I have seen a few people put 2 bikes on a bases and a few who put 3 on a base
but which one should i use
does it depend on what i like he look of or are there specific rules for this kind of thing?

Thanks

Grim

Either way is allowed by the rules: mounted infantry must be based two to four to a base. Whichever you use it doesn't make any difference to how the unit behaves in-game, so it's mostly whichever you like best.

The unit stats tend to be designed to represent stands of three models. On the other hand, basing in pairs gets you more units for your money.

_________________
"Good ale, the true and proper drink of Englishmen. He is not deserving of the name of Englishman who speaketh against ale, that is good ale."
- George Borrow

Base them in the way that looks best for you.

If you are using the smaller square bases, you will fit 2 to a base.

If you are using the strips, probably 3 looks best.

Cheers...

_________________
Frogbear is responsible for...
Previous World Eaters
Previous Emperor's Children
Previous Death Guard
Previous Imperial Fists
Previous Chaos Squats

I use the small square bases with 2 bikes per stand. For SM it means one bike formation is one full squad (10 marines, 10 bikes and you swap out 2 marines and 2 bikes for a 2 marine attack bike).

That is my preferred option as well.

Incidentally, would it be alright to put a character on a stand with another two bikers, thus preserving the total number of biker marines in the unit and creating a differently sized base in the unit from all the rest? Does it say anywhere if the bases all have to be the same size?

From 1.1.2 Stands

• A stand may be no more than 40mm and no less than 5mm across in any direction.
  
• A stand must be at least 20mm across in one direction

_________________
"Play up and play the game"

Vitai lampada
Sir Hemry Newbolt

I was thinking about putting bikes on a 10 x 40 but aligned to the short end so you get a sort of conga line, actually looks quite good

Looks great with 'nids

_________________
If using E-Bay use this link to support Tac Com!
'Abolish red trousers?! Never! Red trousers are France!' – Eugene Etienne, War Minister, 1913
"Gentlemen, we may not make history tomorrow, but we shall certainly change the geography."
General Plumer, 191x