Alpina and Borrani (CMR) 13” Steel Rims

[Conserv]

1 hour ago, quant said:

 

I've read about that 'double hump' in relation to the CMR Borrani steelies before, and once saw the attached diagram as an description.

 

But I never really understood what that 'double hump' is all about.

 

Could you provide some more explanation on this?

e.g. questions that I have are:

• What is the reason for the 'double hump' - is it, so you can run with tubeless tyres (as you mentioned above) ?
• To what extent is there a 'genuine risk' of deflation when you run a tubeless tyre on a 'flat hump' Borrani? 
• What alternatives were made to the 'double hump' CMR Borrani wheels - is it the 'flat hump' as indicated in the diagram, or are there (also) others ?
• Could you show some photos of these different types of wheels, which clearly show these differences (double hump vs. other types) ?  As I've never actually seen the difference / the different type of wheels shown side-to-side
• How can you recognise what type of wheel you have - you mentioned "H2" on the rim - where would this be shown? What if you have another type of rim; what does that show?  Do you have some photos of actual rims showing this?
• Why were these different types of rims made - as I assume they will all made by CMR in Italy?
• Was e.g. the double hump wheel produced later (as like an 'upgraded version') then the flat hump wheel, or where they produced in parallel? 

Ok, lots of questions to better understand of the variaties of CMR Borrani wheels out there.

Thanks for your insights.

 

 

Quant,

 

I’m going to try to keep this brief. And I’m going to somewhat ignore your individual questions, with the hope that you’ll gain a more “global” view of the “hump issue”.

 

1. Humped rims are not a CMR-specific issue. They affect all rims.

 

2. Manufacturers — many manufacturers — seeking to improve their rim designs, found that a hump or two on the rim’s barrel could help hold a tire in place under extreme conditions. If a tubeless tire “breaks its bead” (meaning the airtight seal between the lip of the tire and the lip of the rim is broken), the tire goes flat just when you need it most to be inflated.

 

3. There are single and double-hump rims. Single-hump rims (“H”) generally preceded double-hump rims (“H2”). And there are variations on the hump, such as the flat hump (“FH”). It gets complicated quickly. Someone such as Uli (@uai), who is both German and an authority on rims, likely has a far better handle on these variations than I. But I believe a “flat hump” qualifies as a hump for TUV purposes.

 

4. Here’s where my embarrassing lack of history and German TUV knowledge will limit my comments. Manufacturers, such as BMW and Mercedes, and probably everyone else, were adopting humped rims. I’m guessing they were doing this voluntarily. But at some point — perhaps the mid-1970’s — the German TUV made tubes mandatory if you did not have double-hump rims. I’m guessing this encouraged car and rim manufacturers to move to double-hump designs.

 

5. Somewhere, buried in this thread’s 21 pages of “good stuff”, I noted the first double-hump CMR I saw. I seem to recall it was a rim dated 1980, or thereabouts. But a decade earlier, you could find H2 rims, or FHA-H rims (a variation on the double flat-hump, I believe), manufactured by Lemmerz, FPS, Kronprinz, Ronal, etc.

 

6. Before the humps, there were… no humps. Below are examples of Alpina and Campagnolo alloy rims with… no humps whatsoever! The recessed central area at the center of the barrel is referred to as the rims’ “drop center”. It is un-related to humps, but it does help facilitate the mounting of tires.

 

Regards,

 

Steve

 

[Jam3422]

I've been running tubeless cn36s on my non-double hump Alpina 5.5x13 steel wheels for 4-5 years or so, no problems at all.

 

From what I have read, cn36s were introduced in 1968, so should pass muster with Steve to use on a 2002ti. 

[Conserv]

18 minutes ago, Jam3422 said:

I've been running tubeless cn36s on my non-double hump Alpina 5.5x13 steel wheels for 4-5 years or so, no problems at all.

 

From what I have read, cn36s were introduced in 1968, so should pass muster with Steve to use on a 2002ti. 

Thanks! That’s IF I owned a ti! ??

 

Best regards,

 

Steve

 

[quant]

22 minutes ago, Conserv said:

Quant,

 

I’m going to try to keep this brief. And I’m going to somewhat ignore your individual questions, with the hope that you’ll gain a more “global” view of the “hump issue”.

 

 

Steve, can I please make a download of all your 02 and other automotive related knowledge ??

 

or can you start a YouTube channel - I’ll subscribe !

 

thanks again for sharing your knowledge

[jazz_and_bimmers]

6 hours ago, Conserv said:

Michael,

First: they’re gorgeous!

 

Was the seller, perhaps, German? If so, since your Alpina steelies are not “double hump” (abbreviated as “H2” on the rim), the German TUV would, indeed, require you to use tubes. Without the double humps, tires are slightly more likely to unseat, or “break their bead” during hard cornering or other extreme conditions. The tube would keep the tire inflated if you unseated the tire under those conditions.

