POK, so I made a biketard
As an experiment to see how well the Jalie 3138 pattern fitted my DD I cut it
exactly to her measurements.
The short version is, it fitted her like a glove. Only problem is, it fitted her like a surgical glove and she's used to more of a gardening glove fit
DD is 4.5 and at about the 60th percentile for height. Muscular more than skinny, but not one of those kids that you look at and go "Wow, they have muscles". Absolutely no waist, a bit of a tummy but on the whole fairly normal looking, just not skinny.
I cut the chest area to a size 2.5, waist to 4.5, hips to 2.5 (which effectively just removed the waist so it was straight up and down) and the shoulders/neck, thighs/crotch to a size 4 as that was exactly her girth measurement.
The resulting pattern was so much smaller than her existing size six leotard that I wasn't sure if she was going to be able to out it on, but hers does currently bunch up in various places. Her existing leotard is also quite triangular in shape, widest at the shoulders which is a completely different shape to the Jalie pattern.
As this was an experiment and I wasn't convinced it's was going to actually go on her at all as it seemed way to short in the body (someone did mention this above), I decided not to overlock the seams. I figured I could do it later if it turned out really well, but also, the lycra didn't actually look like it was going to fray, so I was a bit curious. After all, the worst that will happen at this point is a torn seam in training. (So maybe I also couldn't be bothered getting out the overlocker.)
After being pleased that I could actually remember how to thread my machine and then discovering that the bobbin winder wasn't working I sewed the seams in pink and white. I'm considering the little white dots that are showing through because I forgot to adjust the tension a decorative feature, OK?
After sewing all of the seams, she tried it on and declared it very comfortable.
I did the binding as described in the pattern, I didn't watch the video and obviously didn't read closely enough because I couldn't find anything explicitly stating what the binding seam allowance was, so I used 1/4" because it seemed about right, but when I actually sewed it there was barely enough width so I kind of just fudged it. I also only did a token effort to trim the seams before binding. I wasn't sure how important the extra layers were going to be in contributing to the stretch or lack thereof at the neck and armholes. I used a small zigzag across the join.
After the bindings were finished, it fitted really well, with no growing room and no chance of her being able to get it on or off by herself
Before the bindings, the arm holes were stretched quite low on her. After the bindings there was really only just enough room to get it on her. It did need an extra bit in the length. I think although the girth measurement was exactly right, they don't factor in a tummy.
It was stretched enough that it wasn't touching the small of her back.
After letting DS 2.5 try it on and declared it too big for him (it was a bit long, but fitted surprisingly well actually) I chopped off the legs and turned it into a singlet. It's tight, but just about a perfect fit.
I'm a bit undecided whether to just make the next one the same shape but an entire size or even two larger larger, or to add length as well. She certainly needs more wriggle room to be able to go to the bathroom by herself.