Bike tires: choosing the right width and type

The size jungle — ETRTO to the rescue

The same tire can be labeled "700x25C", "25-622", or "28 inches". No wonder it's confusing. The ETRTO (European Tyre and Rim Technical Organisation) system brings order.

ETRTO format: width-internal diameter (in mm)

The number that really matters is the internal diameter (622, 584, 559, 406...). It determines whether the tire fits your rim. A "700C" and a "29 inch" tire have the same internal diameter (622 mm) — it's the same wheel size.

Tire width and rim internal width

The tire must be compatible with your rim's internal width. Too narrow on a wide rim = square profile, poor grip. Too wide on a narrow rim = bulging profile, risk of blow-off.

Recommended compatibility matrix:

Simple rule: tire width should be between 1.4 and 2.4 times the rim internal width. Below 1.4x → too narrow, above 2.4x → too wide.

Also check frame and fork clearance. A tire that fits your rim might still rub against the frame, seatstays, or brake mounts.

TPI — what does it measure?

TPI = Threads Per Inch, the number of threads per inch in the tire casing.

• Low TPI (24-60): more robust casing, more puncture-resistant, heavier, less supple. Ideal for commuting
• High TPI (90-170): finer casing, more supple, better rolling efficiency, lighter, but less cut-resistant. Ideal for competition and performance
• Mid TPI (60-90): good compromise between resistance and efficiency

A Continental GP5000 standard version has 110 TPI. The "S TR" (tubeless ready) version also has 110 TPI but with an additional protection layer. The GP5000 "AS" (All Season) has 110 TPI with a Vectran anti-puncture sublayer.

Compound types

The compound is the rubber used for the tread. It affects grip, durability, and rolling resistance.

Single compound: one rubber across the full width. Compromise between grip and durability. Standard on entry-level tires.

Dual compound: hard rubber in the center (rolling resistance, durability) + soft rubber on the shoulders (cornering grip). Standard on mid-range tires.

Triple compound: three different rubber zones. Best performance but also most expensive. Standard on high-end tires (Schwalbe Addix SpeedGrip, Continental BlackChili).

Puncture protection layers

Manufacturers integrate various anti-puncture technologies:

• Schwalbe Marathon Plus: SmartGuard layer (5 mm recycled rubber). Nearly puncture-proof, but heavy (~700 g in 700x28)
• Continental Gator Hardshell: Duraskin on sidewalls + PolyX Breaker sublayer. Excellent compromise for commuting
• Schwalbe Greenguard: 3 mm natural rubber layer. Standard protection, lighter than SmartGuard
• Vittoria Graphene 2.0: graphene nanotubes in the compound for improved resistance without adding weight

Tubeless also provides protection: preventive sealant (Stans NoTubes, Muc-Off, etc.) automatically seals small holes (up to ~6 mm depending on sealant). It's the best protection against common punctures (thorns, glass) while keeping a light, supple tire.

Road vs gravel vs MTB — which tread?

Recommended pressures by width

These pressures are indicative for a 75 kg rider. Add ~0.2 bar per 5 kg extra, subtract ~0.2 bar per 5 kg less.

Tubeless lets you run 0.3 to 0.5 bar lower than with inner tubes, since there's no risk of pinch flats.

L'Atelier can help you find the ideal tire for your frame, rim, and riding style. Ask your question and get a personalized recommendation.