22 replies to this topic

[antonvrs]

In several threads on this forum there has been mention of dual rear wheels as used on many racing and hillclimb cars in the twenties and thirties. I'm curious as to how this was accomplished.
I'm assuming there must have been a special extra length rear hub- is this correct?
In pictures the rear outer pair of wheels seem to be very deeply offset. Were these special wheels? The normal wheels reversed?
Do any of these setups still exist?
Inquiring minds want to know.
Anton

[Ray Bell]

I'm quite sure many of the ERAs still have the option dual rear wheels... when needed, of course...

[David Beard]

Originally posted by antonvrs
Do any of these setups still exist?

Indeed...

[antonvrs]

Interesting photo, David.
It looks more like two tires mounted on a double width rim than dual wheels.
Anton

[FrankB]

Originally posted by David Beard


Indeed...

It took me a moment to work out just what was happening here - then I saw the trolley jack under the back end...

[john medley]

I bought a pair of dual rears with a basket case project I bought a while back , and they really are crude in the extreme : quite simply one spokeless rim welded onto the normal ( inner) rim still with its normal hub . I was led to believe that the duals had been used on a competition car in South Australia in the 1930s , but I dont know which one . As far as I recall , Tony Gaze's Alta was one of the few users of dual rears in Australia .

I continue to be intrigued as to how the centrelock nut was tightened : did they use an extension that cupped the knockon at one end and was smitten with the hammer at the other , or did they employ a Man who was extraordinarily accurate as he belted the knockon through the hole created by the outer rim ?

[Catalina Park]

John, I remember another use of dual rear wheels in Australia, on a Monaro at the Catalina Rallycross! (and there may have been others!)

[antonvrs]

Re: Tightening the nuts. I've seen pics of a tool used on cars from the '70s(?) which consisted of a long "T" with a socket on the end, supported by a disc which located in the wheel rim. With a shoulder in the proper location on the "T" shaft, one could tighten or loosen the wheel nut without slipping off.
Maybe they had something similar in the '30s?
I've certainly never seen such a tool in period photos- but?
Anton

[Peter Morley]

Originally posted by antonvrs
In several threads on this forum there has been mention of dual rear wheels as used on many racing and hillclimb cars in the twenties and thirties. I'm curious as to how this was accomplished.
I'm assuming there must have been a special extra length rear hub- is this correct?
In pictures the rear outer pair of wheels seem to be very deeply offset. Were these special wheels? The normal wheels reversed?
Do any of these setups still exist?
Inquiring minds want to know.
Anton

I think one of the Auto-Union replicas has been fitted with twin rear wheels?
A-U ran twin rears when they hillclimbed the car in England (as did some ERAs & Bugatti type 59s).

The low top speed in (British) hillclimbs meant they could gear the cars for acceleration, but normal tyres did not offer sufficient grip to prevent wheelspin, so some people tried this every simple way of doubling the tyres width.

It looks more like two tires mounted on a double width rim than dual wheels.

That would not work, the rim needs to hold the tyre in place - you need the full U shape of the rim to locate the tyre, so it has to have a UU section.

Re: Tightening the nuts. I've seen pics of a tool used on cars from the '70s(?) which consisted of a long "T" with a socket on the end, supported by a disc which located in the wheel rim. With a shoulder in the proper location on the "T" shaft, one could tighten or loosen the wheel nut without slipping off.

For the Lotus 49, they used a plywood disc that fitted inside the outer lip of the rim to support the socket that they used to tighten the wheel nut.
There is a pretty common photo of the mechanics tightening the wheel nuts using this arrangement.

That would not work with the pre-war spinner since you need to hammer it tight - there is so much resistance on the spinner that it can't be hand tightened.

I expect they just used the normal copper or lead hammer and tightened the nut in the normal way, albeit with more limited movement of the hammer. As for potential damage caused by the hammer striking the rim, it doesn't look like people were as bothered about presentation in those days.

[Racer.Demon]

Originally posted by Peter Morley
I think one of the Auto-Union replicas has been fitted with twin rear wheels?

