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I am drilling the piano hinge for my seat installation and am looking for suggestions on how much tension to put on the seat back. It seems the vertical part of my seat is a bit long, as seen in the first picture, requiring me to allow the seat to flex a little to get the piano hinge where it needs to be on the crosstie box. I have already drilled the seat bottom piano hinge and have a decent amount of tension on the seat so that it doesn't flex and sag in to the controls. I have come up with 3 options and am looking for suggestions on how to proceed with the back.

Option 1 - Flex the seat back and drill the piano hinge level with the top of the crosstie box. My concern is that the seat back will not have enough tension and be less comfortable.

Option 2 - Drill out the rivets holding the piano hinge to the seat back, cut the seat back just below the holes, rivet the piano hinge on the now shorter seat back and install.

Option 3 - Turn the piano hinge over as shown in the second picture. I understand the piano hinge cannot be loaded as heavily when placed in this orientation, but it seems the seat bottom will see much more load than the back.

Does anyone have any suggestions? Is the seat more comfortable with a taut seat back, or a slacked seat back?

This is just my two cents so take it for what it's worth, but if I were in your shoes I'd strongly consider option #2. I wouldn't want a lot of additional give in the seat back as it has enough give to be comfortable as it is. Plus you could be adding additional stress to the bottom seat pan area of the back isn't supporting anything.

A quick note to the factory tech support may not be a terrible idea just to see what they say.

Again, just my opinion!

Personally I would go the route of option 2. As Mike said, it's the best course of action and I also would be asking tech support.

My opinion only.

I'm with Mike and Robbie on this one. It's not much extra work( if you use a new hinge half and just cut away the current one rather than drilling out all the rivets). I would cut right below the current rivet line through the hinge half and fit from there, that will leave the seat back a little longer than cutting below the hinge half. That will bring the hinge down about where the plans show it on the cross beam. Also, bowing the seat back will be a fight with the fit when you remove the hinge pin and then try to get it back together.

Thanks for the input guys. I am not concerned about the additional work to cut off the hinge and rivet it back on a little lower. I was mostly curious if anyone has seen it to be more comfortable with the seatback taut vs slacked. I have the lowered seat mod, so the load of the passengers is mostly on the bottom 2 hinges.

That seat back will flex even with no slack, and starting off with too much will not make for a comfortable fit. Since you have your bottom hinges in place, if you can sit on that to be sure it is fully stretched out before re-installing the top hinge might avoid any possible problem of later finding it is too short to easily remove and install.

David A.