Hey everyone, I have what I hope isn't a repetitive question. If it is, please direct me to the appropriate thread(s).

I've got a 2005 Night Train with the Harley inverted fork set and the stock wheels and tires. I want to replace them with something else.

I've made my mind up that I'm going to go with a wider tire on the front end, and I believe I've settled on a 21"x3.5" wheel with a 120mm Avon Venom tire. Other than the obvious benefits of less unsprung weight and less rotational weight, is there any benefit from going with a smaller wheel diameter? If I do, are there any other issues with suspension geometry I need to worry about/address?

Same question with the rear. I'm leaning towards keeping the stock size in the back, but going with a 160 on an 18"x4.25" wheel has been suggested as well. My concern here is that the back of the bike will be raised too far and the bike's balance will be affected. If I go with the 18" wheel, am I going to need to lower the rear suspension so the bike doesn't look jacked-up?

Finally, is there an actual, noticeable difference in using lighter wheels?

 

Anyone?