6 replies to this topic

[prseagerthomas]

I wonder if any contributors have the exact details on the wheel sizes as used on the Auto Union, specifically the C Type.

 

All references suggest a standard front fitting of 17" with standard rear fitting of 19", (with the use of 22" on the faster circuits). The earliest reference I have is from Pomeroy's 'The Grand Prix Car Volume 1' where he states the use of 5.25 x 17 front tyres and 7 x 19 or 7 x 22 rears.

 

Photographs however do not seem to back up this information, with brakes filling both front and rear wheels equally.

 

Pomeroy also stated that the W125 Mercedes had 17" front wheels, though again photographs seem to disprove this.

 

Opinions please gentlemen.

 

Thank you, Peter. 

[Allan Lupton]

Posthumus also says 525 × 17 front and 650 or 700 × 19 or 22 rear.

What he doesn't give us is the brake drum diameter but (a) it is not necessarily the same front and rear and (b) the extra diameter due to the fins is also not necessarily the same.

Pom quotes 16.4" brake drum diameter which isn't that likely (being 416.56 mm) and is quite big to fit in a 17" wheel so may be the OD rather than the ID usually quoted.

[Tim Murray]

I’ve checked the technical data in both Le Leggendarie Auto Union by Cancellieri and De Agostini and Auto Union Grand Prix Wagen by Stefan Knittel. Both are agreed that 17” front wheels were only ever used on the Typ A. The Typ C used only 5.50 x 19 front wheels, with either 7.00 x 19 or 7.00 x 22 at the rear.

 

ETA: The 6.50 x 19 rear wheel size was again only used on the Typ A.

Edited by Tim Murray, 20 February 2014 - 18:13.

[Tim Murray]

With regard to the W125, DSJ in his book on the car made no mention of 17" wheels. He listed 4.50 x 19 or 5.50 x 22 at the front; 7.00 x 19, 7.00 x 22 or 7.00 x 24 at the rear.

[prseagerthomas]

Thank you for the replies to date.

 

Allan, I'm guessing that Posthumus will have used Pomeroy as his reference for the Profile data, (and Pom in turn credits von Eberhorst). 

 

As mentioned, contemporary (as well as modern) photographs show wheels of an equal size, the only exceptions being Reims,Bremgarten etc where higher speeds were reached.

 

I note that both authors used drawings showing the same size front and rear and both artists went to the trouble of having taller tyres on the rear.

 

Tim, thank you for the references from two books I was unaware of. Which do you consider to be the better book? Do either give reference to the size of the twin rear wheels used for hillclimbs?

 

Peter.

[Tim Murray]

Tim, thank you for the references from two books I was unaware of. Which do you consider to be the better book? Do either give reference to the size of the twin rear wheels used for hillclimbs?

 

Peter, my problem here is that Le Leggendarie Auto Union is in Italian and Auto Union Grand Prix Wagen is in German, and neither my evening-class Italian nor my schoolboy German is good enough to get a full appreciation of the text.   They’re both similar in concept - both cover the background to AU formation, technical details, racing history etc, but the Italian book is a bit bigger and more comprehensive, with potted biographies of all the drivers etc. It’s also a much better quality book – my copy of the German book is starting to come apart, although it’s not exactly had a hard life. The German book has some fascinating photos that aren’t in the Italian book, and vice versa.

 

They’re both available second-hand:

 

http://www.amazon.co...i/dp/B0000ECHF9

 

http://www.abebooks.co.uk/Leggendarie-Auto-Union-Cancellieri-Gianni-Agostini/5520824706/bd

 

http://www.abebooks....an/9438859273/bd

 

 

As far as I can tell, there’s no mention in either book about the twin-wheel sizes

Edited by Tim Murray, 21 February 2014 - 13:52.

[prseagerthomas]

Tim

 

 

Tim, if there are good images, it is often worth the expense.

 

Pritchard's awful 'Silver Arrows in Camera' has some beautiful clear images which must be factory photographs, together with several of Klemantaski's colour photo's.

 

Peter.