Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Softer rebound springs

Many thanks for the instructions, one for the winter 'to-do' list. Suppose it would be easy to fit Roller bearing at the same time or is that trickier?
Will

DTI and magnetic base set to 0.005" at the periphery of the disc face if someone is watching....if not nip to bearings have no backlash and back to next hole on the castleated nut (as the stub is vertical and horizontal drilled this means back by 1/2 flat is possible of course) that gives a 0.005" clearance by 'feel' as you say. It's almost impossible to explain feel and after 40 years training others I realise that hence falling back on the DTI method which is no use at all to anyone without the equipment. ;-)

Why do You want to fit a roller bearing kit? Low speed steering too stiff? Springing too stiff? Not suggesting You not do this. Just think You might consider why You are doing it and what results You expect. I have spent a lot of money chasing these two items. Not sure I have ever improved this over what the Factory supplied initially. I think My Problem is not keeping the Factory Suspension up to snuff.

Button
Seattle

Afraid not Will, the steering bearing goes under the main Spring on the other side of the stub axle meaning that not only must the stub be essentially removed (OK you can leave it on the king pin sat on the lower lug) the king pin must be lowered from its upper fixing so a much bigger job. To be honest whilst your doing that you might as well go for new hardchrome King pins with spiral grooved bushes, reduced rate rebounds and a Mulfab steering bearing kit with new mainsprings (reduced height to allow for steering bearing). In other words its probably best to just fit rebounds or delay and do a complete front overhaul in one go, greased well you will do well to ever wear them out!

Button - when I replaced the steering dampers on my S1 Roadster with Mulfab bearings the feel was transformed. When I jump in now I still can't believe how light the steering is.

When I did the same job on the 4/4 Anniversary but changing the factory bearings for Mulfab bearings, the steering was lighter, but I think I had the stubs a bit tighter than maybe was optimal, so although the steering was improved, it was not as light as the Roadster.

I already have a pair of Mulfab bearings on the shelf for the new car when the warranty expires. I'm a huge fan..........

+1
I'm about to do the "full Mulfab". Did it on the last car and it was fantastic.
The MMC is ok, it works, but is a start point, IMHO.
It's nice to have the choice I suppose, leave it stock, Mulfab, Rutherford, Suplex or a combination. Thats the beauty of the cars, everyone will have a combination that suits them.
I have it on good authority that MMC use a better quality of suspension component on "their"cars……..

Well I also use the Mulfab thrust bearings and springs on My +8 Bitsa. On the +4 I use the needle thrust bearings and standard setup. On the DHC, at the moment, standard setup and needle bearings. The needle bearings are and idea of John Sheally II. As I have a lathe (new/used) I made up some thrust bearings for my friends using Nylatron Plastic for the holder and the same bearing as Suplex Kit. Although I used a SK bearing not a cheap Chinese bearing (probably would be OK with the Cheap Chinese Bearings. None of My 3 Morgans have the damper blade setup. I have found that they are not needed if the Wheels are properly balanced and alignment (toe in) correct.

However: I had reasons for this. The DHC and +4 are 1960's Morgans. I did not have suspension for My +8 Bitsa so I designed it myself. I did it wrong and have been suffering every since. Too cheap to fix it right. However; I am getting forced into it.

My point is for whoever that is considering modifying their suspension need figure out what is wrong and what might improve it. I have driven a 2005 Roadster quite a bit. IMO it is about as good as it gets. I drove a 2000 +8 for a couple of days. Factory setup. I thought it was OK. My 1963 +4 was a dog. Hard to park, hard at low speed etc. Of course I was used to a 1963 4/4 and that did not help. Gemmer steering cured 80% of the problem. Thrust bearings and a VW type steering damper turned My +4 into a delightful tourer and the most comfortable (compliant) Morgan I own. I learned lever shocks are OK and it was a waste of money to use Koni's on all 4 corners. This was not just a switch shocks and drive. I must of swapped the Koni's with levers a dozen times in a couple of years. There is a lot about quality of tires and air pressure. On My +8 I swapped My Yokohamas with Michelins. The Michelins are (IMO) more compliant than the Yokos.

Ha! Ha! Give Me a soap box and I will give my experiences with Morgan Suspension.

