Same tire, two rules: the Tennessee-Georgia line at Chattanooga

The Georgia line runs about six miles south of downtown Chattanooga. Cross it in an ordinary afternoon errand and the same four tires, on the same car, driven by the same person, are judged against a different rule. Not a different penalty for the same rule. A different rule, because Tennessee's tire statute contains no tread depth and Georgia's does.

This page sets the two texts side by side, because almost everything written about "tire law" online is a national average of fifty states and is wrong in both of the two that matter here.

The two statutes are nearly the same document, until Georgia's subsection (e)

Tennessee's tire section is Tennessee Code Annotated section 55-9-106, headed "Studded tires". Georgia's is Official Code of Georgia Annotated section 40-8-74, headed "Tires". Their opening subsections cover the same ground in near-identical language: no blocks, studs, flanges, cleats, spikes or other non-rubber protuberances projecting beyond the tread; a seasonal or conditional allowance for traction devices; tire chains of reasonable proportions when conditions might cause a vehicle to skid; farm machinery excepted.

Then Georgia keeps going and Tennessee stops.

Both texts below were read on 2026-09-20 from Justia's published 2025 codes. Justia is a republisher rather than either state's official publisher; Tennessee's official free-access publisher is LexisNexis, whose site renders only as a JavaScript application and would not yield the section text.

What Tennessee's tire section says

T.C.A. 55-9-106 opens at (a): "No person shall use a tire on a vehicle moved on a highway that has on its periphery any block, stud, flange, cleat, or spike or any other protuberances of a material other than rubber that projects beyond the tread of the traction surface of the tire, except as otherwise provided in this section."

Subsection (b) is the exception, and it is a dated one. A vehicle may run a tire "that has imbedded in it wire or other material for improving traction on snow and ice during the period of October 1 through April 15 of each year." The same subsection caps the wire in contact with the road at five percent of the tire's contact area "after the first one thousand (1,000) miles of use or operation", and at twenty percent during those first thousand miles, and bars the whole allowance on a vehicle over nine thousand pounds maximum gross weight unless it is a school bus or an emergency vehicle.

Subsection (c) permits "tire chains of reasonable proportions on any vehicle when required for safety because of snow, ice, or other condition tending to cause a vehicle to skid." Subsection (d) exempts farm machinery whose protuberances will not injure a highway. The section's history line is Acts 1982, ch. 856, section 1.

That is the whole of it. There is no depth, no groove count, no measurement.

Where the absence was checked, and how far the claim goes

Chapter 9 of Title 55 is titled "Equipment - Lighting Regulations" and it is where Tennessee puts its vehicle equipment standards. Enumerated in full on 2026-09-20, Part 1 runs 55-9-101 chapter definitions, -102 emergency parts and accessories, -103 and -104 warning devices, -105 televisions, -106 studded tires, -107 tinted windows and -108 airbags. Part 2 runs -201 horn, -202 mufflers, -203 wipers, -204 and -205 brakes, -206 and -207 truck rearview mirror, -212 mudguards, -213 brake fluid, -215 energy absorption and ride height, -216 steering wheels, -217 new tires required on new trailers, and -218 carbon monoxide detectors. Parts 3, 4 and 6 are motorcycles, lighting and safety belts.

Exactly two of those sections are about tires: 55-9-106 and 55-9-217. Neither states a tread depth.

Be precise about what that supports. It supports the claim that Chapter 9 of Title 55 sets no tread depth, which is what a full enumeration of the chapter can establish. It is not a full-text search of every title of the Tennessee Code, which could not be run, because the official publisher renders as a JavaScript application and the two free republishers refuse automated requests. We are telling you where we looked.

What Georgia adds

O.C.G.A. 40-8-74(e), verbatim: "All tires: (1) Shall have not less than 2/32 inch tread measurable in all major grooves except that school buses and commercial vehicles shall have not less than 4/32 inch tread measurable in all major grooves on the front tires and school buses shall have not less than 4/32 inch tread measurable in all major grooves on the rear tires when there are only two tires on the rear; such measurements shall not be made where tie bars, humps, or fillets are located; (2) Shall be free from any cuts, breaks, or snags on tread and sidewall deep enough to expose body cord; and (3) Shall be free from bumps, bulges, or separations."

