California's tread limit is 1/32 inch, not 2/32

Almost every piece of American tire advice is built around two thirty-seconds of an inch. That is the depth the Lincoln-head penny test is designed to find: stand the coin head-down in a groove, and if you can see the top of Lincoln's head you are at or below 2/32.

California does not use that number for a passenger car. Its minimum is half of it.

Vehicle Code section 27465(b), read in full at leginfo on 2026-09-20, says a person shall not use a pneumatic tire on a vehicle axle on a highway when the tire has less than:

(1) One thirty-second (1/32) of an inch tread depth in any two adjacent grooves at any location of the tire, except as provided in paragraphs (2) and (3).

So a Los Angeles driver whose tires fail the penny test is not, on that fact alone, breaking California law. We say this plainly because it is the single most common factual error in tire copy written for this state, and because getting it wrong in the other direction is worse: it lets somebody believe a tire is legal when it is not, or sells them four tires on a false premise.

It does not make a 2/32 tire a good tire. It makes the legal line a bad place to plan around. More on that below.

Read the wording, not the headline number

Two details in 27465(b)(1) matter and are usually dropped.

"In any two adjacent grooves." The measurement is not taken across every major groove on the tire. It is two grooves next to each other, at any location around the circumference. One worn shoulder groove on its own is not the violation described here; two adjacent ones are.

"At any location of the tire." There is no averaging. The worst place on the tire is the place that counts, which is why a tire that is fine across the centre and feathered on one shoulder still has to be measured on the shoulder.

Section 27465(c) then tells you where you may not put the gauge:

(c) The measurement of tread depth shall not be made where tie bars, humps, or fillets are located.

The moulded bars you can see sitting in the groove floor are exactly those tie bars. The correct way to check a tire in California is to put the gauge in the groove beside a wear bar, not on top of one. Reading the bar itself gives you a shallower number than the statute asks for.

Where the 2/32 figure really lives in California law

It is in the same section, one paragraph down, and it is not about your car:

(2) Four thirty-second (4/32) of an inch tread depth at all points in all major grooves on a tire on the steering axle of any motor vehicle specified in Section 34500, and two thirty-second (2/32) of an inch tread depth at all points in all major grooves on all other tires on the axles of these vehicles.

Section 34500 is the commercial-vehicle list. So California does use 4/32 on a steer axle and 2/32 elsewhere, for buses, trucks over a weight threshold, and the rest of that list. If somebody half-remembers a Californian 2/32, this is where they got it. It does not reach a RAV4 in Silver Lake.

There is a third figure in the same subdivision, six times the passenger-car minimum, and it is live in Los Angeles County:

(3) Six thirty-second (6/32) of an inch tread depth at all points in all major grooves on snow tires used in lieu of tire traction devices in posted tire traction device control areas.

That is a mountain rule, and Los Angeles County has thirty-one signed Caltrans chain-control points inside it. Chain control and snow tires out of Los Angeles sets out where they are and what the rating letters mean. Note what it does to the arithmetic: the same tire can be legal on Ventura Boulevard at 1/32 and six times short of what the law asks at a gate on Angeles Crest Highway.

Subdivision (a) is the part that binds us

The rest of 27465 is about the driver. Subdivision (a) is about the seller and the fitter, and it is the paragraph that governs what HopTire may do at your kerb:

(a) No dealer or person holding a retail seller's permit shall sell, offer for sale, expose for sale, or install on a vehicle axle for use on a highway, a pneumatic tire when the tire has less than the tread depth specified in subdivision (b). This subdivision does not apply to any person who installs on a vehicle, as part of an emergency service rendered to a disabled vehicle upon a highway, a spare tire with which the disabled vehicle was equipped.

Four verbs: sell, offer for sale, expose for sale, install. The prohibition covers the act of putting the tire on the axle, not only the act of taking money for it. And the single carve-out is narrow and roadside: it covers the disabled vehicle's own spare, fitted during an emergency service on a highway, and nothing else.

What that means in practice for us:

• We will not fit a tire below the statutory depth to your axle. Not one we supply, and not one you already own.
• We do not sell used tires anywhere, and in California a used tire carries this section with it. Why we will not fit used tires is the longer version.
• We do not fit tires bought elsewhere at all; we supply the tires we fit, so one business answers for both the tire and the work.
• If your off-season set comes off a shelf for a seasonal swap, we measure it before it goes on, and we tell you if it is finished. Seasonal tire changeover covers that visit.

Two more California tire rules people get wrong

Recut and regrooved tires. Section 27460.5 makes it unlawful to "knowingly sell or offer or expose for sale any motor vehicle tire except a commercial vehicle tire ... which has been recut or regrooved", and defines that as "an unretreaded or unrecapped tire into which new grooves have been cut or burned". Section 27461 is the other half and bars the driving: no person shall "cause or permit the operation of" and no driver shall knowingly operate a non-commercial vehicle "equipped with one or more recut or regrooved tires". Two separate sections, two separate verbs. Selling is one offence; running them is another.

