Longmont's Trusted Auto Shop

Hey Longmont — Need Your Car to Run Right? We're Right Here on 1st Ave, and We've Got You Covered.

From a quick tire rotation to a full alignment, Diagonal Tire & Alignment is your neighborhood garage for honest, no-drama auto repair. Stop by or give us a call — we'll get you back on the road safely.

Call (303) 772-7280 See Our Services
Trusted Local Shop
On-Time Service
Friendly & Honest
Mechanic working on a vehicle at Diagonal Tire & Alignment in Longmont, Colorado
Close-up of professional tire installation service
815 1st Ave
Longmont, CO 80501
What We Do

Auto Services We Offer

Whether it's a flat tire, a squeaky brake, or an overdue oil change — we handle it all with care and transparency.

Tire Sales & Installation

New tires, rotations, balances, and repairs. We carry a wide range of brands to fit your vehicle and budget.

Wheel Alignment

Precision alignment to improve handling, extend tire life, and keep your car tracking straight on Boulder County roads.

Brake Service

Pad replacements, rotor resurfacing, and brake fluid flushes. Because stopping is just as important as going.

Oil Changes

Quick, thorough oil changes using quality synthetic and conventional oils to keep your engine running clean.

General Auto Repair

Check engine light? Strange noise? We diagnose and fix the real problem — not just the symptom.

Suspension & Steering

Shocks, struts, and steering components. Ride smoother and regain control on the road.

Interior of Diagonal Tire & Alignment auto repair shop in Longmont
Auto technician performing vehicle inspection at our Longmont shop
Local Longmont Auto Care
About Us

More Than a Garage — We're Your Neighbors

Diagonal Tire & Alignment has been serving Longmont and the surrounding area right here on 1st Avenue. We know these roads — from the daily commute through town to the mountain passes on the weekend — and we know the kind of wear and tear they put on your vehicle.

When you pull into our lot, you're not just another ticket number. We'll look at your car, explain what's going on, and give you an honest assessment — not a upsell. That's the way we've always done it, and it's why so many families keep coming back.

No appointment needed for many services
Clear explanations, no confusing jargon
Competitive pricing with no hidden fees
All makes and models welcome
Why Choose Us

What Makes Diagonal Tire Different

We built this business on a simple idea: treat every customer the way you'd want to be treated.

01

We Listen First

Tell us what you're experiencing — the noise, the vibration, the warning light. We'll figure out what's really going on before we touch a wrench.

02

No Surprises on the Bill

We explain the work needed, give you a clear estimate, and never add things you didn't approve. The price we quote is the price you pay.

03

Quality Parts, Fair Prices

We source reliable parts and don't cut corners. You'll get solid work that holds up — not a quick fix that fails in a month.

04

Right Here in Town

Located at 815 1st Ave in Longmont, we're easy to find and easy to reach. Just drive by when it's convenient for you.

Your Car Deserves a Team That Cares

Don't settle for a shop that treats you like a number. Come see the Longmont mechanic who remembers your name — and your car.

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Get in Touch

Come See Us or Give Us a Ring

We're located right in the heart of Longmont. Stop by during business hours or call ahead — we're always happy to help.

Address

815 1st Ave
Longmont, CO 80501

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