Interpret legacy numeric and alphanumeric tire sizes and comparison charts

The short answer: what a 7.35-14 size means

A 7.35-14 tire uses the old numeric sizing system from the bias-ply era. The first number, 7.35, is the nominal section width in inches. Section width is the distance across the tire from sidewall to sidewall. The second number, 14, is the wheel (rim) diameter in inches. The code does not state the aspect ratio, which is how tall the sidewall is compared with the width. Under a widely used rule of thumb, numeric sizes whose width ends in 5, such as 7.35 or 6.95, are roughly 80-series. That means the sidewall is about 80 percent as tall as the tire is wide.

Conversion charts commonly put 7.35-14 in the same row as the letter-series size E78-14, with radial and metric sizes in neighboring columns. A chart row only groups nominally similar sizes. It does not say that every tire in the row has the same diameter, width or load capacity, and it does not approve any of them for a particular vehicle. To convert a 7.35-14 in practice, read its row, then compare the published specifications of the actual tires you are considering.

Decoding the size families you will see on a chart

Legacy comparison charts mix several notation systems in one table. Each system encodes different information, so you need to know what each code says and what it leaves out.

Notation family	Example	What each part means	What it does not tell you
Numeric (bias-ply era)	7.35-14	7.35 = nominal section width in inches; 14 = rim diameter in inches	Aspect ratio, load rating, overall diameter
Numeric, whole-number style	8.25	8.25 = section width of 8¼ inches	Same gaps as above
Alphanumeric (letter series)	BR78-13	B = load rating; R = radial construction; 78 = aspect ratio; 13 = rim diameter in inches	Section width and overall diameter
Modern metric	e.g. a 195/75R14-style code	Section width in millimeters / aspect ratio / construction / rim diameter in inches	Load and speed rating unless the service description is also listed

The alphanumeric system is easy to misread. In a code like E78-14 or BR78-13, the letter groups the tire by load rating and is not a measurement. The number after it is the aspect ratio, and the final number is the rim size. A letter-series code alone cannot tell you how wide or how tall the tire is.

Aspect ratio and the 90-series / 80-series rule of thumb

Aspect ratio is section height expressed as a percentage of section width. A 78-series tire has a sidewall about 78 percent as tall as the tire is wide. A 60-series tire has a noticeably shorter sidewall for its width.

Numeric sizes never printed an aspect ratio, so charts infer it from the era and the width figure. Coker Tire, a specialist in collector-car tires, uses this pattern. Widths ending in zero, such as 6.70-15, are approximately 90-series, an earlier and taller profile. Widths ending in five, such as 6.95-14 or 7.35-14, are approximately 80-series. Tire Rack's conversion guidance also describes early numeric sizes as roughly 90-series and later ones as roughly 80-series. Treat these as approximations for reading a chart, not as measured dimensions.

Estimating 7.35-14 dimensions from the code (illustrative)

You can turn the nominal fields into a rough size estimate. The calculation below is an illustration built only from the code and the 80-series rule of thumb. It is not a published specification for any tire.

Illustrative estimate for 7.35-14 (assumed ~80-series)

Section width (nominal)   = 7.35 in
Section height            = 7.35 x 0.80        = 5.88 in
Overall diameter          = 14 + (2 x 5.88)    = 25.76 in  (about 25.8 in)

This is a nominal estimate, not a measured or published dimension.

Real tires can land well away from an estimate like this. Running the same math on a 6.95-14 gives 6.95 x 0.80 = 5.56 inches of section height and an overall diameter of about 25.1 inches. Tire Rack's generic chart entry for 6.95-14 lists a 25.3-inch diameter. Coker's specification for its US Royal Dual Redline 695-14, a named product in that same size, lists a 26.6-inch overall diameter, a 7-inch section width, and a maximum load of 1,230 lb at 32 psi. Coker also notes that mounted dimensions vary with rim width and inflation pressure. That is a 1.3-inch spread in diameter between a generic chart figure and one real tire carrying the same size code.

Reading a conversion chart row without overreading it

Tire Rack's chart shows why one row should not be treated as a set of interchangeable tires. Three letter-series sizes sharing the G load letter and the 15-inch rim list the same load but different dimensions:

Size	Aspect-ratio column	Load at 32 psi	Overall diameter	Section width
G78-15	78-series	1,620 lb	28.0 in	8.4 in
G70-15	70-series	1,620 lb	27.5 in	8.6 in
G60-15	60-series	1,620 lb	26.4 in	9.7 in

Subtracting the listed diameters, 28.0 − 26.4 = 1.6 inches between the G78-15 and the G60-15. The shared letter tells you they were grouped by load, and the different aspect ratios tell you their shapes differ. Tire Rack states that appearing together on its chart does not establish complete interchangeability.

Keep the aspect-ratio column heading attached to every size you copy from a chart. A 78-series entry and a 70-series entry in the same row are different shapes.
Read load figures together with the pressure they are quoted at. A load number without its pressure cannot be compared.
Treat a generic chart entry and a named product's specification sheet as separate data. They can differ, as the 6.95-14 example shows.
Record diameter and width differences as plain arithmetic between published figures, and keep that separate from any decision about whether a tire suits your vehicle.

A worksheet for comparing a 7.35-14 with candidate sizes

A simple worksheet keeps chart data, product data and your own calculations from blurring together. Use one line per tire, and fill in only figures you have actually read from a chart or a specification sheet. The sample lines below use the published 6.95-14 figures quoted above. Add your 7.35-14 row and its candidates the same way.

Exact code	Notation family	Nominal fields	Chart or product	Aspect-ratio column	Published diameter	Section width	Load	At pressure	Source
6.95-14	Numeric	6.95 in width, 14 in rim	Generic chart entry	~80-series (inferred)	25.3 in	(as listed)	(as listed)	(as listed)	Tire Rack chart
695-14 (US Royal Dual Redline)	Numeric	6.95 in width, 14 in rim	Named product	~80-series (inferred)	26.6 in	7 in	1,230 lb	32 psi	Coker specification
7.35-14	Numeric	7.35 in width, 14 in rim	(your chart row)	~80-series (inferred)	(from source)	(from source)	(from source)	(from source)	(your source)

Add a separate column for replacement approval and leave it blank until the vehicle manufacturer's information or a tire professional supports filling it in. Matching numbers on the worksheet describe dimensions only. They do not confirm clearance, load suitability or handling on your car.

Next step before choosing a tire

Use the chart only to build a shortlist. For each candidate, get the manufacturer's specification sheet and compare its overall diameter, section width, and load at a stated pressure against what your vehicle calls for, using the door or glovebox placard or the owner's manual. Ask the tire maker or a tire shop whether a specific size and rim width combination is appropriate. Mounted dimensions shift with rim width and inflation, so a size that looks equivalent on paper can still fit differently on your car.