StressedDave Posted September 24, 2007 Share Posted September 24, 2007 I couldn't keep up with that conversation, and I'm a ride and handling engineer by training . The rate calculation is fine, but you'll need to work out where in the travel the tender spring is going to become coil bound and you'll be switching over to the significantly stiffer rate. You'll want to decide where and when that happens as if it happens at the front before the rear you'll be having a significant shift towards understeer and vice versa if vice-versa. As for what's right, you'll need to be working out chosen spring frequencies based on sprung weight, roll moment distribution based on weight distribution and then tune the damper values in based on both. I'd be inclined to set the transition point for the tender springs so that it gets taken up very early on in the roll motion. The last thing you want is for you to think you've taken a set for the corner and then the transition gives you a sea change in the handling. I can't give hard or fast answers without a lot more data. I own the 1/12th scale Tamiya model - does that count? Link to comment Share on other sites More sharing options...
Vinnie_Hki Posted January 8, 2009 Share Posted January 8, 2009 Alex, I mentioned to a few people recently that I was unhappy with the handling of my Nitron shod VX and was looking at spring rates and that the ERS system had appeared on my radar.... They pointed me to you and I searched and found this old thread. So, my question: What was the outcome? What rates did you end up using? Vinnie Link to comment Share on other sites More sharing options...
Alex Wong1697456877 Posted January 8, 2009 Author Share Posted January 8, 2009 I never fitted it. It's still in my garage. I think they are too firm for a road Seven and I guess I ought to sell them. I also bought a set of Caterham Bilstein "Trackday" dampers which use a twin rate rear but I'm still struggling with it. The back of the car doesn't inspire confidence. The setup seems to have quite soft springs but quite stiff dampers. I removed the rear ARB and lowered the back and it's better but still not right. It seems better with my 70 profile 021R's but with x-ply slicks, the back feels a bit jittery. To this day, I cannot get my head around the twin rate system. Welcome to BC! Alex ----- VDU 7X Pics More VDU 7X Pics Link to comment Share on other sites More sharing options...
Petrolhead Posted January 8, 2009 Share Posted January 8, 2009 What up with the handling Vinnie? R5 no more ☹️ Welcome CSR My site Link to comment Share on other sites More sharing options...
Vinnie_Hki Posted January 8, 2009 Share Posted January 8, 2009 What up with the handling Vinnie? Well, as mentioned on the Se7ens list, the new car has Nitrons all round (shocks and springs) and my old car has Bilsteins. Obviously I have plenty of experience of how my old car handles on my favourite test track (a.k.a "the drive home from work" 😬) and I have no doubt whatsoever that the Bilstein setup on that is more balanced, confidence inspiring and grippy than the Nitron shod car. So much so that I nearly ventured off road in the new car when I took a corner at what I thought was a very conservative speed. On track, experience was similar, so this isn't a B road versus track setup issue - the Nitron car is simply not handling as well. So this lead me to investigate the spring rates and my conclusion so far is that the Nitron car has springs which are just too firm at the front and probably at the rear too. However I have also considered the fact that a revalve of the Nitron's may be in order as I hear others have found their "full on" track valves a bit much, even on track. From there I started to look at spring options, possibly at the ERS system from Eibach and thence I heard Mr Wong may well have got there before me (again ) Is it not bizarre that both the cars referred to have Ex Wong gearboxes for example Anyway, that's how I came to be searching BC for Alex's experience to see what solution he had arrived at since he is a very wise man, as demonstrated by his continuing use of the superior power plant Vinnie Link to comment Share on other sites More sharing options...
Petrolhead Posted January 8, 2009 Share Posted January 8, 2009 When I bought my Nitrons for the R500 at first I was not happy, the rears were by far the worst and it turned out to be the rebound was set too high. Once Nitron dynoed my std shocks they then had the right starting place I have to say that Nitrol were excellent and very patient as I thing the shockers went back about 4 times R5 no more ☹️ Welcome CSR My site Link to comment Share on other sites More sharing options...
STEVE GILBERT Posted January 8, 2009 Share Posted January 8, 2009 Exactly the same with my Nitrons on the blade back in 2003. A re-valve sorted it so now I typically run no clicks at he back/4 at front and lots of clicks on track depending on how I want it to feel/weather etc In fairness the LA will always be a bit less compliant. All that said the service from Nitron was first rate and shocks sorted by return of post Steve See My Caterham Fireblade Here. Link to comment Share on other sites More sharing options...
Blackbirdman Posted January 11, 2009 Share Posted January 11, 2009 Interstering to read as I've been thinking about swapping from my rather old and warn Ledas to Nitrons. Matt Life begins at 10,000 Link to comment Share on other sites More sharing options...
