The options below apply to either 4 stud or splined hubs.
As per all modifications, don't forget to inform your insurers when fitting new rims.
A reminder of the Rim sizes on MGBs and BGTs with 4 stud steel wheel hubs:
Rim details:
MGB/BGT -
Rim diameter = 14"
Rim Width = Steel 5J/ Wire (60 spokes) 4.5J
Pitch Circle Diameter = 4-stud 4.5" (114.3mm) (Steel wheels)
Offset = 22mm approximately.
So, keeping the above in mind, what are the restrictions in changing the rim & tyre size on the typical 4-stud hub?
The front is not an issue so much as the back, especially on chrome bumper cars where the tyre sits up into the rear arch, the rubber bumper cars seem less afflicted unless they have been lowered.
Whilst 185/70 14 tyres will generally fit on the 5J rims, wider than this and there may be issues of fit. Owing to the fact that some B/BGTs suffer from an off-centre rear axle there is the risk of some tyre rub on the arches, even on 185/70 14 tyres on 5J rims, although this can be corrected to a degree by the fitting of new rear springs. However, Michael Cornes had to change to 175/75 14 tyres on his BGT, although he was using a set of aftermarket Minilite replica rims which may have had a slightly larger off-set than standard (despite the fact the rims are advertised as suitable for MGB/BGT).
If 195/65 15 tyres are under consideration, then it is likely these will be on a 5.5J rim and the usual approach to countering tyre rub is to roll the wheel arch lip. This is normally done with a large piece of wood levered against the tyre to force the lip inwards - not recommended for the faint-hearted if you value the paintwork. The paint may be flexible enough to withstand the bending, but some remedial paint work maybe necessary. Ed Bracklik has advised me that the chaps at Autobody Services use a large piece of wood cut to the profile of the wheel arch, and then jack the wing out using two body jacks by about 10-15mm. Apparently, the wing profile looks standard and is not noticeable.
It is also feasible to have more radical modifications to the wings such as on this car (owner is/was Joe aka JP1):

Or use Mk1 Golf wing extensions such as below on the car that belongs to Harbans Bhogal sat on 6J 14" Wolfrace Wheels fitted with 225/60 14 Pirelli tyres:

Rims from other car manufacturers
Of course the cheapest and easiest option is to source rims from other car makers. Two often quoted makes are Saab and Datsun from the 70/80s. Rover 800's share the same PCD, but a differing off-set. Saab offered a Minilite look-alike rim on some of their 80s models, whilst Datsun had a variety of rims on offer, with a good supply of aftermarket rims. Be aware of the need for differing nuts when selecting alternative makes.
As JC mentions in his article Reliant Scimitar Dunlop wheels will also fit but as these are a wider rim will need consideration as to rear wing clearance.
TR6 15" rims are also quoted as a fit. Phil recently purchased a set of TR6 rims, but wing modifications will be necessary to get these deep-dish rims to fit. However, according to the Rimmer Brothers site, there are two options, namely 5.5J and 6J, but no mention of the offset dimension.

The picture below is my Roadster I owned in South Africa, which had been imported from the US, and had these Nissan "hot-cross" alloys on when purchased.

I was recently sent some pictures from Mark Langridge with 2000 to 2004 Volvo V40 or S40 Spectra 15" rims & 195/60 15 tyres on a 1976 MGB. He wrote, "Only on the 2000 to 2004 V40 / S40 models - these are referred to as the Volvo Nedcar's. The newer V40 / S40 uses the same 5 bolt pattern as the other Volvos. There are a number of wheel styles volvo used for these cars. I liked this on the most. The MGB centre caps are almost a perfect fit as well. However, to avoid rubbing with the 195 tyre width Mark has used 1/2" wheel spacers and longer studs.
So sticking with standard rim sizes and tyre sizes, the most popular option, and period looking, is the Minilite style. In addition, some of the manufacturers also offer a knock-on version for those with splined hubs wanting an alternative to wire wheels. It is important to talk to the suppliers as often the listed products on the web-sites may not be their complete range, and they may offer a service for specific dimensions to suit your needs.
There are a number of such suppliers, listed below, and not meant to be the complete list either, but a good starting point in any case. Genuine magnesium wheels were first used in motorsport in the 60s offering a reduced unsprung mass for better handling. In many cases the replica wheels are no lighter than the steel rims, so if you are buying for looks only this may not be an issue, but if for performance enhancements, then bear this in mind when choosing rims.
Another problem to keep in mind with aftermarket wheels is that the centre caps may not fit at the back. The rear hub nut protrudes to quite a degree which is not an issue with RO-styles or steel rims with hub-caps, but with some aftermarket centre caps, you may find they are not deep enough to fit correctly.



http://www.superlite-wheels.com/index.html
http://www.performancewheels.com.au/index.asp



The Spitfire looks very similar to the Wolfrace wheel, while the Challenger looks suitable for the B/BGT LE models.
A couple of examples below of photos I have taken on MGs in Australia:
Performance 15" rim with 195/60 15 tyres.

Performance 14" rim with 185/65 14 tyres (which seems a little undersized, but possibly done for reasons of improving acceleration).


www.wolfrace.net - The site is worth a visit to view the museum featuring their range from the 70s.


www.imagewheels.co.uk - A few examples are shown below (these being my choice but there are numerous from which to choose) and the Rostyle look would be fantastic in my opinion, on a BGT, it's just a pity they cost a lot more and few would realise it was a Billet formed wheel! There are a few good choices to suit either the classic look, the modern look, the custom/hot-rod look, or even for the Santa Pod Drag Racer look!

Certainly not cheap but Frontline have these give the Dunlop look as used on the MGA Twin Cam etc and are available to fit either a wire wheel hub or a normal 4-stud hub.



www.compomotive.com (see picture below)

Although I can find no homepage for them, the KN Minator range are available from a variety of sources.

These are Photos I have either taken or seen on the web to provide possible inspiration.






And lastly, just to prove that the PCD isn't an issue, this car belongs to Paul Gasters and uses Montego/Maestro wheels.

And a similar look here seen on this car recently at Cholmondley Castle:

A few more wheel rim options seen at Silverstone this year:



These wheels below recently surfaced in discussion on the MGOC BBS. A fellow MGB owner/member has put them on Ebay but could not see a manufacturer's name except the following markings:
M-MAAL
5(AND A HALF)x 14
MADE IN ENGLAND
TSOST
At first glance they have a Wolfrace look about them.
Many thanks to the various people who have emailed to say that:
Looking at your listing for alternative rims and came across the entry for
the MAAL alloys.
I have a set of these that I bought off a chap who used to
do Datsun Z's and they were apparently an alternative option on the imported
cars. (not sure if they were dealer or aftermarket) The ones I have are 5.5 inch
and wear 195's. They sit quite tight into the arch so I have managed to ease the
arches out a little with no paintwork damage ....remarkable!
In answer to your question regarding the above wheels, I believe they are Midland Metallics, made by a firm called BWA in the Midlands (of course!) I think they stopped trading years ago as I always wanted another set of these, and could not find any!
I believe the wheel which has not been
identified on your website was made by a company known as Midland Metallic and
produced in the early seventies.

