Tuesday, November 18, 2008


In the US, we're 'Geeks', in the UK, we're 'Anoraks', but people who have a keen interest in minutiae can really bolster research when details are needed. Dennis Quinlan and I have had a running discussion over the last 15 years about the origins of alloy wheel rims on racing motorcycles. We had both seen a variety of very old racing wheels, on machines and off, and had come to the conclusion that Borrani were the first producers of flanged aluminum rims. The question became, 'when'?

As we're English speakers with a common interest in Velocettes, we had noted that in the '36 Isle of Man TT, both Norton and Velocette Works racers had used black-painted Borrani alloy rims; presumably the black paint was meant to 'hide' the rims from the competition; but of course the competition had them as well! There have been many stories of riders 'smuggling' Borrani rims into England in 1935, trying to avoid import duty on these expensive new items; one such story has Stanley Woods arguing with a customs officer in England, claiming that he shouldn't be charged duty as the new development of wheel technology was in the 'national interest'. He won the argument.

These rims lowered the overall weight of the whole machine, and helped with the road-holding of sprung front and (by '36) rear wheels, reducing the bouncing mass which the springs and friction shock absorbers had to cope with. Lighter weight allowed the forks to respond more quickly and accurately to road surface changes, keeping the wheels in contact with the road longer over bumps, which means more traction, and the ability to use more power without fear of a skid.

On April 22, 1922, Carlo Borrani took out a license from the Rudge Whitworth Company of Coventry, England, to manufacture car, motorcycle, and bicycle wheel components (yes, the same Rudge which built motorcycles). Thus, 'Rudge Whitworth Milano' was established, with capital of 1.2m lire, and the factory was located at Via Ugo Bassi 9.

Rudge, with their 'Red Hand of Ulster' logo (see right), had patented a new method of mounting wheels, using a splined hub and one central locking nut. This system enabled much faster wheel removal, arousing interest from racing car constructors. Just 12 months after Sr. Borrani opened shop, Alfa Romeo, Auto Union, Bianchi, and Lancia began to equip their racing and deluxe sports toureres with Borrani wheels. Later in the 1930's, the company changed its name to 'Carlo Borrani SpA' (still in business!), and Carlo started to experiment with light, rigid aluminum rims as a replacement for heavier steel items.

These first rims were butt-welded together, with a small plate welded on the rim flange to strengthen the joint. As aluminum welding was still quite an art and certainly an exception, these plates were used for extra security; wheel rims collapsing in a race would certainly be bad for business! The photo above shows the plate clearly in the upper left corner; the bike is Stanley Woods' 1938 Junior TT-winning Works Velocette.

Borrani used a variety of identification stamps on their rims over the years, and it's interesting to note how the changes from the 30's thru 70's; someday a true Anorak will document the evolution of these stamps, and we'll all sleep more easily. The photograph above is from a rim ca. 1936 - Borrani used Italian language stamps until the 1960's. Some claim the earliest rims had the 'red hand' stamp, but I've yet to see one.

It would appear from photographic evidence that the first use of these Borrani rims on a racing motorcycle was in late 1934, and Moto Guzzi was the most enthusiastic early adopter, with Gilera following suit shortly afterwards. The photo below shows legendary racer Omobono Tenni riding the Guzzi ohc v-twin 'Bicylindrica' at the Circuito di Treviso, in late 1934.

By 1935, nearly all the Italian Works racers used alloy rims, and a few English machines (Norton mostly, plus at least one Rudge) sported them as well. The photo below shows a Moto Guzzi Bicylindrica which has been equipped for road use - complete with horn, muffler, speedometer, and license plate - for the Milano-Napoli long-distance road race. Talk about a roadburner!

Another 1935 shot; this time the motorcycle is the Gilera 'Rondine' 4 cylinder dohc water-cooled racer, in March 1935, at the Tripoli GP. Pierro Taruffi rode this machine to victory, using what I believe is among the very first 'dolphin' fairings, of hand-beaten aluminum alloy. His mechanic Orlando Ciceroni sits on the bike, wearing the ubiquitous beret and coveralls of Italian motorcycle mechanics.

In June 1935, the first Borrani rims appear at the Isle of Man; below is Jimmie Guthrie on his Works Norton in the Senior TT, with black-painted alloy rims (and a fully enclosed rocker box - something which didn't 'stick'). Alloy rims also appeared on the Rudge - naturally - of Tyrell-Smith. How Norton came to trump the competition in this regard needs some investigation, as Velocette didn't use them at the TT until the following year.

By 1936 alloy rims can be seen on most of the victorious Works racers from Norton and Velocette (as above on Stanley Woods' 495cc ohc Works Velocette), although they seldom appear on privateer machines until 1938/9. Interestingly, the Italians didn't seem keen to share this racing advantage with German factories, and apparently the Germans developed their own, non-flanged aluminum rims which were rivetted together. I'll post more information about these early German rims as I find photographs and documentation.

