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Avalanche Wheels and Tires Advice

murtaugh87

Full Member
Joined
Jan 6, 2019
Messages
11
I am still pretty new to the Avalanche world. I have a 2005 Av LT and for some reason it came with 265/70R16s. The current wheel/tire combo is 245/75R17 steels and they are ready for the dump. I did notice that the current wheels throw off the speedometer a tad. This I do not mind if there is a simple way to adjust the speedometer being thrown off. I think I sort of want my cake and to eat it here but I definitely want to replace the 17s with something bigger than factory, but I still want alot of rubber wall. I do not want to look like I am running low pros on a pick up. I also do not want to have to lift, although, I would be willing to do a leveling kit. I don't want any rubbing or have to do any trimming to fit my wheels. I also do not want to affect ride quality and risk any damage to my vehicle over time by putting to big of wheels on. I guess with all of this said, my question is, what is the best wheel/tire combo I could go with to accomplish my wants? I was thinking about going no bigger than 18 inch wheels and have no idea on tire size to match. If 18 is to much to fit my wants let me know, but first and foremost, I want to maintain that factory sort of smooth ride, and to not risk any damage down the road to my vehicle by putting on rediculous wheels.
 
There is lots of variables to consider with your list of wants. Trick is to check on a sight like www.tirerack.com for the overall diameter of the stock tires. The closer you come to that diameter you will make your speedometer be as accurate as it can be with factory settings. Thing is though the speedometers on GM trucks are not noted for their accuracy when compared to things like a GPS speed readout. That diameter will also give you the least amount of rubbing since that is what the AV was designed to handle.
One advantage to going to 17" or larger rims is you can then consider doing the mod to your brakes so that your 2005 could have the larger brakes of the second gen AVs (2007+ models).
FYI the 2008 Z71 AV came stock with 18" rims, sorry I don't remember the exact tire size right now but the overall diameter is almost stock so it doesn't throw off the speedometer. Attached is a photo of my 2008 AV rims and tires so you can see the effect.
Those owners who choose to get a larger overall diameter or wider tire will heat and bend the plastic wheel well liner or get a lift kit. To correct the speedometer they usually buy a quality tuner that can change the speedometer settings to handle the larger diameter.
 

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Thank you for the great info! You bring up a great point with the factory GM speedometer issues. What size did your 2008 come with? I could always simply get a speed app on my phone for a while until I get used to judging speed. This would save on the cost of a tune. I think I might go with 18 inch wheels and maybe just a little bigger than the stock total diameter to get some side wall on the tires so that they look beefier. What is your opinion on leveling kits? I have been looking at the Rough Country 2 inch kit. It comes with front and rear shocks as well, which my Av needs anyway. This would also ensure I would have more than enough room to fit an 18 in tire package. I don't want to sacrifice that factory avalanche beautiful ride quality though.
 
My Z71 came with the 18" rims and this tire as stock:

https://www.tirerack.com/tires/tires.jsp?tireMake=Bridgestone&tireModel=Dueler+A%2FT+RH-S&partnum=665SR8ATRHSV2&vehicleSearch=true&fromCompare1=yes&autoMake=Chevrolet&autoYear=2008&autoModel=Avalanche%20Z71&autoModClar=

I have read where several members have used leveling kits and they seem happy with them. From what i have read GM may have put the front end low as a way to improve gas mileage by being aerodynamic and not jacked up into the air stream. I accept the fact that the Av is not an economy vehicle so i don't worry about gas mileage yet i don't feel the need to level my AV. I certainly don't want to raise it and make it harder to clear garage doors and parking garage ceilings. If you lower the rear to level then you may create a weird sag when you do tow or carry a heavy load.
As far as shocks many people are happy with Bilstein shocks that come stock with the Z71 and are a better shock then what comes stock  in the LT AV. I believe the model most select is the Bilstein 5100 but read some older threads in the suspension mod section to get more info.
 
      If you want to ever go with the 2nd gen front brake upgrade then 17?s or larger rims are a must.
  OK so rim size is rim size only determines the amount of rim. The larger the rim the less sidewall you have.
Tire diameter determines your total height. Say a 33? tire is 33? on a 17 or 18? rim. You have less sidewall
on the 18? rim. You decide if you want more rim over less sidewall.
  Just my .02

    Pics when you get your setup.
Have you checked here on feedback of leveling kits?
Offroad: Lifts, Suspension & Drivetrain

 
I?m running 2857516s on my 2003. Installed leveling keys to try to get it not to rub, but it still does. Granted they are a mud terrain tire so I do believe they are a tad bit fatter. If you do install the leveling keys just be sure to install shock extenders as well to compensate for the difference. I?ve heard stories of people with leveling keys hitting bumps too hard and having the front shocks literally pull out. Cranking the keys definitely make the ride a lot rougher, sot hat is something to keep in mind.
 
  You say you need shocks. There are quality leveling kits with the proper shocks lengths.
You can also buy shocks to match your lift. No need for extensions.
 
  From what i have read GM may have put the front end low as a way to improve gas mileage by being aerodynamic and not jacked up into the air stream.
[/quote]

The biggest reason for the front down turn on Burb's, Avy's, and pickups. Is towing or when loaded.
So when loaded or towing you are not blinding on coming traffic and using your head lights for a search beacon.
Not sure on the mileage gain.
 
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