There are not many bike shops in KHH with English service, but I've had good experience with these:
John's Craft Cyclist's Bike Shop
This is by far the best bike shop in town. Run by Justin Wang; an excellent mechanic and all around nice guy.
Located near downtown Kaohsiung in the Lingya district at #77 Szwei 4th Road
(A few blocks north of the 85F Tuntex Sky Tower building)
(07) 336-0734 / 0931-747-428 open Mon - Sat 1:30 to 9:30p.m.
Giant Bike Shop - Tsoying ( Zuoying)
I'm not a big fan of Giant bike shops as they just have ... well ... Giant bikes. But, the fellows who work here speak English well, know their bikes, and do good work. Plus, it's really close to the Tsoying High Speed Train station and my house.
(Head east out the front entrance of the station, past the 7-11 and Linda's Thai restaurant and turn right at the first big intersection (HuaXia rd) and it's on the right just past the Highway 10 overpass - 769 HuaXia)
(07) 341-6972 open 10a.m. to 10p.m. everyday
The closest bike shop to the main train station is also a Giant store. Exit from the rear (North) of the train station onto Juoru rd and turn right. It's a couple of blocks down Juoru on the lefthand side opposite a big BINGO place.
The only Giant shop in Kaohsiung that has touring bikes for rent is the one just south of the Wufu road / Love river bridge.