Complete Guide to Vehicle Modification Laws in Tennessee
Tennessee gives enthusiasts a fair amount of room to customize their vehicles, but several categories carry hard numerical limits that are easy to run afoul of if you don't know them. The figures in this guide were verified against primary statute text (September 2026), so you can use it as a reliable starting point before you start wrenching. Below is a category-by-category breakdown of what's allowed, what's restricted, and what's outright banned in Tennessee.
Lift Kits
Status: Conditional
Tennessee regulates ride height changes closely. For passenger vehicles that have been altered in altitude, the state caps bumper height at 22 in above the ground, measured to any point on a load-bearing member of the horizontal bumper bar. Four-wheel-drive recreational vehicles get more room, with an allowed range of 14-31 in.
On top of the bumper-height rule, Tennessee's "squat" law prohibits a front fender sitting 4 or more inches higher than the rear fender, and lift blocks are prohibited on the front suspension entirely. Penalties for squat violations escalate on repeat offenses within a 12-month period: a Class B misdemeanor with fines of $250 / $500 / $500, with the third offense also triggering a 12-month license revocation.
Cited under Tenn. Code § 55-9-215, with the squat rule codified via 2024 Pub. Ch. 541 (Tenn. Code tit. 55, ch. 8, pt. 2). See the full lift kit laws page for details.
Headlight & Taillight Tint
Status: Illegal
Smoked or tinted film on headlights and taillights is not allowed in Tennessee. Headlights are required to emit white light and taillights must show red, and any film that dims or discolors those colors violates the requirement. No tinting, coloring, or covering is permitted on headlights or taillights if it impairs their visibility or effectiveness.
This falls under Tenn. Code §§ 55-9-402, 55-9-406. Full details are on the headlight tint laws page.
Underglow
Status: Conditional
Underglow lighting is legal in Tennessee, including while driving, but it comes with color and flashing restrictions: no red or blue visible from the front, and no flashing toward the front. Red lights visible from the front are prohibited, and flashing or oscillating lights aren't permitted except on emergency vehicles.
This is governed by Tenn. Code §§ 55-9-402, 55-9-414. See the underglow laws page for the complete rule set.
License Plate Frames
Status: Conditional
Plate frames are legal in Tennessee as long as they don't obscure any part of the plate — numbers, letters, and state identification must all stay visible, with the exception of a trailer-hitch ball. Tinted plate covers are banned outright, even if they don't actually conceal any information.
This falls under Tenn. Code § 55-4-110. Read more on the license plate frame laws page.
Wheel & Tire Protrusion
Status: Legal
Tennessee has no fender-coverage or protrusion rule for passenger cars, meaning there's no statutory protrusion limit to worry about for wide wheel and tire setups.
Cited under Tenn. Code § 55-9-212. Full info at the wheel protrusion laws page.
Light Bars & LED Lighting
Status: Conditional
Tennessee doesn't require a cover on auxiliary lighting, but it does limit how many can be lit at once: only 2 auxiliary road-lighting lamps may be lit at any one time, in addition to the 2 required headlights. Aiming is also restricted — no spot or auxiliary lamp may be aimed beyond the vehicle's left side or more than 100 ft ahead on approach.
This falls under Tenn. Code § 55-9-402. See the light bar laws page for full specifics.
Window Tint
Status: Conditional
Tennessee sets a uniform tint darkness standard across the vehicle: front side windows require a minimum of 35% VLT, and both rear side windows and the back window also require a minimum of 35% VLT.
Cited under Tenn. Code § 55-9-107. Full breakdown on the window tint laws page.
Aftermarket Exhaust
Status: Conditional
Swapping out your exhaust system is legal in Tennessee, but a muffler in good working order is required, and cutouts or bypasses are prohibited. There's no statutory "no louder than stock" rule in Tennessee law — instead, the standard applied is that the exhaust must not produce excessive or unusual noise. Removing the catalytic converter is prohibited under federal law.
This is covered under Tenn. Code § 55-9-202. Full detail at the aftermarket exhaust laws page.
Exhaust Noise
Status: Conditional
Tennessee is one of the few states with a real statutory decibel number for exhaust noise: sound pressure may not exceed 95 dB on any motor vehicle other than a motorcycle. Testing follows the SAE measurement standard.
Cited under Tenn. Code § 55-9-202. See the exhaust noise laws page for more.
Window Banners
Status: Illegal
Aftermarket windshield banners are not legal in Tennessee. Apart from the manufacturer's standard installed shade band, no material may reduce windshield light transmittance below 70% — which rules out printed banners or aftermarket windshield strips entirely.
This falls under Tenn. Code § 55-9-107(a)(1)(B). Full rule text at the window banner laws page.
Lowering
Status: Conditional
Tennessee prohibits modifying a vehicle so that the body or chassis contacts the ground or the fuel tank becomes exposed. Since July 1, 2024, the state's squat law also bans any stance where the front fender sits 4 or more inches above the rear fender — effectively outlawing rear-only lowering setups. On the flip side, bumper height for altered vehicles is capped at 22 in, a limit that mainly constrains lifting rather than lowering.
Cited under Tenn. Code § 55-9-215, with the squat rule under 2024 Pub. Ch. 541 (Tenn. Code tit. 55, ch. 8, pt. 2). Full details on the lowering laws page.
Every modification above links to its full law page with exact limits, statute citations, and exceptions — or browse every Tennessee mod law in one place, free.
This guide is for informational purposes only. Data is AI-extracted from public statutes and may contain errors. Always verify with local authorities.