Suspension: The latest trends

Despite the relatively mild winter giving our road surfaces an easier time, demand for suspension parts appears not to have abated.

MOOG (a DRiV brand) reports that anti-roll bar link stabilisers ('drop links') have very high replacement rates; out of all suspension parts, they are the ones that are replaced most frequently, during a typical vehicle's lifetime. Delphi agrees, stating that link stabilisers are the fastest moving category in its suspension portfolio. Interestingly, the company explains that speed humps, which do not cover the entire road width, are a major influencer in link stabiliser wear rates. For instance, should a car traverse a speed hump that covers the full width of the road, the suspension is compressed equally on both sides, causing the anti-roll bar to pivot. Yet, should a single wheel alone negotiate the speed hump, the antiroll bar becomes twisted. The forces needed to do this are considerable and it is all transmitted through the link stabilisers,

which tend to comprise a relatively lightweight rod with a ball joint at either end. Aside from wear, Delphi reports that this situation can even damage the stabilisers. Should your customer live in a built-up area with such speed restrictions, this is a useful tip to impart. You may also wish to research and upsell uprated link stabilisers, in such situations, such as from the MEYLE HD range.

Aside from control arms and ball joints, KYB Europe explains that its Excel-G shock absorbers ('dampers') are most popular, due to being direct OE replacements for most vehicles. The company highlights that the dampers it produces for the aftermarket are virtually identical to those supplied to the vehicle manufacturers. When we quizzed KYB about these differences, we found them to be very subtle, limited to slightly different valve tuning within the damper, which compensates for the expected wear and tear of surrounding components. Interestingly, warmer climates see higher rates of damper replacements, whereas KYB finds that coil springs are more popular in colder countries, including the UK.

Intriguingly, AIC reveals that stub axles are its most in-demand suspension-related part. The company reveals that they are very susceptible to wear and tear, due to age or improper driving, not helped by the trend of cars becoming heavier.

We were keen to see how 2022's fiscal challenges have filtered to parts suppliers, thus far. Delphi admits that, while there is current pressure on household budgets, from increasing energy costs, shopping bills and fuel prices, high demand remains for its steering and suspension products. The company highlights that both garages and customers realise that these are safety-critical parts and avoid compromising as a result.

MOOG agrees, adding that annual mileage is on the increase and GiPA reckons that they will overtake pre-pandemic levels during 2022, unless fuel prices curtail that prediction. Even so, MOOG reports that workshop visitation frequencies are increasing, as are final invoice values. While DRiV reveals that it is not seeing workshops compromising on quality parts, a greater challenge is posed by motorists choosing to defer preventative maintenance, as they prioritise other rising household costs.

AIC Germany is an automotive spare parts specialist and dynamic problem solver from Hamburg, Germany. With its diverse product range of over 12,500 products in more than 100 article groups, AIC has been firmly established in the independent aftermarket for five decades. Every day, new solutions and products are sought to make everyday life easier for workshops.

Alongside tires and brakes, steering in particular is a technically demanding and, above all, safety-relevant system. If the vehicle veers off track, this can have serious consequences for the car occupants. For this reason, steering parts must not have any defects. After all, the task of the steering system is to steer the vehicle in the desired direction - as precisely and sensitively as possible.

Nowadays, vehicles are becoming heavier and the axles lighter and more compact. As a result, the steering components are subjected to greater stress, making them more susceptible to wear. If individual parts of the steering and suspension are worn, the entire steering system can be damaged. The value retention is influenced by the material of the steering system, as steering parts are often manufactured as rubber-metal parts. This is where the wear occurs. Rubber gets old and porous and can crack. Metal is susceptible to corrosion and can bend. When maintenance is due, bearing bushings and ball heads are visually inspected. Cracked boots, worn ball joints and suspension joints must be replaced immediately. Tie rods, control arms and stabilizers must be replaced as soon as they are damaged and deformed.

In addition to the material quality, the accuracy of fit of the steering parts plays a very important role. The correct adjustment of the axle geometry can be seen in the running pattern of the tires and the stable directional stability of the vehicle.

A defective steering system can therefore have many causes. Be it poor road conditions, natural wear, corrosion and rust, incorrect tire pressure, external force or incorrect driving behavior.

If you want to continue to drive safely, easily and precisely through the streets, then AIC Germany has the right steering parts ready in its program. Wishbones, stabilizers, guide joints, tie rods, coupling rods, bearings, wheel bearings. You will find what you need here. Just ask your wholesaler.

While MEYLE acknowledges that value-priced parts have always had a place in the marketplace, it admits the popularity of such components tends to be determined by vehicle age and value. It cites workshops reporting a small increase for lower-cost repairs but the demand is not significant, as yet.

Invariably, belt-tightening can provide opportunities for counterfeiters. The recent DVSA findings with R90 incompliant

brake parts and other reports about low-grade fuel-borne Eolys-type catalyst additives entering UK garage parts supply chains are worrying developments. While Delphi sees counterfeit activity on high-value items in its other ranges, such as diagnostics or diesel fuel injection components, its steering and suspension catalogue remains unaffected.

