120/70-R14 tires are 0.24 inches (6 mm) larger in diameter than 90/90-R14 tires and the speedometer difference is 1.1%. Viscosities can be related horizontally only Viscosities based on 96 VI single grade oils. ISO are specified at 40°C AGMA are specified at 40°C SAE 75w, 80w, 85, 5w, & 10w specified at low temperature. Equivalent viscosities for 100° & 210°F are shown SAE 90 to 250 and 20 to 50 specified at 100°C.. ISO viscosity classification system Many petroleum products are graded according to the ISO Metric - 90/90x10 (90mm wide/90% of that width is the height x 10in wheel. Not sure why they have 10" measurement with a metric measurements) This is equal to roughly 90mm/81mm x10. 3.00x10 = 76.2mm x10. 3.50x10 = 88.9mm x10. 100/90x10 is nearly a 4" tire (3.93 inches) Hope that helps understand the sizing. moosehunter Discussion starter. Sizes are 90/90-21 (hard only), 90/100-21 front. 120/90-18, 140/80-18 rear sizes. New Mousse design. New mousses are being developed for this tyre - they should be available now with different compounds for hard pack, medium and extreme conditions. The slightly bigger mousses (bigger than the older BIB mousse) in medium compound are aimed to 40, 60, 80, 100, 120 L: 40, 70, 90, 130 L: 31, 50, 71, 95, 132, 150 L (XS-XXL) Material (Main Body) 900D polyester ripstop (100% postconsumer recycled) with TPU-film laminate: 900D polyester (recycled) with PFC-free DWR and TPU coating: 900D polyester ripstop (40% recycled) with TPU weather-resistant coating: The back is 3.5" x 25.4mm = 89mm, so 90/100 x 18 is as close as you will come. This is a very skinny tyre, trust me. The modern equivalents you have quotes as 90% and 80% aspect ratio tyres, so the crown (centre) of the tyre to the rim is 90% (or 80%) of the width, so 110mm x 0.8 = 88mm, so the rolling diameter is close, but the bike will .

90 100 vs 90 90