We were going to write a different article
The plan was to cover "what changed on the 2019 Silverado." We checked before we wrote, and the answer turned out to be: nothing. The Silverado and Sierra 1500 have been 6x139.7 with a 78.1 mm hub bore continuously since 1999. Five sources, no dissent, no transition year, nothing hidden.
| Platform | Years | Pattern | Bore |
|---|---|---|---|
| GMT800 | 1999-2006 | 6x139.7 | 78.1 mm |
| GMT900 | 2007-2013 | 6x139.7 | 78.1 mm |
| K2XX | 2014-2018 | 6x139.7 | 78.1 mm |
| T1XX | 2019+ | 6x139.7 | 78.1 mm |
Twenty-five years, one pattern, one bore. After the Ram situation, where two trucks with the same badge and the same year take different wheels, the GM half-ton is a relief.
So this article is about the traps that are real on a GM truck, and there are three of them.
Trap one: "1500" does not always mean six lugs
From 2001 to 2007, GM sold a truck called the Silverado 1500HD and Sierra 1500HD. It carries 1500 on the badge. It is 8x165.1 - an eight-lug truck - because mechanically it is a 2500 chassis in 1500HD clothing.
An owner of one of these searches "Silverado 1500 wheels," finds a page full of 6x139.7 results, and has no reason at all to suspect the page is talking about a different truck. There is nothing in the name to warn them.
The 2007 model year makes it worse, because 2007 is a split year: the old body continued as the "Classic" alongside the new GMT900, and the 1500HD Classic is in that carry-over group. If your truck is a 2007, establish which body you have before anything else.
The reported hub bore for the 1500HD is 116.7 mm and we could not verify it, so treat that figure as unconfirmed.
Trap two: two eight-lug patterns that look identical
The 2500HD and 3500HD were 8x165.1 for many years, and in 2011 they changed to 8x180. This is a hard cutover, not a gradual rollout: 2010 is one pattern, 2011 is the other.
| Truck | Years | Pattern |
|---|---|---|
| 2500HD / 3500HD | through 2010 | 8x165.1 (8 x 6.5 inch) |
| 2500HD / 3500HD | 2011+ | 8x180 |
The problem is the gap. 165.1 and 180 are 14.9 mm apart on a circle roughly seven inches across. Held up side by side they look the same, and they photograph the same, which is how used wheels get listed under the wrong application and bought in good faith.
They are not interchangeable and there is no adapter we would put on a three-quarter-ton truck to make them so. If you are buying used eight-lug wheels for a GM, the model year is the whole conversation. Hub bore and thread pitch on the 8x180 trucks we could not verify, so we are not printing them.
Trap three: same pattern is not same fitment
This is the one that catches people who did their homework.
A GMT800 wheel bolts to a T1XX hub. Same circle, same bore, it will sit flat and centre properly. That does not mean it fits. Between 1999 and now, GM changed the brake package, the wheel well shape, the suspension geometry and the offset range. A 2001 wheel on a 2022 truck can foul a caliper, sit wrong in the arch, or put the tire somewhere the fender does not cover.
Bolt pattern continuity is not fitment continuity. The pattern tells you the studs line up. Everything else is a separate question.
Factory offsets
The overall factory band is +24 to +31, and that band is corroborated independently. The individual per-wheel figures below come from a single database source each, so use the band with confidence and treat the specific numbers as a starting point:
| Platform | Wheel | Offset | Tire |
|---|---|---|---|
| GMT800 (1999-2002) | 7Jx16 | ET31 | 235/75R16 to 265/75R16 |
| K2XX (2016) | 8Jx17 | ET24 | 255/70R17, 265/70R17 |
| K2XX | 8.5Jx18 | ET24 | 265/65R18 |
| K2XX | 9Jx20 | ET27 | 275/55R20 |
| K2XX | 9Jx22 | ET24 | 285/45R22 |
| T1XX (2021) | 8Jx17 | ET24 | 255/70R17, 265/70R17 |
| T1XX | 8.5Jx18 | ET26 | 265/65R18 |
| T1XX | 9Jx20 | ET28 | 275/60R20 |
| T1XX | 9Jx22 | ET28 | 275/50R22 |
Notice the drift: the early 16-inch steel wheel is around ET31, and the modern 17 to 22 inch wheels sit at ET24 to ET28. That is a real change of roughly five to seven millimetres across the generations, which matters not because five millimetres is a lot but because a single "Silverado offset" figure quoted with no generation attached is meaningless. If a listing gives one number for 1999 to 2024, it has not looked.
The number that should worry you
Factory GM runs +24 to +31. Aftermarket GM truck wheels commonly run -12 to +18.
That is a 30 to 50 mm move outboard per side on a typical purchase, and at the aggressive end it is more. It is the largest routine geometry change made to a vehicle that nobody thinks of as a modification.
What it buys is clearance for a bigger tire and a wider stance. What it costs:
- Scrub radius, which grows close to one for one with the shift. Every force at the contact patch - braking, a pothole, one tire on ice - acts on the steering through that arm. Double the arm, double the torque your hands and your steering components resist. This is what "it tramlines now" and "it kicks back over ruts" actually are.
