It is not first time I use this forum where I have always got the answers to a lot of inquiries…but this time I am a little bit ashame of my inquiry which is certainly going to seem so evident to a lot of you…But as my scottish grandma (really)used to say "there 's not stupid question there is just silly answer …so… Following an excess of optimism I put my elan out of race track during the timing practice of last race …no big accident and car very slightly worn…but steering was touch and needs to be repaired so for 1 st time in 45 years of racing an elan I dismantled the thing and here is my question… Is it ““normal”” that I discover that the 2 rack tie rods are not of egal length …and when I visit all sites with lotus parts they just have one length…Am I stupid or do I have to machine both because even the longer one is shorter than the 160 mm I find everywhere??? Thousand of thanks if somebody can help…
Roger (photo is ten seconds before Iwas too optimistic)
All of the Elan racks I’ve rebuilt or serviced had only one length, i.e. same both sides. A nominal 7.59" or about 193mm from the center of the pivot ball to the end of the threads.
If you are running the 26R front suspension the steering arms may have been bent inwards during set up to allow the ball joint to clear the brake disc. A bit needs to come off the track rod end to accommodate this, but usually it’s taken off equally at both sides.
Dear Graeme and dear Steve ,many thanks for your interest and you are both right …Last evening I was in touch with first owner of the car who gave me the explanation …the car is fitted with a F A N T A S T I C 1,2 wheel turn top left to top right steering that I go on using without any trouble since I own the car(45 years) but it was in period “home made”…because did not exist so short in period and during the cutting of the rack teeth it had been necessary to offset the teeth position on the ruler for ease of machining so tie rod at teeth ruler side is shorter than the original display and if you add the obligation to shift the position of rod end ball joint to clear the rubber protection from brake disc heat…so I am going to machine the tie rod …and once again many thanks for answer…
Roger
It has always been my assumption that the Elan (and Triumph Herald) had the ball joint as close to the disc as it did to help with the steering geometry.
It would have been easy to have a kink in the steering arm so that the ball joint was further from the disc, but instead there is a cutout in the disc backplate so that the balljoint can stick through.
I would be careful about messing around with the steering geometry unless you know what you are doing - the distance from the balljoint on the steering arm and the balljoint on the rack needs to be the same on both sides of the car - and in the right place relative to the centre line to minimise bump steer.
When racing, a hot disc can cook the steering balljoint rubber. I have balljoints with a metal cover rather than the usual rubber boot on the car that I race that avoids this problem. I had understood that they were used on 26Rs.
TTR Front discs and steering arms.pdf (436 KB)
This is the instruction from TTR for fitting the 26R front suspension/steering arms.
The bump steer is usually fiddled with after this on a race car anyway, but I have no doubt you are correct that it will alter it.
With all due respect to TTR’s highly engineered solution (!), heating up and ‘tapping’ a mission critical part with a hammer doesn’t fill me with enthusiasm.
I keep meaning to have a go at figuring out the sensitivity of the suspension to the lengths and positioning of various steering components, but there is a lot going on with intersecting arcs and the like and the maths gets very tricky. Allan Staniforth’s excellent book ‘Race and rally car source book’ has a solution that uses bits of hardboard and string - his string computer - but I don’t think that is sensitive enough. There is software available, but it is designed for racing teams and OEMs and costs £££.
Given that Chapman found it worthwhile to shim the height of the rack to get it right, and Triumph went to all the trouble of having the balljoint as close to the disc as was possible, I would think twice before I changed the placement or length of any steering component - including the position of the steering arm relative to the upright.
There was a recent thread (started be me) about the implications of changing the location of the lower pivot point on the suspension. The final conclusion was is didn’t matter much, but I am not sure I was completely convinced.
https://lotuselan.net/forums/viewtopic.php?f=42&t=47587
Andy.
When I put mine together it looked to me like the original modifiers of the 26R altered the steering geometry both to lower the front end but also line up the joints for bump steer. The upper and lower links define a quadrilateral with a messy corner where the trunnion offsets the joint and the steering axis by about an inch. It appeared to me the bending of the steering arm was intended to bring the ball joint close to in line with the steering axis looking from the front. And it looks like the joints in the rack are pretty close to the line extending from the upper inner joint to the lower inner joint.
I’m not sure about their intention, but that’s how it looked. John
I think I needed to bring in the ball joint by 5mm each side.
The shimming of the rack was done at a later stage and I have virtually no deflection through 2" of bump and 3" of droop.
My roadgoing Plus 2 seems to have cooked a small hole in a new one in a mere five miles or so. 
I think something must be adrift somewhere, or your roadgoing driving style is quite something to behold.
The main effect of bending the steering arm inwards will be to alter the Ackerman effect, the bump steer will be a secondary effect of this. For perfect Ackerman effect drawing a line through the kingpin axis and onwards through the steering arm ball joint should result in the line intersecting the centreline of the car where the rear axle centreline crosses it.
Bending the steering arms inwards will result in this line crossing the centre line of the chassis much further forward thus increasing the Ackerman effect. Unsure just how this will effect the outer wheel when cornering when combined with any bump steer that has been introduced by the necessary shortening of the track rods, and suspension compression changes due to roll, really needs computer modelling to understand this complex movement.
I think your Ackerman assessment is based on a rack behind the front axle?. Its the opposite effect for a front mounted rack. The front mounted rack is harder to work with due to the ideal position of the ball joint being further outboard than the steering axis. Tough to do with a brake disc occupying the same space. You can cheat this a bit by moving the rack rearwards.
