strange subframe interference

[baileyman]

Since I am getting ready to punch some holes in my TTR chassis to match the TTR shell bobbins, I have been doing a lot of sitting, looking, and thinking, just in case a reason shows up to locate them some other way than I have.

And a weirdness showed up.

I have been wondering why I get rubbing between the Fiberglas and steel around the front fork of the frame. Looking at the torsion box area, there seems to be a good 1/2" clearance all the way around. Why is the front then rubbing? Isn't there also a 1/2" clearance? And I was wondering why the middle bobbin on the floor was marking forward of the end of the torsion box. Shouldn't it be next to the end of the straight section?

Well, apparently not.

The central torsion box has fork sections front and rear. The length of the box is 25" to the bends of the front and rear forks. The same measurement on the shell indicates 26". ?!? Thus the flare of the shell surrounding the fork of the frame is pushed forward by an inch, reducing the clearance between the shell and the fork.

All this construction sure looks standard, so now I wonder why it is this way. It is as if the front of the floor is pushed forward an inch. Perhaps this made for needed footbox room. For a guy like me, who is Colin Chapman sized, I can see a couple benefits to pulling it back. I have no trouble with leg length and foot size for one, and two, another inch in the engine compartment could be useful, and three, perhaps noise and heat would pass to the inside less with a bit more clearance and an opportunity to insulate the area.

Does this situation seem familiar?

John