Jesse at 8710 Burnet, 459-1388. He's installed hitches on quite a few cars and trucks for me over the past 15 years.

 

Wow, great pic's and write up. Thanks.

I have one question though that has been bothering me for a long time. That is the 1 1/2" hole in the bumper support. Why such a big hole? I always hate to drill holes in anything, this hole is huge. It has to take all the structural integrety away from that suport in the lateral direction. I don't know if it's a structural component, but it can't take much of an impact from the rear to buckle that support. From the picture, the whole side is gone with the hole. (too many holes in that sentence aren't there?) I like your idea SCModerator to go from the ends. May be a bugger, but you wouldn't have to drill a hole. An electrical fish tape could be used to get the bolt in place. This is the only thing keeping me from ordering the hitch.

Another idea may be to use a self tapping bolt and tap into the bumper support from the bottom. Maybe though, if it's only 80 thousands thick, it may not be heavy enough to hold. Locktite would keep the bolt from backing out, as well as a lock washer.

Well, I lied, one more question. The other hole that has to be lengthened. Is there a way to make the backing plates narrower instead of modifying the car to make them fit? Again I hate cutting and drilling on things, especially a $60K car. The backing plates could even be made beefier but narrower so they fit.

Oh well, any feedback is appreciated.

TeaMan

 

Thank you.

 

1) The hole has to be that big to get the backing plates in. Even at 1-1/2 it was a tight squeeze. I tried the ends of the bumper but there are plates at the end to close them. I could reach around to feel the plates, but I didn't have anyway to get to them to drill a hole through one of the ends.

2) The engineers at Curt would have to answer that, but I believe you are correct. The sheet metal alone can't provide enough strength for the bolts.

3) Again a question for Curt. It took them forever to come up with the design, so I suppose there were good reasons to make the backing plates that wide.

BTW, the hitch and trailer worked fine on a 1300 mile round trip last weekend. At the event, my driving stunk against a couple of C6 Z06's and a well prepared C5 Z06, but that belongs on a different thread.

Seeya,
Tom

 

Thanks Jim. I'll have to see if I can find a way to contact Curt. Good Idea. I do hate drilling holes...

TeaMan

 

I've just reported all of you to the Society for the Prevention of Cruelty to Corvette C6's

 

Gerade 5s aren't weak. They are 80% as stong as grade 8s. He didn't say what size the bolts are but they look like about 7/16. If so, they will take something like 10,000 lb each in shear if they are torqued down solidly. I suspect they would tear out of the sheet metal frame first.

The main advantage in design work to a grade 8 over a grade 5 is that you can often use a one size smaller size bolt with a grade 8. If you aren't size limited, like a trailer hitch mount, there is no advantage to using a grade 8 as opposed to a one size larger grade 5.