You’re right my example was assuming a rack behind the axle, but if the rack is in front of the axle the point of intersection with the car centreline is the same distance but infront of the front axle instead of behind it. So the arms shouldn’t interfere with the disc, but this also depends on hub and upright design. Ideally the kingpin axis (the line passing through the centre of the top ball joint and bottom trunnion ) should hit the ground at the centreline of the tyre contact patch. If it’s much out you start to get a lot of kickback through the steering. Anyone who had an original Mini with wheel spacers on it will know that feeling well!
If the steering arms are cranked the same (closer to the centerline) as a rear rack then yes, the point would be forward. This would give ‘reverse’ ackerman with the inside wheel turning less than the outside. With the Elan the Tie rod ball joints are pushed outward intentionally. The point where the ground level lines on the planes of the rotating wheel intersects starts off in front (toe in), and as the wheels are turned (steered?) further it passes thru infinite/parallel to a point behind the Elan, way behind…
Thanks, that’s interesting, I need to spend a bit of time to understand that geometry.
Hi. As a newbie, and a Lotus Seven owner, I know nothing of parts fitted to the Elan except for the steering and front suspension parts. I am a rank amateur, but I have been completing research into steering racks from the Alder and Alford/Triumph range and how Lotus modified them for use on the various road models (Seven/Elan/Plus 2/Europa). On the Lotus Europa Community forum site, the site administrator has posted a very helpful article from the Club Lotus magazine by Brian Buckland that is mostly appropriate for the Elan. I also have a copy from an old Dave Bean parts catalogue that shows the parts used on the various racks for the Elan, Plus 2 and Europa (DBE Elan, Plus 2 and Cortina parts catalogue). It is possibly a copy from a Lotus manual? I am guessing that all the parts shown are no longer available from DBE. It does indicate that the ‘special’ tie rods for the Elan were 6" long. Mr. Buckland advises that Lotus produced these for the Elan. As another example, Lotus modified the tie rod and outer ball joint for the Seven by removing 3/8 inches and 1/4 inch from the tie rod and outer ball joint respectively. A few errors have inevitably creeped in regarding measurements on the various racks and tie rods. A Seven site for example quotes the tie rod length for a Herald/Spitfire at 8.715 inches (ball centre to thread end). This is incorrect as the measurement of 8.715 inches for a Herald/Spitfire is actually the distance from the centre of the outer swivel (steering) ball joint to the centre of the tie rod ball joint. This measurement is shown in a couple of shop manuals and published books on the Spitfire/Herald. I recently contacted a company in Germany called ‘Bastuck’ who sell the German manufactured steering racks for the Triumph Spitfire and possibly other Triumph models. When I inquired regarding their use on a Lotus, the sales rep was very interested. He sent me some emails of the rack with the gaiter slid out of the way. There is no inner tie rod locking nut fitted on these racks. He also would not say if the rack could be taken apart in order to add necessary rack stops. I am not sure how stops could be added for the Elan or Seven if the tie rod cannot be temporarily removed. I would buy one to find out, but the cost is quite high, and may be useless after I’m finished with it! Triumph forums have likewise fielded questions regarding these racks, but as they are a fairly new product, no one had been required to disassemble one for service. These racks are more expensive than units produced in Argentina. The S. American versions are sealed for life, are unable to be serviced, and according to Triumph forum contributors suffer from poor quality control and premature wear. Dave Bean Engineering had a German rack delivered from British Parts North America, but advised me that they may not be suitable for use on a Lotus. Unfortunately the sales rep did not advise why this was, or how far they had taken the rack apart before returning it to BPNA. If anyone is interested, and the site administrator will allow me, I can add the photos from Bastuck along with the DBE page. Cheers EW
The Buckland article is from CLN Volume 3 in 2011. The spacer table is posted below, but if you want the full article all back-issues of CLN are available for download (for a reasonable fee, I think) to CL members. Some while back I purchased and downloaded all back-issues and marked for Brian Buckland’s articles so if you’re searching for a particular one I may be able to help.
Speaking of steering rack spacers, I have a rack I found and rebuilt as a back-up that has, as I recall, the S1-S3 spacers. If any of you have S4 or Seven S2 spacers but need early spacers and would like to trade, send me a pm.
May help
viewtopic.php?f=42&t=46854
Hello. Thank you for the reference. further down the page, 1owner69Elan has advised regarding rack stops for the Ford Mustang. Mr. Frank Becker at Bastuck (distributor of the German manufactured Triumph Spitfire rack) also advised that the nylon clips designed for the Mustang are the same inner diameter to fit the Bastuck rack. I do not know the width of these clip-on spacers, but by stacking them beside each other, I would guess that the 1.75 inch for the passenger end of the rack, and the necessary width at the driver’s end (there is no lock nut installed at either end on the German rack) could be accomplished. Mr. Becker also advised that metal half pieces would also work on these racks as long as a method of securing them together could be safely accomplished. Temporarily pulling back the rubber gaiters would be the only disassembly necessary to the rack. This would only leave the tie rod and thread length to be determined for use on the Elan. I think that I need to bite the bullet and purchase one hopefully for use or as a spare. If deciding to rebuild a Triumph Spitfire rack, British Parts North America advise that their replacement tie rods are 7.125 inches long end-to-end. The thread portion is 2 inches long. Prices seem to vary wildly on this part. I noted that one U.K. supplier sells them in the 70 U.K. Pounds Sterling range, while BPNA sells them for $16.00 U.S. With the huge price difference, one would hope that the U.K. produced items are of a much higher quality than the cheeper versions. If you require the rack end bush, shims for the inner ball joints, pinion shims, rubber ‘o’ ring for the upper pinion bush, locking tab, and gaiters, one or two Triumph suppliers carry all of these. Cheers EW