Rear Hub Center Bore? Hubcentric Wheel Spacers.
 

Now I'm about to order 1.5" spacers for the rear of my 4WD Blazer and before I purchase anything, I need to know for sure.. What is the Hub Bore of the rear hubs?

I know not to buy flat spacers.. Not to buy lugcentric spacers, etc.. I understand the risk that wheel spacers bring to a vehicle if not installed properly or if the wrong spacers are installed or are improperly torqued.

Trust me when I say that I am a mechanic and have done my research, have the proper facilities and tools to install them properly. I just want to make sure I purchase the correct ones.

The one's I'm looking to buy are hubcentric and have the lip on the outside as well.

They're 5x4.75 to 5x4.75 and 1.5" thick.

Spacers on eBay

My research has told me that I have a 70.5mm hub bore on the rear but before I go spending any kind of money, I want to make absolutely certain that my research is correct and that these spacers fill fit my rear hubs nicely.

I know wheel spacers have been discussed to death here but I haven't seen any mention of the rear hub bore before. That is the purpose of this thread.

Please only helpful input and thanks in advance.

Dan

Wheel Bolt Pattern Cross Reference Database and Conversion Guide: 5 X 4.75

This should help ya out.

Im sorry I dont have an answer to your question as I am totally unknowing on this myself..But I need to get 1.5 in spacers also to make my irocs in the rear fit. Are these the same spacers on ebay that I should also be looking to get?

I actually did buy these spacers that I linked to in the first post. They fit perfectly on my hubs but my factory wheels sit VERY tight on the spacers outer lip. If you're using aftermarket wheels then these should be fine. Just be sure to torque all of your lug nuts to factory spec which for my blazer is 100ft lbs. I'm sure yours should be the same. I also recommend blue loctite on the factory lug studs. This'll keep the lugs holding the spacer to the hub from losing torque and still be removable when you need to remove the spacers.

Even with the loctite, I still recommend removing the wheels and rechecking the torque on the lugs holding the spacer to the hub every few months just to be safe.

100 ft lb? Its 12mm for cryin out loud.

Your lug nuts are actually 19mm and GM's factory torque specification is 100ft lbs.

Says so in the owners manual.

+1. 100ft/lbs is the correct torque for the GM aluminium rims.

The lug nuts may be 19 mm but is the stud thread, 19 mm ? Three quarter inch? What hinda Blazer do you have anyway?
I just made some 2 1/8 adapters for my camaro wheels. The blazer was 5 on 4 3/4 and the camaro was 5 on 120 (bout thirty thou smaller). The blazer has 12 mm lugs and camaro has 14 mm lugs . If the OP wants the cad files I can email em If you need the thread pitch of the lugs just holla. I have torqued the blazer to 65/70 and the camaro to 80/85. One hundred twenty pounds about right for a 19mm LUG. POI sae nuts are measured by thread size, witworth nuts are measured by wrench size.

I'm not saying you're wrong. I know our factory lug stud thread is 12x1.5.

The torque on factory lug nuts on factory studs as published by General Motors is 100ftllbs.

I just bought ready made spacers and simply applied GM'S factory specifications to my blazer. You can torque your lugs however you like. No skin off my back if one of your wheels falls off due to over or under torquing your lugs.

Btw since you asked.. I own a 2000 Chevy Blazer LT 4WD. One of the cleanest most well maintained you'll find in my town.

Boy gotta suck hind tit on this one. Went to the book and found 95 lbs. Just went out put some more on them and found none looser than 65 and the 14mm were at 85. Now 12mm@ 95# and 14@ 100#. Right is bigger than ego!