February 6, 2026

Ridetech Tech Tools: Spring Rate & Shock Length Basics

Table of Contents

Why these tools matter
Step 1: Get the right weight
Step 2: Spring rate without guessing
Step 3: Shock length & travel
Classic mistakes to avoid
Shop Ridetech + suspension parts
Tools & safety notes

Use Ridetech’s Tech Tools Like a Pro

Picking springs and shocks by “forum vibes” is how perfectly good cars end up riding like a shopping cart. The good news: Ridetech has a set of free Tech Tools that make the big decisions way less mysterious:

Vehicle weight database (so you start with real numbers)
Spring rate calculator (so you don’t accidentally build a pogo stick)
Shock length dimension charts (so you don’t top-out or bottom-out your new shocks)

This post walks you through using them in a clean order, with the classic mistakes called out along the way.

Quick shopping links (WSP)

Why these tools matter (the 3-number handshake)

Springs and shocks are a team sport. If you change one without respecting the others, you can end up with a car that:

sits at the wrong ride height even though you bought “the right drop”
runs out of travel and smacks bumpstops on normal roads
feels floaty, harsh, or just plain weird
needs a second purchase to fix the first purchase (the most expensive mod)

The Tech Tools keep you honest on three things that matter more than brand stickers and bench racing: vehicle weight, spring rate, and shock length/travel.

Step 1: Get the right weight (before you touch a calculator)

Start with real-world vehicle weight. Ridetech’s vehicle weight database is a great baseline if you’re early in a build or you don’t have access to scales yet.

Best option: corner-weight scales (each wheel on its own scale).

Load the car like you drive it (driver weight matters, as does fuel).
Include typical cargo if it’s always there (spare, tools, audio gear, etc.).
Record front-left, front-right, rear-left, rear-right.

Good option: total weight + reasonable split.

Use a known total weight (truck scale) and a realistic front/rear split.
It’s not perfect, but it’s better than guessing spring rate off a meme.

Pro tip: what you really want for the spring calculator is sprung weight (what the spring “holds up”), not the full corner weight including unsprung stuff (tires, brakes, part of the control arms, etc.). If you’re not sure, use the database to get close, then refine later.

Step 2: Spring rate without guessing

Ridetech’s Spring Rate Calculator is designed to get you to an approximate spring rate using measurements you can actually take in your garage. The two big reasons people get spring rate wrong:

They use the wrong weight (curb weight, or “my buddy said it’s 3,600 lbs”).
They ignore geometry (motion ratio and spring angle).

2A) Choose the correct calculator mode

Front / independent rear: common for many front suspensions and IRS setups.
Rear solid axle: different geometry assumptions.

2B) Gather the measurements it asks for

The calculator walks you through inputs like sprung weight, motion ratio, and coil spring angle. Here’s what that means in plain English:

Sprung weight: the portion of the vehicle supported by the springs at that corner. (If you have true corner weights, you can get closer; if you don’t, the database helps you start.)
Motion ratio: how much the spring/shock moves compared to wheel movement. This is why “same spring rate” can feel wildly different on two cars. The calculator has you measure two distances (often shown as A and B) to compute it.
Spring angle: a coilover that leans over loses effective rate at the wheel. An angle finder makes this painless.

2C) Use the output as a starting point, not gospel

The calculator’s suggested rate is a first pass based on the accuracy of your inputs. If you later change wheel/tire weight, add a big-block, relocate the battery, or bolt in a roll cage that could stop a meteor, revisit the numbers.

If you want the easiest path: a complete Ridetech kit is often engineered as a system so you’re not mixing-and-matching your way into extra homework. For example:

Step 3: Shock length & travel (the “don’t break stuff” step)

This is the one that bites people the hardest. A shock that’s too short can bottom out. Too long can top out. Either way, the car rides poorly and parts get stressed.

3A) Measure the suspension travel the right way

Ridetech’s shock measurement guide breaks this down by mounting style (eye/eye, eye/stud, etc.). The basic idea is simple:

Full bump (compressed): cycle the suspension to where the bumpstop is engaged as it would be in real life.
Full droop (extended): cycle to max droop (limited by suspension design, straps, brake lines, driveshaft angles, etc.).
Ride height target: where you actually want the car to sit in the middle of that range.

If you’re doing this on an assembled suspension, take your time and be cautious. If you’re building from scratch, many builders do this with the spring removed so the suspension can cycle freely. Either way, the goal is the same: capture real compressed and extended length requirements.

3B) Use Ridetech’s dimension charts to pick the right shock

Once you know the compressed and extended lengths you need for your setup, jump into the charts:

Coil-Over Shock Dimension Charts (includes compressed/extended and “50% / 60%” ride height reference)
Smooth Body Shock Dimension Charts (same idea for smooth body shocks)
ShockWave Dimension Charts (for ShockWave air-spring/shock combos)

The charts are handy because they don’t just list “travel.” They also show a ride-height window (often called out around the 50%–60% range), which helps you avoid a setup that sits too close to full compression or too close to full extension.

3C) Quick sanity check

If your “ride height” measurement is almost the same as the chart’s compressed length, you’re living on the bumpstops.
If your “ride height” is nearly max extended, you’ll top out over crests and dips.
Make sure bump travel exists before the bumpstop. “Low” is not the same as “works.”

Classic mistakes (and how to dodge them)

Mistake: Using curb weight from an internet argument. Fix: verify with scales or the Ridetech weight database, then refine with corner weights.
Mistake: Picking spring rate based on “it’s a street car.” Fix: use sprung weight + motion ratio + angle so the wheel rate makes sense.
Mistake: Assuming a “2-inch drop” equals a “2-inch shorter shock.” Fix: measure bump/droop travel and select shock length from the charts.
Mistake: Shopping shocks by travel only. Fix: match compressed/extended lengths and make sure ride height lands in the chart’s window.
Mistake: Forgetting real-world limits (brake lines, driveshaft, fender clearance). Fix: check those while cycling the suspension.
Mistake: Building the suspension first and measuring later. Fix: measure early, then buy once.

Ridetech Tech Tools (official links)

Tools you’ll want (and safety gear you should not skip)

Tools

Floor jack (quality) + jack stands rated for the vehicle
Wheel chocks
Tape measure (or calipers for tighter packaging)
Angle finder / digital inclinometer (for coilover angle)
Notebook or notes app (write numbers down, don’t trust “I’ll remember”)
Basic hand tools (sockets, wrenches), plus torque wrench for reassembly
If disassembling coilovers: proper spring compressor and the experience to use it safely

Safety notes (seriously)

Work on level ground, use wheel chocks, and support the vehicle with jack stands before going underneath.
Coil springs store a lot of energy. If you’re removing springs, use the right tools and don’t improvise.
Wear eye protection and gloves when working around suspension components.
After suspension changes, get a professional alignment and do a careful test drive in a safe area.
Modifications may affect warranty coverage and handling behavior. Know your limits and drive responsibly.

Wrap-up

If you take nothing else from this: measure first. Ridetech’s tools make it easy to pick spring rates and shock lengths that actually match your car, your geometry, and your ride height goals. That’s how you get “rides better than stock” without buying parts twice.

Your turn: what’s the most “optimistic” spring or shock choice you’ve ever made (or seen)? Tell us your best (or worst) suspension math story in the comments below.