Komatsu D155 Dozer Cutting Edges: 9-Hole Standard vs 7-Hole Straight Blade

🛒 Buy D155 Standard 9-Hole Cutting Edge (ZF)

🛒 Buy D155 Straight 7-Hole Cutting Edge (ZF)

The Komatsu D155 dozer uses two common bolt-on cutting edges: a 9-hole edge for the standard blade and a 7-hole edge for the straight blade. They do not swap, and each one pairs with its own end bits. TTRMCO supplies both edges in the ZF brand, together with D155 end bits, ripper tips and shank protectors in DM and ZF.

What the cutting edge does

The moldboard of a dozer is expensive and is rarely replaced, so a sacrificial steel edge is bolted to its lower face. That edge takes the abrasion and impact of every push. When it wears out you replace a flat bar and a set of bolts, not the blade. The two end bits at the corners protect the ends of the edge, where wear is fastest.

Standard 9-hole vs straight 7-hole

The quickest check is to count the holes on the old edge and measure the distance between the first and last hole. If the edge is worn so badly that the holes are gone, count the holes on the moldboard itself. Parts lists also warrant care: aftermarket catalogues list several different D155 edges by thickness and bolt size, so always confirm hole count and bolt diameter against the part you are removing.

Flip first, then replace

Most dozer edges are double-bevel and reversible. When the first working edge is rounded, unbolt the bar, turn it over and use the second edge. Cat recommends watching the wear indicators on its edges and flipping or replacing before productivity drops; the same logic applies to any brand. A practical rule:

• Flip when the bottom edge is rounded but wear is still well below the bolt holes.
• Replace when wear reaches the bolt holes or the bar no longer sits flat on the moldboard.
• Never run into the moldboard. Once the base of the blade starts wearing, repair costs far exceed a new edge.

Fitting tips

1. Clean the moldboard face so the edge sits flat; a gap lets bolts work loose and shear.
2. Use new plow bolts and nuts; worn heads do not seat properly.
3. Tighten from the centre outwards and re-check after the first shift. Use the torque value from the machine service manual.
4. Corner bolts are sold separately: D155 corner bolt.

For ripper tips and shank protectors on the same machine see our D155 end bits guide.

FAQ

Will a 9-hole edge fit a straight blade?

No. Hole count and spacing differ. Count the holes before you order.

Which ZF grade are these edges?

Both the 9-hole and 7-hole ZF edges are sold in one standard version, as shown on each product page.

Should I change end bits with the edge?

Usually yes. End bits wear faster than the centre; a new edge next to worn corners leaves the blade ends unprotected.

Can the edge be hard-faced or welded?

Welding on heat-treated edges can spoil the hardness and cause cracks. Flipping and replacing is normally cheaper.

Do you export?

Yes. TTRMCO ships to neighbouring countries. Call +98 21 91001357.

Order from TTRMCO

Not sure which part fits? Send a photo of the old part next to a tape measure, plus your machine model. TTRMCO has more than 30 years in road-construction and mining wear parts and is the official dealer of DM and ZF in Iran. Every DM and ZF part ships with a breakage and authenticity warranty, and we export to neighbouring countries.

• Phone: +98 21 91001357
• Mobile / WhatsApp: +98 912 577 7516
• Website: ttrm.ir