 

In the U.S., however — a.k.a., the land of bald tires and “any-lane-can-be-your-lane”, where road safety is considered “over-rated” — there’s no particular reason that you must use a tube on an Alpina steelie, whereas a Borrani wire wheel needs a tube to avoid leaks. The German TUV is simply safety conscious and conservative. Unless…. unless, of course, you’re already running, or plan to run, a tube-type tire, such as a Michelin XAS, the most common original tire on most U.S.-imported ‘02’s, and probably installed by the factory on most Euro-market ti’s and tii’s. 

 

The XAS, introduced in 1965, was also produced in a tubeless version from ca. 1975 until the end of regular production (1985-ish?). But only the original tube-type version has been produced since that time.

 

Considering that you’re rockin’ a ti — I’m guessing with both Alpina steelies and a 235/5 dogleg — you should seriously consider 165HR13 XAS’s for those steelies. Even when Alpina was modding an ‘02 in these early years (before 1974-ish), they stuck with 165HR13 XAS’s. The first photo below shows a no-expense-spared Alpina-modded 1600-2, in 1967, with the 5 1/2” steelies and XAS’s. The second photo shows a no-expense-spared Alpina-modded 2002ti, in 1969, with Alpina 5 1/2” alloys and XAS’s. The only other tire I would consider for a ti is probably the Pirelli CN36 in 185/70 HR13. I’m not certain, however, when the CN36 was introduced; it might have been 1971 or 1972. I haven’t done the research. Of course, I believe a “period look” is supercritical on a ti, but you might want to consider the source for this sage advice… ?

When you order your XAS’s or CN36’s from Longstone Tyre, they can provide tubes — completely optional for the CN36’s in the U.S.… ?

 

Best regards,

 

Steve

 

 

Thank you for this incredible wealth of knowledge, Steve! Yes, I purchased them from a fine gentleman in Munchen.   I plan to mount the Pirelli CN36’s which are currently in my garage. Since I do intend for spirited driving AND authenticity, perhaps I should go the tube route. I purchased the tires from Lucas, so will check their site for the tubes.

Many thanks,

Michael

 

PS

Yes, dogleg, 3:64 limited slip!

Will post some pics and add to Ti registry soon!

Edited August 13, 2021 by jazz_and_bimmers

[Conserv]

Michael,

 

Just as @Jam3422 says above, I’d probably pass on the tubes for tubeless CN36’s. Tubes won’t hurt, and aren’t expensive, but don’t be surprised when the counter person or tech at the tire store gives you an utterly blank look when you mention the tubes. He or she has probably never heard of tubed automotive tires… ??

 

Just saying… we’re not in Germany! ?

 

Best regards,

 

Steve

 

 

 

[Lorin]

1 hour ago, Conserv said:

Michael,

 

Just as @Jam3422 says above, I’d probably pass on the tubes for tubeless CN36’s. Tubes won’t hurt, and aren’t expensive, but don’t be surprised when the counter person or tech at the tire store gives you an utterly blank look when you mention the tubes. He or she has probably never heard of tubed automotive tires… ??

 

Just saying… we’re not in Germany! ?

 

Best regards,

 

Steve

 

 

 

Im going to disagree on running tubes in tubeless tires not hurting anything. Tube type tires without exception (that I know of)  are smooth on their interior to create a low friction surface for the tube to interface with. Tubeless tires on the other hand have a textured or ribbed surface that will create extra heat and can cause failure of the tube. 
 

I would like to hear what the TUV says about running tubes in tubeless tires. 
 

I have a customer with a Land Rover Defender that wanted to put a modern BFG All Terrain tubeless tire on his non hump tube type wheels. I called BFG and they said no tubes in the tubeless tires. 

 

[Conserv]

6 hours ago, Lorin said:

Im going to disagree on running tubes in tubeless tires not hurting anything. Tube type tires without exception (that I know of)  are smooth on their interior to create a low friction surface for the tube to interface with. Tubeless tires on the other hand have a textured or ribbed surface that will create extra heat and can cause failure of the tube. 
 

I would like to hear what the TUV says about running tubes in tubeless tires. 
 

I have a customer with a Land Rover Defender that wanted to put a modern BFG All Terrain tubeless tire on his non hump tube type wheels. I called BFG and they said no tubes in the tubeless tires. 

 

I haven’t heard that previously, Lorin. And it’s obviously relevant to this discussion.

 

Thanks for sharing it.

 

Best regards, 

 

Steve

 

[Conserv]

On 5/8/2021 at 8:01 AM, Alpina-A0 said:

Just wanted to share a couple of pictures of my Car that is equipped with the Alpine CMR Steelies...

I was looking for a post I made a year or two ago, accidentally came across this… again. And have to say. Your car is perfect, Michael!

I wager there will be no complaints if I re-post it here! ?

