DROP LINK HORROR
Discussion
Quinny said:
peaktorque said:
Your last pic has just proven my theory that my rose joints have been fitted (not by me) on the wrong side of the wishbone 'lug'.
I thought they sat at a bit of a strange angle
I can confirm, Mine are fitted same as aboveI thought they sat at a bit of a strange angle
A picture speaks a thousand words......
The suspension was set up by a well known specialist not so long ago I believe
The nylock nut on the O/S drop link was left very loose too
It could explain what that bloody squeaking is too (the drop link nut and lug have taken a bite out of each other!)
taylormj4 said:
Drop link loss wouldn't be too critical unless you happened to be right on the limit at the time (which is probably when it would go I guess ). However, perhaps you should check that the clown hasn't done this to other more critical joints such as the steering ?
Matt
I can attest to that, my SH ones snapped off whilst in France and I had no problem getting home...just made a noise when you went round a corner...). However, perhaps you should check that the clown hasn't done this to other more critical joints such as the steering ?Matt
snorky said:
taylormj4 said:
Drop link loss wouldn't be too critical unless you happened to be right on the limit at the time (which is probably when it would go I guess ). However, perhaps you should check that the clown hasn't done this to other more critical joints such as the steering ?
Matt
I can attest to that, my SH ones snapped off whilst in France and I had no problem getting home...just made a noise when you went round a corner...). However, perhaps you should check that the clown hasn't done this to other more critical joints such as the steering ?Matt
Even more glad I went with the Leven ones now.
OK guys, it's time for my two-penneth........
Rubber gaiters
I have looked at various types of rubber gaiters regularly over the last 7-8 years or so. The problems I have found with them are that although they can improve protection, they can also severely reduce the amount of articulation in the rose joints so that either the movement is restricted or the gaiter itself can catch in the joint & split. I have measured reductions of up to 9 degrees with some designs. Considering the rose joints may only have 13 degrees of movement to start with and the dilemma is quite apparent. Fit a gaiter and the articulation may be restricted to such an extent that the original design may no longer work.
Gaiters have also been known to act as water holders, where water actually seeps into the gaiter and is held there — increasing the level of corrosion. So simply fitting rubber gaiters is not a ‘universal fix’ to wear & corrosion issues.
Rose joint types and specifications
There are several different types of rose joint. The ones I use are Teflon-lined and require no maintenance. Indeed, in my experience, if they are greased this can actually trap debris which gradually works its way into the ball race, causing premature wear — so I recommend that the rose joints on my drop links are NOT lubricated.
Metal on metal bearings need constant lubrication which is why they typically have a grease nipple as they need regular injections of grease to ensure that the metal surfaces do not make contact. If the metal surfaces do make contact, the joint wears very quickly indeed. This is why many old classic cars require all their joints to be regularly greased, compared to modern cars where the joints are usually lined and require no additional lubrication.
The specification of the rose joint is VERY important. When I first started developing ARB drop links for my competition wedge, some 10 years ago, I found that subjective descriptions such as ‘automotive competition quality’ were not a guarantee of suitability for purpose. Indeed, I broke several such products before I learnt this lesson. It is the technical specification that is important — i.e. the breaking strain, articulation angles etc. — and it is this knowledge that I use to specify the rose joints used in my range of drop links.
The articulation requirements are very important and their reduction by fitting gaiters does cause me some concern in that their fitment reduces the amount of movement, potentially causing the rose joint to lock out and break.
Rattling drop links
Rattling isn’t just caused by rose joint wear. It can also be caused by a loose bolt i.e. where the bolt has not been tightened up so that it clamps the rose joint correctly in place. Many people mistakenly believe that the bolt is the pivot point. IT ISN’T. If a rose joint is pivoting on a bolt, it has been incorrectly fitted and it is therefore not working in the way it was designed to work.
I did have one customer who bought some drop links and about 12 months later mentioned to me that they had rattled when he fitted them and that he had taken them off as a result. After asking why he hadn’t talked to me immediately, I suggested that the bolts were not tight enough. He refitted them and they didn’t rattle. OK, he was happy — if a little embarrassed — but it does worry me how many people he had told that my drop links rattled…
Broken drop links
It does happen.
It happens quite a lot with the original drop links and it can happen with any design where there is insufficient articulation for the required movement. The problem is made worse in that TVR were not consistent with the ARB positioning — which means that often the fitting is quite critical and the degree of articulation needs to be as big as possible. I don’t only make drop links for TVRs. I make drop links for a whole range of cars including MX5s, MR2s, Reliants and others. I am currently designing them for Skylines and BMW Minis. I designed the ARB setup for Practical Performance Car magazines Porche 928 racer and their 27 litre Merlin engined SD1. Interestingly enough, I haven’t seen anywhere near the fitting variation with these manufacturers/cars that I have with TVRs. This introduces another variable…..
