AST Suspension At GSM Performance: The 5100, 5200 And 5300 Explained
New at GSM Performance
AST has just gone live on the site, and it arrived big: 524 vehicle specific kits across the 5100, 5200 and 5300 families. That makes it the second largest suspension range we carry, behind BC Racing.
Cameron sums the range up in one line: it is one question asked three times over. Which dials do you want on the car once it is built? Garreth's take was about the company. AST make every damper themselves in the Netherlands, and they own MOTON as well, which says a lot about where their heads are.
So this is the whole AST range on one page: who they are, what the three numbers mean, why the 5100 comes in three packages, and the checks every listing asks you to make before you order.
- AST stands for Advanced Suspension Technology, founded in 2000 in the Netherlands
- Every AST damper we list is monotube and rebuildable
- 5100 adjusts rebound, 12 positions, with ride height on a threaded body
- 5200 adds compression, adjusted on a remote reservoir
- 5300 splits compression into low speed and high speed
- Every 5200 we list has a 5300 twin for exactly the same cars
- Coilover kits carry a 24 month AST warranty
Who AST are
AST, Advanced Suspension Technology, was founded in 2000 by Piet Kreeft and Peter Smits, with the Smits family's machining business behind them. Kreeft is the name that matters to a suspension person. He started in the KONI motorsport department, went on to found Aragosta, worked at WP, and spent close to a decade on IndyCar suspension. AST credits his engineering in Emerson Fittipaldi's 1989 season.
The company is based in Valkenswaard in the Netherlands and says it produces 100% of its products there, springs included. They are coiled in house from chrome silicon wire. Since 2016 AST has been part of the Roosen Industrial Group, and it runs to ISO 9001:2015.
In 2011 AST bought MOTON, the Dutch damper maker whose kits were on 30% of the Le Mans grid in 2000, along with every MOTON design. Both labels are built in the same factory today, sold as AST x MOTON. AST is the broader range, road car through to 3-way motorsport. MOTON is the premium endurance racing line, with its own range on the site and its own guide in this series.
Garreth’s view of that is simple. A company that machines its own parts, coils its own springs and rebuilds its own dampers can answer a question about your car. Plenty of coilover brands cannot.
Three numbers, one question
The family number tells you how many things you can adjust on the damper. That is all it tells you, and it is the right place to start. Ride height is adjustable on every one of them.
| Family | What you can adjust | Reservoir | Top mounts | Listings | From |
|---|---|---|---|---|---|
| 5100 Street | Rebound, 12 positions | None | Uses your original ones | 118 | £1,728 |
| 5100 Street Performance | Rebound, 12 positions | None | Camber-adjustable fronts included | 96 | £2,508 |
| 5100 Clubracing | Rebound, 12 positions | None | Camber fronts and solid rears included | 82 | £2,880 |
| 5200 2-Way | Rebound and compression, separately | Remote, on a hose | Camber fronts and solid rears where applicable | 114 | £3,360 |
| 5300 3-Way | Rebound, low speed and high speed compression | Remote, on a hose | Camber fronts and solid rears where applicable | 114 | £3,672 |
Prices are the lowest listing in each family today, inc VAT. The kit for your car is what counts, and it is usually more than the lowest figure.
The 5100: one damper, three packages
This is where most of the range sits, 296 listings, and it confuses people because the three packages share a damper. Street, Street Performance and Clubracing all run the same monotube with the same 12 position rebound adjuster. What changes is what comes with it.
Street keeps your original top mounts. Street Performance adds camber-adjustable front top mounts. Clubracing adds those plus solid rear top mounts, and it is a coilover at both ends, so you can change spring rates front and rear. Many Street and Street Performance kits keep a divorced rear, with the spring separate from the damper as the car was built, and AST fixes those rear rates per car.
Inverted or non-inverted
AST's rule of thumb is that MacPherson strut cars get an inverted damper, a 44.5mm strut with the piston rod inside it, built to take the side load a strut carries, and double wishbone cars get a non-inverted one. That non-inverted damper is the one AST used to sell as the 4100, which is why some set descriptions on our listings still say 4100.
On the Street package some cars are listed with both. The E46 M3 has an inverted ACU kit and a non-inverted ACS kit a few pounds apart. Cameron would take the inverted one on a strut car every time, for the side load alone, and the listing says which is which in its first line.
The 5200: compression joins rebound
The 5200 adds a remote reservoir on a braided hose, and the compression adjuster lives on top of it. Rebound stays on the piston rod at 12 positions. AST’s own documents disagree by one click on compression: the manual says 11, the brochure 12. AST says the compression adjuster grew out of the one they built for the American Grand-Am series, where AST were a named shock supplier from 2010.
The manual gives a place to start, which is useful on the first drive: rebound on 6 and compression 4 clicks from fully clockwise, front and rear. Custom spring rates are available, and the kit includes springs, reservoirs and, where the car allows it, camber front and solid rear top mounts.
The 5300: compression split in two
On a 5300 the reservoir carries two knobs. The small one is low speed compression, the slow movements: roll, pitch under braking, squat. The large one is high speed, the sharp inputs such as kerbs and bumps. AST’s manual starts you at rebound 6, low speed 3 and high speed 5, and every adjuster works independently.
The detail in our data that surprised us is how closely the 5300 tracks the 5200. All 114 of our 5200 listings have a 5300 for exactly the same cars, and on 82 of them the difference is £312. That is the price of a second compression circuit, and it makes the choice between the two about the driver, not the budget.
