Woke up this morning thinking about the recent replies about the Austin 7, and just had to do
a little comparison of them to the Cyclekart’s we’re assembling. Most of the following is information
taken from various sources on the internet....I think of that as research, so I’m not laying claim any
of it as my own, nor to the validity of it. There’s a ton of detail out there if anyone was interested in
more, but the following caught my eye and satisfied my curiosity…at least for the time being.

Tax Horsepower (RAC horsepower-taxable horsepower)
The 1924 Austin Seven's 747cc engine produced 10.5 brake horsepower, 50% more than its official
RAC (Royal Automobile Club) horsepower rating.
The RAC rating devised in 1910 was DxDxn/2.5 where D is the diameter (or bore) of the cylinder in
inches and n is the number of cylinders.
To minimize tax ratings British designers developed engines of a given swept volume (capacity) with
very long stroke and low piston surface area and low cylinder count.
Early on an identical formula was used in the USA and a similar form in much of early Europe.

1. HP is the output horsepower rating of an engine, while BHP is the input brake horsepower of an engine.
2. BHP is the measurement of an engine’s power without any power losses, more of a theoretical calculation,
while HP is BHP less the power losses.
3. HP is measured by hooking up the engine to a dynamometer with all of it's accessories attached to it, while
BHP is measured in a controlled environment without anything attached to the engine.

When I compare the early stock Austin 7 (pre 1930) to our karts performance wise and
Dimensionaly they really are quite similar. With some minor modification the 200cc
engines we’re using are capable of putting out comparable HP. The physical dimensions
of our karts are just slightly less than those early Austin’s at. 75” WB, 40” Tread. However
they were heavy weights at 794 lbs. next to a CK at 250-300 lbs.
Because of the simplicity of a Cyclekart, we are considerably less weight, typically ½ or less.
Obviously the power to weight ration of an Austin 7 modified for racing would be much, much
higher than in its stock form. So it only seems reasonable that we should experience a
very similar feel to what the early hot rodders felt back in the early to mid 20’s.in our
flimsy contraptions.
Denny G
Sandwich, IL

Your last sentence says it all! And THATS the point of cyclekarts for me.

Thanks for sharing

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"Magic Man"

1927 Nash Modified: Legion Special
"Build" Thread - https://www.cyclekartclub.com/phorum/read.php?2,26661

I think Rhys, who has driven a few of those cars has remarked on the similarity.
Indeed, what it's all about!

Yes, they are quite similar, and even the kart type steering is very little quicker than the so called steering boxes on every A7 I have driven!. You do learn to not grip the wheel too hard fairly quickly! I guess if you have been brought up with the slow (many turns lock to lock) of a typical US car of the earlier (50/60) times then the kart steering can be intimidating.

That's one of the nice things about the newer cars. We added a Chevy Equinox to the stable
this past summer and the steering is really nice and quick. I very rarely am past a quarter turn
one way or the other.
That's never bothered me since I was building and racing go karts back in the late 50's and
then midgets early in mid-life.
I've had a few Ross S10 model steering gears on the shelf ever since I first discovered the karts.
They were designed for International Harvester Cub Cadet garden tractors back in the early 60's
and John Deere later used them also. The IH gears are 2-turn and the Deere are 3-turn and I've
got a few of each I'm going to experiment with. I think Al was the only other guy that I've seen
using them. It's not clear which gear he is using and I've been trying to get him to post some
of the data/geometry that he used on his kart. Not sure if he's using the IH or Deere gear
and would like to know the ratios of his pitman arm/steering arm.
Ya'll have a good day.
Are you still working at the Museum?
Denny Graham
Sandwich, IL

Long since left the Museum, it was like running a creche.
Al told me his was a Cub Cadet early version. When I drove it in November it took a while to realise that the steering wheel was connected to the front wheels, no feel at all. Nice car to drive, but the lack of feel made for HUGE mental changes.

