Are 301 directs 100% efficient?

I have a site that I've spent a shit load of time and money building links to (it has about 30k backlinks right now). However I'm thinking of buying a new domain name which is more related to my niche and contains my target keyword. Will there be any disadvantage whatsoever if I 301 redirect my old domain to this new one?

And also, what happens with regards to deeplinks? Will old-domain.com/forum pass all link juice to new-domain.com/forum?

Thanks.

Just create a 301 for each page of the old site, to the new page. You should preserve the PR and what not, but it can be a bit touch and go (although i've seen no evidence either way).

The thing is because you can cheat the system (by mass linking old internal pages to say one new page that might not be even slighly similar), you should really try to 301 old pages to new pages, that are very similar if not identical. If you do that, it normally works out ok.

301 redirects will keep your PR, and google SERPs. Google will eventually (not over night) convert all the old search URLs over to your new site automatically. You can also use webmaster tools to do it in bulk (kinda gives google a heads-up about the site move, and they process the new links faster).

The one thing you must ensure is that google sees no 404s. Make sure all your old links are active with 301 redirects. Only after google has migrated all your SERPs to the new domain, can you remove the old site.

Note: Any backlinks you have to your old site may be a problem if you have to remove the old site.. Keep this in mind, or provide indefinite 301s, which will keep your PR intact.

In short, yes. Your new domain will get all the link juice from your old domain as long as you keep the 301s intact.

Thanks for the replies.

Basically, what I need to do is this:

old-domain.com -> new-domain.com
old-domain.com/forum -> new-forum-domain.com

I have one site, a blog and forum on the same domain, but I want to split them into two domains.. retaining all link juice. Is that possible? I don't feel like creating 301 redirects for 5k+ pages as Entrepreneur suggested.

@Abstroose
I think this can be done through coding if the url structure is same between old and new sites.
I have one question: does it matter if the page is complete different between old and new sites? I mean, can we transfer link juice from high pr site(maybe bought) to our niche sites regardless of their content?

The general rule with 301 redirects is the search engine assumes the old and new urls contain the same content, though they assume some changes such as website style and layout.

@Abstroose
As long as the forum layout (pages, etc) are the same, you can use a simple apache rewrite rule to 301 all forum pages in bulk. Even if the layout is not the the same (ie. moving from one forum software to another), you can still accomplish this with apache 301 rewrite rules, though it will be a bit more involved.

Everything will be identical...the URL structure, the content, the layout. It's just a matter of redirecting everything from domain.com/forum to the root of another domain - all the category and post URLs will be the same.

Thanks for your help.

I also have another query regarding this.

if oldsite.com shows 30k backlinks in Yahoo Site Explorer, and I then add a 301 redirection to newsite.com, will newsite.com now show 30k backlinks in Site Explorer or 0?

no, the backlinks will not show in Yahoo explorer. The redirect will not "move" the links but some people feel that the search enigines will count the value of backlinks from the old page to the new page. I do not though.