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by Rex_tulips - 30/07/25 07:59 PM
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Joined: Feb 2016
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Talk Morgan Guru
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Talk Morgan Guru
Joined: Feb 2016
Posts: 7,943 Likes: 218 |
I don't suppose anyone has had a go at fitting Rogers bump stops to an ARP4, with coilovers instead of leaf springs, have they? When loaded my springs do bottom out, with quite a bang too. The alternative is harder rear springs, but that will harshen the ride too or get some longer springs and wind up the clearance a bit. Unfortunately these bumps stops need a damper hoop to attach to and I’m fairly certain the 5 link cars don’t have them. PaulJ, I have a 5 link Roadster and have swopped the OE coilovers for some designed by SSL (Suplex) you get 2 springs of different rates, adjustable spring preload & adjustable shocks, worth speaking to them The SSL coilovers Jon describes work in a counter-intuitive (to me) manner. ![[Linked Image]](https://i.imgur.com/XYguLx8.jpg) The two springs top long, shorter slightly stiffer lower operate in series to mutually dilute overall spring rate. This gives a softer ride for the first approx 25mm of compression travel from static. Further compression causes lower spring to become coil bound despite its standalone higher rate. This leaves upper spring only in play and an instant rise in overall rate to limit roll, as no series rate dilution. The factory OE answer to limit roll was to use a single high rate spring which worked, but left a harsh ride. The SSL solution answers both these issues with softer more compliant ride stiffening quickly to limit roll to an even greater degree than OE, and instantly noticeable on first corner after fitting 
Richard
2018 Roadster 3.7 1966 Land Rover S2a 88 2024 Royal Enfield Guerrilla 450 1945 Guzzi Airone
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Joined: Oct 2011
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Talk Morgan Addict
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Talk Morgan Addict
Joined: Oct 2011
Posts: 3,514 Likes: 8 |
Firstly, Roger thanks for moving my question here, I'd overlooked the fact that I was in the For Sale section.
With regard to not having a hoop or leaf springs, yes I understand that Rogers assisters won't work as designed, however, I didn't know if with some modifications and using other parts of the rear axle/body set up they might work. I already have the SSL rear spring setup with the double springs which generally work well, but not with two up and a case on the back. They also seem a little short as I have them wound up to the top to give as much movement as possible. Maybe another inch or two would work better, (as the Bishop said to the actress), which is why I wondered if Rogers assisters would work as better bump stops than the chassis does, but with a slightly different type of fitment than the current design?
As. a matter of interest, does anyone know the spring rates of the two springs supplied by SSL?
Paul [At last, I have a car I can polish]
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Just barreling along Talk Morgan Guru
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Just barreling along Talk Morgan Guru
Joined: Nov 2015
Posts: 7,910 Likes: 242 |
Paul, If you have the SSL upgrade then in effect you have bumpstops, they are the white coloured rubber inside the top spring as shown on Richard's photo above
Jon M
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Joined: Feb 2016
Posts: 7,943 Likes: 218
Talk Morgan Guru
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Talk Morgan Guru
Joined: Feb 2016
Posts: 7,943 Likes: 218 |
Firstly, Roger thanks for moving my question here, I'd overlooked the fact that I was in the For Sale section.
With regard to not having a hoop or leaf springs, yes I understand that Rogers assisters won't work as designed, however, I didn't know if with some modifications and using other parts of the rear axle/body set up they might work. I already have the SSL rear spring setup with the double springs which generally work well, but not with two up and a case on the back. They also seem a little short as I have them wound up to the top to give as much movement as possible. Maybe another inch or two would work better, (as the Bishop said to the actress), which is why I wondered if Rogers assisters would work as better bump stops than the chassis does, but with a slightly different type of fitment than the current design?
As. a matter of interest, does anyone know the spring rates of the two springs supplied by SSL? Sorry don't know the rates Paul, but Dan at SSL would be able to tell you. My thought's given the explanation above which came straight from Dan, are that too much pre-load would bring the lower spring closer to being coil bound so you would have less travel from static before the higher rate kicked in, defeating their object to some degree. The prototype pair on my Roadster have the pre-load shown in image above as pre-set by Dan. Whilst I have played with damping I'm satisfied with pre-load as is, even two up, full tank and with humungous case on the back courtesy of 
Richard
2018 Roadster 3.7 1966 Land Rover S2a 88 2024 Royal Enfield Guerrilla 450 1945 Guzzi Airone
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Joined: Oct 2011
Posts: 3,514 Likes: 8
Talk Morgan Addict
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Talk Morgan Addict
Joined: Oct 2011
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Jon, not the full SSL upgrade, just their dual springs as described by Richard. I'm still using the standard Spax dampers which I don't think have those rubber bump stops, although it is a couple of years now, since I changed the springs. I must revisit this ongoing project again some time and remind myself just what I have. Hence my questions before I get down to it.
Paul [At last, I have a car I can polish]
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Joined: Jul 2011
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Has a lot to Say!
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Has a lot to Say!
Joined: Jul 2011
Posts: 1,179 Likes: 17 |
Whilst looking for something else I came across This which does not reflect my understanding of Roger’s Bump Stops. The way I understand them is that they are not to compensate for sagging springs but purely to prevent the springs “banging” against the frame. I believe some have cut the frame away a bit where the springs tend to contact, but that looked quite a difficult job to me. I am very pleased with Roger’s stops. They do the job they were designed for.
4/4 Ivory 4.1:1 axle, Mercedes A200 AMG
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Joined: Dec 2008
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Roadster Guru Member of the Inner Circle
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OP
Roadster Guru Member of the Inner Circle
Joined: Dec 2008
Posts: 21,871 Likes: 168 |
Sadly, GoMog has a toxic opinion of TM.
"owners are currently being advised by a British forum, not noted for mechanical expertise"
Just how it is......
DaveW '05 Red Roadster S1 '16 Yellow (Not the only) Narrow AR GDI Plus 4
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Joined: Jan 2021
Posts: 150
L - Learner Plates On
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L - Learner Plates On
Joined: Jan 2021
Posts: 150 |
I have one of the last 4/4s. My rear driver side spring has sagged a little compared with the passenger side. Not much, not enough to justify a change that could in truth just sag again. I have decided just to keep an eye on it. I did spot contact marks with the rear inner wheel arch. Inspection shows the profile of the inner arch cutaway does not ideally match the location of the axle to prevent contact free travel on compression. I have remodelled the inner arches with a pad saw. I have also fitted Rogers’s bumps which seemed a logical thing to do as, although it is a long time since I last had one, cars with such springing arrangements usually have a rubber stop fitted to prevent a metal on metal collision on full upward travel if memory serves.
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Joined: Dec 2008
Posts: 21,871 Likes: 168
Roadster Guru Member of the Inner Circle
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OP
Roadster Guru Member of the Inner Circle
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Posts: 21,871 Likes: 168 |
The truth is that Rog's units are assisters, rather than bump stops, which give a progressive resistance towards full compression, and stop the diff casing hitting the tool tray, which can happen even on new Trads.
They transformed the bump feel on my Roadster, even with its six leaf agricultural spec springs, which are still cambered as they were when new.
DaveW '05 Red Roadster S1 '16 Yellow (Not the only) Narrow AR GDI Plus 4
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Joined: Jul 2007
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Member of the Inner Circle
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Member of the Inner Circle
Joined: Jul 2007
Posts: 26,761 Likes: 425 |
Dave, I think they work well with older spings. Belle at the moment seems fine but I suspect I will be investing at a later date in some. John
JohnV6 2022 CX Plus Four 2025 MG ZS EV aka Trigger
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