285/35 R21 doesn't belong to the most popular dimensions for allround tyres - there are 0 tyre models available, which can be compared to
155/60 R15,
170/60 R17,
160/60 R14. Let's break down the sizing - 35 is height of the tyre, which is calculated as 35% of the tyre width (285mm), which means the sidewall height has 99.75 mm. The wheel diameter is R21, which means it fits to a 21 inch/533.4mm diameter wheel. The total circumference of the tyre is 2302.47 mm, which is very similar to 235/75 R15
(2304.36 mm), 275/55 R17
(2306.87 mm), 205/80 R16
(2307.19 mm), 235/70 R16
(2310.33 mm), 275/45 R19
(2293.68 mm), 225/55 R19
(2293.68 mm), 295/30 R22
(2311.58 mm).
