The axle on my rear bike wheel snaped and the bearings need replaceing, so i bought new ones how do i fit these as it seems the rear gear cogs are in the way of me inserting one set of bearings

Single speed bikes are often known as Fixed gear or fixie bikes.
But Most people don't know the difference between a fixie and a single speed bike.
It's all in the hub
Mechanically, the difference is so small that you might not spot it even when you are looking for it. It all comes down to the rear hub and how the single cog is connected to the rest of the drivetrain. Single speeds are fitted with a freewheel cog that rotates freely one way but locks up the other. This means that the cog will turn the rear wheel when you pump those pedals, but then freewheel when the rear wheel starts turning faster than the cog - much like a geared bike.

When it comes to Fixies, it has no mechanism on the hub. The cog is fixed into the hub. If the rear wheel turns, the cog turns, and if the cog turns, the pedals turn with that. I admit the difference is not so small, but one that has a huge effect on how a bike rides and requires some consideration before you decide on a bike.
If you want to know more about Single speed and fixed gear bike
Have look on this
Gear bike review Blog.


Best Fixed Gear Bikes In 2018 Enjoy Your Ride On Cool Fixie Bikes

Put the rear up on jack stands and remove the wheels and brake drums. Then unbolt the rear differential cover and drain the gear oil. Then, you remove the pinion securing bolt. DO NOT ROTATE THE WHEELS AS THIS CAN CAUSE THE PINION GEARS TO FALL OUT. Push the rear axle shaft inward toward the vehicle and remove the "C" clip that secures the axle to the pinion gears. Then pull the axle shaft outward and out of the axle housing. Inspect the axle shaft for scuffing and excessive wear on the place where the wheel bearings rest. If there is excessive wear, you can use a "repair bearing", which is modified to install so it runs on an unworn part of the axle shaft. Otherwise a regular replacement bearing is fine. You need a slide hammer removal tool to extract the old bearing from the axle housing, and a bearing install tool to insert the new one without damage. Once the new bearing is in, reinsert the axle shaft, secure with the "C" clip, and pull outward to latch the "C" clip into its recess. Install the pinion bolt. Reinstall the differential cover with appropriate gasket or sealer. Fill differential with approved gear oil in the recommended amount. Ensure that if the rear is a positraction rear end there may be an additive required to the gear oil for proper operation.

Park Tools has the best bicycle tools in the business. Most reputable bike shops will carry them.

does it make the "clicking" noise when coasting, pedaling or both? If it is only when pedaling, check to make sure the cranks are not rubbing on a chain guard or hitting the frame, if not then the chain is probably too tight and it is the gear cog teeth meshing with the tight chain. Loosen the rear axle nuts and slide the rear wheel forward slightly, this should take care of it. If the noise happens while coasting then one of the wheels could be rubbing on the frame intermittently, or the hub bearings could be too tight (also making it difficult for small legs to pedal) and the bearings are crushed and flattening making the "clicking" noise as they are being ground up.

sounds like it may be a couple things, this this is a five year old post, this is for other users. In your case the wheel may not be seated in the dropouts correctly, loosen the quick release or axle nuts and pull the wheel as far back in the drop outs as it will go and retighten. If it is still rubbing then the drop outs them selves are out of alignment. Most competent LBS's (local bike shop's) have a set of drop out H tools that are used to check front and rear drop out alignment and can be used for minor adjustment of the drop outs. In a more extreme case the frame could be out of alignment or one of the drop outs could have been welded incorrectly and the frame sneaked past the manufacturers quality control processes. When rebuilding your hubs make sure there is an equal amount of axle protruding from each side of the hub to insure that it is centered properly. Some hubs use 8, 9, or 10 bearings, as long as they all fit in the hub race without binding or overlapping (so to speak) you are ok and they are easy to loose. I use a telescoping magnet to extract them from the hub when I rebuild. Most LBS's will sell you new bearings, just take the old ones in and they will have a tool to measure the diameter to provide you with the right size. One more thing; there are standard drop out spacing sizes, measured on the inside faces of the drop outs, and depending on how many speeds your rear wheel has. 6-7 speeds is 120mm on older bikes from the 80's and before. Most bikes today have 135-145mm spacing to accommodate the larger gear clusters of 8,9,10,11 speeds.

very likely that chain links not "fitting" cog teeth . if both chain and cogs are brand new, then skipping should never happen. more often than not, a repair would require both new chain and new rear cogs, and possible new fron t chain wheel. all depends which item are worn. I would probably get a new chain firstly, then see if this fixed the problem. nigel

Congratulations on learning to ride the bike. I use the rear gears mainly i.e. the gears on the right hand side. Each rear gear makes a little difference so it makes it a little easier to go uphill. (When the chain is on the back smallest cog wheel it's hardest to pedal and easiest on the largest. The reverse is true of the front cog wheels) If you come to a very steep hill you should use the front gears i.e. the lever on the left hand side. This makes a bigger difference to the effort needed to climb a hill. When you have put the front gear into the easiest position, (on the smallest cog wheel) you can still use your rear gears to make it easier still. For going on flat ground or downhill most people keep both sets of gears on the hardest gear. (The front gears on the largest cog wheel and the rear one on the smallest) However there's no rule that says you have to. Use the one that feels you're using just enough energy to turn the pedals and in time you won't have to even think about the gears. I hope this helps.

You need at least 5 bicycle specific tools to do this. Refer to: Parktool.com

The rachets in the rear gear cog have gone bad.  Buy a new gear cluster and have it installed on your rear wheel.  about $30

Here is a guide on how to change the rear seal and bearings on a ford mustang
http://fhmotorsports.blogspot.com/2013/07/how-to-change-rear-axlewheel-seal-and.html