I’ve seen ARB faces that were angled at 45 degrees. Imagine what happened to the articulation in that case. I’ve seen ARBs that were located directly under the mounting hole so that the original drop link had to be bent and forced into fit. Sometimes the drop link needs to be fitted on the other side of a ARB or a mounting plate can be required. I suggest in the fitting instructions that some experimentation is needed because of the variations in position. I really wish TVR had been consistent as it would have made my job easier, as well as that of the guys fitting them. In other words, despite trying to make the design as widely applicable as possible, there are times when the guys at Blackpool seem to conspire against us.
It doesn’t help as Peaktorque has experienced, when fitters do not tighten up the bolts so that the drop link is not clamped. Or not tested the fitting afterwards to make sure that the joints do not lock out…
I strongly encourage customers who are in any doubt whatsoever about the fitting of their drop links to get in touch — with photos. If people have broken them for whatever reason, I usually look kindly on them. If you’ve got any questions, please talk to me!
OK, there have been a few instances where my drop links have broken — but the failures have been due to the rose joint locking out and being stressed. This induces a stress fracture and is a common failure mode for all rose joints, irrespective of manufacturer or material. Rose joint manufacturers only specify the loading when the joint is used within the specified misalignment and with the load acting on a bearing. A 5000lb breaking strain spec rose joint does not mean it can take that load in all conditions. Lock it out and it will break at a much lower load.
The question of choice of materials also arises. There is also a school of thought that says stainless steel shouldn’t be used in suspension components because of its tendency to break (rather than bend) on impact. OK, drop links aren’t safety-critical — but that brittleness makes correct fitting even more important, if stainless components are used.
Rubber top bush
When designing my rear drop links, I didn’t put a rubber bush at the top as I have seen this type of joint break and in some cases actually tear the mounting plate off the wishbone. It would have been a cheaper and easier solution if I had taken this route — but the engineer in me overruled the accountant. If rubber bushes cause the ARB problems, why keep them? Any drop link that uses this type of joint, irrespective of what is made of, applies twisting forces to the mounting plate. It has to, as this is the only way it can move. These twisting forces on the mounting plate can cause it to break. The original drop links with rubber bushes at both ends did this. TVR’s solution was to make the mounting plate stiffer and stronger. This certainly helped preserve the wishbone — but then caused the original drop links to start breaking at a higher rate…..
The Wedges have this type of joint on the front and rear shocks and, guess what, I have broken them and damaged the mounting plates. When I added a proper joint, the problems went away. I can’t see any point in retaining a rubber bush in a design that is supposed to be getting rid of them.
Possible enhancements to my range of drop links
As I’ve already outlined, there are arguments for and against the use of rubber gaiters. There will also be some instances where differences in alignment and space issues mean that they cannot actually be fitted. However, if people would feel happier with gaiters fitted, I will source some appropriate ones and offer them as an option. They would have to be packed with grease to prevent the water ingress problem.
Similarly, stainless steel rose joints could also be provided as an option – but the incremental cost may well be over 50%. This would increase the cost from £69.99 a pair (inc VAT and UK delivery) to somewhere around £110 to £120. There is also the argument that says if a rubber gaiter is used then stainless steel is not needed, especially if the result is effectively almost doubling the cost.
I hope that helps!
Rubber gaiters
I have looked at various types of rubber gaiters regularly over the last 7-8 years or so. The problems I have found with them are that although they can improve protection, they can also severely reduce the amount of articulation in the rose joints so that either the movement is restricted or the gaiter itself can catch in the joint & split. I have measured reductions of up to 9 degrees with some designs. Considering the rose joints may only have 13 degrees of movement to start with and the dilemma is quite apparent. Fit a gaiter and the articulation may be restricted to such an extent that the original design may no longer work.
Gaiters have also been known to act as water holders, where water actually seeps into the gaiter and is held there — increasing the level of corrosion. So simply fitting rubber gaiters is not a ‘universal fix’ to wear & corrosion issues.
Rose joint types and specifications
There are several different types of rose joint. The ones I use are Teflon-lined and require no maintenance. Indeed, in my experience, if they are greased this can actually trap debris which gradually works its way into the ball race, causing premature wear — so I recommend that the rose joints on my drop links are NOT lubricated.
