I think I've got most bases coverd in my world:

– Nicolai Heilus CC
– Cove Handjob in 115mm travel guise
– Boardman Hybrid commuter
– Retro Raleigh single speed drop bar thingy

I think 4 or 5 should be enough. I have a super duper road bike, winter road bike, mountain bike (hard tail 29er in my case) and a RoadRat for hacking, bit of off road mucking about. If I lived somewhere else I may justify a full susser and that should be enough. Oh, and maybe a single speed road bike and a single speed mountainbike.
Is that enough?

1 * FS
1 * HT
1 * SS
1 * CX
1 * RB (rat bike as a spare for lending out)

Would like to add a tandem, and maybe a 29er

Got, FS, Hardtail, Cheap Road bike and a commuter. Need a singlespeed mtb, and a summer road bike, maybe a cyclocross, fancy a unicycle and a tandem too.

Hmmmm…..

Mine:
– S-Works Stumpy full-sus
– Sunn Crosss single-speed
– One-One Pompino fixed
– Hoffman dirty 130 BMX

Nominally mine:
– BMX that I bought down the dump and did up for a laugh – turned out to be a bit small, so need to sell it
– Orange Clockwork that I bought on Ebay (1999 model, near mint condition, mix of XT+LX, manitou forks, 14" frame – for £120!) This was bought for an ex-girlfriend, but we split up before she paid me for it. Might sell it at some point.
– Old 1994/95 Marin Eldridge Grade – £15 down the dump 🙂 Again, I need to clean this up and sell it on.

Mine but stored in my dad's shed 120 miles away:
– Beautiful early 90's steel lugged Massi racer, with full period Campag Record groupset.
– Early 90's Saracen that I had running as a SS back when I was a student in 1994-97 (proper old skool!)
– A Raleigh Grifter (bought for £10 – needs a lot o TLC)
– 1988 Muddy Fox Courier – massive 21" frame! My first MTB – well it wasn't really mine, my dad bought it, by I adopted it pretty quickly 8) Classic bike now!

So 11 by my reckoning!

I have 3
– big squishy bike
– medium squishy bike
– road bike

I'd like
– light squishy bike
– 4X hardtail

I like the n=1 idea, and as I seem to have to much time on my hands at present I have taken it a step further.

Lets assume that there are 3 displines and within each disipline there are other disiplines therefore:

d=3 were:

d1=3
d2=5
d3=3 therefore d=(3*11)+n

So it is suggested that if you required a bike for each 'd' you should therefore happily own 34

however if you follow it further to find the square root the result is:

5.83 which when you add in the GF factor (or BF factor just to be fair) may be more acceptable in keeping the peace. There maybe other 'd's to add in to the sub 'd's, but I think d=3 is a fair assumption

therefore the answer is 5.83 🙂

(sorry cant seem to do the little science symbols on here but you get the idea)