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Odd Mod?? - IanClayton - 20-04-2020
Noting that Jon 'oldtrim' E is now flirting with a similar 750 special to the one I used to own, I'm minded that mine had a V peculiar mod. in that the drag link tube was divided,offset and pivoted on the side of the chassis. Maybe dating from it's early days as a race car.
This mod had the effect of 'gearing up' the steering and giving a much reduced lock to lock movement. It made steering with the non standard smaller wheel quite heavy at anything under 15-20 MPH and I had thought about going back to a standard set up but 'never got around toowit'
I've never seen a similar mod on any other special and wonder (1) why it was done? and (2) anybody else ever come across anything like it elsewhere?
RE: Odd Mod?? - Bob Culver - 20-04-2020
The geometry of the Seven steering is abyssmal in that rocking the car generates a major steering reaction, one reason the cars tend to dart off course on unduating surfaces. There may be some pivot point which improves things. Ideally, when the car is rocked the steering wheel (with no play) should not turn.
RE: Odd Mod?? - Alan - 20-04-2020
But, Bob, surely making the link shorter would make things worse, unless I’ve visualised things wrongly. And, why would you want to make the steering ratio higher? It’s too fast as it is.
RE: Odd Mod?? - Bob Culver - 21-04-2020
I guess ideally the drop arm should be near the ball joint. I dunno the exact arrangement described. Maybe it raised the pivot point so the drag link was more horizontal.
The steering is certainly fast by most standards. But saved me from some terrifying metal road oversteer lurches and near roll overs on occasions. I have had grass trapped by the rim and returned to earth.
When running the Seven I was never fussed when finding adresses if went past. It was just a flick of the wrist to do a U turn. With later cars, despite similar turn circle, it was major undertaking.
From TV GP cars seem to steer like Sevens.
In my younger days I had driven little else. A mate gave me a drive of his fathers Ford Pilot with lots of lost motion. I pulled out to overtake a car and ended up on the far side grass! I was not too embarassed. Mates were scared to take the Seven past 40 mph.
RE: Odd Mod?? - Charles Levien - 21-04-2020
(20-04-2020, 09:41 PM)Bob Culver Wrote: The geometry of the Seven steering is abyssmal in that rocking the car generates a major steering reaction, one reason the cars tend to dart off course on unduating surfaces. There may be some pivot point which improves things. Ideally, when the car is rocked the steering wheel (with no play) should not turn.
Worth looking at some of the work the late John Miles did on Austin Seven steering geometry — notably to reduce bump steer and to improve steering control over uneven surfaces.
I have his mod fitted to both Special and Opal - basically a 20% extension to the steering arm in conjunction with use of rose joints for the linkage.
This seemingly small mod makes a big difference to handling and, particularly on the special, contributes a lot to the enjoyment of driving it purposefully.
Charles
RE: Odd Mod?? - David Stepney - 21-04-2020
Much of the curious handling problems, especially on standard cars, appears to stem from 'roll oversteer'. because of the rear suspension geometry, as the car corners and leans over, the outer rear spring compresses, moving that side of the axle back which has the effect of pointing the nose further into the corner. I quickly re-learned how to use this for hurrying a box saloon round bends! Can be fun on bumpy roads, though.
RE: Odd Mod?? - Charles Levien - 21-04-2020
(21-04-2020, 10:57 AM)David Stepney Wrote: Much of the curious handling problems, especially on standard cars, appears to stem from 'roll oversteer'. because of the rear suspension geometry, as the car corners and leans over, the outer rear spring compresses, moving that side of the axle back which has the effect of pointing the nose further into the corner. I quickly re-learned how to use this for hurrying a box saloon round bends! Can be fun on bumpy roads, though.
How true this is — I remember going round a roundabout a bit too fast in a tourer with my passenger asleep resting his head and arms on the top of the door. It was late at night and after a party. At the height of oversteer his door flew open. I got him back by jerking the steering wheel which was a relief. Odd thing was that he had no recollection of this having happened.
Happy days.
RE: Odd Mod?? - Peter Clayton - 21-04-2020
(21-04-2020, 07:50 AM)Charles Levien Wrote:(20-04-2020, 09:41 PM)Bob Culver Wrote: The geometry of the Seven steering is abyssmal in that rocking the car generates a major steering reaction, one reason the cars tend to dart off course on unduating surfaces. There may be some pivot point which improves things. Ideally, when the car is rocked the steering wheel (with no play) should not turn.
Worth looking at some of the work the late John Miles did on Austin Seven steering geometry — notably to reduce bump steer and to improve steering control over uneven surfaces.
I have his mod fitted to both Special and Opal - basically a 20% extension to the steering arm in conjunction with use of rose joints for the linkage.
This seemingly small mod makes a big difference to handling and, particularly on the special, contributes a lot to the enjoyment of driving it purposefully.
Charles
Looked up this John Miles mod, and tome it would slow the rate of turn as the link length , drag link to king pin is increased . Would this possibly reduce the steering lock ?
RE: Odd Mod?? - Charles Levien - 21-04-2020
(21-04-2020, 06:36 PM)Peter Clayton Wrote:(21-04-2020, 07:50 AM)Charles Levien Wrote:(20-04-2020, 09:41 PM)Bob Culver Wrote: The geometry of the Seven steering is abyssmal in that rocking the car generates a major steering reaction, one reason the cars tend to dart off course on unduating surfaces. There may be some pivot point which improves things. Ideally, when the car is rocked the steering wheel (with no play) should not turn.
Worth looking at some of the work the late John Miles did on Austin Seven steering geometry — notably to reduce bump steer and to improve steering control over uneven surfaces.
I have his mod fitted to both Special and Opal - basically a 20% extension to the steering arm in conjunction with use of rose joints for the linkage.
This seemingly small mod makes a big difference to handling and, particularly on the special, contributes a lot to the enjoyment of driving it purposefully.
Charles
Looked up this John Miles mod, and tome it would slow the rate of turn as the link length , drag link to king pin is increased . Would this possibly reduce the steering lock ?
Hi Peter,
Thanks for posting up the photo.
I havnt found this mod to have any appreciable affect on steering lock. The lower geared steer just makes driving more enjoyable and if you’re pushing it a bit on a winding country road it feels more in control.
Charles
RE: Odd Mod?? - Nick Lettington - 21-04-2020
I spent a very enjoyable hour in John's home in Norfolk during which time we discussed how this might be done a little simpler at the other end of the drag link, making the connection on a shortened drop arm on the steering box. I guess you'd run the same risk of running out of travel? I'd bought a set of 15" wires from him off Ebay. It doesn't pay to have regrets, but I do wish I hadn't been short on time and a fair trot from home.