Hello all.

I was at the tire shop, looking at the Baja MTZs. I told the tire guy that I am thinking of going from my stock 265/75/16 to 305/70/16.
He advised against it, saying I will have to have the speedo recalibrated and I will loose the ABS feature.

So whats the real scoop on these 2 issues? Are they really a big deal?

Are there any other issues I sould know about? MPG change dramatic?

Thanks in advance for the help.

 

He doesn't have a clue. They are stock diameter on my truck, just a wider 33". They will fit with no issues beyond maybe a little sway bar rub at full lock.

 

you will probably lose some mileage due to width of tire. That may be the standard answer on most vehicles, but most tire shops have no clue when it comes to the Hummer. Most of them will not sell you anything other than the stock size tire.

 

You are going from a 31" to a 33" from the 265's to the 305's which will cause your speedometer to be slightly off. That can be corrected with a PCM tune. Do a search. As far as loosing your ABS that will not happen. Just don't mix your sizes. Good Luck

 

I just put the Baja MTZ's 305's on mine about a month ago. You won't lose ABS but you will lose some MPG's (about 2-3mpg). I'm not sure about the speedo....I had Pep Boys order them (paid 260 each, free shipping to the store).

 

Thanks everyone for your feedback! I thought he was full of sh$t, but needed confirmation.

LostSoul, I just ordered my MTZ 305s at PepBoys too.
Did you have them level your H3 and do an alignment too?
I wonder if PepBoys does their alignment off of stock Hummer standards or do they look at actual geometry.

 

I wouldn't let my local Pepboys wipe my butt.

I get my alignments from a local Firestone store. I have the lifetime alignment deal from them. Very good service.
They printout the before and after settings with graphics that make it very easy to understand. My truck is leveled and has additional beefed up front end parts, it's nowhere near stock and they have no problems with aligning it using the actual geometry.

Like RKSmith noted above,DO NOT mix sizes. That means that your spare tire MUST be the same diameter as the road tires or you WILL cause damage to your drivetrain.

 

I might..... just sayin.

 

You will love the MTZ. Very quiet on the road and very aggressive look especially when leveled. You will feel the extra weight of the tires when accelerating, steering, and braking (took a minute to judge when to come to a complete stop, give yourself a little more time and space to come to a stop). Also if you go thru drive-thru car washes...those days will be over, especially if its the type which pushes the vehicle thru...
Also expect some rubbing when making sharp turns (mine rubs when making a sharp right turn, when making a U-turn for example) but as Tainter and Doc said in my tire thread, the rubbing isn't much to worry about...

I had them do the alignment but the mechanic was afraid to adjust the torsions so I did it myself prior to getting the tires and alignment done. I don't quite agree with the alignment results as they claim they could not get the camber to 0.00 degrees. I have unlimited alignments with them for 5 more months and planning to take it back to have them re-align. I'll see if I can find the alignment sheet and will post it later.

 

Not sure what the car wash comment is about? We have 315/75R16s on 1 and 37x12.5R16s on the other and go through the car wash several times per week.