One car, every AST rung
The E46 M3 is one of the cars AST covers with all five kits, so it shows the ladder cleanly. The GR Yaris is the modern example. Both tables read live prices.
| BMW M3 E46 | Part number | Price |
|---|---|---|
| AST 5100 Street | ACU-B1103SD | £2,604 |
| AST 5100 Street Performance | ACT-B1103SD | £3,072 |
| AST 5100 Clubracing | ACC-B1107SD | £3,480 |
| AST 5200 2-Way Motorsport | RIV-B1103SD | £5,064 |
| AST 5300 3-Way Motorsport | RAC-B1103SD | £5,376 |
Five kits for one car. The jump that matters is from Clubracing to 5200, where the reservoirs arrive.
| Toyota GR Yaris | Part number | Price |
|---|---|---|
| AST 5100 Street | ACS-T2404SD | £2,652 |
| AST 5100 Street Performance | ACT-T2404SD | £3,072 |
| AST 5100 Clubracing | ACC-T2404SD | £3,444 |
| AST 5200 2-Way Motorsport | RIV-T2404SD | £5,688 |
| AST 5300 3-Way Motorsport | RAC-T2404SD | £5,988 |
The same five steps on a current car.
Where the range is deepest
BMW and Porsche lead by a distance, then the Japanese performance cars and the hot hatches. A kit often covers several models, so the counts below are listings that name the make, not models.
| Make | 5100 listings | 5200 listings | 5300 listings |
|---|---|---|---|
| BMW | 75 | 23 | 23 |
| Porsche | 38 | 13 | 13 |
| Honda | 27 | 11 | 11 |
| Subaru | 21 | 7 | 7 |
| Ford | 20 | 7 | 7 |
| Renault | 15 | 8 | 8 |
| Mini | 21 | 5 | 5 |
| Audi | 14 | 4 | 4 |
| Nissan | 10 | 5 | 5 |
| Mitsubishi | 12 | 4 | 4 |
| Toyota | 9 | 5 | 5 |
| Volkswagen | 10 | 4 | 4 |
The twelve makes with the most AST listings. The full list is on the AST category page.
Some cars sit at one end only. Donkervoort and TVR are 5200 and 5300 only in AST’s own finder. Lotus gets the non-inverted 1-way plus the motorsport kits, with no Street Performance or Clubracing packages.
What the listings ask you to check
The application notes on our listings come straight from AST, and a few of them turn up often enough to be worth knowing before you look.
- EDC. BMWs with factory electronic damping need a delete kit, ordered separately
- 3 bolt or 5 bolt. Several BMW M cars changed top mount pattern mid life, and the part number follows it
- LCI or pre LCI. The facelift split on BMW listings is a different kit, not a note
- Body work. Some cars need the strut tower modified for the camber top mounts or to fit the reservoirs
- Strut diameter. VW Group cars list their strut size, 55mm on most of the current ones
- Droplinks. A part number ending SD includes adjustable droplinks; others may need them adding
Zero preload
AST ships kits with no spring preload set. It has to be set before the car goes back on its wheels, with at least 5mm clearance to the tyre.
Quick disconnects
Where a kit uses quick disconnect couplings, connect them all before lowering the car. With them open the oil has nowhere to go.
Alignment after
Any change of ride height changes the geometry. Book the alignment as part of the fitting, once the car has settled.
Servicing, rebuilds and warranty
Every AST damper we list is rebuildable. AST does not publish a fixed interval, it asks you to agree one with your dealer based on use, and to use an official rebuild centre with genuine parts. In the UK that is Racesport, near Brackley. AST’s warranty on coilover kits is 24 months, and its racing springs carry a lifetime warranty against breaking.
A rebuild also lets the valving change. AST says its kits can be revalved to order, which matters if the car changes job, from road to a championship, a few seasons in.
Common questions
Is AST the same company as MOTON?
Yes. AST bought MOTON in 2011 and builds both labels in its factory in the Netherlands. AST is the broader range; MOTON is the premium endurance racing line.
Can I drive a 5100 on the road every day?
That is what the Street package is for. AST pitches it as the best road balance for everyday use, with the rebound adjuster there if you want the car firmer on a track day.
Is a 5200 too much for a road car?
AST describes it as primarily for track use, but usable every day. If the car does both and you will actually use a compression adjuster, it is a sensible kit. If not, a 5100 Clubracing is the better money.
Can a 5100 be upgraded later?
AST describes the inverted 5100 as upgradeable to 5300 specification. Talk to us about your exact kit before planning on it.
Do AST kits come with springs?
Yes. Rates come from AST’s development work for the car, and on coilover rears you can change them. Custom rates are available on the motorsport kits.
What does SD mean on the end of a part number?
On the kits we have checked it means droplinks are included. Other suffixes such as /1 and /2 separate variants for one car.
Where we would start
Cameron would put most road cars on a 5100 and most track cars on a 5100 Clubracing, and tell you to spend what is left on tyres and a proper alignment. Garreth agrees for the first car, less so for the second. If a car is doing a season of trackdays on sticky tyres, he thinks the 5200 pays for itself in the first wet session, because being able to soften compression is the adjustment you miss most.
Where they agree is the 5300. Buy it when somebody is going to write the settings down.
The next guide in the series covers MOTON, then each family gets its own. If your car is already on the list, send us the registration and we will find the part number with you.
Manufacturer reference: AST x MOTON. Shop the range: AST 5100, AST 5200 and AST 5300.
Give us the part number and the registration. We will confirm the application, the top mount pattern, EDC and any body work before you commit.
Send the registration or VIN, what the car does (road, track days, a championship) and anything already changed on the suspension. We will match it to the right part number and talk spring rates with you before anything is ordered.
