This is one of those things - you will either know immediately what we're talking about here, or you won't care!

It all really depends on how much space you have relative to your inventory size.

  • More bikes than space - leading to piles or stacks of bikes.  Hence "back of pile" problem.
  • Plenty of space - meaning you can 'pick out' individual bikes.

'Piles of bikes' kind of shop

Take a look at this image, does it look familiar?

If this looks at all familiar then you will understand this statement:

"I have so many bikes I would never dream of searching through piles of bike just to find a particular one.  I just need to know I have enough of that kind of bike to take the booking.  I then give the customer the first from the pile." 

In which case you will want to make use of the powerful BRM feature: 'GBAL'; Generic Book', Allocate Later.

'Neatly racked / accessible bikes' kind of store

If however you are spoilt for space relative to your inventory size you may be more familiar with this kind of thing:

You can pick out individual bikes.

This is definitely easier to handle.  Customer books.  Allocate an actual bike. Give to the customer, Track that bike.

See Also

GBAL booking 

putting barcodes on your bike 

auto-allocate bikes when taking online bookings