Metal on metal bearings need constant lubrication which is why they typically have a grease nipple as they need regular injections of grease to ensure that the metal surfaces do not make contact. If the metal surfaces do make contact, the joint wears very quickly indeed. This is why many old classic cars require all their joints to be regularly greased, compared to modern cars where the joints are usually lined and require no additional lubrication.
The specification of the rose joint is VERY important. When I first started developing ARB drop links for my competition wedge, some 10 years ago, I found that subjective descriptions such as ‘automotive competition quality’ were not a guarantee of suitability for purpose. Indeed, I broke several such products before I learnt this lesson. It is the technical specification that is important — i.e. the breaking strain, articulation angles etc. — and it is this knowledge that I use to specify the rose joints used in my range of drop links.
The articulation requirements are very important and their reduction by fitting gaiters does cause me some concern in that their fitment reduces the amount of movement, potentially causing the rose joint to lock out and break.
Rattling drop links
Rattling isn’t just caused by rose joint wear. It can also be caused by a loose bolt i.e. where the bolt has not been tightened up so that it clamps the rose joint correctly in place. Many people mistakenly believe that the bolt is the pivot point. IT ISN’T. If a rose joint is pivoting on a bolt, it has been incorrectly fitted and it is therefore not working in the way it was designed to work.
I did have one customer who bought some drop links and about 12 months later mentioned to me that they had rattled when he fitted them and that he had taken them off as a result. After asking why he hadn’t talked to me immediately, I suggested that the bolts were not tight enough. He refitted them and they didn’t rattle. OK, he was happy — if a little embarrassed — but it does worry me how many people he had told that my drop links rattled…
Broken drop links
It does happen.
It happens quite a lot with the original drop links and it can happen with any design where there is insufficient articulation for the required movement. The problem is made worse in that TVR were not consistent with the ARB positioning — which means that often the fitting is quite critical and the degree of articulation needs to be as big as possible. I don’t only make drop links for TVRs. I make drop links for a whole range of cars including MX5s, MR2s, Reliants and others. I am currently designing them for Skylines and BMW Minis. I designed the ARB setup for Practical Performance Car magazines Porche 928 racer and their 27 litre Merlin engined SD1. Interestingly enough, I haven’t seen anywhere near the fitting variation with these manufacturers/cars that I have with TVRs. This introduces another variable…..
I’ve seen ARB faces that were angled at 45 degrees. Imagine what happened to the articulation in that case. I’ve seen ARBs that were located directly under the mounting hole so that the original drop link had to be bent and forced into fit. Sometimes the drop link needs to be fitted on the other side of a ARB or a mounting plate can be required. I suggest in the fitting instructions that some experimentation is needed because of the variations in position. I really wish TVR had been consistent as it would have made my job easier, as well as that of the guys fitting them. In other words, despite trying to make the design as widely applicable as possible, there are times when the guys at Blackpool seem to conspire against us.
It doesn’t help as Peaktorque has experienced, when fitters do not tighten up the bolts so that the drop link is not clamped. Or not tested the fitting afterwards to make sure that the joints do not lock out…
I strongly encourage customers who are in any doubt whatsoever about the fitting of their drop links to get in touch — with photos. If people have broken them for whatever reason, I usually look kindly on them. If you’ve got any questions, please talk to me!
OK, there have been a few instances where my drop links have broken — but the failures have been due to the rose joint locking out and being stressed. This induces a stress fracture and is a common failure mode for all rose joints, irrespective of manufacturer or material. Rose joint manufacturers only specify the loading when the joint is used within the specified misalignment and with the load acting on a bearing. A 5000lb breaking strain spec rose joint does not mean it can take that load in all conditions. Lock it out and it will break at a much lower load.
The question of choice of materials also arises. There is also a school of thought that says stainless steel shouldn’t be used in suspension components because of its tendency to break (rather than bend) on impact. OK, drop links aren’t safety-critical — but that brittleness makes correct fitting even more important, if stainless components are used.
Rubber top bush
When designing my rear drop links, I didn’t put a rubber bush at the top as I have seen this type of joint break and in some cases actually tear the mounting plate off the wishbone. It would have been a cheaper and easier solution if I had taken this route — but the engineer in me overruled the accountant. If rubber bushes cause the ARB problems, why keep them? Any drop link that uses this type of joint, irrespective of what is made of, applies twisting forces to the mounting plate. It has to, as this is the only way it can move. These twisting forces on the mounting plate can cause it to break. The original drop links with rubber bushes at both ends did this. TVR’s solution was to make the mounting plate stiffer and stronger. This certainly helped preserve the wishbone — but then caused the original drop links to start breaking at a higher rate…..
