Durometer and Suspension Bushings
In the World of suspension, bushes play a pivotal role in the handling and steering of your Porsche. One of the best ways to understand what suspension bush is right for you is by using a durometer, or the scale whereby a durometer measures. In layman’s terms, a durometer is a device – and scale – that calculates the hardness of an object and how it is likely to react to varying levels of force.
Understanding durometer measurements
It’s important to note that the term “durometer” can refer to both a device and a measurement.
Durometers measure on a scale known as “Shore Hardness.” There are three main levels to “Shore Hardness” – OO, A and D. Shore A measures the hardness of stiff materials like plastic, Shore D is used to calculate materials that are more flexible (such as standard rubber), and Shore OO is for much softer rubbers or gels.
Regardless of which material you are measuring with a durometer, the Shore scale will only be calculated in sets of 10 – with lower and higher acceptance limits of -5 and +5 in-between. For example, a hardhat may have a Shore hardness of 80 D, while a polyurethane suspension bushing may fall under 85 A. It’s good to note that all of these individual scales cap at 100.
When it comes to suspension, you’re likely to only hear the Shore Hardness A scale used.
Durometer and Suspension
Despite the above potentially being deceivingly confusing, durometers and the shore scale are important for Porsche modifications and play a big role in suspension. Why? Because it helps us calculate and determine the stiffness and hardness of suspension bushings.
Suspension bushings have a profound impact on the way your car steers and handles, and a durometer helps us to apprehend what bushing is a fit for your respective driving requirements.
For instance, if you planned on creating a one-of-a-kind off-road 944 beast or a track-day burner you would need a suspension bushing with a higher durometer so that bushing can provide resistance against, and withstand excessive pressure.
On the other side of the coin, however, for a ride where you require less intensive support and want looser control, you may want to go for a softer rubber bushing that has a shore hardness of around 60 A – it’s all dependent on you as a driver.
Although, there are limits to both ends of the spectrum.
For example, a bushing that’s too tough can impair driving capability (especially in day-to-day terms), while a bushing that’s too loose may punish your suspension setup by causing misalignment.
In terms of sports performance, stiffer suspension bushings are considered better.
Tougher bushing in the engine mount, for example, one that is crafted from polyurethane, benefits your throttle response as it minimises parts from moving and misaligning.
Bushings For Performance
ROHLER PERFORMANCE ENGINE MOUNT KIT FOR PORSCHE 996 / 997
Performance engine mounts (PAIR). Included two M12 x 1.75 Nuts
Includes separate inserts for varying densities
Includes all 3 inserts for varying densities
Shore ratings 65A Street
Shore ratings 75A Fast Road (including in engine mounts)
Shore ratings 85A Track
Fits:
Porsche 996 C2, C4, C4S, Turbo, GT2, GT3
Porsche 997 C2, C2s, C4, C4s, Turbo, GT2, GT3
Replacing your factory engine mounts with these performance semi-solid mounts will dramatically decrease engine movement which then will result in better acceleration and handling of your Porsche.
CNC machined mounts with PU bushes are absolute must have for any car on track or on the street. Very easy to replace by experienced DIYers.
For 911 & Porsche world article / fitment guide pdf please CLICK HERE
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For example, a Porsche that you plan on taking onto the race track needs the absolute hardest bushings available (for example the Powerflex bush bar 16mm black stabilisers which have a 95 A shore hardness) as it enhances speed and also reduces the impact that bitter racing conditions have on your vehicle.
Although this can have a hugely positive impact on your driving experience, it’s important to note that the consequences of tougher bushings include harsher noises and vibrations, especially at standstills.
For day-to-day driving, increased noise and vibration are obviously not ideal, which is telling as to why manufacturers mainly opt for standard rubber bushings that have around a 60 A durometer.
Deciding on a Bushing
When it comes to selecting bushings, it is really dependent on your individual desires.
If you want a drive that is quiet, and comfortable, and your rides are generally undemanding, sticking with rubber 60 A suspension bushings may be your perfect option.
