JAL73 Posted April 19 Author Share Posted April 19 the other issue i have, which i think is also suspension related, is when you go over bigger bumps/ potholes you sometime get a horrible (bang/ crash) noise coming from rear of the car but whenever i look under the car i cant see/feel anything loose. I thought it sounded like it was coming from DeDion tube but HWM who service the car assure me its not that, so maybe its the dampers. Curious as to whether others out there have experienced similar and managed to trace the source of it? Link to comment Share on other sites More sharing options...
150SV Posted April 19 Share Posted April 19 24 minutes ago, JAL73 said: the other issue i have, which i think is also suspension related, is when you go over bigger bumps/ potholes you sometime get a horrible (bang/ crash) noise coming from rear of the car but whenever i look under the car i cant see/feel anything loose. I thought it sounded like it was coming from DeDion tube but HWM who service the car assure me its not that, so maybe its the dampers. Curious as to whether others out there have experienced similar and managed to trace the source of it? Yep, exactly the same here…. nothing obvious underneath the car either. im starting to wonder if I have a dead damper. biggest issue is this is the only 7 I’ve done mileage in , so have nothing to base it on, I terms of TATDS Link to comment Share on other sites More sharing options...
Ainsley Posted April 19 Share Posted April 19 (edited) I would jack the car up, take the dampers off and check the movement of the suspension to make sure there is no interference. Also check the dampers are not hitting their limits. Also see if both dampers rebound the same. Edited April 19 by Ainsley Link to comment Share on other sites More sharing options...
Ivaan Posted April 19 Share Posted April 19 It could be the fuel sender unit bouncing around in the tank. Does it happen when the tank is full or empty? Link to comment Share on other sites More sharing options...
150SV Posted April 19 Share Posted April 19 17 minutes ago, Ivaan said: It could be the fuel sender unit bouncing around in the tank. Does it happen when the tank is full or empty? It’s too loud and to metallic to be that I think. Link to comment Share on other sites More sharing options...
JP Posted April 19 Share Posted April 19 Worn shock bush / rose joint? Link to comment Share on other sites More sharing options...
150SV Posted April 19 Share Posted April 19 14 minutes ago, JP said: Worn shock bush / rose joint? The only ones I’ve not been able to properly inspect are the rear uppers, but there’s doesn’t appear to be any play in the suspension . Link to comment Share on other sites More sharing options...
Nigel B Posted April 19 Share Posted April 19 Removing the rear ARB is such a common recommendation, but it’s one that I find puzzling. For the last few years, I’ve been playing around with the ARBs on my car, trying to hone the balance of grip, front to rear. I’ve tried most combinations, from fully stiff, to fully soft at both ends, including removing both bars (though I haven’t tried removing both bars at the same time). I’ve had a lot of fun trying the various combinations & I’ve learned a lot about how different settings affect the handling balance. I drive the car for a fair few miles after each change to try to really understand the pros & cons, not just for one blat. I feel that the increased sensitivity to the handling that I’ve developed as a result of trying different set ups has actually improved my driving. It’s something I’d recommend, although I do think you need to have a good basic set up (corner weights etc) before you start experimenting with the ARBs. On Blatchat, Pistonheads & the various Caterham Facebook groups, I’ve seen owners claim that removing the rear bar has ‘transformed the handling’. But when I tried removing my rear bar I really didn’t like the feel of the car at all. The increased roll at the back made it feel lethargic & considerably less agile. It was particularly noticeable when you wanted to change direction quickly, when negotiating a tight combination of left & right bends, for example. There was a pronounced sense of ‘waiting for the car to settle’ with the rear bar removed. I also felt the car’s tendency to ‘lift off oversteer’ was exacerbated to quite a degree. With a moderately stiff rear bar the ‘lift off oversteer’ tendency is pretty much eliminated. Although the ride quality was improved, I didn’t feel it was as ‘night & day’ as people claim & it certainly wasn’t a sufficient improvement to make up for the disadvantages. Perhaps different people focus on different aspects of a car’s handling? For me, a nice balance of grip between the front & the rear of the car is a key factor in how enjoyable it feels to drive. I wouldn’t want to adversely affect that in the pursuit of improved ride quality, particularly in a Caterham. Perhaps the answer is to seek out better surfaced roads? Link to comment Share on other sites More sharing options...