- Wheel bearing life. The load line from the contact patch is supposed to pass between the bearing races. Moving the wheel outboard converts part of a radial load into a bending moment the bearing was never sized for. A hub that would have lasted the truck's life stops doing that.
- Coverage. BC requires the fender or flare to cover the tread. Poke that clears the fender does not clear the regulation.
We fit aggressive wheels regularly and we are not talking anyone out of them. We would just rather you chose the number deliberately.
A modern GM-specific clearance issue
On the current trucks the fitment question people run into is not the bolt pattern - it is brake caliper clearance, particularly on levelled trucks running wheels that are not much bigger than stock. The caliper boss on the back face of the wheel is the contact point, and the fix is usually a thin spacer in the 6 mm to 3/8 inch range purely to clear it.
We would rather fit a wheel that clears on its own than solve it with hardware, so if you tell us what you are looking at we will check the back-face clearance before anything is ordered.
Tire sizes by setup
| Setup | Typical wheel | Tire |
|---|---|---|
| Stock | 17x9 +1, or 20x9 +0 to +20 | 285/75R18 or 295/70R18 without mods |
| 2 inch level | 17x9 +1, 20x9 0 | 33 inch generally needs the level |
| 2 to 3 inch lift | 17x9 -12, or 20x10 -19 | 33 to 35 inch |
| 4 to 6 inch lift | 22x12 -44 | 35 inch |
Single-source, and worth reading alongside the offset section above. Several of those setups are 40 mm or more outboard of factory.
Torque
We could not source a GM lug torque figure to a manufacturer-hosted document, so we are not printing one. Door jamb placard, owner's manual, and re-torque at 100 kilometres. That last one is free on anything we fit and it is the single cheapest thing you can do to keep wheels attached.
Wheels we can get
6x139.7 is the most heavily served truck pattern there is, which is good news and also means there is a lot of junk in the market. What we stock or order regularly:
- Black Rhino - the widest range of widths and offsets in 6x139.7, which is exactly what you want when you are trying to make a controlled offset change rather than the biggest one available.
- Fast HD - load-rated, sensible offsets, built for trucks that work.
- Level 8 - clean and well priced, strong in the 17 and 18 inch sizes where the winter sets live.
- Dirty Life - the lifted look, mostly aggressive offsets.
- RTX - practical, plain, good winter-set value.
Two we fit regularly. Between them they make the point this whole article is about:
Fast HD Recon, on the left, is the half-ton answer: 18x9 and 20x9 in 6x139.7. Worth noting that those two sizes carry different offsets - +10 on the 18, +25 on the 20. Same wheel, same pattern, and they will not sit the same way under the truck. Do not assume the 20 behaves like the 18 because the name matches.
Black Rhino Armory, on the right, is shown in its eight-lug form - and this is the one worth stopping on. Black Rhino sells the Armory in 6x135/6x139.7, in 8x165.1, in 8x170 and in 8x180. One model name, four different hubs, and in a photograph they are close to indistinguishable.
That is not a criticism of the wheel. It is the mechanism behind every wrongly listed used set on the market. Somebody who owns an 8x180 Armory and lists it as "Black Rhino Armory, came off a GM" is not lying to you. The name is right, the picture is right, and the wheel still will not go on a 2010.
For the eight-lug trucks, tell us the year first. That is not us being difficult - it decides which of two near-identical patterns you need.
The short version
- Silverado and Sierra 1500 has been 6x139.7 / 78.1 since 1999. Nothing changed in 2019.
- The 2001-2007 1500HD is an eight-lug truck despite the badge.
- The HD trucks changed 8x165.1 to 8x180 for 2011, and the two look identical.
- Same pattern for 25 years does not mean the same wheel fits. Brakes, arches and offsets all moved.
- The real modern issue is caliper clearance, not pattern.
All specifications above are North American market only.
Confirm the fitment with us before you order. Give us the year, model and trim and tell us what tire you want to end up on, and we will tell you what has to happen to the truck to get there.
About SHC Auto
We have been fitting wheels and tires in Victoria since 1991, out of the same shop at 474 Bay Street. Alongside wheels and tires we do suspension and lift work, window tint, paint protection film, vinyl wraps, ceramic coating, paint correction and detailing, caliper painting, chrome delete, and vehicle graphics and signage. We also do the things most shops send out: curb rash repair and wheel refinishing, TPMS sensor supply and fitting, tint removal, and re-torque after install.
The catalogue on our website is a fraction of what we can actually order. We are an authorized dealer for more than three hundred aftermarket brands, and a good number of them never made it onto the site because there is no data feed for them. That includes most of the lift and levelling kit market. If you cannot find something, ask us rather than assuming we cannot get it.
SHC Autographx and Tires
474 Bay Street, Victoria, BC
Monday to Friday, 9:00 to 5:30. Closed weekends.
Free shipping anywhere on Vancouver Island.
Planning a build? Bring the truck by 474 Bay Street. It is much faster to look at what you have and tell you what it will take than to work it out over email.