Big, most of my tow time was car hauling. I think you're thinking properly. In the case of lashing down the taco, I would use hooks in front and tie backs around the rear axle in back, in a X pattern on at least one end. Capture the front suspension, the rear won't jounced much. If something happens to make a strap snap, you'll have other things to worry about. I have always used---
http://mrproducts.com/collections/t...own-ratchet-wheel-strap-the-original-tie-down
M&R stuff. Top notch and US made. 10k rating on each, so really don't worry about breaking one.
The wheel bonnets are for cars like your Audi that you can't get under to grab something decent to hook to. Regarding the rails, sounds like E track, and I don't know if that's good to tie a car to. Bikes maybe.
Regarding the 102" trailer, that's great, but you should know about the 102 CMV restrictions in certain locales- it applies to that also. NJ is a real PITA and they enforce it.
https://rv-roadtrips.thefuntimesguide.com/2009/07/rv_size.php
I asked that also Wayne, I want to be able to go about anywhere. In Calif they had similar lane restrictions in place. Its mainly for Hwy's with lanes of less than 10' (7 Frwy) was one such Hwy the lanes didn't change when 102" trailers and Container and Pigs came out to make it legal for trucks with 102" trailers they renamed the road 710. Bingo it was somehow safe to pull 102" and oversized permitted loads ON THE SAME SMALL LANES, I think the reason was to keep Commiecalif from being sued if there was an accident.
Montana is no different, but where the lanes are small are mostly in far reaches and not much traffic. Barney's look the other way unless the driver is having obvious issues.
https://www.pegasusautoracing.com/group.asp?GroupID=ETRACK
E-Track Modular Tie-Down Rails & Anchor Fittings
Customize your trailer to fit your exact requirements with E-Track, the most versatile, most flexible tie-down anchoring system around.
The basis of the E-Track system is the heavy-gauge steel track with evenly-spaced pockets. A variety of anchor fittings clip into the pockets without the need for tools or extra hardware. Fittings can be moved, removed, and added at any time, making E-Track an excellent choice for a variety of hauling uses!
•Dual-purpose trailers: Haul your racing machine on weekends and your work machines during the week! Snap-in fittings and anchors can be easily moved -- without tools -- as your needs change.
•Shared trailers: Haul a variey of cars and equipment without being "tied down" to one layout.
•Your own custom trailer: The wide variety of fittings allows you to build your trailer just as you want it and change it at any time!
•Tow vehicles: Use E-Track in your truck or van to keep all kinds of cargo secure.
E-Track can even increase the resale value of your trailer by making it instantly useable by the next owner!
The basis of the E-Track system is the E-Track itself. Painted 12 gauge steel rails have slots every 2 inches to accept modular E-Track fittings and anchors. Low profile (just 1/2 inch high) keeps the track out of your way when not in <script id="gpt-impl-0.6570585324009146" src="http://partner.googleadservices.com/gpt/pubads_impl_81.js"></script>use. Track measures 5 inches wide by 2.5 foot or 5 foot long. Either length can ship by UPS. 1/4 inch diameter mounting holes on 2 inch centers are provided on both sides of the E-Track. So long as the underlying structure is adequate, a safe working load of 470 pounds per bolt can be assumed. This conservative rating is based on an internal bolt tensile stress of 17,500 psi which provides a safety factor of 4.85 when using an SAE Grade 5 bolts with 1/4-20 thread. The 2.5 foot length has 30 mounting holes. The 5 foot length has 60 mounting holes.
Those tracks for tie downs aren't like the ones on the side of freight vans used with certain types of load locks these are some BEEFEY tie downs that were used by this Trailer manufacture when they built my FIL's years ago. He used a single ratchet strap over the center of his tire. When I tied down his Crown Vic he asked what I was trying to do pull the floor up or mash the car onto the deck of the trailer? I LIKE THINGS THAT DONT MOVE!! which sounds funny coming from a Tanker Yanker in a previous life form
I'm not sure if this is the same thing that they use but when I called they said that they used a tie down that they always have, this looks very similar to what was in another trailer we had.
https://www.pegasusautoracing.com/productselection.asp?Product=2365