Motor Grader Ripper and Scarifier: Shanks, Teeth, Depth

A motor grader’s scarifier carries 9 to 11 teeth set roughly 116 to 267 mm (4.6 to 10.5 in) apart. Its rear ripper carries only 3 to 5 shanks, set roughly 533 mm (21 in) apart. That spacing, not the number of teeth, is what decides which of the two you put into the ground.

Close teeth lift and loosen a surface so the blade can cut it. Wide shanks break a hard layer open. Put them the wrong way round and you either stall the machine or get a loosened mess the blade cannot hold. This guide explains both attachments the way a parts counter names them: the tooth and shank counts, the digging depths, the wear items, and which grader class takes which. For the full part-group picture, read motor grader parts and components; to raise a request for a ripper, scarifier or their teeth, use the attachments page.

What is a scarifier on a motor grader?

A scarifier is a toothed frame that drops in front of the blade and rakes the top layer loose. The teeth are short and sit close together. Scarify means to scratch or score a surface, and that is exactly the job: it does not dig a trench, it breaks the crust so the moldboard behind it can shave the material off cleanly.

On most Indian graders the scarifier is a V-type frame, which means the tooth holders are arranged in a shallow V with the point leading. The V lets the middle teeth enter first and the outer teeth follow, so the machine is not fighting the whole width at once. BEML’s own specification sheet for the BG605I lists its scarifier as V-type, 2-stage adjustable and hydraulically controlled, with 11 teeth across a 1,225 mm (48.2 in) digging width and a scarifier base of 1,000 mm (39.4 in). Two-stage adjustable means the frame can be pinned at two positions so the digging angle changes: that sheet gives a standard digging angle of 66 degrees, adjustable between 72 and 60 degrees.

The angle matters more than operators expect. A steeper tooth bites in and holds depth on a hard surface. A flatter tooth rides and tends to skip. A straight scarifier, where the holders sit in one flat line instead of a V, is also offered on some machines and spreads the load evenly across the full width, which suits softer material and a steady finish.

What is the difference between a motor grader ripper and a scarifier?

The ripper is the heavier of the two and it mounts at the back. A ripper is a frame of long, widely spaced shanks, a shank being the steel leg that carries the tooth, which is pushed down into a hard layer to crack it open. Because the shanks are far apart, each one concentrates the machine’s weight and pushing force into a narrow line instead of spreading it.

Caterpillar’s technical specification sheet for the 140 motor grader shows the gap plainly. Its front V-type scarifier has 11 shank holders at 116 mm (4.6 in) spacing. Its rear scarifier has 9 shank holders at 267 mm (10.5 in) spacing. Its ripper has 5 shank holders at 533 mm (21 in) spacing, with a penetration force of 9,440 kg (20,812 lb) and a prying force of 11,877 kg (26,184 lb). Same machine, three different tools, and the spacing quadruples from the first to the last.

Figure 1: why spacing decides the job

Read it as a rule of thumb: many close points share the load and loosen a surface, few wide points concentrate the load and break one. Spacing figures above are from the Caterpillar 140 sheet and will differ by machine.

How many teeth and shanks does each grader class take?

Tooth and shank counts follow the machine’s weight and engine power, because a shank can only pull as hard as the grader can push. The 42 motor graders listed here run from 74 HP (55 kW) upward, and the option lists widen as the class gets heavier.

This is a general guide based on machine size class. Always confirm the fit with your machine’s operator manual or the manufacturer before buying or fitting.

Two things in that table surprise people. First, the heavier machine has fewer ripper shanks, not more: Caterpillar’s 140 sheet lists 5 shank holders against BEML’s 3 on the BG605I, and neither is near the tooth count of a scarifier. Second, a scarifier does not get more teeth as the machine grows. Eleven is the common number across classes, and what grows is the width, the depth and the force behind each tooth. If your machine needs to work lighter ground, the answer is to pull teeth out rather than to buy a different frame. Caterpillar’s 140 sheet names a front V-type setting of “5 or 11 tooth”, so running fewer teeth in the same holders is a designed-in option, not a workaround.

How deep can a motor grader ripper and scarifier dig?

Both work in the top half-metre, and the ripper is not always the deeper of the two. On the Cat 140 sheet the front scarifier reaches a maximum scarifying depth of 467 mm (18.4 in) while the ripper reaches 426 mm (16.8 in), so the scarifier actually goes deeper. On the BG605I the order reverses: the scarifier reaches 390 mm (15.4 in) and the rear ripper 460 mm (18.1 in).

The lesson is to read your own machine’s sheet rather than assume the ripper is the deep tool. What the ripper always has is force, not depth: that 9,440 kg (20,812 lb) penetration figure on the Cat 140 is why it enters ground a scarifier only scratches. Neither number is a target to chase. Full depth in hard material loads the machine heavily, and most operators work at half the rated depth and take a second pass. Depth is also the reason the attachments are not interchangeable with blade work: for how far the moldboard itself cuts, see cutting depth and blade reach, and for the angles that do the shaping, blade angles.

Choosing a grader for ripping work? Compare power, weight and blade width across the full listed range on the motor grader page before you fix a class.