Two more subsections are worth knowing if you buy secondhand. Subsection (f): "No motor vehicle shall be operated on a public street or highway with tires that have been marked 'not for highway use,' 'for racing purposes only,' or 'unsafe for highway use.'" Subsection (g) bars retreaded, regrooved or recapped tires on the front wheels of buses.

Read (e)(1) carefully and notice three things a summary loses. The figure is measured in all major grooves, not in the best one. It is a different figure, 4/32, for commercial vehicles and school buses on the front. And the measurement is barred where tie bars, humps or fillets sit, which are exactly the raised features a hurried check tends to land on.

Georgia puts money behind its number

Two decisions are annotated against 40-8-74, and both turn on the 2/32 figure. In Ga. DOT v. Heller, 285 Ga. 262, 674 S.E.2d 914 (2009), a city employee who cleared a taxi "was not shielded from liability by the doctrine of official immunity because: (1) inspection of tires was a minsterial act; (2) the employee did nothing to verify whether the taxi's badly worn tires had the legally required minimum amount of 2/32 inch of tread on the tires under O.C.G.A. 40-8-74(e)(1); and (3) the employee had no 'discretion' to ignore this minimum legal requirement."

A number in a statute is one thing. A number a court has treated as a non-discretionary duty is another. Tennessee has no equivalent, because it has no number.

Studs flip at the line too, and Georgia's own position is contested

Tennessee expressly permits studs from 1 October to 15 April under 55-9-106(b). Georgia is harder to state, and we are going to state both halves rather than pick one.

The annotation printed against O.C.G.A. 40-8-74 reads: "OPINIONS OF THE ATTORNEY GENERAL Studded tire prohibited. - Studded tire is a metal tire within the meaning of O.C.G.A. 40-8-74 and may not be used on vehicles operated in this state. 1968 Op. Att'y Gen. No. 68-487."

But the code's own subsection (c)(2) permits "tires equipped with safety metal spike studs upon any vehicle when required for safety because of snow, ice, or other conditions tending to cause a vehicle to skid", which sits awkwardly against an opinion issued in 1968. Both are on the page. We are not going to tell you a 1968 Attorney General opinion settles it, and we are not going to tell you the code text overrides the opinion either. If studs matter to you on the Georgia side, that is a question for a lawyer, not a tire fitter.

One deflating footnote on how much any of this matters in practice: Chattanooga's normal annual snowfall at Lovell Field is 3.9 inches, across 2.7 days a year with an inch or more. The statutory window is real and it is dated. The demand behind it is small.

Nobody in Hamilton County is going to measure your tread for you

The one vehicle check tied to a Hamilton County registration was the emissions test, and it is gone. TDEC, in its own FAQ published 17 August 2021: "After Jan. 13, 2022, persons registering their vehicles in Hamilton, Rutherford, Sumner, Williamson and Wilson counties will no longer be required to get a vehicle emissions test." The same document sets out the chain: "EPA's approval will be effective Sept. 16, 2021, which is 30 days after publication in the Federal Register. Tennessee law states that the elimination of vehicle emissions testing will be effective Jan. 14, 2022, which is 120 calendar days following EPA's approval."

The federal side is EPA's final rule at 86 FR 45871, published 17 August 2021 and effective 16 September 2021, titled "Air Plan Approval; TN; Removal of Vehicle I/M Program for the Middle Tennessee and Hamilton County Areas". The state side is T.C.A. 68-201-119, whose subsection (b)(1) reads "Notwithstanding subsection (a) or any other law to the contrary, no inspection and maintenance program shall be employed in this state on or after the effective date of this subsection (b)... except in accordance with subsection (c)." Subsection (c) is the Davidson County carve-out. Nashville kept its programme; Hamilton County did not.

And when the test did run, it never touched a tire. The Hamilton County Clerk's own pre-2022 explainer, document BK529 dated 13 February 2020, describes a tailpipe test, a gas cap check and a tampering check for 1975 to 1995 petrol vehicles, an OBD check and "a pressurized gas cap leak check" for 1996 and newer, and a ten-second idle opacity test for 1975 to 2001 diesels. Tailpipe, gas cap, engine computer. No wheels, no brakes, no tires. It cost $9 and it no longer exists.