 

Best regards,

 

Steve

 

 

 

[Conserv]

Relative Rarity of the Various CMR Versions

 

Elsewhere on the forum, we recently mentioned the relative rarity of various CMR steelies. And I added the following content to that thread. But I thought that I should also insert this same data here, in this much larger discussion of CMR steel rims.

 

And, making no pretense that the following method approaches statistical sampling, if we look solely to the examples in my CMR database (summarized in the spreadsheet at bottom) at the time I stopped collecting examples — a few years back — here is, at minimum, a suggestion of relative percentages of the various versions:

 

Alpina vs. Borrani

30 of 162 examples were Alpina = 18.5%

132 of 162 examples were Borrani = 81.5%

 

Alpina

8 of 30 examples were 5” = 26.7%

22 of 30 examples were 5 1/2” = 73.3%

 

Borrani

6 of 132 examples were 5” = 4.5%

31 of 132 examples were 5 1/2” = 23.5%

78 of 132 examples were 6” = 59.1%

     (43 or 32.6% were ET17 and 35 or 26.5% were ET30)

17 of 132 examples were 6.5” = 12.9%

 

Again, nothing about my collection methods suggests statistical sampling (e.g., Is someone with a set of old 5” rims in their attic less likely to participate in a car forum than someone with a set of new, to them, 6” rims? Maybe!) 

 

But given my own exposure to CMR rims — which was extremely limited during the ‘02 era, I guess I didn’t hang with the cool kids ? — the above percentages do not appear to contradict the frequency with which I have encountered the various widths in recent years.

 

Best regards,

 

Steve

[1dollar93]

I'd like to begin by thanking everyone for the insane amount of time and attention to detail in this thread. It comforts me, considering I'm on a vision quest of my own regarding these wheels. My name is Mike and I'm a research-aholic. I've seen a few threads here and there, as well as a few posts on this thread regarding the "correct" Borrani grey-beige paint. I'm going to refinish my set and I'm ultimately going to go with what I think looks best against my colorado/primer car, but I wanted to contribute to the conversation.

 

The internet has fewer photos of the grey painted wheels than the chrome/silver wheels, but they are out there. I scoured and pulled down as many differing greys as I could, and I present them to you here, in no particular order.

 

 

 

Again, thank you to those who contributed photos to this thread, as many of these photos were culled from within. I would like to get close to deciphering why there are so many different greys, and more importantly, narrowing down to the ultimate Borrani grey/beige paint code. Attached for your consideration are a couple photos of my "pimp hand" gold wheels with multiple different paint chips for choice. These photos were taken in cloudy conditions, so they may differ from the above photos. What do we think?

 

 

Edited December 22, 2021 by 1dollar93

[Conserv]

I believe the answer to the “Why are there so many color variations on a single brand of rims?” is precisely the same as the answer to “Why are there so many color variations on 2002’s’ subframes and suspension components?”

 

And the answer is….

 

It really didn’t matter much, to either the manufacturer or the original purchaser!

 

In the case of the rims, some owners would be painting the rims whatever color they wished. And no particular color went with every body color. The odd gray-beige factory color appeared to be replaced by a generic silver in the late 1970’s, which was, in turn, replaced with black around 1980, which might have been used until the end of production, ca. 1983.

 

Your second and third photos appear to show Alpina steelies, so Alpina probably had something to say about their color. I have not yet seen an Alpina steelie painted at the factory in that distinctive gray-beige “Borrani shade”, despite CMR being the source of both! And many of the photos above represent post-factory paints. Still, I wholeheartedly agree that two original-paint sets of Borrani’s are unlikely to match each other perfectly.

 

Below is my set of original-paint Borrani’s, in a 5” width! They’re all 5” (R1-484), manufactured October 1972, bought together off of a German ti. And yet there are both (slight) color variations among the four rims and a fairly dramatic color shift from “group photo” to “individual portrait”!

 

I would choose a color for Borrani’s that best blends with my car’s color. To be honest, neither Polaris (my ‘76) nor Inka (my ‘73) goes well with the distinctive gray-beige!

 

Thanks and regards,

 

Steve

 

 

 

 

[2002iii]

I would go with the agate grey. To my eyes it looks the closest, not to dark not to light.

 

If you cant narrow it down to one color you could try painting each wheel a different color and try them on the car, lol.

[jazz_and_bimmers]

Hi Friends!

 

Just wanted to share updated photos of my 1970 Ti after installation of CMR's and Pirellis.

 

Merry Christmas!

[Conserv]

3 minutes ago, jazz_and_bimmers said:

Hi Friends!

 

Just wanted to share updated photos of my 1970 Ti after installation of CMR's and Pirellis.

 

Merry Christmas!

 

Not too shabby!

 

Seriously, the car looks utterly fabulous! 

 

Merry Christmas to you as well,

 

Steve