I want to get a set of these wheels for open track/DEs; I know the tires will fit on the 6" rims but will I have more sidewall flex than with a 6.5 or 7"? I'm trying to keep the weight down as much as possible. What's the best width?

Thanks.

 

7.0 imho

Alex

 

205/50-15 tires will fit on rims as narrow as 15x5.5" but it is not ideal. Everything is a compromise of weight vs fitment and contact patch. For the best traction in your case you might want to consider 15x7" rims with 225/45-15 tires. If you want to use 205/50-15 tires (you have them already) then 15x7" would be recommended. The added weight of the wider rim is offset by the better fit/contact patch.