Chain of events

[fossie]

Just change the sprocket to 530 and use chain.

[sparki]

you need at least a 17 530 on the front otherwise it'll rub on the swingarm due to it being physically smaller in size... 17 is kinda normal to use with a 530. rear wise... depends on how you want it geared. some use a smaller 42 for less fuel when touring.... i have a 45 on the back of mine and that is more than fine going around the country imo... faster off the line maybe a 48 but tbh i have no issues with my 45 rear 530. mounting holes on the 750 and 1100 wheels are the same. if you go 17 on the front and 42 on the back it'll rev less on the motorway but really depends when you want the power.

[Pedda]

Gearing calculations are easy. No higher mathematics, just basic arithmetics.
To find closest gear ratio for a 630 to 530 conversion, start from stock ratio.
630 pitch: 42 / 15 = 2.8
Now you start from your 17 T front sprocket.
530 pitch: 17 * 2.8 = 47.6

You can't have a 47.6 teeth rear sprocket, obviously; so you either take 47 or 48, doesn't matter really.

[Pop-Kat]

If you want to swap cogs around your better off going 18-48, that will give you similar to 17-45 then you can try 17-48 easily and wheelbase will only alter slightly as it's just one tooth off the front sprocket.. But if you fit 17-45 then want to go 17-48 you'll probably need a longer chain, so you'll never try it.

Front sprockets are cheaper than rears too