2019 Sierra- largest tire on stock suspension

[Nosaves]

Just wondering if anyone knows what the largest tire is you could fit on an 18” rim on a 2019 Sierra with stock suspension? Currently it sits on the stock 265 65 r18’s. Wondering if 275 70 r18’s would fit perhaps?

[BradenP]

8 hours ago, Nosaves said:

Just wondering if anyone knows what the largest tire is you could fit on an 18” rim on a 2019 Sierra with stock suspension? Currently it sits on the stock 265 65 r18’s. Wondering if 275 70 r18’s would fit perhaps?

Pretty sure I seen a post where they had 275/65s and they fit. 70 I cant weigh in on. I bought an LT with the 2 inch GM lift and im currently trying to find out what size 20 inch tires I can fit as well, I read someone fit 35x12.5/20s on it with the standard 2 inch factory lift but...I still have no definitive answer before I order my tires

[z1boss]

8 hours ago, Nosaves said:

Just wondering if anyone knows what the largest tire is you could fit on an 18” rim on a 2019 Sierra with stock suspension? Currently it sits on the stock 265 65 r18’s. Wondering if 275 70 r18’s would fit perhaps?

 

20 minutes ago, BradenP said:

Pretty sure I seen a post where they had 275/65s and they fit. 70 I cant weigh in on. I bought an LT with the 2 inch GM lift and im currently trying to find out what size 20 inch tires I can fit as well, I read someone fit 35x12.5/20s on it with the standard 2 inch factory lift but...I still have no definitive answer before I order my tires

 

It all depends on what rim you will be using?  Are you both using stock rims?  Or do you plan to change rims?

[BradenP]

6 minutes ago, z1boss said:

 

 

It all depends on what rim you will be using?  Are you both using stock rims?  Or do you plan to change rims?

stock 20s, with the 2 inch factory lift. Id like to stay stock too. Thanks for the reply

[z1boss]

12 minutes ago, BradenP said:

stock 20s, with the 2 inch factory lift. Id like to stay stock too. Thanks for the reply

So assuming you have a Silverado? Since you said LT...Honestly, your gonna be pushing it pretty close with a 35x12.5. Will it fit? Yes.  Will it rub? Possibly.  Not every tire is true in size and it all depends on what tire you end up getting.  A lot of manufacturers say it's a 35 and it ends up measuring out at 34 or 34.5.  There is an easy fix for the Silverado in the event it does slightly rub.  There is a extra bracket on the back of each front mudflap that can be removed easily and allow you to pull back the mudflap to gain more clearance (I can give you step by step instructions).  I'm running 33.5x12.5 on my stock height Trailboss but I have a 20x9 with 0 mm offset rim.  This offset caused it to rub slightly at full lock and after doing this quick mod, no more rubbing.  Based on my experience and what I see in terms of clearance in my wheel well, I believe you can fit a 35x12.5 in there if you have the stock wheels.  It shouldn't rub but at the very worst all you will need is to do the mudflap mod as I mentioned and you should be fine.  Hope this helps.

[BradenP]

2 minutes ago, z1boss said:

So assuming you have a Silverado? Since you said LT...Honestly, your gonna be pushing it pretty close with a 35x12.5. Will it fit? Yes.  Will it rub? Possibly.  Not every tire is true in size and it all depends on what tire you end up getting.  A lot of manufacturers say it's a 35 and it ends up measuring out at 34 or 34.5.  There is an easy fix for the Silverado in the even it does slightly rub.  There is a extra bracket on the back of each front mudflap that can be removed easily and allow you to pull back the mudflap to gain more clearance (I can give you step by step instructions).  I'm running 33.5x12.5 on my stock height Trailboss but I have a 20x9 with 0 mm offset rim.  This offset caused it to rub slightly at full lock and after doing this quick mod, no more rubbing.  Based on my experience and what I see in terms of clearance in my wheel well, I believe you can fit a 35x12.5 in there if have the stock wheels.  It shouldn't rub but at the very worst all you will need is to do the mudflap mod as I mentioned and you should be fine.  Hope this helps.