While there are downsides to rubber suspension bushings as they age – for example, they can harden over time due to wear and tear – they are relatively easy and inexpensive to replace.
Where rubber may bend, become friable and lose its form, polyurethane is far more likely to maintain shape and provide security for your suspension’s alignment as it is a tough synthetic material that doesn’t fray easily.
At the same time though, polyurethane bushings may only inconvenience your day-to-day driving by cramping up steering and handling.
On the other hand, softer, factory rubber bushings would be absolutely inadequate for a Porsche that is often off-road or on the track.
This is because soft suspension bushings can cause suspension misalignment and also magnify the battering your Porsche takes on the track due to the fact they cannot withstand as much pressure as their racing-focused counterparts.
If you’re looking for an upgrade on your factory suspension bushings but don’t want the intense vibration and sounds of the toughest that are available, we recommend opting for something like the Powerflex 15mm Stabiliser Bar Bushings (purple) as this is the best of both Worlds.
With that out of the way, let’s take a look at what are the best suspension bushings for both track and street driving.
Street Upgrade Options
STABILIZER BAR / DROP LINK BUSH REAR 15MM FOR PORSCHE 911 / 914 (OE PART 90133379302)
SET OF 4
Rear stabilizer bar bush – 15mm.
Rear drop link bush – 15mm.
Fits – left and right side.
Fits:
Porsche 911 1965-1973 Rear
Porsche 914 1970-1976 Rear
Note: Please check anti roll bar diameter before ordering.
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STABILIZER BAR BUSH REAR 16MM FOR PORSCHE 911 / 914 POWERFLEX
SET OF 4
Rear stabilizer bar bush – 16mm.
Rear drop link bush – 16mm.
Fits – left and right side.
Fits:
Porsche 911 1965-68 L / T / TU Rear 4 required per car
(Stabiliser bar and Drop link)
Porsche 914 1970-76 Rear 2 required per car
(Stabiliser bar)
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Track Upgrade Options
STABILIZER BAR BUSH REAR 16MM FOR PORSCHE 911 / 914 POWERFLEX BLACK SERIES
Rear stabilizer bar bush – 16mm.
Rear drop link bush – 16mm.
Fits – left and right side.
Fits:
Porsche 911 1965-68 L / T / TU Rear 4 required per car
(Stabiliser bar and Drop link)
Porsche 914 1970-76 Rear 2 required per car
(Stabiliser bar)Powerflex Black Series – Designed for the Track – Ready to Race – Engineered to be the best.
Powerflex Black Series bushes are manufactured using a 95 Shore A compound to provide maximum control of chassis geometry. This compound can be up to 80% more resistant to load than standard rubber and 25% stiffer than our purple performance material.
If your requirements are purely for the ultimate in handling and chassis performance then Powerflex Black Series are unique, offering the most precise and accurate alignment for your chassis.
Replacing your car rubber suspension bushes with Polyurethane Suspension Bushes will give you:
– Better road holding
– Constant steering geometry
– Increased tyre life
– More responsitive steering
– Longer service life of suspension components
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STABILIZER BAR BUSH FRONT 22MM FOR PORSCHE 911 POWERFLEX BLACK SERIES
SET OF 4
Fits:
Porsche 911 1984-86 3.2L and Turbo Front axle – Please choose by size
Porsche 911 1987-89 3.2L and Turbo Front axle
Powerflex Black Series – Designed for the Track – Ready to Race – Engineered to be the best.
Powerflex Black Series bushes are manufactured using a 95 Shore A compound to provide maximum control of chassis geometry. This compound can be up to 80% more resistant to load than standard rubber and 25% stiffer than our purple performance material.
If your requirements are purely for the ultimate in handling and chassis performance then Powerflex Black Series are unique, offering the most precise and accurate alignment for your chassis.
Replacing your car rubber suspension bushes with Polyurethane Suspension Bushes will give you:
– Better road holding
– Constant steering geometry
– Increased tyre life
– More responsitive steering
– Longer service life of suspension components
Shop it here.