I done this particular crushing for a while but stoped it after a bad combining of pack and wrap with it. The main difficulty is having the ideal spacing between the posts.
I was in a social parody group for people who like trampling or been trampled by others or people like me trample and get trampled. This group catered for the full range of people; those who stood on heads, chest, stomachs, limbs, or a combination.
With my endless desire to have my belly compressed and lack of people to do it I set up my own squashing systems. This one used a closet doorway and a car tyre. I made a video which I posted on the club website. Someone there saw it and decided it was lengthy and edited it. Some very important things were no longer said on the video, which could have got people hurt if they tried.
So I am writing this as a warning guide. It also explains what is happening.
The first thing to mention is I use sitting down to create the crush. The lower I go the crush becomes parabolic in intensity (a property of sideways rotating tyre in). Also when a person sits down their belly expands. So as I sit results in my belly wanting to expand as the tyre is exponentially driven in at an increasing rate. The squash does feel more intense because the tyre is going faster as well as stopping a natural expanding occurring at the same time.
I have taken some stills (photos) while I was doing this video. Some will not match the video content because of the editing of the video.
There are two photos of looking down the rib cage from the top; photo called lighter shows the tyre when it was on the original squeeze before I intensified it. The photo called deepest squeeze show the tire in another 2 inches.
The video show at the start my set up; the gap between the post, the gap left between me and the other post, the gap left by the tyre between the posts, plus last of all me sitting in the gap and the tyre beside me which showed how deep, how much displacement of the belly occurs when I am in the crush about to come. This is quite important to notice that as later when I remove the tyre while sitting down I had got the comment of how much stomach started to appear. This is an indication of the high parabolic rate of displacement while the belly was trying to expand during sitting.
Watch the crush again as the compressing everything in the abdomen while the belly trying to expand because of the sitting. The displacement is exponential as the tyre levels out. This is a white-hot compression of the stomach.
Now there is already a piece missing out of the video. A person cannot displace that much belly first time without some failed attempts. Front to back the displacement is 12 inches. On my first attempts the tire was pumped to 12 PSI. When I sat down the tyre sidewalls compressed as well as me. As I sat in the crush the intestines adjusted and the tyre pressed in deeper allowing the sidewalls flattened. I released and resat 4 times before the tyre was not severely collapsing because the load was too much.
To explain what 12-PSI means (pounds per square inch) it states every square inch has the pressing of 12 pounds. The tyre is 4 inches wide with 10 inches long contact area. That is equivalent to using 160 lbs to press the stomach.
I increased to 25 lbs per square inch, which is the same as using 1000 lbs (453 Kilograms), in limited depth crush (the gaps between post set the depth), pressing down for a more rapid displacement. At 12 lbs the tyre sidewalls gave with low resistance and at 25 lbs the tyre digs in deep more quickly. The tyre sidewalls still bulges under the workload but it has more resistance not to.
I have several goes at this pressure and when I could sit 2 minutes without being to uncomfortable I pump the tyre up to 35 PSI. Yes with the force of 1400 lb (634 kilograms), sitting down still squashes the sidewalls slightly but increases the tyre speed of being driven in. The video took days to do as I was working towards an immense crush. I sat in the 1400 lb compression for 4 hours a day. I took a risk and pumped the tyre up 50 PSI (2000 lbs) on the last days. Over pressurising tyre cause tyre rupture and it is not as harmless as popping a balloon.
Putting the tyre in at that pressure does a more instant crush. You feel every thing crushing to minimal size instantly. This was white-hot but not immense. I wanted to do a deliberate immense crushing of which I had unintentional done in the past. Westmere Lake tree branch where I passed out; for 11 hours staying in a extreme crush, white-hot immense compression. The trick is not to introduce it slowly as I would abort long before immense level but just go there lighting fast.
Using the same doorframe (note there is no door to cause complication of spacing) I place a 4 by 2 against the frame, which reduce the gap by 2 inches. The picture deepest squeeze shows looking down the ribs the tyre is 2 inches deeper in me. 40 square inches by 2 inches equals 80 cubic inches more displacement. Someone will say I have got the math wrong. Feel free to explain in the comments.
This was white-hot; I lasted seconds on the first go, lowered the tyre pressure and tried again and again.
When I hit the 2-minute mark I went back up to 35 PSI and stayed in that for thirty minutes. I noticed the tyre was not fully flattening in the sidewalls so I went to 50 PSI. At that pressure it took 15 minutes for the tyre overpowered the resistance my belly was involuntary tensing. This was eye rolling crush, white-hot, immense crush sensations. I started wish I gassed up the intestinal system to feel the vibrations again. I didn't miss the smell.
In the missing (edited out) video it showed I had brought a television into the room to watch during the hours of sitting. I did 6 hours in all at this set up as I knew this was a one off. There was a couple of times when I thought I was going to throw up but the sensation rolled into another one. There were times I had quivers.
The next day at work I had massive aches when I stretched.
I took some photos of side on during the numerous squashes. You can see the penetration but also the draw back of using the tyre.
The tyre presses the centre in the deepest but has less pushed in as one moves to the outer edge. This shaped the skin and if one is flat tummy at the start would actually stretch the skin. I was going from convex to concave so I had the amount of skin.
I changed by using pack and wrap with the tyre to drive it in. The doorway was too narrow for this and the uprights in the shed were to wide to get very intense or immense pressure on. The Volks Wagon Beetle (16 inch rim) wheel fitted the gap well but tyre was narrow not covering the belly area well. It drove in the section above the hipbone (my sweep spot) very well but as always 30 minutes in I wanted more of the belly compressed/displaced. I tried packing the gap between the uprights but that got fiddley so I gave up in the end.
Oh how I would like to experience the Lake Westmere crushing again and again.