If there is one aesthetic accessory that commands more debate, confusion,
and disappointment it has to be the wheel. Since the inception of the Mini, many
manufacturers have produced a vast array of different designs and sizes of rims
still surface through garage clearouts and the like. Many of the rims
specifically made for the Mini generally fit with no problems, others have been
adapted from a rim made for another vehicle. Some rims are from other vehicles
where determination on the part of the owner has made them fit-sometimes using
dubious and dangerous techniques! I am not exactly sure at this point where this
article is going-but I think I really want to generalise for the time being on
certain points and perhaps do a more "facts and figures" article in the next
issue. "Into the valley of death rode the six hundred"........
For starters, second hand wheels. If it were possible to manufacture wheels second hand, at second hand prices, you would become a multi-millionaire in a very short space of time. Practically every one wants a set of second hand wheels. Very few want to buy a new set. Someone will have to take the plunge sooner or later, as someone will have to buy a new set to create a second-hand set. So please be realistic. Mind you, I also think this situation has been fuelled by people selling second hand wheels far too cheaply considering their new cost. Particularly when you bear in mind that they come with tires on usually. Definitely a buyers market. In actual fact, even purchasing new wheels it is pretty much a buyers market. The huge amount of competition in this area means that vendors sell wheels at real knock-down prices just to stay in the market. Some with tires. There is very very little profit in these particular areas, so bear this in mind when you are buying a set. Don't be surprised by refusal if you ask for any discount because you are buying a set. They rely on you buying a set, not too many people buy just one wheel, so look for a small margin of profit on a set rather than next to sod-all for one.
Now, when looking at second hand wheels, some things to look for. Anything advertised as mag/alloy is a dodgey thing to buy second hand. They should be date stamped, and check for cracks or severe pitting. The nature of the material they are made from is to deteriorate slowly over a period of time, accelerated by daily use where they are subject to all weathers/road salt/lots of brake dust. They are originally made for race-use as the material is extremely light, and are therefore only expected to do a limited amount of mileage. Any chunk missing in the rim will probably indicate that they have had a hard life. Repairs are not often successfully carried out as specific skills and material are required. Hence repairs tend to be pretty costly.
The general appearance of the rim will be a fair indication of their condition. Beware any that are relatively old, but have been painted. This can mask several nasties, the worse being rims that have been repaired with body filler. Seriously, people do this. Severe scuffing around the outer rim will indicate that it has been scrubbed along curbs when parking, or in severe cases curbed whilst being driven enthusiastically. The only problem with this, apart from tatty appearance, is that there may be stress fractures that you cannot see. There you are, driving along one day when a lump of the outer rim exits stage left, the tire instantly deflates, chaos ensues.
One of the biggest problems of buying second had rims (I'm gonna shorten this to SHR, save on ink!) are the wheel nuts. I'd like a pound for every time someone wants to buy a set of wheel nuts for a set of SHR they have just bought! Don't be fobbed off with "they're easy to get mate, no problem" or "they're more or less all the same." On later rims this is less of a problem as a vast majority use steel inserts in the stud holes to take standard type wheel nuts. These are easily identified as there is what appears to be metal washer with a concave dish in it pressed into the wheel where the wheel stud comes through. These by and large, take the standard 30" taper nut. There are also a number of chrome domed nuts that are direct replacements for the standard type that look a bit more chic. There are, of course, exceptions, and one particular case is the rims fitted to the modern Coopers. These use a nut with a taper washer on, but this is a 60 degree taper, same as they used to fit to the old Rostyle rims. They are fitted as standard with a nut (Part no. NAM 9075) That has a stainless steel cover fitted. These look pretty, but are a right pain, as the covers come off easily especially having been subjected to the duress of visiting a national wheel and tire specialist where air tools abound. Instant ruination. They are expensive too. There is a replacement that is a one piece item and about half the price. Mini Spares sells them, naturally. One further complication caused by this insert is that on some wheels (most notably on the bigger rims) is the depth of the insert, plus the depth of the shoulder underneath it may mean that the wheel stud still does not come through far enough to give proper engagement by the nut. New longer studs must be fitted, as a guide to be safe thread equivalent to around one and a half times the diameter of the stud must be in the nut.
A hole that is a parallel bore, with either a square edged recess or 45 degree recess indicates that a special nut is required with relevant washer. These are called tube nuts, as the nut has a round tube that goes through the rim to locate it on the studs. Now, unfortunately, there are many many permutations with this set up - particularly wheels produced in the '70's and '80's. If you come across a set of rims with these wheel nut fittings, ensure you can get wheel nuts to fit -having a set made will cost a fortune. If the owner does not have a nut as a sample, leave a deposit and take a wheel to a reputable mini specialist. Mini Spares keeps around six or seven types of nut so can help in most instances. If this is not viable, and accurate set of measurements and general diagram would be O.K. Do not think that knowing the manufacturers particular rim brand will do, as the manufacturers didn't necessarily stick to one type or design of nut. Wolfrace "Slot-mags" or "Superslots" for instance had at least three different nut types during their production run.
