Wheels, tyres and fitment, explained
Guides
Clear answers to the questions people ask before they buy wheels, tyres or suspension. Each guide uses worked examples and links to the tools that do the maths.
Wheel basics
Understand the measurements before choosing a wheel.
ET vs backspacing: measure and convert wheel position
Convert offset to backspacing with worked examples, understand the rim flange allowance, and measure a loose wheel without confusing nominal width.
Read the guide · 5 min
How to measure a wheel bolt pattern, including five studs
Measure wheel PCD correctly on four, five, six and eight stud patterns, avoid near-match mistakes, and check the other dimensions before a wheel swap.
Read the guide · 5 min
Hub-centric vs lug-centric wheels: choosing hub rings
Learn what hub rings do, how to specify their inner and outer diameters, and why centring, wheel seats and vibration need separate checks.
Read the guide · 5 min
Wheel offset explained: choosing ET without guessing
Understand positive and negative wheel offset, calculate inner clearance and outer position, and choose an ET using measurements from your own car.
Read the guide · 5 min
Tyres and sizing
Match the tyre, wheel and car without guessing.
Plus-sizing wheels: tyre diameter and speedometer changes
Work through a 17 to 18 inch wheel change, compare tyre diameters and speedometer effects, and understand why a 3% rule cannot approve fitment.
Read the guide · 5 min
Staggered vs square wheels: tyres, rotation and AWD
Compare square and staggered wheel setups, calculate front-to-rear tyre diameter, and understand rotation limits and all-wheel-drive requirements.
Read the guide · 5 min
How to read a tyre size, load index and sidewall markings
Decode tyre width, aspect ratio, rim diameter, load and speed markings, then calculate sidewall height and diameter using a 225/45 R17 example.
Read the guide · 5 min
Tyre stretch explained: appearance, approval and safety
Understand what stretched tyres are, distinguish a taut approved fit from an unapproved rim width, and assess the safety claims without forum folklore.
Read the guide · 5 min
How to choose wheel width for a tyre: use the approved range
Choose a rim width using the exact tyre manufacturer's data, distinguish measuring rims from approved ranges, and check the effect on inner and outer clearance.
Read the guide · 5 min
Clearance and suspension
Plan for steering, suspension travel and real roads.
Rolling vs pulling arches: clearance, paint and rust risks
Compare arch rolling and pulling, identify what is actually rubbing, and plan bodywork without assuming a guaranteed clearance gain or crack-free paint.
Read the guide · 5 min
Brake caliper clearance: checking wheels with a template
Check spoke and barrel clearance for standard or upgraded brakes, print a brake template at the correct scale, and understand what offset cannot prove.
Read the guide · 5 min
Flush, poke and tucked fitment: measure the whole tyre
Understand flush, poked and tucked wheels, calculate how width and offset change the look, and check clearance beyond a parked side-on photograph.
Read the guide · 5 min
How lowering changes wheel fitment, camber and clearance
Plan wheels around lowered suspension, understand camber and toe changes, and check spring-platform, arch and bump-travel clearance in the right order.
Read the guide · 5 min
Wheel spacers: safety checks and how to choose a size
Calculate spacer effects on offset and track width, distinguish slip-on and bolt-on systems, and check hub engagement, fasteners and moving clearance.
Read the guide · 5 min
Lifted truck wheel fitment: backspacing, 33s, 35s and trimming
Plan larger truck tyres around lift-kit requirements, backspacing, steering and articulation. Compare 33 and 35 inch tyres without assuming a lift guarantees clearance.
Read the guide · 5 min
Wheel construction
Compare weight, manufacturing and load ratings.
Wheel load ratings, JWL, VIA and TÜV: what to check
Screen wheel load capacity against axle requirements, understand JWL and VIA markings, and read TÜV-related documents for the exact wheel and application.
Read the guide · 5 min
Forged vs flow-formed vs cast wheels: what you are buying
Compare wheel manufacturing methods without the marketing shortcuts. Understand strength, stiffness, weight, testing and how to compare exact part numbers.
Read the guide · 5 min
Wheel weight and unsprung mass: what lighter wheels change
Separate unsprung mass from rotational inertia, compare complete wheel-and-tyre weights, and assess lighter wheels without invented horsepower equivalents.
Read the guide · 5 min
Build planning and style
Choose a direction, price the whole job and check the details.
How to preview car mods before you buy them
Avoid expensive regrets: how to see wheels, colours, wraps and stance on your own car before spending, and how to check the parts will actually fit.
Read the guide · 4 min
How to plan a car build on a budget without buying parts twice
Build a realistic modification budget around maintenance, tyres, fitting, alignment and insurance, with a worked £3,000 plan and a sensible order of work.
Read the guide · 5 min
UK car insurance: declaring wheels, wraps and other modifications
Prepare a clear modification list for your UK insurer, check acceptance and replacement cover separately, and understand why undeclared-change outcomes vary.
Read the guide · 5 min
How to choose wheels that suit your car's style
Compare JDM, Euro, OEM+, stance, track, overland and VIP wheel styles using proportion, finish and practical requirements rather than copying a parts list.
Read the guide · 5 min
Troubleshooting
Know what to check when a wheel change does not feel right.