Advice sought re suspension and shocks

PostPost by: Apx » Fri Jul 04, 2014 12:59 pm

After a slowly deteriorating ride and handling on my ?lan its time to replace the suspension, ( shocks, springs, etc.)
The current set up is Armstrong and has worked well enough but has now given up the ghost. I am after a good road car for british roads and as Armstrongs are not available anymore, i am interested in advice and experiences as to possible replacements. Its been done before in this forum but one of my main concerns is to spend money on parts that are not going to be utilised properly on the road. For example are Koni rear shocks really worth the ?350 a pair? Any comments or experiences welcome
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PostPost by: UAB807F » Sat Jul 05, 2014 7:05 am

Hi there,

Yep, as you say the thorny suspension question has been done before and has almost as many answers as forum members, we all have our own take on the issue. You're going to get a lot of answers.... :D

I suppose the main thing is to ask yourself if you were happy with the OEM design when you first got the car or last refreshed it, because if so the easiest solution is to just renew all the various bits with standard parts.

If you hanker after "something better" then it's a whole can of worms.

I approached it by asking myself "do I want the car to look different ?" and the answer was "no". Second thing was "am I good enough to be able to define the geometry ?" and again it was a "No".

All I'd do with adjustable wishbones is set them up either to standard or what someone more qualified would tell me to do. And as I'm not doing track days with differing surfaces, and sticking to k/o steel wheels and 80 series tyres with no bodywork mods then spending on adjustable wishbones seemed a waste in my case.

I just wanted something for a road car, but even with Lincolnshire pot-holes I wanted a firmer, more modern feel to the ride. So in the end I fitted higher rate springs and adjustable dampers from Pat Thomas. Similar (if not exactly the same) kits will come from TTR and most of the usual suppliers. It uses adjustable AVO dampers with Kelvedon specified springs.

I spent over ?600 and could easily have taken it closer to the ?1k mark, but I'm happy with what I've got. The car is firmer and feels transformed within my limited abilities, but it's not uncomfortable on poor road surfaces. YMMV as they say.....

Brian
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PostPost by: Apx » Sat Jul 05, 2014 5:35 pm

I am split between standard or fast road shocks and whether to put adjustable platforms on the rear turrets, anyone ideas on spring rates?
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PostPost by: rgh0 » Sun Jul 06, 2014 1:32 am

Below is what I have tried over the years and it generally aligns with the recommendations in the Dave Bean catalogue.

If wanting to explore stiffer springs for road use the first thing I would fit would be a bigger diameter roll bar this sharpens the turn in and keeps the car more stable in corners without affecting the ride. You could use a 3/4 inch bar ( up from the standard 11/16 inch). You can also fit a spacer of about 30 mm on the rear strut under or on top of the Aeon rubber spring so as to bring it into play a little earlier in roll without affecting normal ride. This combination makes a car that corners well and more stably with the grippier modern road tyres without affecting ride.

The next step is about a 50% increase in spring rates front and rear to 120 lb/in front and 100 lb/in rear. Once you start upping the spring rates the ride will get worse but this first 50% step does not affect the ride much and the handling improves another step. You can stick with the same roll bar or take it up another step to 13/16 inch. You will need adjustable mounts to set the ride height correctly as you start increasing the spring rates.

Another step up in spring rates to 150lb/in front and 120 lb/in rear and roll bar to 7/8th inch (or more) is OK ( just?) for the road but starting to get noticeably less comfortable and is at the soft end of the range for a track car. This is probably to far for what you want.

I have tried another step up again but this got seriously firm in ride and made wet driving on the track to difficult for me at least :shock: .

cheers
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PostPost by: UAB807F » Sun Jul 06, 2014 5:15 am

Apx wrote:I am split between standard or fast road shocks and whether to put adjustable platforms on the rear turrets, anyone ideas on spring rates?


