Lando Norris, McLaren, Paul Ricard, 2019

Analysis: McLaren follow 2019’s trend for trick suspension

F1 technology

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McLaren have followed the practice adopted by rivals including Mercedes and Williams by using a suspension trick to lower their car’s ride height while cornering.

The team has done this by increasing the offset of the pushrod mounting in their suspension.

All teams have exploited a suspension solution called ‘pushrod on upright’ for over 10 years. It’s a relatively simple set-up where the pushrod that controls the wheel’s movement is mounted to the pivoting upright and not the lower wishbone.

When mounted to the wishbone, the pushrod that transfers wheel and body movements to the springs and dampers inside the nose of the car, is unaffected by the driver steering the car. When the pushrod is mounted to the upright (POU), when the wheel is steered the pushrod can move in or out with the movement of the upright depending on the geometry employed. The offset of the pushrod mounting relative to the steering axis reflects the movement of the pushrod as steering lock is applied. Whereas 10 years ago the offset might be just 5-8mm, now it’s multiples of 10.

Mercedes suspension
Mercedes suspension

Currently the teams use the POU geometry to lower the car as the wheel is steered. This reduces the front wing’s gap to the ground and the rake angle of the long underbody is kept constant, rather than rising and lowering as the brakes are used on and off through a corner.

Just two years ago quite extreme POU geometries were being employed, such that the pushrod mounting extended out through the wheel and the pivot point could be seen emerging from the brake duct. This extreme practice was cracked down on, with similar reasoning to the ban on interlinked suspensions, as there was a clear aerodynamic effect.

Not published in the rules, but issued via technical directive that the media/public do not get to see, the demand given by the FIA was that for ever 12 degrees of steering lock the ride height change must be less than 5mm. Since then most teams have returned to smaller pushrod offsets, that placed the pivot point back inside the wheel or brake duct.

Last season Ferrari were among the first to increase the offset once again. This is less visible on the Ferrari as their suspension set-up is different to its rivals. They run a conventional wishbone set-up where both the front wishbones pass inside the wheel to mount to the upright. This placed the steering axis well inside the wheel and the offset for the pushrod as a result is well inside the wheel.

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In contrast, many other teams now mount the wishbones much higher relative to the wheel. This means the upper wishbone does not project into the wheel, but instead a camber plate extends out from the wheel to meet the wishbone. In this set-up, the steering axis already extends outside of the wheel, so to add offset to the pushrod mounting the mounting sits well outside the front brake ducts. This makes it more visible and can appear a more extreme set-up than Ferrari’s solution, even if the actual pushrod offset is the same.

Lando Norris, McLaren, Paul Ricard, 2019
Norris took fifth on the grid
When Mercedes were noted for their pushrod offset at Monaco – onboard footage from the Fairmont Hotel Hairpin, the tightest corner on the calendar, revealed the extent of their the ride height change at the hairpin – it was realised that this was not a new Mercedes trick, but was in fact merely an extension of a long standing set-up option.

Quite how teams can legally employ such large offsets and achieve such visible ride height changes is less clear. Unless the unpublished technical directive has been withdrawn or superseded, then it may be that teams are running geometries still within the 5mm ride height allowance at lesser steering angles, but greater steering angles the POU effect is proportionally greater. However it is achieved so far this season we have seen Williams and now McLaren greatly increase the POU offset.

This weekend McLaren can be seen to have a pushrod pivot well inboard of the brake duct and even greater than when the car appeared at its launch. This should give the drivers some extra consistency and performance through the corners from the better controlled front ride height as the driver turns the car through corners.

Given their strong performance in today’s qualifying session, where they lapped 3.5 seconds faster than last year and claimed the third row of the grid, it and every other innovation on the MCL34 will have the eye of the team’s rivals.

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Craig Scarborough
Craig Scarborough is RaceFans' new technical contributor for 2019....

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9 comments on “Analysis: McLaren follow 2019’s trend for trick suspension”

  1. I am getting the feeling that, apart from Mercedes, McLaren have been one of the few teams consistently with the tyres in a good place.

  2. So if this is what McLaren, Merc and others are doing, what is it that Haas is not doing.?
    Clearly they can’t get the tyres to work while most other teams do and some teams have mastered the trick really well.
    Craig S. great article. If McLaren does well in the race, there should be a couple of weeks worth of typing just dealing with their updates and changes. Looking forward to it.
    Thanks for this.

  3. So is this another area where Ferrari have a development bottleneck this season?

    1. No, Ferrari lead this direction last year “Last season Ferrari were among the first to increase the offset once again”. It’s just hidden due to their different wishbone geometry

  4. RocketTankski
    22nd June 2019, 20:21

    McLarens are going crazy thanks to this one weird trick

  5. Interesting. I notice, however, that the angles you show for the upper A-arms are not correct, as all the cars, I believe, actually exhibit a drooping angle from the chassis. I’m wondering if the introduction of the bigger wheels will allow teams to build better geometry for camber change in the front suspensions. As is visible on the Mercedes, the teams are extending the upper mounting point on the upright almost to the middle of the tire in an attempt to normalize the A-arm angle. I know these cars don’t have much suspension travel so this is not as critical, but looking at current rear suspensions one sees normal looking A-arm angles, similar to the angle shown in your drawing. I think back to the twin keel solutions from the past and wonder if that solution might not be useful now, with the high noses, or is that ruled out by regulation?

    1. You’re right the wishbone geometry as drawn was simplified for this post.
      Teams want the wishbones as high as possible, so a lower keel placement, even though legal, would be undesirable. However a keel on the top of the nose for the front leg of the upper wishbone would be legal and desirable!

  6. @scarbs, So the 18″ wheels should allow more room for this geometry ?

    1. That’s a good point, there is more space.
      I suspect the upper wishbone mount can be brought inside the wheel to reduce the blockage it creates. I doubt the upper wishbone could be mounted any higher as its already as high as the monocoque allows.

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