Wow, people can be way too serious sometimes...
I have a feeling the bike rider is Billy(stuntman),if so I don't really know what his point was either
Yea, that was me...
1 - i'm good friends with NSXalot
2 - I agree with his point that helmets have different safety standards and are designed for different types of impacts
3 - While agreeing with post #2 by my buddy lance, I jokingly stated "try telling that to this guy" - who (as docjohn figured out) was me.
4 - I've been riding for over 16 years, and have raced everything from karts to Formula cars to Sports cars for over 9 years...
...ok i'm done with numbers.
It was a joke -
to show exactly what not to do (nomex, car helmet, gloves, shoes, etc...). FYI I had leathers on under the racing suit.
My post did not lead the OP to believe that nomex was a good abrasion resistant material nor that car helmets were acceptable for riding, I agree with Post #2s statement.
For the OP - You can use car and kart helmets interchangeably, my advice would be to get a good helmet for that and a separate for bike use. You can get good bike helmets that are pretty inexpensive -same for car helmets.
A great car helmet option would be the HJC AR11. IMO it's 95% as good as the benchmark Arai GP5 for less than 1/2 the cost:
http://www.thebellstore.com/Auto/HJCHelmets/hjcautohelmets.html
www.thebellstore.com -has a lot of good deals on bike helmets as well. Arai is still the benchmark, but HJC, Bell, and many other companies offer great products for lower prices.