Getting the best out of standard suspension components for touring driving today

Yep some really good country pubs and fabulous wine country…… which part of Thailand do youlive

I took my normal fun drive yesterday about 40 miles each way of highway, back roads and one covered bridge. All six of my shocks were set halfway, 10 clicks. I occasionally notice a bit of hop at rear going over bumps. At the halfway point, I set all at 5 clicks from the lowest setting. No hop but the car felt a bit spongy. I think I’ll try Clive’s trick of using a low and high setting on each pair of rear shocks and bump the fronts up to 8 clicks.

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Just a wild guess, Dave. If you try different settings on the rears, I suggest the stiffer one be the front. Another piece of blind speculation based on a shorter lever arm length to the trailing arm, which has to resist any resulting torque. Could try both ways, if it shows any difference at all.

I’d make a general suggestion to adjust one end at a time, it can get very confusing to interpret the interactions if you adjust both together. The rear will probably be easier to “read” the changes because you’re sitting so close to the rear wheels, so you might do something like:

  • set the front moderately soft to reduce its influence on the overall feel (no specific feel of hard or soft).
  • run rears full stiff, or close, as a calibration point
  • run rears very soft
  • look for a rear setting that gives a good balance between the two extremes of comfort and control. Around this point you’ll be feeling the front is lacking something, so
  • move to the front, similar process to the rear

By now you should be well-attuned enough to recognise which end would benefit from the next adjustment, you have a couple of options here:

  • an iterative process that can go on a long time.
  • a beer

I’m guessing the rear will be easier to get a positive conclusion because the structure is stiffer and you’re sitting closer to it.

Good luck

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Koh Samui. A lot to like

Dave,

A few suggestions on areas / parameters to consider in your evaluations:

Primary ride - dampers controlling the body motion as suspension moves in response to moderate / large road events (smooth inputs, not pothole impacts!)
Front : rear ride balance (moving together or in opposite directions?)
Secondary ride - smaller, quicker inputs where the wheel / tyre is “rattling” or “bouncing” between the road and the damper force, not having enough time or strength to push through to disturb the main body mass
Impacts - single sharp inputs such as road cracks, drain covers, cats-eyes in UK

Considering both the feel and sound in the above.

Not overlooking handling effects:
Steering effort and feel - response to small quick steering inputs (eg avoiding a stone in the roadway) and slower inputs as in entering and leaving a turn. Rear changes can also affect steering feel.
Roll and recovery
General confidence & control feel

All the above at normal road speeds and conditions - no racetrack or heroics required. The slower you go, the more you learn. (Someone famous said that).

The important point is to consider the areas that matter to you, in your typical use of the car - your roads, your speeds, your loading.

Some find it helpful to use scores for the different attributes. Then you can make charts!!! :joy:

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Love Koh Samui …. Been there a couple of times …can’t remember hotel but out of town ……maybe Bandera ? ….got to know exec chef a local …… he took us out to a local’s restaurant non tourist ……had a fabulous deep fried fish that tasted devine ……very very friendly place especially outside the crowed down town area

Bandara? Nice relaxed place, we live a few miles around the coast. Please let me know if you plan to return, I’m sure we could have some good discussions.

Funny you should say that, Paul. I’ve had an interesting time finding a 33mm hole to put in that bar. It was part of the Grand Upgrade where I make a set of “universal” test fixtures that connect to a new holder for the load cell. Great results every time, once I find a 40mm hole to accept the loading head. The delivery man is weary from bringing ever larger drills up the hill.

Then I thought “this isn’t complex enough” and started on a fixture to make a fully urethane rear cradle mount. Two days later I have a colourful CAD model to ensure precision in my errors. The next big decision is whether I pour the urethane in natural state or add some vibrant colour (with vibrant cost for fluid, shipping, duty etc.)
I favour bright green…


Not much else to report - will get feedback on dampers and mounts when weather and calendars permit.

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Change of heart. The future is blue

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Do these holes serve a purpose on any model?

No: they are just for mirror-image installation ease, or registration holes for manufacture.

I was hoping you’d say that, I’d like those ears to go away. I think that mount was a catalog part in its day, maybe those holes gave it wider application.

The cut off corner is required to clear the chassis rail?

Hi Clive…yes the holes used to attach the rear setting link when setting rear camber…details in service manual…

Aha!

That’s a new piece of information to add to my knowledge base… :slight_smile:

Hi Paul…in practice its impossible to compress the springs enough to fit the link…however with the IRS on the bench and the shocks/springs not fitted/disconnected the link can be easily used to set rear camber…Steve

Thanks Steve, interesting detail. I plan to cut the ears off my test pair to get a more consistent urethane fill, would need a different approach for camber setting.

That assumes a favourable response to on-car testing of the first pair of mounts, part rubber / part urethane with bolted reaction plates. Any next step would develop the idea in a more feasible direction.

Put a bag of cement at the trunk or just remove one of the springs.

You can mount a hook anywhere and make different setting links, what matters is that the the overall distance is the same.

I had 2 guys sit in the rear of a fhc…it dosnt compress the springs enough to fit the link…disconnecting one spring dosnt do it…you have to get creative and work out other ways to do it…not difficult

If it’s a struggle to get to the specified ride height you could adjust the target camber to the ride height you have. I have a theoretical curve of camber vs ride height somewhere, from memory the camber will be 0.25 degrees more positive if the car sits 20 - 40 mm higher than nominal. To be particular you might want to check that on your specific car and record a new target value for future checks. Keeping in perspective that the car + driver probably have a combined age north of 100 years, we’re not talking about the Flugplatz here.

I’d be quite confident using this method at the rear because the transverse links have solid joints, so won’t deform at different loading conditions. Slightly less so at the front because I think the torsion bars impart some sideways load to the control arms, probably not significant relative to their surroundings.