Centre caps are an even harder problem to sort out. The styles, types, and fitments were even more numerous than the wheel nut thing. Much of the former applies to centre caps, so bear this in mind too.
Fitment. Oh dear, this is going to be difficult! Now all those with drum brakes all round are more or less home and dry. You can fit practically any of the sizes available, the only problem you will encounter is the offset (depth of wheel from where it butts up against the brake drum to the inner rim). Dependant on how deep this is will determine whether you will need to fit some kind of wheel spacer or not. As there are numerous widths of spacer available, you should be able to solve any problem here.
Whilst we're on the subject of spacers, I may as well cover them here. Firstly, only use the solid competition type spacers (these come with longer studs where necessary). Do not on any account, fit those awful star shaped thing that come with "stud extensions". These are a combination of a nut that screws onto the existing stud with a threaded piece sticking out of the other end. they are dangerous, and should not really be allowed in shops for sale. I have seen many with sheared off studs, both the new threaded piece and with the original stud broken off inside it. Not a great design. They are also a pain as they have to be removed to get the brake drum itself off. This is undoubtedly one of the reasons they shear the studs off. Funnily enough, a number of these spacers come with a warning by the manufacturers that they should not be used with alloy wheels. I have asked several manufacturers, but got no explanation!
I believe it goes back years and has something to do with the amount of stud left sticking out - so don't worry.
The proper spacers are available in 3mm, 5mm,3/8", 3/4" and 1". Plenty of scope there. Problems come when fitting them to cars with disc brakes on, or the GTS, and late Cooper brake drum. The smallest spacer will fit O.K. You can even fit the 5mm ones to the drums or discs, as long as you use longer wheel studs (ENJO-1039 with the drums, 21A2064L stud needs to have the dome on it's head ground off to ensure maximum clearance of calipers, etc.
There is a malicious rumour going around that fitting wheel spacers and wide wheels will cause rapid wear of wheel bearings. Tosh! Certainly if the wheel bearings and related components are already in a bad way, then yes they will wear out quicker. However, when in good order there is very little accelerated wear. Much of this is dependant of the rim offset, and there is one wheel that has a very small offset which makes the wheel stick out much further than any other, and that is the Weller steel wheels (usually white). The offset on these rims is so shallow I think it is a negative amount on the 6X10" rims. This offset is in reference to the centreline of the wheel. Generally when a rim is made wider, a larger portion of the extra width is put on the inside of the rim. this is to ensure the status quo between rim centreline and hub angle is maintained. (More about this in Calver's Clinic in the next issue). The design of the 6" Weller rim puts most of the extra width to the outside, which means that this status quo is spoiled - sometimes the design is referred to as "reverse rim". This basically describes exactly what people eons ago used to do to increase the track width of their cars and make the wheels stick out. They literally drilled the wells off of the standard rim, and turned the outer rim round, then welded it back on again! Nightmare! Some went as far as cutting the outer rim in half and adding in a strip of metal to make the rim even wider! This was known as "banding". So a set of banded reverse rims used to be all the go. They were also far cheaper than proper alloy rims, a luxury only really available to serious racers of the time.
Whoops, side tracked a bit there. Erm, oh yeah. The other commonly misunderstood statement is that putting wider wheels on a car will make it "bump steer". Cobblers. Bump steer is a very misunderstood phenomenon and is caused by the relation of angles created by the top and bottom suspension arms and steering track rod as they go up and down. It could be said that wider wheels would magnify the cars existing bump steer, but certainly would not cause it. This magnification is once again kept under control by careful wheel design - here the 6"X10" Weller dips out again. More accurate explanations will have to be waived here as it is quite a complex subject in itself, with many permutations and several influencing factors. Please trust me on this!
O.K., back to "fitment". As far as I know, the only type of 10" wheel you need to fit with spacers to the standard drum brake fitting is the 6"X10" Mamba, which has a very deep offset. Remember that the law requires the tire to be "covered", so check how far the tire sticks out from the wing and apply wheel arch extensions if necessary. There are a myriad of these available. I intend to cover arch types in another article. Probably in the next issue would be sensible! Many of the 5"X10" wheels will fit with the original fitment 145/70/10 tires without arches. Most are marginal when 165/70/10 types are fitted, so apply arch extensions to be prudent. Incidentally, you cannot fit 145/70/10 tires to 6"x10" rims, to far to stretch them!
So onto what wheels will fit what disc brake setups. Are you sitting comfortably?
