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❄️ Snow Blower Troubleshooting

Snow Blower Leaving
a Strip of Snow

Your snow blower clears most of the driveway — then leaves a stubborn ridge or strip down the middle or edge. Five causes account for nearly every case. Here's how to find yours and fix it.

5
Root Causes
#1
Scraper Bar
15 min
Most Fixes
2–4
Seasons/Scraper

Start Here: Where Is the Strip?

The location of the snow strip narrows down the cause significantly before you turn a single bolt. Look at where the strip appears after a pass and use that to guide your diagnosis.

Strip runs down the center Check First

A strip specifically down the middle of the cleared path usually points to a scraper bar that's bowing slightly — slightly concave with wear. The ends contact the ground but the center doesn't. Skid shoe misadjustment can also produce this pattern.

→ Go to Cause 1 (Scraper Bar) and Cause 2 (Skid Shoes)

Strip runs along one edge Check Parts

A strip on one side — left or right — almost always points to a broken shear pin on that side. The auger on the side with the broken pin has stopped turning, so snow on that side isn't being fed into the impeller.

→ Go to Cause 4 (Shear Pins)

Thin icy layer left across full width Check First

A thin layer across the entire clearing width — not a ridge, just a film — is usually a scraper bar that's worn too far down and can no longer be adjusted lower, or skid shoes set too high, holding the entire housing off the ground uniformly.

→ Go to Cause 1 (Scraper Bar) and Cause 2 (Skid Shoes)

Ridge on the clean side of each pass Technique

Snow spilling over onto the already-cleared side during each pass is a technique and speed issue — the impeller can't process snow fast enough at the current ground speed or pass width. This worsens in wet or heavy snow.

→ Go to Cause 5 (Operator Technique)

The 5 Causes — and How to Fix Each One

Work through these in order. Causes 1 and 2 account for the majority of strip complaints — check them before assuming a mechanical failure.

1
Most Common Cause
Worn or Misadjusted Scraper Bar
Two-stage machines · Steel scraper bar · Adjustable on most models
Easy
Difficulty
15 min
Fix Time
Socket Set
Tools
$15–$40
Part Cost (if worn)

The scraper bar — sometimes called the shave plate or scraper blade — is the flat metal bar that runs across the bottom of the auger housing. Its job is to chisel that last layer of snow and ice off the pavement and feed it into the augers. When it's worn down, adjusted too high, or bowing in the middle, it can no longer contact the ground effectively and leaves a layer or strip of snow behind.

On two-stage machines, the scraper bar is typically steel and wears down gradually over two to four seasons. Many bars are reversible — you can flip the bar over to expose a fresh edge before replacing. The bar is also independently adjustable on most machines, separate from the skid shoes, using slotted mounting holes.

  • 01

    Inspect the scraper bar for wear and bowing

    Park on a flat surface and look at the gap between the scraper bar and the ground. It should be about 1/8 inch — roughly the thickness of a coin. If the gap is larger, or if the bar bows up in the center while touching at the edges, adjustment or replacement is needed.

  • 02

    Tip the machine back and loosen the scraper bar hardware

    Carefully tip the blower back so its weight rests on the handlebars — secure it so it won't tip unexpectedly. Loosen (don't remove) the bolts securing the scraper bar at the bottom of the housing. The bar should now be free to slide in its slotted holes.

  • 03

    Pull the bar down as far as possible, then tighten

    Pull the scraper bar down to the lowest position in its slots and tighten all hardware firmly. If the bar has worn unevenly, try flipping it over to expose the other edge before pulling it down. After tightening, go straight to Cause 2 — skid shoes always need re-adjustment after any scraper bar change.

  • 04

    If it can't go lower, replace the bar

    If the bar is already at its lowest setting and still leaves a gap, the bar is worn past the point of adjustment. Order a replacement from your machine's manufacturer or a parts supplier using your model number. Scraper bars run $15–$40 for most residential two-stage machines.

Bottom line: Check the scraper bar before anything else. It's the most common cause of a snow blower leaving a strip, it takes 15 minutes to inspect and adjust, and the fix costs nothing if the bar still has adjustable range.
2
Very Common
Skid Shoes Set Too High
Two-stage machines · Steel or poly skid shoes · Bolted to auger housing sides
Easy
Difficulty
15 min
Fix Time
Socket Set
Tools
$10–$25
Part Cost (if worn)

Skid shoes are the two steel plates attached to the outside of the auger housing — one on each side — that regulate how close the housing sits to the ground. They protect the auger housing and scraper bar from contact with the surface. When they're set too high (which raises the housing too far off the ground), the scraper bar can't reach the snow layer, no matter how the bar itself is adjusted.

Skid shoes also wear down over time, just like the scraper bar. As they wear shorter, the housing drops lower — which actually improves clearing on paved surfaces. But if you've recently replaced the skid shoes with new, thicker ones without re-adjusting to match, the housing is now riding higher than before.

