Lotus 9

[willga]

I've read a number of accounts of the variability amongst Mark IX's:
That some chassis were very similar to VI's, while others were more like XI's, and that the works LeMans car was something different altogether, with a deDion and disc brakes.

Does anyone have any record of chassis numbers, or have a timeline of what modifications occurred when?

[Rupertlt1]

Some detailed pictures of Len Bastrup's Lotus Mk IX at Watkins Glen 1955 here:

https://revslib.stanford.edu/catalog/qt197jc2499?

https://revslib.stanford.edu/catalog/vz096mk4657

https://revslib.stanford.edu/catalog/wr779fp9013

[PeterMorley]

Originally Posted by willga

I've read a number of accounts of the variability amongst Mark IX's:
That some chassis were very similar to VI's, while others were more like XI's, and that the works LeMans car was something different altogether, with a deDion and disc brakes.

Does anyone have any record of chassis numbers, or have a timeline of what modifications occurred when?

Production Lotus VIII, IX & X were all based on the basic Mark VI frame, with different outriggers etc. for the different bodies, engines etc.

The first Mark VIII (works car SAR5) had a completely different type of chassis that was 'fully triangulated' and very impractical.
Similarly the works IX apparently had a chassis that was closer to the later Eleven chassis.

Most IXs had the large 'turbo-finned' alloy drum brakes but the first two Sebring cars had smaller drums and some chassis differences since they were effectively prototypes and not all the latest parts were ready.

Some IXs were built with solid rear axles but tended to be upgraded to De-Dions, similarly some cars (e.g. VIs & VIIIs) supplied with smaller brakes were upgraded to 'turbo-fins'.

The second works Mark IX (XPE6 Peter Jopp's car) had disc brakes I think some of the last IXs were fitted with disc brakes as they became more widely available.

UK cars were supplied as kits so there would have been some variations between them (such as Dick Steed's car built using the running gear from his Mark VIII) but US cars were factory assembled so would be more alike.

There were some bodywork variations - such as the air duct in the rear body of some cars and John Coombs' car that had cut down rear wings.

[Rupertlt1]

For picture collection go here:

https://revslib.stanford.edu/catalog...=Lotus+Mark+IX

Two Ontario Lotus IXs:

Lotus IX – Imported by Autosport, Cooksville, ON: (Jack Wheeler & Bob Hanna)? Tom Gilmour ---> Dennis (Denny) Coad ----> John Headon ---> ??? --->???
Tom Gilmour's Mk IX was c/n 147. Per Pat Dennis: “I know that Gilmour bought the Racing Car show Mk IX chassis that was on display with a "wire-form" body, had it completed and sent to him.” The year 1955. Car painted red. Raced as #133 and #131?

Lotus IX – Imported by Jerry Polivka---> Stan Ward ---> Harold Lazier & Bill Muir --> Jack Boxtrom
Chassis #? Polivka car was white with thin green noseband, #145; blue when Harold Lazier & Bill Muir bought from Stan Ward, and then repainted green. Now?

[PeterMorley]

Apparently chassis 147 (the last Mark IX) that was bought by Gilmour had been on display in the Coventry Climax showroom in Piccadilly with a polished chassis and running gear (with the wireframe/skeleton bodywork to show these features off).
Presumably it had been prepared like that for the Racing Car show prior to visiting the Climax showroom.
It was completed before shipping to Autosport Motors in Canada in late 1956/early 1957.
IIRC it was fitted with disc brakes.

The Polivka car (shared with R Davison?) was chassis 138 the second last Mark IX and first appeared at Harewood Acres in October 1956.

[Rupertlt1]

If you look in the picture selection at Post #4 you will see the car displayed at the Racing Car Show 1955.

Bob Davison of Buffalo, NY, raced MK IX, race number 142. I think this is a different car to the Polivka one?

[Rupertlt1]

Originally Posted by PeterMorley

The Polivka car (shared with R Davison?) was chassis 138 the second last Mark IX and first appeared at Harewood Acres in October 1956.

Polivka raced the Lotus IX #145 at Harewood Acres, Ontario, on 4 August 1956 - listed in programme plus there are pics in the Revs Digital Library.