Graham Hutton Posted April 19 Share Posted April 19 It's very interesting. I also much prefer my car with a relatively stiff rear ARB. My Core 1 setup transformed the front massively but it took a bit of playing around to to get the rear to feel better. I actually ended up making some massive changes to the damper settings to make sure I could feel the difference and ended up settling on a setting which is about 75% of the way to the hardest setting. I found the most annoying bumps were those long duration ones like the dips you sometimes get on dual carriageways. The compression at speed took ages on a soft setting and was over much quicker and more comfortably with a stiffer setting. Not what I expected at all but to be honest, I am very happy with it now both on the road and the track. 2 Link to comment Share on other sites More sharing options...
Nigel B Posted April 19 Share Posted April 19 That’s an interesting observation Graham & I’m glad it’s not just me who prefers the feel of the car with the rear ARB! Years ago, I had a couple of weeks off work. The first week, I visited my Dad, driving down from Scotland to the Midlands in the Caterham. The following week, we had a week away in the Highlands. We took my every day car, which was a Clio 172 at the time. On the drive north I was bemused by how ‘baggy’ the Clio felt, assuming my perception of it was down to the contrast with a week spent driving the Caterham. However, as the drive progressed, I started to feel there was a problem. When we arrived at our accommodation in the Cairngorms, I had a peek under the back of the Clio & discovered drops of oil, leaking from the rear near side damper. It felt very much as you describe. The problem was most noticeable on subtle dips or rises on the dual carriageway, where the car would momentarily feel ‘floaty’ & unsettled. I bit the bullet & replaced all the springs & dampers (with new, standard spec ones) & wow, what a difference that made! The car no longer felt under damped & as you describe, it would deal with & recover from lumps & bumps far more quickly. 1 Link to comment Share on other sites More sharing options...
Ballast-ic Posted April 19 Share Posted April 19 I recently replaced my rear shocks with Protechs and noticed an immediate difference in improved road holding, so you don't need to spend £thousands on Nitrons and the like. Having adjustable dampers is also a bonus so you can tighten up for track days. Echo previous comments on tyre pressure and ARB. When I first got the car, tyres were at 21 cold and it bounced around like a wild thing. Dropping down to 18 cold transformed it. Also setting rear ARB to lowest setting definitely helped make it more predictable. Fiddling with relatively small settings in a number of areas make significant differences, but the biggest difference I did was the Protechs, which were bog standard from Protech. 1 Link to comment Share on other sites More sharing options...
Ainsley Posted April 19 Share Posted April 19 What is the recommended pressure for road use for a 420R ? Link to comment Share on other sites More sharing options...
Dan R Posted April 19 Share Posted April 19 Anecdotally 18psi seems to be a good starting point for 13inch wheels. 2 Link to comment Share on other sites More sharing options...
JAL73 Posted April 20 Author Share Posted April 20 13 hours ago, Ballast-ic said: I recently replaced my rear shocks with Protechs and noticed an immediate difference in improved road holding, so you don't need to spend £thousands on Nitrons and the like. Having adjustable dampers is also a bonus so you can tighten up for track days. Echo previous comments on tyre pressure and ARB. When I first got the car, tyres were at 21 cold and it bounced around like a wild thing. Dropping down to 18 cold transformed it. Also setting rear ARB to lowest setting definitely helped make it more predictable. Fiddling with relatively small settings in a number of areas make significant differences, but the biggest difference I did was the Protechs, which were bog standard from Protech. I've had a look on the Protech website but when you search for their Caterham offerings it says 'no products listed' Which particular damper and spring combination did you go for? Do they have fitting/ geo setup facilities there also or supply only? Their product offering seems dramatically cheaper in price than the more well known brands offered by the well respected Meteor motorsport. Just wondering if anyone has any experience comparing Protechs vs Nitrons, Core or Penske - is it a question of you get what you pay for or are these Protechs really just better value for money. My question is in the context of ride comfort on the road, not shaving seconds off laptimes. Link to comment Share on other sites More sharing options...
