Hi there, just posting to inform others looking to change up the tyre size on their 20" suzukas (2020 Allspace R-line) that moving up to 255/45r20 is a bit of a risk. I got a set to replace the fronts (original 255/40r20 Pirelli Scorpions - lasted 30k on the front) and whilst it looked like it had about 3-5mm of clearence from the lower spring collar, they actually just touch under load. A short drive showed some wear marks on the upper-inner sidewall of the new Continental Premium contact 6's. I ended up putting those tyres on the back and opting for 245/45r20 for the front (which looks odd, but fits fine).

There is a 1% difference in front and rear tyre heights.

I originally wanted 45 series rubber as the front lip of the car catches on my driveway and I was hoping the extra cm or so would help with that. Doubt that will be the case though now as the back is about 4mm higher at axle, relative to the front.

There are real tyre sizing differences in bulkiness, so make sure you measure yourself before fitting if looking to move up a size.

For the record I wasn't a fan of the Scorpions. I'm hopeful the Conti's work better.