Which parts of a ripper and scarifier wear out?

The frames last for years. What gets ordered again and again is the small steel at the bottom end, and knowing the right name saves a wasted trip to the parts counter.

• Teeth and tips. The replaceable point at the end of each tooth or shank. It is the fastest-wearing item on either attachment and it is meant to be sacrificial: it protects the holder behind it. Tips are usually held by a pin or a retainer, so they come off without cutting.
• Shanks. The steel leg itself. Shanks bend before they break, and a bent shank pulls the machine off line. Check them for straightness whenever a tip is changed.
• Shank protectors. A sleeve or guard welded or bolted over the leading face of the shank, taking the rubbing wear so the shank does not thin out.
• Pins, retainers and bushes. Each tooth holder and the lift linkage pivot on pins. Worn pins give a loose, rattling frame that works unevenly.
• Lift cylinder and hose. Both attachments are hydraulic. A cylinder that will not hold position usually means seals, and a frame that drifts down on its own is a cylinder or valve fault, not a worn tooth.

Worn tips are easy to spot. A new tip has a defined point. A worn one is rounded and short, and the first sign in the cab is that the attachment stops holding depth and starts riding over the surface. Replace a full set rather than single tips, because uneven tip length makes the frame work crooked and throws the load onto whichever tooth is longest. The same wear-part logic applies across the machine: the parts and components guide covers the cutting edge and end bits, and the wider parts and running costs hub covers filters, oils and other service items.

When should you use the scarifier and when the ripper?

Three site situations cover most of the decision.

A worn gravel or earth road with a hard crust. This is scarifier work. The crust is thin, the material under it is reusable, and you want the full width loosened so the blade can reshape and re-camber it in the same pass. A ripper here would leave deep lines the blade then has to chase.

Compacted hard pan under the surface. Hard pan is a dense layer that has set almost like weak rock. If the scarifier teeth skip across it without entering, the ripper is the tool. Rip it in one direction, then cross-rip at an angle if the pieces are still too large, and grade afterwards.

Old bitumen surfacing being broken up. The ripper again, for the same reason: a bitumen layer has to be cracked before anything can lift it. Work shallow at first and let the layer break in plates rather than forcing full depth.

Two habits matter whichever tool is down. Rip and scarify going forward in a straight line, not on a turn, because a shank in the ground turns into a lever when the machine articulates, and that is how shanks bend and holders crack. And lift the attachment fully before travelling, since the Cat 140 sheet notes the raised ripper beam still adds 1,031 mm (40.6 in) to the machine’s length. For how the articulation joint and the circle work together while all this is happening, see how motor graders work.

What does fitting a ripper or scarifier add to the machine?

Weight, mostly, and it is not trivial. BEML’s BG605I sheet puts the scarifier at an extra 635 kg and the rear mounted ripper with its counterweight at an extra 1,930 kg, taking the machine from 14,700 kg with a ROPS cabin to 16,880 kg with the ripper fitted. Caterpillar’s 140 sheet lists a mid-mount scarifier package at 917 kg (2,017 lb), a front scarifier at 434 kg (956 lb) and a rear ripper at 1,104 kg (2,429 lb).

That extra mass is useful and costly at the same time. A rear ripper behind the back axle acts as a counterweight, which helps the blade hold a line, and this is why the ripper is often sold with a counterweight as one option. It also raises axle loads, uses more fuel, and changes how the machine must be loaded on a trailer. Before fitting either attachment, check three things: that the machine has a free hydraulic circuit and the control for it, that the mounting points exist on your frame rather than needing fabrication, and that the loaded weight still suits the trailer and the route you move the machine on.

Several things move what a ripper, scarifier or a set of teeth costs: the number of holders on the frame, whether the tooth is a plain point or a hardened and protected one, the shank section size, whether a counterweight is included, and whether the machine needs the hydraulic circuit added. Pricing sits with the dealer who knows your machine’s serial number and the circuit it already has.

Choosing between the two for your own machine

Start from the ground you work, not the attachment list. If most of your work is maintaining earth and gravel roads, a scarifier earns its keep almost every day and the ripper sits idle. If you break up old surfaces, work in hard dry ground, or open new alignment, the ripper is the one that lets the machine work at all. Operators on mixed road contracts often carry both, and those are the machines where the published option list is worth reading before purchase rather than after.

Match the class to the work next. A light grader with a 3,000 mm blade and a heavy grader at 196 HP (147 kW) are not doing the same job, and an attachment sized for one will either overload or underuse the other. The motor grader types, brands and applications guide sets out the classes, and the spare parts page is where a request for a specific part goes.

Ready to shortlist a machine? See the full listed range on the motor grader page, where power, weight and blade width sit side by side.

Figures on this page are quoted from the makers’ own published specification sheets for the BEML BG605I and the Caterpillar 140 motor grader, and are indicative of their class only. Specifications vary by variant, by model year and by the options fitted, and makers change them without notice. Always confirm tooth and shank counts, depths and weights for your exact machine against its own operator manual, the maker’s current sheet or your dealer before buying or fitting anything. DesiMachines is not liable for changes made after this page was published.