The biggest problem here is getting a wheel that fits over the front brake caliper. The rear is far less of a problem than the front, and all that has been discussed about the type of drum with the built in spacer applies here. So, back to the caliper clearance problems.
As with everything there are exceptions to the rule and ways to engineer your way around just about everything. Right now I'm going to be dealing with pure bolt on jobs. Essentially there are two groups of disc brake set ups that need to be considered. Group one we will call the 7" variety, and will encompass the early 7" diameter discs from the 997 and 998 Coopers, and the 7.5" diameter discs from the 8" variety covering the later 1275GT's that had 12" both Metro type disc brake set ups. Funnily enough all of group two have the same disc diameter at 8.4".
We're going to approach this back to front as anything that will fit the 8" type, will fit the 7" type. The problem comes when trying to do the reverse. There is not one ten inch diameter wheel that will fit over the 8" caliper without "engineering". There is just not enough clearance within the rim. Basically forget it as a bolt on. To clear the 8" type irrespective of whether you are using the 2 pot Mini caliper or the 4 pot Metro disc brake set ups you will need a minimum rim diameter of 12".
You will need to check the centre hole of the rim, as the Metro drive flange that the studs stick out of has four raised location lugs. The hole in the middle needs to be 2.6 inch diameter to fit, or simply have the lugs machined off.
The exception to the rules here, is the use of Alloy 4 pot calipers on the 7" type discs. Although a vast majority of aftermarket alloy 10" wheels will fit, there are one or two that don't. One is the mamba, so check this out carefully.
So what about width? No real problems here, as getting rims of 12" wider than 6" is a rarity, avoid them if you find some. As for 13" wheels, it is possible to get these up to 10" or 12" wide, but you will not get tires to fit for road use. It really is not worth going over 6" wide or a road Mini unless it is purely aesthetics you are after. No more handling performance as far as grip is concerned is achieved as the tires available for 7" or 8" rim widths are made for cars a great deal heavier that the Mini, so never get up to anything like a sensible working temperature. If anything they will cost performance through excessive rolling resistance created by the extra drag on the tire contact patch. Clearance problems also rife with not just body work, but tear radius arms as well. As a rule, 5 or 51/2" wide is O.K. with 12" Diameter rims-5",51/2" or 6" wide for 13" diameter rims.
Next problem is tires. For the 12" rim with 5" or 51/2" width, you can fit standard 145/70/12 tires, or the newer 165/60/12 low profile types. On 6" width rims, you will have to go for the 168/60/12 ones. It is possible to fit some of the cheap and readily available 155/70/12 tires to any of these widths, but my advice is DON'T! They were made for bigger heavier cars with soft suspension and make the car very bouncy as they are somewhat balloon like. Most of them cause rear radius arm and rear shock absorber clearance problems. Just do not do it. Please? You are far better off fitting the equally cheap and available 145/70/12 items. Fitment of the 6" wheel with the 16/60/12 can cause fouling on the bodywork, usually in one area only an is easily solved. This is at the front of the front wheel arch, about four inches up from the bumper. Exactly where depends on the cars ride height. In some instances it is so slight that a packing washer between the front subframe mount and front panel will of the job. Otherwise some careful trimming with sharp tin shears is needed.
Now, 13" rims. Ignoring the 7" and 8" wide one for the time being, there is essentially two tire types that will fit with minimum problems. The easiest is the 175/50/13 profile, the other is the 165/60/13 as fitted to the Metro Turbo. How much which fouls and by how much is dependent on a recipe of wheel offsets and car ride heights. Nearly all 13" rims will foul the front leading edge of the front wheel arch to some degree. Only the narrower rims of certain makes JUST clear, and even then it is not necessarily guaranteed. I once embarked upon a project to sort out those that would and those that wouldn't. The tire manufacturers were ready to be more than helpful, but I couldn't conjure up sufficient budget to cover the wheel types - Very very few were in favour of "loaning" me a rim of each type, I would have to buy them! Wonder what they were afraid of?
There are other factors that influence the "fouling" problems, but are caused by non-standard suspension so will be covered in the next issue. Unfortunately newer Minis suffer more problems in this department than the old ones. As we have detailed in previous Mini Tech News, the newer models bodyshell/subframe layouts are all over the place - largely caused by bodyshells being built using press and assembly tools well past their sell-by-date. Some times a tire will foul on one side but not the other, sometimes on both, sometimes on neither. It really is a lottery in this department. In many instances, the previously mentioned packing washers do the trick.
Last but not least for this issue on the subject - 14" rims. There are a few, that will fit relatively easily. Don't go wider than a 6" rim you will have to use a 45 profile tire. Cost is usually the reason for opting for something else and the fact that they are very very rare on the second hand market. Fitment of this size of rim results in an eye-ball rattling, teeth jarring, harsh ride. Be prepared for much fiddling to get them to fit.
Article Date: Jan 30, 2000