Remember, as Tim Harris said, "Drive on a smooth road for a smooth ride. Drive on a rough road and get your teeth knocked out". I embellished Tim's quote a little bit.

Button
Seattle

In the past I’ve fitted Pete Mulberry’s steering bearings and the recommended 140lb springs, and adjustable AVO’s, along with hard chrome kingpins and new bushes, which improved the ride and steering considerably, but I still felt the front end of the car was far too firm.
After reading the suggestion of shortening the rebound springs - and safe in the knowledge that the Rutherford rebound springs are available - I thought well, if my efforts don’t work and it does all go a bit tits-up then I can just buy these new ones and everything will be fine again. So with this option as a back-up, I confidently set to work with the angle grinder and took 20mm off each rebound spring.
And I’m glad I did, as not only has it considerably softened the ride and made the steering even easier, but it’s also given me an extra 20mm of welcome ground clearance. I’m no racer, and no doubt some spirited driving on a track may come up with some shortfalls of this mod, but for everyday motoring the improvements have been considerable. A softer ride, a more ‘settled’ feel on the road, and lighter and more feel to the steering. All for a few hours work and, most importantly, zero cost, too.
So if anyone’s contemplating forking out loads of money on trying to improve the ride quality (and ground clearance) of their Trad, I reckon they could do worse than give this free option a try first.

I'm no engineer but I do have that sort of brain. I have learnt a few things from our own PJB and from Dan White at Suplex and I have also done a little research on my own.

It may seem strange but in the Morgan suspension when both springs are under compression the spring rate is the sum of the two spring rates. I think of it as the lower rebound spring exerting a pre-load on the upper load bearing spring. To take simple numbers (not real!!) if the upper spring has a rate of 150 lbf/in and the lower rebound spring has a rate of 100 lbf/in as long as the lower spring is under compression the total rate is 250 lbf/in. The moment the lower spring is fully extended, say when the car is cornering hard or hits a bump, the rate drops to that of the upper spring alone, that is to say (in the case of this imagined example) 150 lbf/in. This is the famous falling rate which leads to the nodding dog syndrome.

If you soften the lower spring you also soften the initial ride. Say the rate of the lower spring is reduced to 50 lbf/in the combined rate in our example is reduced to 200 lbf/in and will undoubtedly give a more comfortable ride but you will still have a falling rate when the lower spring ceases to provide that "pre-load" effect.

Obviously if the lower spring is softened and the upper spring is increased in rate the transition will be reduced (the reduction in the rate is equal to the rate of the lower spring)but the ride in the initial phases, that is over small bumps, will remain hard, if not harsh.

Ok so what happens if we select a spring that is going to give the ride we want and a length that give the desired ride height and do away with the rebound spring altogether? The result in a straight line would probable not be bad and the bounce and rebound could be controlled by a good set of dampers. Naturally some sort of rising rate system in extreme bump would be desirable, long tapered rubber bump stops or a supplementary rising rate spring could be used

The only problem is that to get minimum roll in cornering you would need fairly high rated springs or "sway bars".

If a fairly high rated re-bound spring that barely touches the bottom of the stub axle at static ride height is used the moment the car starts to roll the stub axle on the inside of the corner comes into contact with the rebound spring, the rate of the two springs then combines but, in this case, to limit the action of the upper spring in pushing down the unloaded wheel. The effect is to limit body roll.

These principles, in full or in part, are what all the suspension designers use. Each designer tunes the system to his requirements and those of his clients. At the end of the day it is a matter of driving style and the compromise between comfort and handling. There is only so much that can be done to tune a system that has inherent limitations.

I hope I have been clear in my layman's explanation.

For a more scientific and/or detailed explanation of the Suplex system check out Peter Ballard's discourse at Morgantica. It includes a description of the falling rate system on older Morgans: https://sites.google.com/site/morganatica/suspension/springs-progressive-rising-rate

Is a coil spring load consistent up to coil binding?
I presume it would be after the initial load is applied from the unloaded situation.
I must admit that I struggle to rationalise the spring rates combining in this situation. That being the case though and with the rebound spring unloaded, as the stub moves down - inner wheel on a corner - then as the main spring decompressed and the rebound begins to compress, presumably the rate is at a minimum, and this is why some owners have found an initial roll when turning in?