Hi, looking to buy some bigger axle forks, my current hubs are 15mm, is it an easy conversion if i want 20mm axles?

yes.

how to video on the Hope site.

yup get the 20mm kit and then just do a service type breakdown and swap the innerds 🙂

http://www.cyclistno1.co.uk/features/maintenance/hope-pro-ii-rear-hub-service.htm

Edit: Front just FYI as you just swap out the adapters 😳

http://www.cyclistno1.co.uk/features/maintenance/hope-pro-ii-front-hub-service.htm

Just done the same conversion myself

The 20mm conversion cups are slightly different to the 15mm ones. Basically pull the old cups out and then offer the new 20mm cups up and hold in place with the steel retainer clips you get with the kit. The video on the hope website is really good if you’re not sure

Surely for the front hub you just pop out the 15mm adapters on both sides and pop in your new 20mm adapters? No breakdown/service required (if I understand correctly). Coincidentally, someone has just put some adapters in the classifieds (not me btw!)

No not for the front (sorry wasn’t clear of me) – but thought the link maybe useful if the OP wants to do a bearing change at the same time 🙂 😳

As above the only difference is the with the “steel retainer clips” on the 20mm adapters 🙂