anyone recommend a shop with a good range and sensible prices ?

I am interested in this as well, been to AutoBoy near the Ambassador Hotel in Najomtien but the choice was quite limited

There are plenty, most of which are located along Sukhumvit Road. Try somewhere like Siri-Anan who have quite alot of choice and sometimes do deals on certain brands. See map with locations of the ones i know of: https://www.google.co.th/maps/ms?msid=203220213817008928024.0004e092f0ab945349b90&msa=0

I go to Maxxis up towards Naklua on Sukhumvit heading North. It's about 2-3 kilometres past Bangkok Hospital Pattaya. There's a big Maxxis bill board on top of the building so it's hard to miss!

They do thing to Western standard there. They use good mechanical tyre changers so alloy rims are less likely to be damaged.

They have a good selection of alloy rims and tyres to choose from.

If you drive on Sukhumvit from Soi Boonkanjana to Naklua, you'll see about fifty outlets. If you drive the extra 12 klm's or so to Laem Chabang, you'll see another fifty.

They're nearly as common as 7/11's and ATM's.

Got mine changed a few weeks ago at a place between BOY Air and the Toyota Garage heading into Pattaya along Sukhumvit (forget name but there is a car wash attached to it). Exchanged my tyres+alloys for good price and they have a large selection of alloys / tyres, all in all very happy......but....

...A word to the wise. Perhaps it was just another 'coincidence' or perhaps it was me being naive (probably the latter!). I had agreed price for alloys - OK, then came the choice of tyres - Thai, Japan, China etc etc. Wanted a decent tyre but nothing too expensive. Long story short, agreed on a brand of tyre + total price for everything, my tyres were then taken off the car and a few minutes after this was done, yep, you guessed it, "Mister, sorry but we have only 2 tyres left for this type.". Of course after looking at the next brand up (a little more expensive) they only had 3 in stock. Surprisingly my patience was realtively OK as deep down inside I had wanted the more expensive tyres that I eventually got but again ensure they have EVERYTHING in stock there and then and insist in physically seeeing them before they proceed to take off your own tyres!

Rich