In 205/55 R16 91V, 205 is width, 55 is profile, 16 is rim diameter, 91 is load index and V is speed rating. Match the complete approved specification, not only the three large size figures.
How to read a tyre size is easier to understand when you separate the immediate decision from the checks behind it. In 205/55 R16 91V, 205 is width, 55 is profile, 16 is rim diameter, 91 is load index and V is speed rating.
The large size numbers are only part of the decision. Construction, load capability, speed rating, seasonal design, vehicle approval and the way the car is used all influence whether a tyre is a sound match.
Short answer: In 205/55 R16 91V, 205 is width, 55 is profile, 16 is rim diameter, 91 is load index and V is speed rating.
What you need to know
The important detail
Match the complete approved specification, not only the three large size figures.
Check this point against both the fitted tyre and the vehicle handbook before building a shortlist.
What it means in practice
Some vehicles use different front and rear sizes.
Keep comparisons like-for-like; a cheaper product with a different specification is not a direct alternative.
What drivers often miss
XL, run-flat, directional and manufacturer markings can affect suitability.
Ask the retailer to confirm suitability in writing when the marking or vehicle requirement is unclear.
Confirm the vehicle-approved fitment or seek professional advice before ordering.
A sensible check, step by step
-
Copy the entire specification from the tyre and vehicle guidance.
-
Compare products in the same size, load, speed and seasonal category.
-
Confirm fitting, delivery and disposal costs before paying.
Common mistakes to avoid
- Relying on a single quick glance instead of checking the whole tyre and its inner edge.
- Using a generic number or internet tip when the vehicle handbook gives a specific requirement.
- Assuming a tyre is safe because no dashboard warning is showing.
What to do next
Check the complete tyre specification and condition in good light. Write down anything that differs between the four corners of the car. If the tyre may be unsafe, avoid unnecessary driving and arrange an inspection by a competent tyre professional.
Quick questions
Can I rely on a visual check?
No. A visual check is useful for obvious damage, but pressure, tread depth and internal condition may need the correct gauge or a professional inspection.
Should I check only before an MOT?
No. Tyres change between tests. Regular checks and a check before long journeys are a better routine.
What if I am still unsure?
Treat uncertainty about damage, fitment or pressure as a reason to ask a competent tyre professional before continuing a journey.
Find local tyre help Search tyre prices →