I can tell you what I've fitted but as I said before, these things are personal and you may have a different outlook on what's good/bad or what you're trying to achieve. My aim was simple - a firm ride which wouldn't shake the car (or me) to pieces on B roads and to stop banging the exhaust when the suspension bottomed out, which was a regular thing despite having new OEM springs & rubber helpers. What Pat recommended scored on all counts.

Rohan's comment about adjustable platforms is spot on. You can calculate the fitted spring lengths and hence ride height, but being able to adjust the base position makes it all so much easier.

The front dampers have 16 clicks for the full range with 1/4 turn per click. I initially set at 8 clicks, half way in the range. These have 175lbs/ins springs (75lbs/ins OEM)

The rear Dampers have 5.5 (or 6 ?) turns for the full range, again initially set at half way. These have 140lbs/ins springs at 3" diameter so smaller than OEM. (67.5lbs/ins)

Like Rohan, Pat also advised a thicker ARB and I should have bought one but to be honest I was hesitant about spending the cash on what seemed to be a fairly large increase in spring rate and I wanted to keep something in reserve just in case I needed to get softer springs. So I held back on that one.

Now I've driven the car, done the sums and understand a little more how these things work I realize I should have listened at the time. I have an new ARB on the "project" list. :)

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PostPost by: Apx » Sun Jul 06, 2014 11:09 am

Guys,
Many thanks for the replies, i had not thought of the ARB but if recommended then i will have to look into cost. Two remaining questions :- Are adjustable mounts worthwhile on the rear turrets and would a longer progressive bump stop work the same as the space idea put forward ?
Neal
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PostPost by: rgh0 » Sun Jul 06, 2014 11:26 am

Yes adjustable spring mounts front and rear needed if going for higher spring rates
A longer rubber spring with a similar spring progressive rate would be an alternative to adding a spacer to the standard Aeon spring

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PostPost by: elancoupe » Mon Jul 07, 2014 2:25 am

When I purchased fast road shocks/springs from TTR, I asked him about ARB sizes. I had been running a larger front bar. His first question was "what size tires are you using? I told him that I had been using slightly wider tires, but was going to return to stock size. His reply was " Stock tire, stock bar." As per his advice, I reinstalled my stock ARB. I have been most satisfied with the whole package.

As an aside, if you go with adjustable perches, I highly recommend getting the car corner weighted. When I put my kit on the car, I was most careful to set the perches equally, and spent a lot of time fussing with ride height. When I did get the car corner weighted, I was shocked at how much adjusting was needed to set the weights. It was well worth it, the cars sits and looks right, and handles great.
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PostPost by: rgh0 » Mon Jul 07, 2014 2:52 am

I think stock size tyres = stock size bar is more than a little simplistic and I would have hoped for a better answer than that from TTR as there are many more variables IMHO. That answer also surprises me as TRR are the original "stiff spring setup" for an Elan people and I find their spring rates very nervous and very hard to drive smoothly on the track. Maybe our tracks are rougher here than in the UK or maybe its just I am a hopeless race driver which I would not necessarily dispute :lol:

Driving preference, type of tyre both size, profile and rubber compound grip and spring rates and use of car will all contribute to roll bar selection.

The original bar size was selected to match the low grip cross-ply tyres the Elan originally came with. Lotus stuck with the spring rates and bar size during the life of Elan production even after they moved to radials in the late 60's. Modern tyres, even cheap 155 / 80 x 13 or similar have much greater grip than those original tyres and the Elan is too soft in roll as a consequence I believe. I also believe it sits down on the rear outside wheel to much in roll resulting in a difficult to manage oversteer which is why I like the rear Aeon springs to have a spacer added to control that in combination with a bigger front bar.

If running the original cross-ply tyres then I am sure the Lotus original setup was absolutely the best possible compromise on ride and handling as those guys knew what they were doing but those times have long gone now. As always with Lotus there is no absolutely correct answer on most topics and changes to the original Lotus handling set up is always going to generate discussion as compared to Lotus we are all amateurs.

