noun, adverb
flushness; tsuraichi
Automotive term for the condition where a wheel face is flush with the fender, a key concept in stance and fitment culture. Also used as an adverb to describe something being flush or level.
このホイールはツライチでかっこいい。
These wheels are flush with the fenders and look cool.
ツライチに調整するにはスペーサーが必要だ。
You need spacers to adjust it to be flush.
フラッシュ is a general loanword for 'flush' in various contexts, while ツライチ is a specific automotive term for wheel-to-fender flushness.
Compound of 面 (つら, 'face, surface') and 一 (いち, 'one'), literally 'surfaces become one'. The exact derivation is uncertain, but it likely originated in automotive customization circles to describe a perfectly flush fit.