Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Front Suspension Geometry - Bump Steer Related

The MTW is a modern design. There are designs of the 1930's with a lot more suspension travel and less bump steer. The irony is that the Ace on which the MTW was based has a better set-up.

Harald

For the fear of being tar and feathered i thing i would choose the Ace given the choice. I like the detail with exception of that roll hoop but that is just me

funny you should mention the ace. i by chance bumped in to one while out in my morgan today in san francisco. we had a great chat and took tons of pics, especially related to the suspension. will be making a post in a bit but until then here's some eye candy to support your cause, and yes that roll hoop is quite unfortunate vs the rest of the car which is stunning

I will raise my hand, would love to have a fix. Don't really care about the warranty. R

I gave up the idea of a warranty so long ago. What with constantly mucking with this creature, there are just so many reasons why any manufacturer would just shrug and go, "Hey, you messed with it so you're not covered!"

I break warranties.

If I can't mess with it, I don't feel like I own it.

Please see my separate post om moving wish bone.
Not sure it has anything to do with the bump steer, but it is definitely suspension related.

With the photos of the Liberty Ace it is interesting to note:
1. The steering assembly in front of the motor looks fine. Where is the problem with putting it there where it allows better steering geometry? It could easily be partly concealed behind a number plate mount(or if no front plate badge mount).
2. The steering rods are parallel to, and almost the same length as, the lower wishbone.
3. A line drawn down to the ground through the king pin still falls to the inside from the contact patch. Obviously it is very difficult with such narrow rims and tyres to get it within the contact patch which would be ideal.

I did buy a Triking - I am very happy both with the looks and that there is no bump steer

I have no bump steer on my Aero Cycle Cars either. The problem is that in essence Morgan have gone for a sliding pillar look with their upright. The camber is fixed, it cannot be adjusted, and it looks excessive, anyone know what it is, it looks in excess of 3 degrees, when 1-1.5 degrees is the norm.

next take a look at the wishbones, almost similar length, so arcs of travel are out. The precise location of the steering rack and angles in both planes of the track rod arms/ends is absolutely paramount, and is fundamentally wrong. They've used Mini/Metro ball joints top and bottom of the upright, however by using one at the top, there is no ability to adjust camber. Any vehicle built using Chapman/Lotus unequal length wishbones has used a top joint from a Ford Transit (drag link joint) either with a 20mm thread or an 18mm thread, thus allowing for adjustment....this is standard practice.

It is impossible to get exact "centre point steering"/"scrub radius"....ie extend the line down through both top and bottom ball joints on the upright to the ground alongside the tyre, then measure the lateral distance to the tyre wall. It can be achieved of course by the wheel having an offset, as of course modern cars always do now. If using motor cycle wheels (centre laced, or MWS MG TA outer laced wheels (as Morgan do) and these wheels are 2.5 inch rims shod with 19 x 4.00 tyres...and the wheels have no offset 9they clearly don't) then the extended king pin line will never intersect the centre of the tyre, but will come to within 25-30mm of the tyre's inner edge.

I've no idea why Morgan have exceeded even this...Triking and I manage within reason to get the closest, 25-30mm....we manage this by being tiny tiny one man band businesses, yet Morgan employ how many....over 180!?

My guess is having looked very closely at the suspension is that they've used or modified standard bolt on splined adaptors, rather than go to a specialist company called Orson Equipment to have had made combined splined hubs that could easily have achieved a far better centre point/scrub radius.

The wishbone length issue has not been thought out properly, they've tended to have gone for aesthetics rather than standard mechanical theory.

I drove their factory demonstrator around Blyton Park's track last October and found the front end extremely heavy. the overall experience was good on a track with no bumps of course. The following week the offside wheel came off this very car, as we know. Morgan have subsequently improved their wishbones apparently, but when both my fabricator and I looked closely at the top wishbones in particular, the welding looked rather lumpy and done rather cold, thus the "thick to thin" welds were incorrect.

There is room for a lot of improvement....so come on Morgan, do so!

I can't comment on the bevel box issue, but this is made by Quaife too, as well as the "cush drive" attachment between engine and gearbox.

So, to re-iterate, bump steer is primarily an issue of rack location and angles of the track rods and steering arms, and is so fundamental.

A very good book to read on front suspension is by Des Hamill, and has some easy to understand diagrams and text...it is a must.

The trouble is, that to fix the geometry is a big job, a whole new design of the front end, wishbones and uprights and even attachment points, and, sadly, I can't see Morgan doing this, or, to be frank, even being able to or wanting to. They seem to have their head in the sand and are pretending it isn't a problem, along the lines of "it's part of the Three Wheeler driving experience", which it is - but needn't be.

If someone could work out an aftermarket fix, I'm sure they would earn some money, as well as the gratitude of hundreds of owners worldwide.