How can the various uprights and stub axles be identifdied?
How can the “larger” bearing (GT 6) upright be identified from the “smaller” bearing Spitfire front upright?
Bob
1969 Elan +2
How can the various uprights and stub axles be identifdied?
How can the “larger” bearing (GT 6) upright be identified from the “smaller” bearing Spitfire front upright?
Bob
1969 Elan +2
Hi Bob
All knock on uprights used the larger GT6 uprights, stub shafts
Bolt on wheels used the early spitfire equivelents.
The stub axles are 5/8"and 1 inch in diameter on the spitfire/bolt-on hubs The stub axles are 3/4" and 1.060" on the GT6/knock-on
Gary
What if a P.O. replaced a KO original upright with an earlier spitfire (bolt on) upright?
Would the hub fit onto the stub axle?
Could a larger (GT 6) stub axle fit onto a small bearing upright?
Bob
Hi Bob
Inner and out bearings are different as well as the Hubs (Elan and
Plus 2 knock-on hubs are also different),stub axles and uprights. It would be easier for a upright assembly to be swapped onto a bolt on wheel car than a knock-on wheel vehicle but that doesn’t mean much to the average Lotus home/pro mechanic. If it can be done wrong, it may very well be done wrong…
Gary
Thanks Gary.
I have a Bean calalog. I will use it as a reference. I am now into front end alignment and wissh to cover all bases. Thanks again.
Bob
Front Suspension 1967 S3 coupe
Can you visually tell the difference between an upright for a bolt-on axle from an upright for a knock-on axle if no axle is fitted?
I would hate to take mine apart, including removing the axles from the old uprights only to find that I had got the wrong new uprights.
A good indicator but maybe not 100%, this cast in pip indicates a late casting that has the larger taper bore.
It is possible to do the full GT6 conversion to bigger bolt on hubs / bearings / axles / uprights…I have done this (part by error, then by design).
I have just one suggestion: whilst this works for Girling AR calipers (alignment) i have not tried it with the original calipers…
Is it possible to spot…no, IMHO.
The tapered stub axle hole is also smaller in the “bolt on” upright, if the two types were together you would see a visual difference.
My PO had fitted the wrong upright then by hand, ground down the taper to make the larger stub fit!
There are a number of aftermarket hangers available that allow a variety of caliper to fit this upright.
GT6 hanger = P16 Spitfire hanger = P14.
Can I tell by measuring the outside and inside diameters of the axle tapered hole with a digital caliper. If so does anyone know what the figures should be?
Outside stub hole measures about 27.5mm on the big upright and small upright is about 26mm.
Inner hole size is 21.5 for big upright and 20mm for smaller upright.
Thank you.
I will measure the pair (that I bought off a fellow member here) tomorrow, before I go ahead with ordering a new set of Trunnion bits from Sue Miller.
Are these for bolt-on axle stubs or for knock-on axle stubs ?
Knock on uses the big stub which needs a bigger hole in the upright.
Bolt on uses a smaller stub so the upright has a smaller hole for it to fit into.
I know that but alas your message above with the measurements is ambiguous unless big upright means the same as big stub and small upright means the same as small stub.
Sorry to be so fussy, but there was talk elsewhere about different sized uprights for higher performance, viz Spitfire versus GT6 which has confused the issue. There seems to be four possible combinations not just two.
Yes there are 4 types of uprights that I know of. Later Spitfire and gt6 changed the steering arm design so that the rear mounting bolt was not used and instead the steering arm went under the stub axle fixing nut and I think the front mounting bolt location was changed slightly.
So, there is a late and early stub (longer fixing thread on the late) and a late and early upright to match… both of these in two sizes but afaik the Elan only uses the early type.
I measured my two spare uprights. They do have the pointy blip pictured above.
The first has the large size of the sub axle hole as 25.9 mm and the small hole as 19.7 mm and the distance across the upright is 50.9 mm
The second sample has 27.33 mm large hole, 21.14 mm small hole and 50.85 mm across the flats.
Converting to inches I calculate this as a taper of 0.244/2.004 hence 0.127564 inches per inch for the first one and 0.244/2.002 hence 0.121878 for the second one.
That’s for both ways from the axis so the taper along the axis is half that 0.0609 so the angle of the taper is arc-tan of that figure which is 3.487 degrees from the axis or 6.974 degrees for the full taper.
Does this sound like the figure for a bolt-on stub axle or for a knock-on stub axle, which?
Sounds like you have one knock on upright and one bolt on upright in your spares stash?