  • 01

    Check tire pressure on both sides first

    Uneven tire pressure causes the machine to lean slightly, which throws off skid shoe adjustment. Check the sidewall for the rated PSI and equalize both tires before adjusting anything else.

  • 02

    Place a spacer under the scraper bar

    Park on a flat, level surface. Place a spacer under the scraper bar: use coins (approximately 1/8 inch) for paved driveways, or a thicker shim (1/2 inch) for gravel. This sets the target gap between the scraper bar and the ground.

  • 03

    Loosen skid shoe bolts and lower shoes to the ground

    Loosen the bolts on both skid shoes. Let each shoe drop down until it contacts the flat surface. While holding the shoe firmly down against the surface, tighten the bolt. Repeat on both sides. Use a tape measure to confirm both shoes are set at the same height.

  • 04

    Verify the auger housing isn't contacting the ground

    After adjusting, confirm the auger housing and auger blades are not touching the ground — only the scraper bar (at the spacer gap) and the skid shoes should contact the surface. If the housing still drags, the skid shoes may need to be replaced with longer ones.

Key detail: Skid shoes always need to be re-adjusted after any scraper bar adjustment — the two are interdependent. Skid shoes are also reversible: flip them when one side wears down before replacing entirely.
Gravel driveways: Never run the scraper bar close to the surface on gravel. Use a 1/2-inch spacer or higher to keep the housing elevated enough that the auger won't throw stones. A projectile from a snow blower auger can cause serious injury.
3
Mechanical
Worn or Slipping Auger Belt
Two-stage machines · Belt drives impeller · Gradual wear over seasons
Moderate
Difficulty
30–60 min
Fix Time
Socket / Wrench
Tools
$10–$30
Belt Cost

On two-stage snow blowers, a belt transfers power from the engine to the auger and impeller. As this belt wears, stretches, or glazes over, it slips — reducing the rotational speed of the impeller. A slower impeller means snow isn't thrown as effectively, which can leave snow behind as the auger feeds more than the impeller can clear.

A slipping belt often manifests not as a strip of snow but as reduced throwing distance combined with more snow left behind — particularly on heavy or wet snow that demands full impeller speed. If your throwing distance has also gotten noticeably shorter, belt slip is likely involved.

  • 01

    Access the belt by removing the belt cover

    With the engine off and key removed, remove the belt cover panel — usually held by a few bolts on the front or side of the machine. Your owner's manual will show the exact location for your model.

  • 02

    Inspect the belt for glazing, cracking, or fraying

    Look at the belt edges — they should be smooth and even. A glazed (shiny) sidewall indicates slipping. Any cracks, fraying, or visible damage means the belt needs replacement before the next use. A belt that looks intact but has glazed sidewalls is still a replacement candidate.

  • 03

    Replace the belt using your model's exact belt number

    Order the replacement belt using your machine's model number — belt dimensions vary between machines and a wrong-size belt won't tension properly. Belt replacement on single-stage machines is a simple DIY job; on two-stage machines it requires dismantling more of the drive system and may warrant a dealer visit if you're not comfortable with the process.

Sign to watch for: If your machine used to throw snow 30 feet and now barely clears 15–20 feet, the auger belt is a prime suspect even before you notice snow being left behind. Reduced throw and leaving snow often appear together as a belt wears.
4
Mechanical
Broken Shear Pin on One Side
Two-stage machines · One broken pin = one idle auger section
Easy
Difficulty
10 min
Fix Time
Hammer / Punch
Tools
$5–$15
Pin Cost

Shear pins — also called shear bolts — are sacrificial fasteners that secure each auger section to the auger shaft. They're designed to snap if the auger hits a solid obstacle like a buried rock or chunk of ice, protecting the gearbox from expensive damage. When one breaks, the auger section on that side stops turning while the shaft continues rotating — the auger spins freely around the shaft without engaging.

A broken shear pin on one side produces a very specific strip pattern: a strip along one edge of the cleared path — the side where the auger is idle. The other side clears normally. If you've recently hit something solid or heard a loud bang from the machine, a broken shear pin is likely.

  • 01

    Check each auger section by hand (engine off, key removed)

    With the engine off and key completely removed, grip each auger section and try to rotate it. If one section spins freely without resistance — without turning the auger shaft — the shear pin on that side is broken. A working section should have resistance and turn the shaft with it.

  • 02

    Drive out the broken pin remnants

    Align the hole in the auger section with the hole in the shaft. Use a hammer and punch to drive out any remaining broken pin fragments. Both pieces of the pin must be fully removed before the new pin can be inserted.

  • 03

    Install the correct replacement pin only

    Install the manufacturer-specified shear pin for your machine — not a hardware-store bolt or substitute. The shear pin is engineered to break at a specific load; a stronger substitute won't shear when needed and can damage the gearbox. Stock several spares — keep them attached to the machine or in a pocket when clearing snow.

