Trouser seat misfit

[Herrick Postman]

Hello,
Hoping someone here may be able to give me some insight and advice on the cause/remedy for this  ill fitting trousers seat.
This pair of trousers (not my work) belong to my kilt making mentor, all of his trousers display this fault to the same or greater degree.
I will be cutting him a pair of trousers in the new year and would like to be armed with the knowledge of how to avoid this misfit in future.

I have been doing some reading on trouser fitting faults and remedies and haven't seen anything that looks quite like this, my best guess at this point would be to let out the underside at fork in some way. Any thoughts or advice would be much appreciated.
Thanks

[Henry Hall]

I'll offer two possible causes: too much length at the top of inside leg (maybe not); or the entire cut of the trousers is too 'open' (as if made for standing with a wide stance). Try standing with legs further apart and see if the problem 'disappears'.

[Kiem]

The last picture makes me think that the seat angle needs to be straightened.

I assume the problem is less when the back part is pulled up, or when the hip is pushed (rotated) backwards?

The creases in the last picture suggest the trouser is cut for backward tilted hip, and the wearer is forward hip.

[peterle]

Three people, three opinions.

My first try would be to scoop out the seat seam a lot more (just by basting it first). I think the seat seam is not curved deep enough, the seat is blocked and can´t move upwards where it belongs to  and therefore the fabric bunches up left and right of the seam. (when you look close you can see the center back is pulled downwards a bit). the upper end of the folds indicate where you have to start the scooping.  I also think  the curved area of the seat seam should get a good stretch with the iron before sewing. This should help to create a smoother line derictly below the butt.

[Kiem]

I might need to add that I'm just a hobbyist, so I'd take others advice over my own.
I do like to look into this because it can also help me learn to understand fitting issues better. So I hope you don't mind me learning along side of you 


Could you add some pictures of the pattern? I think that might be helpful.

I found these pictures that used to be on the cutter and tailors forum, unfortunately the forum seems offline again?!?
Thes pictures are of horrible quality because I have no acces to the originals, but they do show the problem you present in the pictures so I hope they will be somewhat helpful. Maybe someone has the original scans of these?







The last picture is from King Wilsons: The Art of cutting and fitting. I think the entire book might be posted here on the forum.

[Hendrick]

I agree with Peterle; the back seat seam lacks depth down from the hip height. But I also think that the seat is too straight and when you simply make the back "fork" bigger, the trouser will lack hip circumference...

[Henry Hall]

It clearly doesn't lack hip circumference. However the seat seam has a fault and I think it is in the lower part where it runs into the fork, as evidenced by where it is gathering. It would be best to see a draft.

[posaune]

well another opinion tthrown in
I too agree with peterle. The back pants is pulled down at CB. Means not enough crotch length. I think about 2 cm. It maybe length and width what is lacking. The pants rear can not come up.
I would pin out part of the access at the rear in a horizontal tuck we assume at right leg. Start at side seam and put some of the access between two fingers at crotch . Then you open the back crotch till up to waist band and you pull the right leg into the left leg.  You pin the horizontal dart close (over the crotch seam). The left leg crotch is longer - secure this length under the waistband with a pin.  Now you pin the legs together  following the right leg crotch seam from the crotch point up to the waist band.  The right leg crotch is wider. You copy the form of the right crotchseam with thread to the left side. Look that you have a nice form. You unpin the whole back and pin the pants again together. And then you baste following your basting thread of the left side.  Let the customer try the pants on. If you are on the right track you can cut the crotch seam out. I f it is still not enough do it again.
There might be a higher hip too.
lg
posaune