. I think it would be a little too involved and complicated to try and switch a braking system just for a brake bracket. I checked for any other hubs or solutions and could not find one. To have a 6x5.5 lug pattern and then take in account the width of the stud you would have to have at a minimum 6 1/8" and then more space past that. A 6 1/2" mounting surface would be what you need and the Trailblazer rotors won't allow it. So for now i'm trying to return the wheels and get my money back and probably go with some 22" Trailblazer SS wheels. If anyone has any thoughts, feel free to share.
 
#7 ·
It would only bring them in 1/4" and they would still stick out pretty far. I did find out that the Chevy traverse/GMC Acadia use the same brake Caliper bracket as the Trailblazer SS and EXT models. So if I could get the Traverse/Acadia hub to fit then the rotor and brake bracket would also fit. I took measurements and the spindle is 3 5/8" and the new hub is 3 3/4" so 1/16" would have to be ground off for it to fit. Then the hub and rear axle would have to be re drilled and you would have the 6x5.5 swap. It's not a straight swap, you would have to modify the spindle but it could be done. I'm debating getting the parts and attempting it. I can sell these Sierra wheels so I might be stuck with them for a while.
 
#10 ·
Apparently it is far easier to do a conversion to the 5 lug 4.75 inch bolt pattern, and some of the SS guys have already done it. IDK if it violates TOS to post a link to another forum, so I won’t post a link, but — google it and you will find it.

Apparently you just use S10 front hubs and have your rear axles redrilled and you are set.
 
#12 · (Edited)
Tpms in Tahoe z71 wheels

I am installing 05 tahoe z71 wheels on my trailblazer. Will trailblazer tpms sensors fit in the Tahoe z71 rims? I would like to be able to check the tire pressure on the DIC with the Tahoe rims. Or is it possible to just put oem Tahoe tpms sensors in and get them programmed to my trailblazer? :hijacked
 
#13 ·
Hey Lynch, you have Tahoe wheels and 1.5 adapters? How much do your front tires stick out? I have been considering this and can’t get any good pics. Mine is a daily driver. I’d like bigger, wider tires, but can’t have to much sticking out. Thanks in advance
 
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