Lots of politics going on there at the museum??
That's good to know, about the Ross gear that is. Al wasn't sure what it was when I
talked with him on the phone last fall, must be his advanced years. Kidding, (he's
the same age as me, by the way!)
I don't understand why you wouldn't get any feed back using that gear, unless the front
end geometry or the linkage ratios weren't correct. If ya want more feel, add more caster
or move the contact patch. I see guys making an all out effort to intersect the king pin and
tire CL then with this light of a front end loading you end up with no road feel.
I had planned to roll the Riley chassis out into the drive and make some turning radius
measurements, but 4-6" of snow put the kibosh on that idea.
The weather this weekend gives new meaning for me to the the term...."Drifting". The drive
has been 'drifting' all night and now I'm gonna have to shovel again today!!!!
dg

It seemed to me that while Al's steering does have feedback, it was just startling to go it from pure gokart, where you feel every pebble. You usually think of how the ratio effects your steeering input. But thats a two way street. A little bump or rock can move the steering wheel 2" with direct linkage. Every bit of ratio diminishes that
effect. While obviously not as responsive, the karts with steering gears I've tried are less fatiguing to drive.
But, that razor sharp 1:1 feel really grows on you.

Denny
Snow will make the perfect platform to get an exact measurement for your turning radius, and if you have any
"push" it will really show up on the slippery surface. Don't waste this opportunity.......don't be so hasty to shovel.
And Rhys
Creche has a whole different meaning here in North America.......thru me off for a moment!
But, I bet it was???

So what is a creche in US terms?
The issue was that on any slightly unpleasant days the "young mums" would come in, sit down spend hours on texting and such, and let the pre-school kids do whatever they wanted. I was there to look after a "Hot Rods and Cool Customs" exhibition, not run a pre school kid management exercise, so I quit. I now run the European operation for Racetech who market, race seats, harnesses and such. So much for retirement!
Way off topic, again!

Retirement.......that's something you really need to work
at else it slips away from you.
And.....I been working at it real hard for 14 years.
dg

Nativity Scene

the Austin Seven is the car I wish to copy with my build. To all who call in I am open to any suggestions as to building etc.
The photos attached here are what I am going on and this afternoon I am going to start drawing a chassis plan to get the 'design' sorted.
Now then as the idea is to be able to run Tieton this year, I will follow their guide lines as to overall length and wheelbase etc.

The front axel on the original cars was quite a complicated forging. I am thinking of fabricating mine up from hollow rectangular section and flat bar top and bottom. Drill thru and fit all the bushings etc. I am thinking of doing the same as Austin did with the kingpins.

Well I better get drawing. I am also back out to Mission in the morning to complete the workshop bay.

Stay safe everyone

James J.

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"just another colourful stitch in the rich tapestry of life"

CK Skunk Werks, Mission BC

IMHO, what makes an Austin 7 credible as a CK, is that it has the transverse leaf spring. The axle is not a complex forging (I cut one down for the "Great Austin 7 CycleKart build off" I took 2" out of the middle of the simple I beam to make it measure, ie a genuine Austin 7 axle.
If I were to do another, it would be a profile cut piece of 1/8" plate for the vertical with strips of the same top and bottom. The original is less than 1/4" on the vertical face.
The one you have shown James is very similar to the one Johnny Dumfries did for that build off, which Dennis Thomas, He, and Bob completed cars. Mine was snatched up by someone who liked what I was doing for the Bruce McLaren inspired car before I completed it (and lead me close to doing a full size one for the McLaren Trust).
Photo is my own A7 special.

Hi Rhys and thank you. I was thinking of the profile cut too, but was over thinking the strength. I have found a drawing on the net of the front axel so I will dig that out and get the size I should make it. But if I go on the usual build details here, 1 ¼" seems like the target size for the height and ⅞" wide. I will tack weld first and then bore all the holes for the bushings and then finish weld the whole unit.
I will get the front spindles profile cut and then machine down to size etc.

At this stage I am still trying to find a suitable second hand mill/drill but one will come up.

That is a very nice looking A7 you have there. That has just got to be a lot of fun to drive.

James J

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"just another colourful stitch in the rich tapestry of life"

CK Skunk Werks, Mission BC