Rex Posted May 1 Share Posted May 1 My sump used to scrape and occasionally the car would bottom out. I got coil-overs for the front and cranked them as high as they would go. No more scraping-no more bottoming out. Link to comment Share on other sites More sharing options...
ScottR400D Posted May 2 Share Posted May 2 9 hours ago, Rex said: My sump used to scrape and occasionally the car would bottom out. I got coil-overs for the front and cranked them as high as they would go. No more scraping-no more bottoming out. That sounds a logical way to go………….. Link to comment Share on other sites More sharing options...
Miker7 Posted May 3 Share Posted May 3 What is the normal ride height for a 7 on 14" wheels. I had a look last night and with non adjustable shocks I've got over 90mm (70mm + 18mm planks and a bit of a gap) under the sump. Link to comment Share on other sites More sharing options...
SM25T Posted May 3 Share Posted May 3 Check it with the equivalent of your weight in the car. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted May 3 Member Share Posted May 3 7 minutes ago, Miker7 said: What is the normal ride height for a 7 on 14" wheels. I had a look last night and with non adjustable shocks I've got over 90mm (70mm + 18mm planks and a bit of a gap) under the sump. "A widely recommended minimum is the ability to roll a Coke can under the lowest point. That's 66 mm. But there are many experiences in the archives describing 75 mm as being needed to clear obstacles." Jonathan Link to comment Share on other sites More sharing options...
Colin_T Posted May 3 Share Posted May 3 (edited) I was advised 80mm for road, 70mm for track. I run my sump at 80mm seeing as I can’t buy a replacement one…. Edited May 3 by Colin_T Link to comment Share on other sites More sharing options...
Miker7 Posted May 3 Share Posted May 3 2 hours ago, Jonathan Kay said: "A widely recommended minimum is the ability to roll a Coke can under the lowest point. That's 66 mm. But there are many experiences in the archives describing 75 mm as being needed to clear obstacles." Jonathan Appreciate that's "normal", but on my roadsport I can't adjust the springs so i was wondering if my height is "normal" for 14" wheels or if it indicates something is amiss? On the bright side, i should have no issue getting onto the brake rollers this evening for the MOT. Link to comment Share on other sites More sharing options...
StevehS3 Posted May 3 Share Posted May 3 1 hour ago, Miker7 said: Appreciate that's "normal", but on my roadsport I can't adjust the springs so i was wondering if my height is "normal" for 14" wheels or if it indicates something is amiss? On the bright side, i should have no issue getting onto the brake rollers this evening for the MOT. I think it somewhat depends on the engine fitted. For example, the Sigma is a less-tall engine than the wet sump K or Duratec, so an extra 10mm under the sump might give a similar ride height. Link to comment Share on other sites More sharing options...
SM25T Posted May 3 Share Posted May 3 I recall Sigma having 110mm under the sump from new Link to comment Share on other sites More sharing options...
Miker7 Posted May 3 Share Posted May 3 56 minutes ago, StevehS3 said: I think it somewhat depends on the engine fitted. For example, the Sigma is a less-tall engine than the wet sump K or Duratec, so an extra 10mm under the sump might give a similar ride height. This is on a wet sump K Series - so potentially a little high but also in the ball park for normal based on the Sigma comment above so stop wondering and start worrying about the MOT 😄 1 Link to comment Share on other sites More sharing options...
JP Posted May 3 Share Posted May 3 (edited) Just had a look in my assembly guide for a k-series: My K-series SS was on 14"s and did not have adjustable suspension. Perhaps adjustable was only std on those Ks with 13"s? With 14"s, you would have an extra 12-13mm of clearance. 66mm might be the diameter of a coke can, but 75mm is roughly the length of a SwissCard...of course, that's not much use if you don't have one... Edited May 3 by JP Link to comment Share on other sites More sharing options...
JP Posted May 4 Share Posted May 4 (edited) So...I planned to do a rough check of ride height today, just to get it in a safe ball park range for a first longer drive out to get a full flat floor set up next week. I seem to have fallen at the first hurdle in that I've run out of front spring adjustment with a sump that is way too low at 55mm. My car was originally a SS with widetrack non-adjustable suspension on 14" wheels. In my rebuild I switched to Pro-Techs, but re-used the front springs because they were more or less new when I took the car off the road. I sent the old front shocks to Pro-Tech so they could see that they were for wide track (they have the extension piece at the top). Here is the position today on 185/60/13 R888Rs: 55mm sump clearance (without me in the car): And shock adjuster position: Do I just need longer springs, or should the shocks go back to Pro-tech for longer shocks? If I just need springs, any recommendations? Need quick delivery becuase the car is booked in for a FF setup on Thursday... Edited May 4 by JP Link to comment Share on other sites More sharing options...
