Geringhoff Northstar upgrade kits

The Calmer upgrade kit fixes many
of the mechanical problems with this head.
These parts will allow your geringhoff head to
perform better than a new or chopping corn head.
100% satisfaction guaranteed!

BT Chopper Stalk Rolls

Through the integration of multi-length blades,
Calmer Stalk Rolls have a patented “open window”
feeding chamber to guarantee the efficient
flow of cornstalks into the corn head to
become chopped into “confetti-like” pieces
by 20 razor-sharp blades.

Multi-Zone Beveled Stripper Plates

Our patented stripper plates have a wider
front opening to help prevent the bulldozing
of cornstalks when slightly off the row. The
beveled stripping area mimics the bottom
portion of the corn ear to help reduce
butt shelling problems and trash intake.

Chain accelerator sprockets

Calmer Gathering chain drive sprockets
increase chain speed to synchronize gathering
chains with the stalk rolls to reduce trash intake
and prevent the chain lug from inhibiting
the entry of cornstalks.

slower crown gear

calmer sells a 32-tooth crown gear
to slow down the entire corn head
to reduce ear bounce and butt shelling.

(not for 12+ row heads with single drive)

Grass Knives

calmer grass knives are designed for
factory geringhoff nose cones to help
prevent the back wrapping of grasses
or weeds around the spirals.

Geringhoff Northstar
Upgrade Kit Explained

Follow along with the inventor himself, Marion Calmer, as he explains the extensive benefits of the Calmer BT Chopper® Upgrade Kit for your Geringhoff Northstar corn head. These patented performance parts not only enable your Geringhoff head to perform better than a new head, but also help make you more money by reducing a pass across the field, eliminating the chopping of stalks, improving planting operations, and increasing yields. We guarantee your satisfaction or your money back! 


follow our recommended steps for maximum performance

Step 1



Reliable stalk rolls are critical to a an effective corn head. That’s why Calmer invented the World’s Only All-Weather Stalk Roll™ known as the BT Chopper®, which is the only roll in the industry with a patented “open window” feeding chamber for guaranteed stalk engagement and processing in all crop conditions.

The 10 razor-sharp knives on each stalk roll cut, chop and shear cornstalks into confetti-like pieces for accelerated decomposition. As a result, you’ll be able to reduce a management pass across the field, improve planting and increase yields. Calmer Grass Knives match the curvature of the factory nose cone to  prevent the back wrapping of grasses.



multi zone beveled stripper plates from calmer features

“…Calmer’s rolls really chewed up the stalks like we wanted. Very pleased!”

Scott Allison

Macob, IL

Multi Zone Beveled Stripper Plate Calmer Kit

Reduce Butt Shelling and Decrease Intake of Material Other Than Grain (MOG) aka “Trash” Into Combine

Calmer’s Patented Multi-Zone Beveled Stripper Plates have a wider front opening that helps minimize the bulldozing of cornstalks when not fully aligned with the row. This wider retrieving area is flat to reduce ear wedging and beveled in the back stripping area to allow the stalk rolls to engage the ear shanks, leaves and husks, which significantly reduces trash intake into the combine. The patented beveled edge emulates the rounded bottom of the corn ear to help reduce butt shelling problems by displacing the energy around the base of the corn ear.

Are you experiencing other stripper plate problems on your corn head? read more



gathering chain accelerator Sprocket

drive and idler sprocket for chain timing case 4000

By speeding up gathering chains with Calmer’s larger 12-Tooth Drive Sprockets, stalk roll speed is better synchronized to gathering chain speed. This allows for more of the plant to be processed at the corn head and prevents the gathering chain lugs from inhibiting the entry of the cornstalks as they travel into the row unit.  

“Just awesome! The Trash Kits did a great job of tearing up the stalks. It actually did more than we expected!”

– Travis Walton
Linwood, NE


32-Tooth Crown Gear

drive and idler sprocket for chain timing case 4000

Factory NorthStar corn heads run too fast. To solve this problem, Calmer sends a 32-tooth crown gear with the full BT Chopper® Upgrade Kit. By installing this smaller crown gear, the corn head will run slower, decreasing both ear bounce and butt shelling problems. 

Big picture Economics

Follow along with George, a long-time user of Calmer parts, as we explains the economics behind installing these patented parts on a factory corn head. 

Complete the ROI plan to see how



 No Feeding Chamber

Factory Geringhoff NorthStar stalk rolls are designed with flutes that are the same length, which create a wall of rotating steel and prevents the the entry of cornstalks.

This flawed design results in the premature wear in the first few inches of the stalk roll as the remaining length of the blades stay in usable condition since stalks cannot travel into the head.

CASE IH stalk roll design problems

Factory Geringhoff stalk rolls have ineffective spirals and a constant overlap in the entry area which fails to perform as needed.


