Every guy who’s run a single auger vertical for a few years hits the same wall. The herd grew, the loads got bigger, and now the mixer takes forever or you’re running an extra load a day. That’s usually when the twin auger conversation starts.
What a second auger changes
A single auger tub is round. One auger, one rolling column of feed.
A twin auger vertical mixer is longer, shaped like two round tubs joined together. Two augers turn, and feed moves between them as well as up and down. You get more volume without making the machine much taller.
That’s the big one. More capacity at the same height. Your loader doesn’t need to reach any higher.
Mix time and consistency
On bigger loads, two augers working the material usually means a faster, more even mix. There’s less volume per auger to roll and cut.
With smaller loads in a twin, you need enough feed in the tub for both augers to work properly. A half-empty twin doesn’t mix as nicely as a full single.
Power and the driveline
Two augers means a gearbox setup that feeds both, and the tractor has to turn it. Twin machines generally need more horsepower than a single of similar height. How much depends on the size, the ration and how hard you process bales.
The gearbox design matters too. We wrote up what planetary stage count means under real loads in this gearbox piece, and it’s worth reading before you buy.
When single still makes sense
- Smaller herds with full loads that fit a single tub.
- Tight yards where a longer machine is a problem.
- Lower horsepower tractors.
- Simpler upkeep: one auger, one set of knives.
When twin pays off
- You’re running extra loads a day because the single is maxed.
- Your loads are big enough to keep both augers working.
- You want more capacity but your loader height won’t go higher.
- Time on the tractor seat is costing you labor every day.
Bottom line? Don’t jump to a twin because it looks bigger. Jump because your loads fill it.
How auger shape affects the mix
Not all augers are the same. The pitch of the flighting, the angle of the cone, and where the knives sit all change how fast feed rolls and how much it gets cut. Two single auger machines can behave differently.
In a twin, the two augers also pass feed back and forth across the middle of the tub. That cross-movement is one reason twins can mix big loads evenly without needing to be taller.
When you look at machines, ask to see the auger. Look at the flighting edge, the knife positions and how the auger meets the floor. Better still, watch one mix a ration like yours.
Loading a twin properly
Twins like to be loaded evenly. If you dump everything on one side, one auger does most of the work and the mix is uneven to start with.
- Spread bales so both augers get a share of the processing.
- Add grain and minerals across both sides of the tub.
- Watch the minimum load. A twin needs enough feed in it for both augers to work.
Knife count and cutting
More augers usually means more knives in the tub. That can mean faster processing of long forage, but also more knives to check and change. Factor that into your running costs.
Unloading
Twin auger machines are longer, so think about where the discharge door sits and how evenly feed comes out along the bunk. Some setups use a door on the side, some at the front. Match it to your feed alley.
A simple decision test
Write down your biggest load today, your biggest load in three years, your loader’s reach and your tractor’s real horsepower. If a single auger handles all four comfortably, stay single. If the biggest load needs a taller single than your loader can reach, that’s where a twin earns its keep.
Talk numbers, not looks
Every dealer will tell you their twin mixes great. Ask them for minutes per load on a ration like yours, and ask to speak to a customer running one.
Gearbox loads with two augers
Two augers share the work, but the drivetrain now feeds both. Gearbox design matters here, because the load on each auger isn’t always equal, especially during bale processing or when the load isn’t spread evenly.
Ask what gearbox setup the twin uses, what the service interval is, and whether there’s a two-speed option for start-up and processing. Starting a full twin on a rough PTO engagement is hard on the whole driveline, so ease into it every time.
Real costs over time
Running costs on a twin are a bit higher in some areas: more knives, two auger bearings, and a driveline that serves two augers. They can be lower in others: fewer loads per day, less tractor time and fuel per tonne mixed.
Work it out per tonne, not per machine. That’s where the true answer is.
Common mistakes with twins
- Buying one too big and running half loads.
- Loading everything on one side.
- Skipping knife checks because there are more of them.
- Pairing it with a tractor that’s at its limit.
The short version
A twin is a great tool when your loads fill it. If they don’t, a well-sized single will often serve you better. Be honest about your numbers and you’ll pick right.
Our take
We built the VT twin auger series for exactly that middle ground, herds that outgrew a single but don’t need a truck-mount. Bring your load sizes and your tractor specs to a dealer and size it on paper first.
