from 3 inches side seam to 2 inches speedo

[Torchwatch]

Classic European swim briefs tend to have 2" sides while a 3" side is preferred in the USA. These were intended for use in club swimming and training by swimmers of all ages and abilities in front of families and spectators, they were accepted as being of decent cut by swimming officials worldwide.
Somewhere between 2" and 1" and suit changes name from a swim brief to a swim bikini. The 1" suits are a bit more daring and less acceptable for the club training/racing circuit, more suited to private pools and the beach.

To reduce a 3" suit to 2" you have to cut away either the waist or the leg elastic. Cutting away the waist elastic creates a low waisted suit (Japanese style), while cutting away the leg elastic produces a high cut suit. It is your choice.

You will need 12mm (!/2") elastic of replacement waist elastic and 6mm (1/4") elastic for leg elastic. The original elastic cannot be reused.
If you are cutting off the waist elastic cut just inside the fabric under the original waist elastic, although this is only 1/2" lower you will lose another 1/2" of fabric when you fold it in the hide the new elastic.
Working out how much fabric to cut off with the leg elastic is more difficult, you may also wish to alter the style of the suit.
You will need an overlocker to sew the new elastic onto the edge of the suit and after folding the elastic in (and returned the waist string into position) a sewing machine to sew the fold closed.

It is a lot of hard work and easier to buy the suit you wanted in the first place or to make a suit from scratch using a paper pattern to a design you like.

[Byron]

Have to agree - a hell of a lot of trouble to maybe ruin what was well made in the first place, and then perhaps not be satisfied with the result.
Btw look out for 5cm - that is the 2" you require and so much on the market is sized metrically.

[Byron]

Not the Olympics and a bit of digital manipulation I think we can say for this well known diver: http://swimmerie.tumblr.com/image/30093827186

[louis]

Well explained Torchwatch, we hereby name you as official taylor of our board.
And yes byron manipulation indeed.

[kumu]

The sides on my turbos look to be about 2 inches, thats another reason I like them so much.

[louis]

Yep even if I do like 3 inches sides I prefer much more 2 inches sides.
I already ordered turbo suits and cant wait to feel them on me , and am sure that I will appreciate them just like you do.

[kumu]

they are real sturdy suits. speedos feel kind of light and you can forget you are wearing them, I always feel the turbo around me and it is a very nice feeling