Richard, thanks for confirming that! I had forgotten about that response, and dug this thread up instead as it's in a bit more of a suitable location.
Made similar discoveries today in my "rack attack" session.....
If you look closely you may spot that one of these racks is slightly distorted.
After a bit of straightening of the Chevette rack, I laid it out with an SS1 item for some comparisons.
Chevette rack above in these photos.
Chevette coupling on the right -
SS1 Above, Chevette Below
From top - SS1 Modified for more lock, SS1 stock, Chevette -
Measurements as follows in the comparison of SS1 and Chevette racks
Travel per pinion turn:
Travel as assembled:
Max number pinon revolutions possible on rack teeth (un-assembled):
Number of turns at pinon from lock to lock as assembled:
SS1 Standard - 2.9
SS1 Modified - 3.3
Chevette Standard - 4.2
So what does this all add up to?
The SS1 rack is quicker, with a higher ratio.
The overall travel is greater on the Chevette rack in standard guise.
The Chevette rack will fit an SS1 without altering the steering geometry. However it will require the longer Chevette flexible coupling to prevent the steering wheel fouling the column shroud.
Fitting a Chevette rack to an SS1 will lighten the steering / decrease the effort. But at the cost of the more direct sporting feel that the original rack gives. Though this may be a fair trade off for those who struggle at parking speeds (and I know a few owners who had to give their SS1's up for this reason)
From a Chevette owner's prospective (or I suppose for a drift / auto test SS1), it is possible to modify the SS1 rack by reducing the overall length of the stops / lock collars. Doing so will give a similar total travel as a standard chevette rack, but in approx 1 less pinion turn.
Wannig in France did modify a rack to do away with the Reliant track rod system in place of self contained (Meganne?) track rods. I believe he had trouble with too much lock causing the tyres to rub, which would suggest that there is a bit more lock to be had out of the SS1 rack than the one I have pictured above.
The construction of the racks is quite different, the Reliant uses alloy housings at either end, and if worn, it does require machining for the fitment of brass bushes into these ( An idea pioneered by owners of the TVR S Series I believe?)
The Chevette track rods are a service item and easily replaced. The SS1 items can be adjusted provided the nylon cups are not worn.
I do have a single example of an SS1 rack that appears to be fitted in a Chevette housing. Whether this is an original item from the factory, or a hybrid I am not sure.
'84 SS1 1300, '86 SS1 1800ti, '87 SS1 1300
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