The truth is, BMW didn't need the weight savings, as their supercharged ohc Works racers were a good 50lbs lighter than the nearest Norton or Velocette! By contrast, the NSU dohc blown racers could have used any lightening they could find, as their all up weight was over 450lbs - almost 100lbs more than the nearest Norton. DKW 'lightweights' were a misnomer as well, being considerably heavier than their 250cc competition, but they produced (like their BMW/NSU brethren) so much more horsepower than their English rivals, that perhaps the designers felt the weight was a non-issue, which proved true only on the fastest and least 'bendy' circuits.

Many thanks to Dennis Quinlan for his information! Also, images are taken from Mario Colombo's excellent Gilera Quattro and Moto Guzzi books, and Mick Woolett's Norton.


Anonymous said...

Hello Paul,
Your current blog...good one!
I had a note from Ivan Rhodes saying that he had seen my blog...so either me or yourself should drop him a further note indicating your blog continues the thread with more detail.
I intend to write a story on the alloy rim for Jim Scaysbrook's "Old Bike Australasia" which would appear in the edition after the one at the printers.
With your information and mine, if you are in agreement, I will incorporate both blogs into an article with joint authorship.
I'll arrange for a copy to be sent to you in due course.
Keep up the good work!

Kindest regards,

Anonymous said...

Hi Paul,
Best wishes from South West-Germany.

Nice Story about Alloy Rims,but I will response that(if you like it).You know that I ´ve seen some more German pieces in original condition than others,so I will tell you today that DKW had Alloy Rims(not flanged) wich looked like these Standard Steel rims.

They´re made by aircraft alloy not welded,just hold by a thin steel clamp am some rivets on there open Ends to connect them. Highly polished. There was a German Company logo stamped on(I can't recall which),example the Schneeweiß 250 Kompressor rear Rim.
The NSU Works started in 1938 with Alloy Rims sometime shown only in front or rear but also both,and in 1939 the all had the Flanged Borani Type 21 "in Front and 20x2,1/5 Rear,also some Singles started on this.There are still old Boranis,and also unknown with little shorter flanged versions fitted.post war there was a German Brand WEINMANN who used these Alloy´s.
You can see all Photos of the pre war NSU´s on the website of Heinz herz,ask him for copy´s or look just in thge outsold Book "NSU RENNGESCHICHTE "from 1982 written by Dieter Herz and Karl reese ISBN 3-87943-797-1

Rememeber also the Silver Arrows Auto Union and Mercedes GP cars who rolled also on Alloys.....regard
My NSU Racing Cars have BBS /SPIESS Triple screwed magnesium Wheels which are the lightest ever built.Germany had sometimes also good ideas,today i´m afraid it is copied in China ore where ever before the Germans start to produce them......

best regards

Anonymous said...

Sign me up as an Anorak...I find this stuff fascinating. Thanks, Jerrykap

Anonymous said...

Hi Paul,

I have enjoyed your web page for some time and I'm slowly working through the informative articles. Well done.

The purpose of me contacting you is in relation to the identification of Borrani rims. A small group of Ducati bevel drive owners got together last year, in Perth Western Australia, wanting to talk, ride and associate with other likeminded owners. ( the group has grown to 60 plus) The one question that keeps coming up is the identification of Borrani rims, and there supply history to motorcycle companies. Your Borrani article goes some way to help identify Borrani's numbering system but I couldn't find any reference to the numbers themselves. i.e. 4777, 4026 etc...

Do you know of anybody/company that has put such a list together. Any feedback would be greatly appreciated.

On another note a couple of guys from Perth are heading over to the Moto Giro in May this year. Last year a Green Frame 750 Ducati was sent over, this year it will be a 750 Sport and a GT.

(photo attached of the inaugural bevel ride last year)



Anonymous said...


I found it interesting reading, your article about the Borani rims.

I dont know if it helps but i forward you a couple of pictures of a german aluminium rim as used on the racing BMW s, compressors and R51 RS just before the war. I couldnt believe it when i discovered, but it seems only rivited!



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Anonymous said...

Enjoyed the article! Well done.

Bill M said...

excellent info! I've been doing a lot of research into classic wheels for our group and I'll be sure to have them reference your site.

Bill M.

Anonymous said...

Great artical, I must have one of the holy grail of borrani motorcycle rims.....with the mythical red hand of ulster stamp on it!!!! its a a wm1 x 19 x 40 hole on my pre war triumph t100 racer special.....I will send you a photo.
Regards, George....'in Ulster N.Ireland'

andrew john said...

thats true nice artical abt rims thanks for sharing


Anonymous said...

great it is correct, stamping on light alloy Borrani rims from 1939 till april 1951 had a little hand logo. the company from RW-Milano changed in Carlo Borrani SA in 1939 forced by the Italian laws.
If anyone is more interested in info please contact me at m.bosisio@ruoteborrani.com

Best Blogs said...

It is very excellent information! I've been doing a lot of research into alloy wheels for our group and I'll be sure to have them reference your site. You really did a great job by posting it.

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