I am making my brother a birthday cake for his birthday tommorrow. It is nothing fancy just an 8" plain maderia cake with a jam and buttercream filling and a 5" plain maderia cake with a strawberry mousse filling. What i need to know is since the top cake is only a little 5" and is probery only about 2.5" in height, do i need to put dowels in the bottom cake. The top cake will be on a small cake board so do you think i will need support or can i get away with not putting any in?

I would still put something in ... it doesn't have to be much but I would probably use something...depending on how you are decorating the 5 inch. Just so it doesn't sink into your 8"

It probably wouldnt sink into the cake or anything, but it will keep it looking level if you put dowels in it.

Could i use plastic drinking straws instead of dowels or does it have to be dowels?

Madeira cake is very sturdy, so you maybe OK, but straws to support underneath may give you peace of mind!

Thankyou for all of your help. I will post a picture when it is finished.

One can safely go up 4-5" before needing to dowel.
A 5"x2" cake on top of an 8" will be perfectly safe. No chance it will 'sink into' the lower cake.
If you do decide to dowel it you must put the upper tier on a cake board the same size. Push straws/dowels into larger cake and cut off at the heigth of that cake. If your lower cake is not perfectly level you find the spot that is the highest and put one dowel in - cut at surface; remove and cut all the rest of the dowels that same length.
It would be good practice for future cake to go ahead & dowel this one but realize it is totally UNnecessary

am making a cake about the same size and am gonna put dowels in just for practice too

Finished at last!!!!! I decided to put straws in instead of dowels just for the practice. http://www.cakecentral.com/cake-photo_1207153.html

Great job on the cake.

awww it looks adorable!

Thanks guys