In reality, jeans only have a better slide time than leather in their advertising claims.
Yes, I know, we have jeans with a CE AAA rating. They are undoubtedly more protective than motorcycle jeans of yore – things have come a long way. So, why don’t race suits use this material?
The CE testing (a lot better than not having independent tests) does not drop clothing from a meaningful height. But in a real-life crash, we fall from around a metre (or more in a highside) onto the ground. This “impact abrasion” matters: decent quality leather is highly resistant to it, but the currently available non-leather materials are massively damaged by it. So, racers wear leather because, for now, it’s the most protective gear in reality.
In addition, leather won’t melt onto your skin in the heat caused by a long slide, and tight leathers act as a splint. Leather trousers’ ability to act as a splint has been found to preserve life in the event of severe pelvis injuries.
By all means, wear motorcycle jeans – I have some for urban riding – but let’s not kid ourselves that they are in the same protection league as leather.