Most people get wheel fitment wrong because they focus on wheel size and ignore the number that actually matters: offset.

Here's the quick breakdown:

What offset actually means:

• Higher offset (e.g. +45) = wheel sits further IN toward the suspension

• Lower offset (e.g. +15) = wheel sits further OUT toward the fender

• Zero or negative offset = aggressive poke, needs guards or rolling

Common mistakes I see daily at the shop:

❌ Buying 18x9.5 +35 for an S15 and wondering why it tucks

❌ Going 18x10 +15 on stock guards with no roll = instant rub

❌ Ignoring tyre stretch — a 225 on a 9.5" wide wheel isn't the same as a 265

❌ Copying someone else's spec without checking hub bore and PCD

The formula that actually works:

1. Start with your factory wheel specs (size, offset, PCD, hub bore)

2. Decide flush, poke, or tucked

3. Use offset to dial it in — every 5mm of offset change = ~5mm of wheel position change

4. Match your tyre width to the wheel width for the stretch level you want

5. Check inner guard clearance at full lock — most people forget this

I've been fitting wheels professionally for years and I see the same mistakes on repeat. Built FitmentLab to fix that — real fitment specs from someone who does this every day, not just forum opinions.