Tag Archives: Las Vegas mass shooting

Take cover, I have been thinking again

Yeah, Ha Ha, I have been thinking again, about stuff. Lots of stuff, but mostly about camber control and lots of wheel travel on the TGS2, or rather the TGS2.1. The TGS2 has a straight tube front suspension with too much brake for the tire, The TGS2.1 has IFS with VW uprights and disc brakes and suspension geometry inspired by Trophy Trucks.

Starting from the beginning I went back to first principles and my weight and balance for the car and divided up the car into two halves. Then I figured out what tire to use on a car that weighed twice as much as either half. The back half was easy, I was looking at a car that was slightly under a ton with 240 HP, similar to a modified early Miata. The current hot tire for the Miata is the 245/40-15 size from a number of different manufacturers. It fits a 15 X 8″ wheel that is very easy to track down. The front is another kettle of fish completely as there are not many hot street cars weighing in around a thousand pounds or a little less running a 15″ diameter rim. There were two divergent characteristics of the cars I found that fit the model for the front half of the TGS2.1. Either they were very stiffly sprung with basically no suspension travel and wide tires, or they were very softly sprung with several inches of travel and skinny tires. Ideally I would run something as sticky as the 245/40 but 122 mm wide, but that is a non-existent tire size. Also ideally I would run something very close to the 22.7″ diameter of the 245/40, so looking for 22.5 to 23″ finds me the 195/50-15 at exactly 22.7″ diameter and available in compounds running from 100 UTQG wear to 540. The 245/40 are available in UTQG wear ratings of 100-300, so a compatible grip level is attainable.

The design inspiration I mentioned, Trophy Trucks, are off-road racing vehicles with more than 20″ of travel at the front end. As part of the design the front suspension has both pivots on a single lower frame rail for both sides of the car. There is a single frame rail in the center of the car with the lower A-arm inner pivots on either side, and a triangular bulkhead running up from that, that carries the upper A-arm inner pivots. The purpose of such long suspension arms is camber control over the long travel of the front suspension. Well camber control is really good for short suspension travel as well, but lightweight cars with limited suspension travel need more camber change than 2½ ton trucks trying to maintain a straight line through the desert at over 100 MPH. So while the suspension arms on a Trophy Truck are nearly the same length to minimize camber change over 20+” of travel, the TGS2.1 will have a large difference between the upper and lower suspension arms to get more camber change with body roll and limited suspension travel of a road car. I’ll have to run it on my suspension spreadsheet to find the actual length of the upper arms and the location of the inner pivot vertically.

As I was finishing up this post I started getting Twitter notifications about something that had gone down in Las Vegas other than Saturday night’s truck race. Some idjit decided to shoot up a country music concert from a sniper’s nest in another hotel a quarter of a mile away, and brought a freaking arsenal of 10 full and semi auto weapons, dozens of magazines, and thousands of bullets. In the process of spraying the audience at the concert with bullets he hit about 600 people and killed 58 or basically proving the “9% fatal” statistic for small arms fire. I’m assuming because of the lack of cover and no return fire the number of hits far exceeded the 20% of shots fired that is normal for a firefight, but I haven’t seen a report on the number of spent brass found yet. And yet this mass shooting has fewer fatalities than the Nice truck attack, again proving that motor vehicles are the perfect murder weapon.