How does 301 redirect affect SERP

We have 2 sites that are basically online directories, One site has been on the web for over 10 years and has very good search engine results. We created a new site that is an enhanced version of the old one and would like to have all traffic go directly to the new site. we are leery or redirecting the old site in fear of losing traffic. Page ranks for both sites are the same PR4 and after reading posts on Alexa rankings the general consensus is that they don't mean much unless you want to sell the domain as the site has a much better Alexa ranking than the new one.

Any comments would be appreciated


Thanks

You will lose traffic this is the risk. I recommend not to redirects and just slowly improved the old site. This is much more safer.

Why do you loose traffic? If you set up a proper 301 redirect you tell the crawler "Anything found here is now on this URL". Then you keep your "standing" for all the SE´s. Or do I miss some point?

Very true... 301 is the SEO friendly redirection and wont harm any website (in terms of traffic) if used in proper manner.. but here he want to redirect 10 years old domain to the new one... what i know is goolge keep more trust for older domains then the new ones... so it could be risky in this way...

If there are very less number of links to be redirected to the new domain, there will not be a problem. But in case if u have more number of URL's to be redirected then it will affect the server working conditions (speed, maintenance etc.).

As u said the old site is more than 10 years old, then if u redirect certainly there will be some traffic loss.

Instead of doing 301, it is better to improve the old site as per ur needs.

Actually Google does follow 301 redirects properly but if there is change in URL, the nature of Google is it will not display the new permanent location right away in the index..there is an adjustment period for this. And during this adjustment period the old URL will slowly lost its juices because Google will transfer the previous Page rank , other factors to the new URL. And during this transition one can experience a drop in rankings temporarily that affects traffic.

The effect is high if the URL to be changed receives high traffic from Google and it is ranking well.However once the transfer is completed, rankings will go back to normal or even better.

@Emerson: You´re totally right! I thought about long-term effects, but short-term he´ll loose traffic. But if it is a very popular site the decline on traffic will also be really short, won´t it?

Yes it will just be temporary, though I do not have a definite time but as the redirect gets older then the site will come back to rankings naturally.

I have seen sites come back within one month , some sites will mature with 3 months.

Sorry how can I see redirect links from a website who is receiving these links???