Yes, indeed:




More Alta shots:










And of course there's the 312T6...

[David Beard]

Seen recently at Shelsley Walsh....

[uechtel]

Paul Greifzu at the Sternberg hillclimb, GDR 1950

[GBarclay]

In recent years in the Pikes Peak hillclimb, there has been a Freightliner "truck" running in the heavyweight class.

A detuned diesel from the Euro truck series powers this beast. Linked rear suspension, that can run single or dually rear wheels. The crew can change depending on track conditions. Dually rear wheels for the more open coursses, singles for tight twisty climbs.

The team is based out of Hollywood, California. I have seen them at Pikes Peak, more recently at the Lands End hillclimb near Grand Junction Colorado. I think the truck may have competed in the better known NZ climbs.

Very impressive beast. Quicker than our VW GTi rallycar by about 15 seconds on a 6 minute climb.

[Richard Neale]

In period on Bugatti's you had to change the rear axle tubes and half shafts to fit the special cast twin wheels. These axle tubes were shorter than the standard ones so that the inside wheel came further inboard and the outer wheels didn't stick out too far.

[Graham Clayton]

John, I remember another use of dual rear wheels in Australia, on a Monaro at the Catalina Rallycross! (and there may have been others!)

Catalina Park,

Didn't Peter Brock run his XU-1 Torana rallycross car in the early 1970's with dual rear wheels on some occasions?

[Lee Nicolle]

Catalina Park,

Didn't Peter Brock run his XU-1 Torana rallycross car in the early 1970's with dual rear wheels on some occasions?

In 70s Aussie rallycross quite a few cars used dual rear wheels with rally tyres at times, usually to the detriment of the axles and diff.The HDT Torana used them for a short period, as did Warwick Hendersons 350 Monaro. In SA Colin Hanks used duals on his Holden powered Viva, I think Phil March did too on the Datsun and the Charlie Orlando Torana.
Because of the unsprung weight they broke diffs and axles regularly and as far as I remember every one went back to single rims with wide rally tyres, wet weather race tyres or speedway tyres.
On those cars it was simply an extra rim with a small spacer welded to the inner rim, and they were bloody difficult to remove the tyres

[onelung]

Allow me the off topic indulgence please, but Lee's "they were bloody difficult to remove the tyres" prompted this post.
Anyone who has wrestled with a beaded edge veteran car tyre will surely have the same thought I did ... "how the hell do they deal with THESE?"
And, one can also try to imagine having to deal with them in the mud and muck of the Western Front. The mind simply boggles.

[ghinzani]

Seen recently at Shelsley Walsh....

Any pics of the front? Looks like Dunlop gearbox tyres at the back, wonder how sticky they were?

[Graham Gauld]

Former Porsche driver who was successful in the Pan American Road Races, Jaroslav Juhan, who was later to become involved in the De Lorean affair, developed a double wheel system aimed at road cars but as far as I am aware no manufacturer took the idea up. About eight years ago I visited him at his then-villa near Cannes and he led me to the villa behind his Cadillac fitted with the twin rear wheels. As far as I am aware he may still have the car.

[Lee Nicolle]

Talking about dual rear wheels look at Ray Bells post 205, page 6 on the commercial vehicle nostalgia thread. A Chev Blitz with duals all round! It would be fun to steer!

[Ray Bell]

That one was a Ford, I'm pretty sure, Lee...

They reckoned it wasn't all that bad, actually. But I suspect they only used it in muddy conditions.

[terry mcgrath]

two Jaguar SS100's have run with dual rear wheels one of course being 18008 the works racer
terry

[onelung]

The brain cells have at last aligned to remind me that at a Geelong Speed Trial event some years ago I spotted a special (Austin? Morris?) - no bodywork, side valve, supercharged and ... dual rear wheels !
Silly me - thought "this guy's having a lend of himself!" However .. departure from the line was accompanied by protesting smoke-wreathed tyres as the car rapidly disappeared into the distance!
I'll never make assumptions about supercharged side valve race engines again: particularly when they're fed on alcohol fuel.
BTW - anyone able to ID the car?