Airless tires. Section 27470 was added by SB 891 and took effect on 1 January 2024. Subdivision (b) deems a nonpneumatic tire to be a pneumatic tire for the purposes of section 27465, among others. So the 1/32 minimum reaches an airless tire too, however little it looks like the thing the statute was written for.

You can still be cited above 1/32

Because California's number is so low, the tread statute is not the section that catches a genuinely dangerous tire. Section 24002 is:

(a) It is unlawful to operate any vehicle or combination of vehicles which is in an unsafe condition, or which is not safely loaded, and which presents an immediate safety hazard. (b) It is unlawful to operate any vehicle or combination of vehicles which is not equipped as provided in this code.

A tire showing cord, a separated belt, a sidewall bulge or a cracked casing can sit at 3/32 or 5/32 and still be an immediate safety hazard. That is a judgement at the roadside rather than a measurement against a number, and it is the realistic route for the tires that actually fail. If you want the list of what that looks like, bulge in a tire sidewall and bubble in the tread cover the two people see most.

California's own air-quality regulation says something similar in a different register. 17 CCR 95550(c)(14) defines an "Unsafe Tire" as "any tire considered unsafe in accordance with standard industry practices, due to tire tread wear, age, tread irregularity, or damage", with examples including "any tire with exposed ply or cord, sidewall crack, bulge, knot, or ply separation". Note what sits in that list next to tread wear: age. That is the subject of when to replace tires in Los Angeles, and in this state it is the stronger argument of the two.

Nobody is going to measure it for you

California does not inspect tires at registration. The only recurring test in Los Angeles County is the biennial smog check: Health and Safety Code 44011(a) requires a certificate of compliance or noncompliance every two years in a designated area, the DMV's Smog Inspections page lists Los Angeles among the counties where it applies at renewal, and the same page exempts gasoline vehicles less than eight model-years old, 1975-and-older gasoline vehicles, 1997-and-older diesels, diesels over 14,000 lb GVWR, and electric vehicles. Nothing in that test looks at a tire.

So there is no appointment on your calendar at which somebody else tells you your tires are done. The measurement is yours, or ours.

What we do about it

We measure all four tires and the spare at every visit, in the groove beside the wear bar, and tell you the number rather than a verdict. We read the DOT date code while we are there. If the tires are sound we say so and go. If they are not, we supply and fit replacements at the same address on the same visit.

When to replace your tires covers the general decision, repair or replace a tire covers a damaged tire rather than a worn one, find your tire size covers what a replacement would be, how many tires to replace covers two against four, and our Los Angeles service area covers where we come. For the money, what tire repair costs in Los Angeles.

Our price: $145

A mobile puncture repair is $145 for the first tire and $50 for each additional tire in the same visit, with no separate call-out fee. Wheel off, tire demounted and inspected from the inside, plug and patch fitted the way the US Tire Manufacturers Association requires, remount, rebalance, TPMS reset where the vehicle supports it, refit. Repair is subject to on-site inspection. If the damage cannot be repaired safely we tell you on the spot, you pay for the inspection and not for a repair that was not done, and you decide what to do next.

For a fit we need level, paved, legal ground with room to work at one corner of the car. In this city the sign at the kerb usually decides that: see street sweeping and mobile tire service.

Questions people ask

• What is the legal tread depth in California? One thirty-second of an inch in any two adjacent grooves, at any location of the tire, under CVC 27465(b)(1). Higher figures apply to the commercial vehicles listed in Section 34500, and to snow tires used instead of chains in a posted control area.
• Does that mean the penny test is useless here? It is the wrong instrument for the legal question, because it is built around 2/32. It is still a fair warning that a tire is near the end of its useful life. Use a gauge if you want the number the statute uses, and put it in the groove beside a wear bar, because 27465(c) excludes tie bars, humps and fillets from the measurement.
• Is it legal to drive on a tire at 2/32 in California? On a passenger car, the tread rule in 27465(b)(1) is not breached until you are below 1/32. But CVC 24002 separately makes it unlawful to operate a vehicle in an unsafe condition presenting an immediate safety hazard, and that can apply to a tire well above the tread line.
• Can you fit the worn tires I already own? No. We supply the tires we fit. Separately, 27465(a) bars a dealer or retail-seller-permit holder from installing a tire below the statutory depth on a vehicle axle for use on a highway, so a worn tire is not something we can put on your car whoever owns it.
• What about refitting my own spare at the roadside? 27465(a)'s exception covers a person who fits "a spare tire with which the disabled vehicle was equipped" as emergency service to a disabled vehicle on a highway. We are not a roadside service: we book visits to cars parked at a fixed address. Mobile replacement against using the spare explains the difference.
• Does the smog check look at my tires? No. HSC 44011 sets a biennial emissions requirement and the DMV lists Los Angeles County among those where it applies at renewal. Nothing in it measures tread.