Thanks a million! I do a lot of highway driving, so im going with the KO2s which look aggressive but are a little smaller than its true size like you say, even if it rubs, ill do that mod for the mudflaps. Just a little steel brack behind the flap, do you remove it completely? 

[z1boss]

Just now, BradenP said:

Thanks a million! I do a lot of highway driving, so im going with the KO2s which look aggressive but are a little smaller than its true size like you say, even if it rubs, ill do that mod for the mudflaps. Just a little steel brack behind the flap, do you remove it completely? 

 

KO2s run smaller than stated size so that is in your favor.  Below are the instructions.

 

You remove the 3 torque screws on the front side of the mudflap, then remove a 10 mm bolt on the back side.  The mudflap can then be pulled away from the truck body and pushed towards the engine bay.  There will be another torque screw holding the carpet wheel liner to the bracket, remove this and pull the wheel liner up and away as much as you can.  This will give you access to the bracket behind it.  The bracket has 4 bolts that have 13 or 14 mm heads.  Remove those and the bracket comes off.  Then put everything back in reverse order.  The final step is to drill a small hole on the back side of the carpeted wheel liner near where it attaches to the rear front mudflap and insert and zip tie it into that new hole and an existing hole on the body near it to pull the flap back.  Do not drill thru the mudflap, just the carpet.  Repeat for the other side.  I can send you a picture of what mine looks like now with the zip tie if you want but the whole process took me about 30-45 total for both side and I wasnt in a rush

[BradenP]

1 minute ago, z1boss said:

 

KO2s run smaller than stated size so that is in your favor.  Below are the instructions.

 

You remove the 3 torque screws on the front side of the mudflap, then remove a 10 mm bolt on the back side.  The mudflap can then be pulled away from the truck body and pushed towards the engine bay.  There will be another torque screw holding the carpet wheel liner to the bracket, remove this and pull the wheel liner up and away as much as you can.  This will give you access to the bracket behind it.  The bracket has 4 bolts that have 13 or 14 mm heads.  Remove those and the bracket comes off.  Then put everything back in reverse order.  The final step is to drill a small hole on the back side of the carpeted wheel liner near where it attaches to the rear front mudflap and insert and zip tie it into that new hole and an existing hole on the body near it to pull the flap back.  Do not drill thru the mudflap, just the carpet.  Repeat for the other side.  I can send you a picture of what mine looks like now with the zip tie if you want but the whole process took me about 30-45 total for both side and I wasnt in a rush

Pics would be good, the instructions are good, just a little hard to understand, ideally they wont rub but if they do I can fix it with this if you do have some pics. Thanks a bunch!

[z1boss]

Just now, BradenP said:

Pics would be good, the instructions are good, just a little hard to understand, ideally they wont rub but if they do I can fix it with this if you do have some pics. Thanks a bunch!

 

I can snap a pic later today of what mine looks like now as well as the location of the screws to remove and the actual bracket itself.

[BradenP]

1 minute ago, z1boss said:

 

I can snap a pic later today of what mine looks like now as well as the location of the screws to remove and the actual bracket itself.

Awesome, really appreciate it, now i can order my tires !

[Nosaves]

2 hours ago, z1boss said:

 

 

It all depends on what rim you will be using?  Are you both using stock rims?  Or do you plan to change rims?

Stock rims my friend. 

[z1boss]

14 minutes ago, Nosaves said:

Stock rims my friend. 

Then yes 275/70R18 will definitely fit.  Its comes out to 33x10.8 which is identical to the other OEM tire size available as an option on the Sierra if you get the 20s instead of the 18s.  The Sierra wheel well is smaller than the Silverados so you cannot go too much bigger on a stock Sierra (non-AT4).  I'm guessing a 275/75 or a 285/70 may slightly rub at full lock since both are 34s

[z1boss]

7 hours ago, BradenP said:

Awesome, really appreciate it, now i can order my tires !

 

 

First picture is the T-15 screws on the front of the mudflap.

 

 

Second picture is the 10 mm bolt on the back side of the mudflap

[z1boss]

This picture is of the zip tie point.

 

And this is the bracket

[Nosaves]

I think I’ll go with 285 65 18s. I wonder if they will rub? Hmmm....