The NorCal Modification

Blog Post

Want to go off-roading or just change the look of your vehicle? You might increase the size of your wheels. If you’re used to modding your vehicles, you probably know that there are all kinds of adjustments you might need to make when increasing your wheel size, from using lift kits to knowing the formula for plus-sizing. 

One common adjustment you might need to make is the NorCal modification, sometimes known as the NorCal trim. This mod originated in Northern California, where it got its name. It’s something we can do for you, though experienced modders may be able to do it themselves.


What is the NorCal mod used for?

When you increase the wheel size on certain vehicles with square wheel wells, you might notice there’s rubbing near the back of the wheel well that impedes your ability to turn. This issue is most common on GM/Chevy models like the Silverado. The NorCal mod was thought up to solve this problem - and it’s user-friendly enough that experienced hobbyists with the appropriate tools may be able to tackle the mod themselves.


What is the NorCal mod?

At the top, we mentioned that the NorCal mod is also known as the NorCal trim. That’s because the process involves cutting, bending, and hammering the parts of the wheel well and fender that are rubbing against the wheel until you have enough clearance, effectively “trimming” your fender.


What do I need to perform the NorCal mod?

If you’re inexperienced, you’ll need help from the pros - you can visit our tire shop in Edmonton and have us perform the NorCal mod for you. Those who have experience will need:

  • A lift or a jack + jack stands
  • A torque wrench
  • An air body saw or cut off saw
  • A permanent marker (like a Sharpie)
  • A pry bar
  • A file or grinder
  • Black paint
  • A big hammer


With all that in place, you’ll be able to perform the mod. Looking at that list of equipment, you’d be forgiven for thinking it’ll look like a hack job - but when done correctly, the NorCal mod doesn’t change the appearance of your vehicle at all since most of the work is being done inside the wheel well.


How do I perform the NorCal mod?

We’re going to give the briefest description of how the mod works. A few things to keep in mind:

  • Every make and model is different, so you’ll need to adjust accordingly.
  • This description is incredibly brief, and skips over certain details. That’s because we’re assuming you know what you’re doing. If you’ve never done a mod before, or you’re in any way unsure, get us to do the work for you instead.
  • This is a text description. If you’re a visual learner, it’s a good idea to look at some YouTube videos. 

Lift your vehicle, then remove the wheel

Simple enough.

Take out the fender liner

More often than not, you won’t have to remove the whole fender liner - just the part that covers the area where there’s rubbing. You can then tie that part with a line to hold it in place when you work. If you want as few obstructions as possible, just remove the whole thing.

Draw a cut line

This will guide you when you actually start cutting. You’ll usually want to end the cut line just before the bottom rear corner of the fender.

Cut and bend

There’s no great way to describe this part using text, so we highly encourage you to look up a video. Essentially, you’re going to cut the lower part of the fender, pry it back, then make another cut along the inner pinch weld. You’ll take your file or grinder, smooth out all of your cuts, then hammer the metal of the lower part of your fender back in place.

Use black paint to cover any exposed metal

This preserves the look of your vehicle, all while helping you to prevent rust.

Put everything back in place

The fender liner, the wheel, and everything else.


A straightforward, useful mod

If you have the know-how and the tools, the NorCal mod is a simple way to increase the size of your wheels without having to deal with rubbing. And if you don’t have the know-how or tools, don’t worry - we can perform the mod for you.