SM25T Posted April 20 Share Posted April 20 I couldn't justify spending thousands on other brands for my road touring use. They just do the job well and are great value for money. Speak to Matt at ProComp Motorsport and ask what model of one way adjustable dampers needed from Protech Link to comment Share on other sites More sharing options...
SM25T Posted April 20 Share Posted April 20 On my 2002 SV I gave the following info. All measured with dampers on car Fronts:- 384mm fully extended 363mm with car on ground but no occupants (currently 250lb springs). Bushes 32mm long both ends with sleeves to suit 5/16" bolts. Rears:- 480mm long fully extended. 465mm long with car on ground but no occupants (CC progressive springs). Sleeves in bushes 35mm long to suit 1/2" dia bolts. Road use only. Often 2 up (100kg plus 70kg) plus tools and luggage in the boot. But can be driver only. Set it up before with our weights on seats ... front height to suit required sump clearance. Then rear of chassis +15mm. Link to comment Share on other sites More sharing options...
Ballast-ic Posted April 20 Share Posted April 20 38 minutes ago, JAL73 said: I've had a look on the Protech website but when you search for their Caterham offerings it says 'no products listed' Which particular damper and spring combination did you go for? Do they have fitting/ geo setup facilities there also or supply only? Their product offering seems dramatically cheaper in price than the more well known brands offered by the well respected Meteor motorsport. Just wondering if anyone has any experience comparing Protechs vs Nitrons, Core or Penske - is it a question of you get what you pay for or are these Protechs really just better value for money. My question is in the context of ride comfort on the road, not shaving seconds off laptimes. I got 400s shocks. Just ring them and they will advise on best option. For the money they are great and definitely improve the ride. Link to comment Share on other sites More sharing options...
Miker7 Posted April 20 Share Posted April 20 Matt (procomp) supports a lot of the locost and Westfield racers. From my limited dealings with him he's very down to earth and practical. He won't sell it if it doesn't work & that's kept him and his father before him in business for years. I'm sure spending more money will get you better quality, but I think of it as deminishing returns. I don't need to chase 0.1s a lap so I don't need 2k shocks. 3 Link to comment Share on other sites More sharing options...
7 wonders of the world Posted April 20 Share Posted April 20 Rear noises from the rear end... Check the front radius arm mounts these often work loose cap head is access from the inside and partially hidden by the seat. 1 Link to comment Share on other sites More sharing options...
SM25T Posted April 20 Share Posted April 20 Mine are Protech 400 series 1-way adjustable, revalved by ProComp. Link to comment Share on other sites More sharing options...
mph Posted April 21 Share Posted April 21 Tyres — here's Avon's own documentation. It says 22-27 HOT, which I've found tends to be 18psi cold. Avon Tyres Motorsport - Lotus Seven Club - 2021 Edition.pdf 1 Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted April 21 Share Posted April 21 2 hours ago, mph said: Tyres — here's Avon's own documentation. It says 22-27 HOT, which I've found tends to be 18psi cold. Avon Tyres Motorsport - Lotus Seven Club - 2021 Edition.pdf 2.52 MB · 2 downloads The recommended tyre temp range of 60C-90C hot would give a cold pressure range at sea level and 20C ambient of 15PSI cold for 90C at 22PSI hot to 22PSI cold for 60C and 27PSI hot. 1 Link to comment Share on other sites More sharing options...
SM25T Posted April 21 Share Posted April 21 JAL73 ..... see private messages Link to comment Share on other sites More sharing options...
SM25T Posted April 24 Share Posted April 24 Gone very quiet here ? Link to comment Share on other sites More sharing options...
150SV Posted April 24 Share Posted April 24 10 hours ago, SM25T said: Gone very quiet here ? Been to cold and wet here to even think about blatting, and I’ve been to busy to even open the garage tbh Link to comment Share on other sites More sharing options...
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