We did not read a Tennessee Department of Safety page on 2026-09-20, so this page does not tell you what Tennessee does or does not inspect generally. It tells you what those documents say about Hamilton County, and what Chapter 9 contains.

What that means for a Chattanooga driver, practically

Two rules, one car, one afternoon:

• North of the line, there is no measured tread figure in Tennessee's equipment chapter to fall short of, and no scheduled appointment at which anyone looks.
• South of the line, in Catoosa, Walker or Dade County, 2/32 inch in all major grooves is the written standard, with 4/32 on the front of a commercial vehicle, plus the cut, bulge and separation rules in (e)(2) and (e)(3).

We are deliberately silent on one adjacent question. Whether those three Georgia counties sit inside or outside Georgia's emissions programme was not confirmed at a Georgia source on 2026-09-20, so this page does not say. If registration on the Georgia side matters to you, ask Georgia.

What we do about it

We measure. At every visit we take a tread depth on all four tires and read the DOT date code, and we tell you both numbers whether or not you are buying anything. In a market where the state sets no figure and no annual appointment exists, somebody has to, and the honest version is that the person selling you tires should hand you the measurement and let you decide.

We supply the tires we fit, which is why one business answers for both the tire and the work; we do not mount tires bought elsewhere, and we do not sell or fit used tires.

The national tread law page covers the general position, Georgia's tread rule in Atlanta covers the same statute from the other end of the state, and when to replace your tires covers the decision the measurement leads to. Find your tire size tells you what you would be buying and how many tires covers two against four.

Closer to home: what tire repair costs in Chattanooga has the tax and the local shop prices, mobile tire repair in Chattanooga covers the visit itself, steep driveways and tight spaces covers where we can and cannot work, mountain roads covers Lookout and Signal, and our Chattanooga service area covers where we come.

Our price: $145 for the first tire

A mobile puncture repair on one tire is $145, and $50 for each additional tire in the same visit. That is the price, not an estimate and not a starting figure. It covers getting to the car, the wheel off, the tire demounted and inspected from the inside, a plug and patch, remounting, rebalancing, a TPMS reset where the vehicle supports it, and the wheel back on. There is no separate call-out fee.

If the damage turns out not to be repairable, we tell you on the spot. The inspection is charged, because establishing it means travelling to the car, taking the wheel off and the tire off the rim. The repair is not charged, because it was not done.

Questions people ask

• Does Tennessee set a minimum tread depth for a car? Not in Chapter 9 of Title 55, which is where Tennessee puts its vehicle equipment standards. We enumerated the whole chapter on 2026-09-20 and found exactly two tire sections, 55-9-106 and 55-9-217, neither of which states a depth.
• Does Georgia? Yes. O.C.G.A. 40-8-74(e)(1) requires "not less than 2/32 inch tread measurable in all major grooves", with 4/32 inch on the front tires of school buses and commercial vehicles, and the measurement may not be taken where tie bars, humps or fillets are located.
• How far is the Georgia line from downtown Chattanooga? About six miles. Fort Oglethorpe, Ringgold and Rossville are all ordinary errand distance from the city.
• Are studded tires legal here? In Tennessee, yes, between 1 October and 15 April under 55-9-106(b), with contact-area limits of twenty percent for the first 1,000 miles and five percent after that, and not at all on a vehicle over 9,000 lb gross weight unless it is a school bus or emergency vehicle. In Georgia the position is contested: a 1968 Attorney General opinion calls a studded tire a metal tire that "may not be used", while the code's own subsection (c)(2) permits safety metal spike studs when conditions might cause a vehicle to skid. We state both and pick neither.
• Will anything in Hamilton County make me fix a tire? No scheduled check will. The emissions test that was tied to registration ended on 13 January 2022 per TDEC, and while it ran it tested the tailpipe, the gas cap and the engine computer, not the tires.
• Do you fit tires I bought elsewhere? No. We supply the tires we fit, so one business answers for both the tire and the work. We do not sell used tires either.