The Wedges have this type of joint on the front and rear shocks and, guess what, I have broken them and damaged the mounting plates. When I added a proper joint, the problems went away. I can’t see any point in retaining a rubber bush in a design that is supposed to be getting rid of them.
Possible enhancements to my range of drop links
As I’ve already outlined, there are arguments for and against the use of rubber gaiters. There will also be some instances where differences in alignment and space issues mean that they cannot actually be fitted. However, if people would feel happier with gaiters fitted, I will source some appropriate ones and offer them as an option. They would have to be packed with grease to prevent the water ingress problem.
Similarly, stainless steel rose joints could also be provided as an option – but the incremental cost may well be over 50%. This would increase the cost from £69.99 a pair (inc VAT and UK delivery) to somewhere around £110 to £120. There is also the argument that says if a rubber gaiter is used then stainless steel is not needed, especially if the result is effectively almost doubling the cost.
I hope that helps!
I had loads of rattle when fitting SH'd drop links, and email later followed by me putting them on correctly & they have been great for the past 3 years or so. Lasted many track days as well. Not a bother now.
Something else to note is that the original ones mask the fact that the roll bar can slide to one side , fitting the new rose jointed ones meant that the roll bar had to be very much central.
Something else to note is that the original ones mask the fact that the roll bar can slide to one side , fitting the new rose jointed ones meant that the roll bar had to be very much central.
SILICONE KID said:
I fitted standard rear droplinks ,after 12 months they were k
rd so i opted for Steve Heath droplinks and up to yet i have had no problems .Its about time Steve designed some univeral steering joints instead of those cp steering UJ`s ..
Great suggestion! I've spent a small fortune last year on 'poor quality looking' replacement steering CV joints. They don't look like they will last long (hopefully looks will be deceiving) .rd so i opted for Steve Heath droplinks and up to yet i have had no problems .Its about time Steve designed some univeral steering joints instead of those cp steering UJ`s ..crackedfinger said:
I had loads of rattle when fitting SH'd drop links, and email later followed by me putting them on correctly & they have been great for the past 3 years or so. Lasted many track days as well. Not a bother now.
Something else to note is that the original ones mask the fact that the roll bar can slide to one side , fitting the new rose jointed ones meant that the roll bar had to be very much central.
Quite true, a couple of jubilee clips on either side of the mount keeps it central.Something else to note is that the original ones mask the fact that the roll bar can slide to one side , fitting the new rose jointed ones meant that the roll bar had to be very much central.
I'm on my second set of Steve's rear drop links after a broken drain cover smashed off the rear nearisde ARB bracket from the chassis mounted plate in France last year. The drop link on that side also broke as the ARB was forced backwards, also creasing the exhaust. Solution was to remove all of it and crack on with the next 1500+ miles of alpine passes without any issues.
I've had no rattles at all in the sets I've fitted and I'm very happy with 'em. I can attest to the design being excellent in that a more 'sturdy' design would have not solely distorted the wishbone as it did , but potentially rip it etc and the journey would have been over. So far the car's done about 20k miles with Steve links and no issues, rattles etc . . you really do have to get the fitting right and a ramp rather than axle stands where you can see the links in 'natural' position helps a lot to get them in their correct arc of movement allowing them to articulate etc ..
I'm surprised no ones seen fit to raise the issue of stainless steel fittings in a stressed location, I presume therefore that this isn't a concern to anyone ?
I've had no rattles at all in the sets I've fitted and I'm very happy with 'em. I can attest to the design being excellent in that a more 'sturdy' design would have not solely distorted the wishbone as it did , but potentially rip it etc and the journey would have been over. So far the car's done about 20k miles with Steve links and no issues, rattles etc . . you really do have to get the fitting right and a ramp rather than axle stands where you can see the links in 'natural' position helps a lot to get them in their correct arc of movement allowing them to articulate etc ..
I'm surprised no ones seen fit to raise the issue of stainless steel fittings in a stressed location, I presume therefore that this isn't a concern to anyone ?
Bassfiend said:
Hmmm ... have a nasty rattle/thumping that comes from my OSF suspension over bad surfaces and (fairly frequently) when releasing the brake pedal after braking ... still got to try to work out what it is. 
Phil
Just to complete the circle - mine turned out to be a shot top-wishbone rear bush...Phil
Both OSF top wishbone bushes replaced last Saturday morning by Neil Garner for £130(ish) - one more job ticked off the list.
Phil
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