KYB adds that it seeks out counterfeit goods proactively but it warns that it is becoming increasingly easier for fake components to slip through the net. A particular issue is when motorists purchase spare parts on online shopping channels in a bid to save cash. KYB emphasises that not only can such products be of extremely poor quality, but its analysis has also revealed higher failure rates. To be sure, it recommends that you source its products through the authorised dealers, listed on its website.

MOOG, meanwhile, highlights its newly-launched QR code. Once scanned with a smartphone camera, you can be certain that the product is a genuine MOOG part, while also doublechecking the part number, specification and applications. In addition, the QR code permits you to access warranty conditions, aftersales support and installation guides.

While many workshops are debating whether they should increase labour rates, or not, components manufacturers are facing the same quandary. Comline's findings reflect those of many other companies we contacted, by reporting that the situation is a difficult balancing act, because the industry, as a whole, has suffered from price increases, to which it is not immune. For instance, aluminium prices have increased considerably, not helped by Russia being a major metal exporter. Transport costs have also rocketed. While Comline admits to raising prices, it has been absorbing as much of the rising costs as it can.

Warranty claims cause inconvenience for all parties, hence why quality suppliers strive to prevent the situation from arising in the first place. Component failure, especially from companies that supply the VMs and those that work to OE quality standards, is extremely rare, due to the extremely highquality control measures that are necessary. Many suspension manufacturers, therefore, cite incorrect fitment as a major cause of premature failure. With this in mind, such businesses provide as much help and support to technicians as possible. Yet this is a two-way deal. Technicians also need to help the supplier and manufacturer to understand more, when a problem occurs.

Comline reveals that its most common reason for warranty rejections is lack of information and the company advises and welcomes gaining and sharing as much information as possible to help the process run smoothly. These include technicians supplying images of the affected component and details that include when the part was fitted and removed, plus information about the circumstances that lead up to the failure. Comline explains that it needs such information not to be difficult but, because speed is of the essence, it needs to act quickly, should a manufacturing defect be responsible. The company adds that such evidence is essential for data gathering, too. If a pattern of failure can be identified, the information can be shared with its contractors.

Many other brands highlight the importance of keeping up to date with current fitting techniques. AIC advises that suspension struts, dampers and control arms that are mounted in rubber bushes must not have the fixings tightened, until the car is back on its wheels. Should they be tightened with the wheels hanging, the bushes will be placed under permanent tension at normal ride height, causing premature failure. Furthermore, using an impact wrench on damper fixings can damage their internals. AIC and KYB concur that holding the piston rod with mole grips damages its polished surface, which will tear the internal rubber seal, causing oil to leak from the shock absorber soon afterwards.

AIC and Arnott stress also the importance of not inflating replacement air suspension springs, with the wheels supporting the vehicle's weight. Not observing tightening torques is also a common issue that can result in excessive noise and reduced operating life of parts, heightening the need for technicians to heed the specifications and ensure that their torque wrenches are calibrated correctly.

The main components of an air suspension system, the air springs and air struts, contain rubber sleeves. Rubber is a natural product prone to wear and tear causing the air sleeve to be the first component to wear out.

Often, the rubber will dry rot and small cracks form where the air sleeve continuously rolls up and down the rolling piston during the spring movement. When the vehicle is being inspected, it is recommended that the air sleeves are checked for these small cracks and, if present, replaced to avoid the cracks developing into a bigger leak over time.

Typically, a high-quality air spring should be replaced every six to ten years. Outside conditions including climate, road conditions, and constant abrasion of dirt and road debris also influence the functioning and life span of these air suspension components. Additionally, colder temperatures make the rubber stiffer and less flexible while hotter conditions will make the rubber dry out faster. Both hot and cold temperatures can give an already worn air sleeve the final push to burst.

Quality is of key importance when it comes to determining the product’s lifespan. In addition to rubber, other components including crimping rings, O-rings and piston material are also important. Although some cheap aftermarket air springs might look identical to the original part at first glance, the differences can be quite substantial! Making concessions such as using inferior rubber, lower grade parts and/or consolidation in piston design can result in lower burst pressure, difficult fitment, impaired damping comfort and more NVH (noise, vibration, and harshness). Arnott wants to ensure a safe drive with long-lasting products and therefore choses to use the highest quality rubber (Continental ContiTech) and other Tier 1 components for their air springs and struts. is highly recommended. Even if the leak only occurs in one corner of the vehicle, it is still recommended to replace the other side as well. The rubber of the air spring/strut on the opposite side has most likely been exposed to the same road and weather conditions as the failing side and has therefore faced the same wear and tear. Thus, there is a high probability that the air spring/strut that has not failed will have similar issues to the one that has in the near future if not replaced.

Replacing in pairs is commonly advised for conventional shock absorbers to avoid difference in dampening efficiency on the same axle. This dampening functionality difference between new and old is also the case for air suspension struts. If not replaced in pairs, the ride, handling, and stability of the vehicle is substantially impaired which could lead to unpredictable driving behaviour and dangerous situations.

Although replacing in pairs is not mandatory for most Arnott parts, it is still highly recommended. It will not only ensure a safe, comfortable ride but likely also prevent another trip to the workshop.