It is interesting that Lotus have generated new suspension packages for the later 80 and 90's Esprits based on modern tyre availability, its a pity they have not gone back and done the same thing for the Elan and Plus 2 but I guess the demand and potential revenue is not there to justify the work.

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PostPost by: Apx » Sat Aug 02, 2014 9:39 am

An update for those who are interested or newbies like me interested on how others have set their cars up......

I contacted Kelvedon Motors and had a talk to Pat stating my requirements for British Roads and after all the advice received i settled for the following.
Front adjustable fast road Avo shocks and 150 springs and on the rear adjustable spring mounts fast road adjustable shocks with limited droop and 125 springs. I fitted progressive bump stops to the rear.As the suspensions were off, I renewed all of the bushes with "polys" renovated the wishbones, painting etc and i renewed the steering and top ball joints. Taking advantage of the fact that the car was apart, i took out the diff, checked it over and painted it, on replacing i fitted a diff brace bar as i had obtained drive shafts to replace the doughnuts which were fitted.
I am still in the adjustment phase, but i have to say that the car is transformed, it handles well and is not grounding on Kents roads despite having what appears to be less clearance, even with the wife on board! I now realise how knackered my old suspension must have been, but with a gradual decline i suppose i didn't notice it. I am still getting use to the driveshafts, there is no surge or indeed delay on acceleration anymore. Pat as with others on this site advised uprating the ARB, at present i haven't, my thoughts are to try the car with the old one and then fit a borrowed 26r one to see what the difference is before buying my own. I'll update later with the results.
During the process this site has been excellent, although time consuming, sorting through the archives for advice and answers. Pat at Kelvedon was great and i phoned him a couple of times for help re adjustment settings and the welding required for the rear shocks. He had the time to explain and advise always saying to call back if anything else was needed. I had a very bad experience with Hammerite paint not drying, despite being correctly applied and with the hot weather we've had. I had to dry in an oven, ( mrs not impressed) and the makers were useless when asked for help. I got metal paint from screwfix for the rest of the parts and it was easy to use, cheaper and looks good. only time will tell how it lasts.
Sorry for the poor pics the best i can do with an iPhone... Now i have to plan for hood replacement and the dreaded respray!
Attachments
IMG_1057.jpg and
IMG_1048.jpg and
IMG_1051.jpg and
IF EVERYTHING SEEMS TO BE GOING WELL, YOU HAVE OBVIOUSLY OVERLOOKED
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PostPost by: UAB807F » Sat Aug 02, 2014 3:47 pm

Thanks for the update, it's always interesting to hear how these things work out.

Your experience is almost identical to mine, although I didn't mention it at the time, I also found Pat to be an extremely helpful guy. Like you he told me the best ways to get the rear spring conversion in place and a guide to how to set it up.

And like you, the car was transformed. The new ARB is still on my wish list but it will happen some time this year.

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PostPost by: publicrealm » Sun Jan 25, 2015 1:41 pm

Hi Guys,

I'm a complete newbie on here (and am useless technically - so totally intimidated by the technical expertise on the board :oops: ).

I have a nice 1968 Elan +2 but am advised it needs new springs and shocks all round (and whatever other gubbins that implies).

I only use the car for an occasional spin - never fast or demanding - so bog standard issue is what I want.

As I will need to get these fitted for me I'm just wondering what price ballpark I'm in - any advice appreciated?
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PostPost by: KevJ+2 » Sun Jan 25, 2015 5:47 pm

I would think it's the other gubbins that will put the estimate up. I would expect to replace a few bearings, discs, mounts etc.at the same time. Is a friend or garage doing the work? If it were me, I'd be looking to rob my piggy bank of about ?750 - ?1000 Some may say more, some less depending who does the work.
Hope this helps.
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PostPost by: publicrealm » Sun Jan 25, 2015 7:22 pm

Thanks for the quick response Kev,

I will be paying a garage to do the work and had about ?1,500-1,750 in mind (Euro)- so I may be in the right ballpark.

Regards,

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