to change sizes (of bike)

[yuechu]

大家好！

I recently got a new bike, but the first one I got was the wrong size. I had to take it back in to exchange it for a slightly smaller one. How would you say this in Chinese? Would you say "我得(=not sure how to put this verb in the past tense)换（个？）大小."?
(Is 大小 the appropriate word here?)

Thanks!

 

[skating-in-bc]

換尺寸, 換個小一點兒的

 

[Winston97]

you can say: 尺寸换个小点的

 

[hx1997]

换个大小 is fine too to me.

 

[yuechu]

Thanks, Skating-in-bc, Winston97 and hx1997! 😃

How about 换个尺寸? Does that sound ok too? (I think 尺寸 is more formal than 大小, right?)

 

[SuperXW]

How about 换个尺寸? Does that sound ok too? (I think 尺寸 is more formal than 大小, right?)

Ok too.
尺寸 is more formal than 大小, however, 换个... is not formal.
If you want the really formal expression (i.e. in some documents), it could be 需更换尺寸.