IKB Posted January 11, 2009 Share Posted January 11, 2009 My head hurts ☹️Did Mr Chapman have this problem? Link to comment Share on other sites More sharing options...
captain chaos Posted January 11, 2009 Share Posted January 11, 2009 Vinnie, What spring rates does your Vx have? and which Nitrons do you have? Cheers Gary vx & with Nitrons also... Link to comment Share on other sites More sharing options...
Vinnie_Hki Posted January 12, 2009 Share Posted January 12, 2009 Hi, Apologies for the tardy reply 😳, I wanted to get the rear wheel off to be double sure: Front springs are 275lb and the rears 130lb. As to the shocks themselves not sure the proper name but they are the ones that are one way adjustable, not two-way i.e. I have these NTR Sports I think. FWIW, I think the other car (On Bilsteins) runs 250lb and then the "Caterham 21" progressive rate spring at the rear which IIRC is 160 - 210lb. To be fair the Bilstein setup has probably been pushed harder and for longer on long trips where the back of the car was fairly well loaded with luggage and I would be two-up, but I have ´been very happy with them. The Nitron car has freestyle front and rear ARB's on full soft at the moment. Part of the problem at the rear is connected to the rebound rate I think (If I understand the terms right) as my scariest moment came when going over a crest. I'd say I took the crest at 65 - 75% speed of what I would consider "better watch myself here" 100% in the Bilstein car so was caught out when the rear of the car set off on its own for a walk about in the adjacent forest - fortunately I caught it and we carried on unscathed. It would seem to me that the rear wheels got too light as we went over the crest and lost contact with the road. I could be talking through my 🙆🏻 about the cause, but I know the result. Vinnie Edited by - Vinnie_7 on 12 Jan 2009 19:57:29 Link to comment Share on other sites More sharing options...
Petrolhead Posted January 12, 2009 Share Posted January 12, 2009 I was running 130LB springs on the R500 and with the std setup the Nitrons were simply too hard. I would send them back to Nitrol for a revalve, I did 4 times but it was worth it. Dave Pratt (GrimReaper on BC) then sent his back asking for the same settings as mins as he was having the same problem and is now happy. So, if you send them back ask for the Ellis/Pratt setup 😬 R5 no more ☹️ Welcome CSR My site Link to comment Share on other sites More sharing options...
captain chaos Posted January 12, 2009 Share Posted January 12, 2009 Sorry to be hi-jacking here Alex... Vinnie, I'm on 300 front, 165 rear. I have the 3 way adjustable (more adjustment than I know what to do with , but I've had a bit of time at the Ring and a day at Donnington (Nov) but due to cold temps I wasn't able to really load the Dampers. However, compared to my Spax the car seems to be more stable in the turns but less so under braking. What do you look at if the car seems to' pivot a little', like the back feels skittish under hard braking? Freestyle ARBS front and back both at 30% from full soft... Gary Link to comment Share on other sites More sharing options...
Vinnie_Hki Posted January 12, 2009 Share Posted January 12, 2009 Hi, Assuming that was a question It seems to me that the harder the spring the quicker mass is transferred from one place to another. Under heavy braking if the rear is rapidly unloading and thus losing grip, becoming skittish, then it suggests to me that the weight was suddenly transferred to the front due to the spring there being a bit too strong. Put another way, softer springs at the front would mean the transition would be slower and less likely to unsettle the car. ARB setting will only come in to play if you are cornering and braking etc - assuming this (skittishness) happens in a straight line then the ARBs can be largely discounted. Take all that with a pinch of salt as I do not profess to be a suspension guru, but that's my impression. What's you bhp and and how would you describe the under / oversteer balance? I found on track - e.g. mid speed hairpin corners, I was having to be brutal with the throttle to light up the rears a little to bring the front round IYSWIM - otherwise the front just pushed out wide due to understeer. On longer faster corners I was adjusting my lines to allow for the front to understeer away from the apex. The Bilstein car tends more towards oversteer FWIW. Interesting data input on spring rates though thanks - your springs are harder all round than mine, but there is of course the crucial difference in balance. Your fronts are about 9% stiffer but your rears 26% stiffer. This is where I run out of knowledge (Maybe earlier and I just don't know it of course!) but it seems to me that a stiffer rear spring will assist with the rebound speed? i.e. a stiffer spring will force a damper to droop back down faster than a softer spring? Hence as my Bilstein rear is 160 - 210 and yours are 165, but my Nitron car has 130's we may have something to experiment with Vinnie Link to comment Share on other sites More sharing options...
captain chaos Posted January 13, 2009 Share Posted January 13, 2009 I had the advantage of bumping into Guy (Nitron) whilst at the Ring (he was working on an M3GTR at the time)...he confirmed my springs were about right and gave me some base settings to play with...he told me not to touch the...( as write this I've forgotten but I have it written down at home)..one of the compression settings and work with the other and the rebound... It's a black art and I wish i could test it often enough to actually make some meaningful adjustments... Link to comment Share on other sites More sharing options...
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