How to properly change website url w/o losing SE rankings

[cobrakoi]

Let's take the following scenario and give me your opinion on what to do.

I have two websites for two different products however they are in the same market. One site is called widgets.com and the other site is called gadgets.com. The site gadgets.com is ranked in the first page of google for a really popular keyword in addition to having a PR6.

I want to consolidate the two sites into one site under widgets.com by using a subdomain under widgets.com for the gadgets.com website such as gadgets.widgets.com.

I will redirect all traffic to gadgets.com to gadgets.widgets.com however I am afraid that I will lose my first page ranking for gadgets.com.

Why do I want to do this?

Primarily branding. By combining gadgets.com into gadgets.widgets.com I can furthur expose the widgets.com brand instead of advertising as two seperate brands. What do you think?

[tedster]

You will most likely lose rankings for some period of weeks. If your long term business plan works best with one domain, I'd say consider the drop an operating expense.

[BigDave]

Like tedster said, it will be weeks at least. It is even possible that it will never return to its former glory, or it might even exceed its former glory.

But no matter what, it will have a negative impact for at least several weeks.

When you change things, you cannot expect everything related to that thing to remain the same. If you file a change of address with the post office, most of your mail will get to you eventually, but it will be delayed and some of it will never arrive.