JP Posted May 4 Share Posted May 4 If I go with longer springs, does a 9" spring sound right? I think my current springs are std 7" (1.9"ID) 150lb - the markings are not clear. On the car they are approx 5" long and I think 2" compression with about 130kg on them sounds about right for a 150lb spring? So if I want an extra 20mm sump clearance I think need a little over 1" extra spring length (assuming the spring is at roughly 45degrees) and say another 1" so that the spring adjuster isn't right at the end of the threaded portion of the shock? Should I change the spring rate too? Its a road car with occasion track days, say 3-4 per year max... Link to comment Share on other sites More sharing options...
ScottR400D Posted May 4 Share Posted May 4 In all honesty I’d get someone who really knows what they’re doing to sort this. Just guessing rarely works out. 1 Link to comment Share on other sites More sharing options...
JP Posted May 4 Share Posted May 4 Cheers @ScottR400D - I'll get on to Protech and PT who will do the setup. I was rather hoping that there might be an obvious solution that I can address before the appointment next week. I fear I may have to post-pone the setup... Link to comment Share on other sites More sharing options...
7 wonders of the world Posted May 4 Share Posted May 4 Proptech should also be mounted the conventional way up to as there are a twin tube design and can cavitate is run inverted. Link to comment Share on other sites More sharing options...
JP Posted May 4 Share Posted May 4 Cheers @7 wonders of the world - I did ask Pro-Tech before flipping them and they said that it wouldn't be an issue, but I'll check again with them when I discuss the solution to the ride height problem. Cheers for the heads-up. Link to comment Share on other sites More sharing options...
SM25T Posted May 4 Share Posted May 4 (edited) Change to stiffer springs. 55mm without your weight is way too low. My SV was fitted with 170lb springs and I changed to 250, then 300 👍 the spring is much longer too. Edited May 4 by SM25T 1 Link to comment Share on other sites More sharing options...
Area Representative Golf Juliet Tango Posted May 4 Area Representative Share Posted May 4 30 minutes ago, JP said: Cheers @7 wonders of the world - I did ask Pro-Tech before flipping them and they said that it wouldn't be an issue, but I'll check again with them when I discuss the solution to the ride height problem. Cheers for the heads-up. Like you, I found Protech very obliging. It's great to support them. Excellent service, nice design and good pricing. Link to comment Share on other sites More sharing options...
SM25T Posted May 4 Share Posted May 4 I was advised that they must be mounted with the adjuster downwards when I bought mine. Link to comment Share on other sites More sharing options...
JP Posted May 4 Share Posted May 4 Thanks @SM25T - it looks as if mine will be coming off again shortly anyway...☹️ This is really irritating. I was really looking forward to getting the last of the key bits of the rebuild done and just enjoying the car again... Link to comment Share on other sites More sharing options...
SM25T Posted May 4 Share Posted May 4 I got advice and my springs from ProComp Motorsport in Birmingham 1 Link to comment Share on other sites More sharing options...
BenF Posted May 5 Share Posted May 5 On 04/05/2024 at 14:32, SM25T said: Change to stiffer springs. 55mm without your weight is way too low. My SV was fitted with 170lb springs and I changed to 250, then 300 👍 the spring is much longer too. The longer the spring (all else being equal), the lower the spring rate. I guess the stiffer springs are longer just because they are also different in terms of the spec of the spring. I'd try to stick with a softish spring for road use, but as said, an expert who's sold springs for Caterhams before can advise. Link to comment Share on other sites More sharing options...
OldAndrewE Posted May 5 Share Posted May 5 2 hours ago, BenF said: The longer the spring (all else being equal), the lower the spring rate. Slightly misleading statement there. What governs the spring rate (assuming wire diameter and diameter of coil remains the same) is the number of coils. So if you lengthen the spring by adding coils then yes, the rate will be lower but if it is lengthened by spacing out the same number of coils then the rate remains the same. Link to comment Share on other sites More sharing options...
BenF Posted May 5 Share Posted May 5 Yes, that's why I said "all else being equal" Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now