Since the Transit van was introduced in 1965 people have been customising them, alloy wheels has always been a popular option. Unfortunalty the transit has a PCD (thats pitch circle diameter) of 160mm x 5 shared only with the Tata. so alloy wheel choice has been very restrictive.
The most common way to fit alloys of a different PCD is to have adapters made (information on adapters can be found elsewhere on this site), an adapter is a block of metal that bolts to the Transit hubs and has studs which match the new wheel. There are a few problems with this,
- Extra strain put on the wheel bearings
- Steering geometry is altered
- Wheels are further out in the arches oftern requiring flared arches to be fitted
The best way to do this is to redrill the origanal hubs, in this article im going to describe the entire process from start to finish.
The van is a 1996 smiley transit swb - fitted with a cosworth V6 engine, the wheels which are going on the van are granada scorpio 16" alloys, although the same process can be followed for almost any 5 stud alloy!
also note this article is concerned with the 5 stud transits from 1986 to 2000 and NOT the 6 stud heavy duty vans!
1st off unless your van is off the road a pair of replacement hubs are required as this process takes a while, you should be able to get them off most breakers or off Ebay, be prepaired to pay £20+ for a pair! they are all the same from 1992 to 2000 but the earlier vans from 1986 to 1992 are different to be sure what van you have ask in Mk3/4/5 section of the site forum
Strip down - When you recieve them they will proberbly have the brake disks attached , they will need
removing, to do this the easyest way is to loosen off the 5 securing bolts a few mm, stand the hub on a firm surface and strike down on each one in turn. Don't worry about damaging the bolt heads as they will not be needed. It's up to you if you want to save the brake disk but they are available new in pairs very cheaply! Reapeat this and eventually the disk will come loose, some are harder than others and soaking in penetrating oil can help.Once the disk loose undo all the 5 retaining bolts and the disk should come off with a little help.
Next remove the 5 studs in the same way strike down on each one, they are only pressed in so fall out easly, again they are no longer required.
The final thing to remove are the dust seals and the bearings - just the rollers and the inner races, for the moment leave the outer races in place, personally new bearings are not expensive and for peace of mind i would replace them for new ones.
Now your hubs should look like the picture shown.
The next step is to clean out all the old grease from inside, this needs to be done very well if you are shotblasting them for the next stage.
Shot blasting - If you have access to a shot blaster or know 
someone who can get this done then its the ideal way of preparing the hubs for the next stage. To prepair the hubs for shot blasting i bolted them together and cut rubber covers to protect the machined face where the brake disk sits and also to stop any shot going inside, if for any reason shot does get inside it will need to be removed as i grain of shot will destroy a wheel brearing in minutes.
The area that needs cleaning is the recess arrowed in red, so pay particular attention to that area. If you can't get them shot blasted then it is possable to clean the area up with a rotary wire brush or pencil grinder. but it is essential it is thoroughly cleaned for the next stage of the process.
Welding - Once the cleaning is done the next step is to fill the recesses with weld, now this is not a job for an in-experianced welder, if you have any doubt in your ability then get a proffesional welder to do it for you. It can be done either arc/stick welder or MIG, it will just take a bit longer with MIG. Most home MIG welders used for body work will not be suitable, they wont have enough power to do the job. The Transit hubs are cast steel - not cast iron, they are also not forged.
When i welded mine i took a while between each run - that way the hub will not get too hot and distort, its also important to evenly balance the weld out as its built up. It doen't matter if the weld is higher than the hub face, but it must not be lower.
Once done it should look like this. The reason i left the inner bearing races in was to protect that face from weld splatter. they can now be removed, you should be able to get a long drift through and knock them out but if not weld a piece of metal across and use that to knock them out.
Normalising - If possable it is advisable to normalise the hubs this is done for metalurgical reasons the treatment required would be heatd up to 850 degrees for 1 hour and then slow cooled in a protective atmosphere. I would reccomend this is done.
Machining - The next step is to have the hubs machined, at this point you should have a good idea of what wheels you are going to fit and what PCD they are, and also what size the centre boss is.
The transit has a 63mm centre bore, if your chosen wheels have one larger than that then you will also need a spacer made up, if the gap is only a few mm then the spacer will be too thin, so the best option is to have the hub boss machined down allowing a thicker spacer to be fitted. A tip is to look at all the different manufacturers using the same PCD as the one you are using and have the centre boss machined down to the smallest - that way you are increasing the choice of alloys you can fit. Eg. mercedes alloys will fit on granada hubs but granada wheels wont fit on mercedes hubs.
If you dont have access to a machine shop you (like me) will have to pay a profesional machinist to do the next step. For this conversion as mentioned earlier is having granada scorpio alloys fitted, they are a PCD of 112mm x 5, (the x 5 relates to the amount of studs) I took the hubs to a machist and asked for :-
Hubs to be faced flat
sorry guys and gals this article is unfinished, i'll be updating it as soon as i can!!
Luke