Patented “Open window” Feeding Chamber

Through in integration of multi-length blades, the Calmer BT Chopper® Stalk Roll possess a patented “open window” feeding chamber to allow corn stalks to travel efficiently into the row unit to become chopped into small pieces.

This design performs in all crop conditions, guarantees the traction of stalks for processing, results in longer stalk roll life, reduces low ear snap, and prevents the bulldozing of stalks at the end of the  rows.

Multi-length blades allow cornstalks to feed into the row unit. 



 Limited Residue-to-Soil Contact

Straight-fluted knife rolls for Geringhoff NorthStar heads have too much overlap in the entry area, which prevents cornstalks from engaging properly with the flutes to become processed.

Failing to properly process cornstalks prevents residue-to-soil contact, leading to the immobilization of critical nutrients on the soil surface, slower degradation rates and a wet mattress of cornstalks in the spring.


Cornstalks failed to enter the knife chamber, resulting in little residue-to-soil contact and slow decomposition rates.


10 intermeshing Razor-sharp blades

 Superior Residue-to-Soil-Contact

Calmer Stalk Rolls are designed with feeding chamber to allow stalks to travel easily into the row unit to become processed. 

Once engaged, 20 intermeshing, razor-sharp blades cut, chop, and shear cornstalks into confetti-like pieces. This process exposes the pith of the stalk and places the residue strategically over the row for superior residue-to-soil contact, accelerated decomposition, easier planting and higher yields!

Cornstalks are easily engaged and processed for superior residue-to-soil contact and rapid decomposition..



Factory straight stripper plates are not formed to match the natural shape of the bottom side of the corn ear, which causes kernel loss upon impact by displacing all the energy on one kernel.

Also, because these plates don’t match the curvature of the ear leaf, the ear shank cannot get close enough for the stalk roll blades to grasp and process it at the corn head. This results in the husk staying attached to the ear and sends it and more material other than grain (MOG) into the combine.

Factory Geringhoff plates don’t match the bottom portion of the corn ear, increasing kernel loss and trash intake into the combine.


Patented Multi-Z Beveled Stripper Plates

Calmer’s Patented Multi-Zone Beveled Stripper Plates are wider in the front to reduce the bulldozing of cornstalks when off the row.
The flat contour in the front reduces ear wedging and the bevel in the back stripping area allows the stalk rolls to engage more ear shanks, husks, and leaves, reducing trash intake. This bevel also does a better job at displacing the energy upon impact of the corn ear, which reduces butt shelling.
These beveled stripper plates are hardened for extended life.


Calmer Beveled Stripper Plates Minimize Kernal Loss

Calmer’s patented bevel mimics the bottom portion of the corn hear to reduce kernel loss and trash intake. 


slow Gathering Chain Speed

Synchronizing gathering chain speed to stalk roll speed is critical to ensuring the entire cornstalk is processed as the corn head. If gathering chains are running too slow, like on the Geringhoff NorthStar corn head, the chain lugs have often inhibits the efficient entry of cornstalks into the row unit.  


patented accelerator sprocket

Calmer’s patented 12-Tooth “Accelerator” Drive Sprockets increase the speed of gathering chains to better synchronize chain speed to stalk roll speed. 

This will help reduce trash intake into the combine and allow cornstalks to travel into the row unit without the lug inhibiting entry.

(Available for splined shaft only) 


Fast corn head tip Speed

From the factory, Geringhoff NorthStar corn heads run one of the fastest tip speeds in the industry. As a result, these corn heads are known for excessive ear bounce and kernel loss.  


32-tooth crown gear

Calmer suggests installing a 32-tooth crown gear in the gear case to slow down the entire corn head. These slower head speeds will help reduce ear bounce and kernel loss problems. Crown gears are included with the full Calmer Upgrade Kit.
(Not for 12+ row corn heads with single drive.)

Get MORE than you bargained for this fall with Calmer's BT Choppers® and Residue Management Upgrade Kits

With Calmer Upgrade Kits, you're getting more than just corn head parts, you're getting peace of mind that your residue management and corn head problems are solved for good during harvest. 


Agronomic and Mechanical Advantages

Mechanical Advantages

    • Compatible with all Tillage Systems
    • 25% Less Hp Needed than with Chopping Heads
    • Superior Cornstalk Flow to Engagement
    • Better Ear Separation
    • Less Tire Wear
    • Less Butt Shelling
    • Increased Harvesting Speeds (Achieved through a combination of installing Calmer® products and proper combine settings)
    • Lower Spread Load

Agronomic Advantages

    • Unmatched Residue Decomposition
    • Warmer Soils
    • Drier Soils
    • Increased Earthworm Populations
    • Reduced Nitrogen Penalty
    • Easier Planting
    • Higher Yields
dave hula recommends calmer stalk rolls

Still not convinced?

Look at the Benefits on The Ground

read the reviews from other farmers or review the scientific studies. Either way, the message is clear: Calmer BT Choppers® manage cornstalks for healthier soils, higher yields and profits.