Prevention tip: Walk your driveway before the first snow of the season to clear rocks, extension cords, and any buried debris. A single rock at 1,000 RPM auger speed breaks a shear pin instantly — and potentially causes other damage too.
5
Operator Side
Ground Speed Too Fast or Pass Too Wide
All machine types · Heavy or wet snow conditions · Easy to correct
No Parts
Difficulty
0 min
Fix Time
None
Tools
$0
Cost

Even a perfectly adjusted machine leaves snow behind if it's being driven too fast through heavy snow. When ground speed is too high, each section of snow spends less time in contact with the augers, and the impeller can't throw what it can't fully process. The overflow spills back over the sides — creating a ridge on the clean side — or simply isn't picked up at all, leaving a trace behind.

This problem is more pronounced in heavy, wet snow than in light, dry snow. Manufacturers consistently recommend taking narrower bites — one-third to one-half the machine's width — in heavy conditions, and slowing ground speed while keeping auger RPMs at full throttle. The auger should always be spinning at full speed; only the pace you walk changes.

  • 01

    Slow your ground speed — especially in wet or heavy snow

    In dry, fluffy snow a full-width pass at normal walking speed is fine. In heavy, wet, or deep snow, slow down significantly and take narrower passes. The machine handles a smaller volume better than it handles a faster pace.

  • 02

    Take one-third to one-half width passes in heavy conditions

    Don't try to clear the full width of the machine in a single pass through deep or wet snow. Overlap each pass by half or more. This sounds slower but is typically faster overall — a full-width pass that leaves a ridge requires an extra cleanup pass anyway.

  • 03

    Keep auger RPMs at full throttle; slow the machine, not the engine

    Always run the engine at full throttle so the auger and impeller are spinning at maximum speed. The adjustment when conditions are difficult is to slow your walking pace — not to throttle back the engine. A slower impeller leaves more snow behind.

Quick test: If the strip problem only appears in heavy or deep snow conditions — but the machine clears cleanly in light snow — technique is almost certainly the primary factor, not a mechanical issue. Try narrower passes before diagnosing anything further.

Scraper Bar Height by Surface Type

The correct scraper bar and skid shoe height depends on what you're clearing. Paved and gravel driveways require very different settings — using the wrong setting for your surface is a common cause of both leaving snow behind and causing damage.

Surface
Concrete / Asphalt
Low Clearance
Target Scraper Gap 1/8 inch (coin thickness). Skid shoes set to allow scraper bar to skim just above the surface. On perfectly flat pavement, this leaves almost no snow behind.
Adjustment Note Use a coin or paint stir stick as a shim under the scraper bar when setting skid shoes. Check the gap once a season — wear changes it gradually.
Surface
Gravel Driveway
High Clearance
Target Scraper Gap 1/2 inch or more. Skid shoes raised significantly to keep the auger from reaching the gravel layer. Expect to leave a thin snow layer — it's by design on gravel.
Adjustment Note A snow blower on gravel will always leave some snow behind — that's the tradeoff for not throwing stones. Use a thick shim (1/2 inch) when adjusting shoes. Some operators use compacted snow as a base layer all season to avoid this.
Surface
Pavers / Brick
Medium Clearance
Target Scraper Gap 3/16–1/4 inch. Raised slightly above standard pavement setting to handle minor height variation between pavers. Non-abrasive poly or composite skid shoes recommended.
Adjustment Note Steel skid shoes can scratch or chip pavers over time. Poly skid shoes protect the surface and are gentler on the shoe itself. Expect slightly more snow left behind than on flat concrete — this is normal.

Preventing the Strip Before Next Season

Most scraper bar and skid shoe issues that cause strips can be caught in a pre-season check that takes under 30 minutes. Here's what to inspect before the first snow.

Before First Snow

Inspect and Adjust Scraper Bar

Set the machine on a flat floor and check the scraper bar gap. It should be about 1/8 inch off a flat surface on pavement settings. If the gap is larger or uneven, adjust before you need the machine — not during a storm.

Before First Snow

Equalize Tire Pressure

Uneven tire pressure causes the machine to sit at a slight angle, which throws off skid shoe adjustment and can create a strip on one side. Check both tires against the sidewall rating before any seasonal adjustment.

Before First Snow

Stock Spare Shear Pins

Keep four to six manufacturer-spec shear pins stored on or near the machine. Hitting a buried rock is unpredictable — being able to replace a pin in the driveway beats ending a session early or causing gearbox damage trying to push through with a broken pin.

Pre-Season Check

Check Belt Condition

Remove the belt cover and inspect the auger belt for glazed sidewalls, cracking, or fraying. A belt that looks marginal before the season will almost certainly fail mid-season. Replacement is inexpensive compared to the inconvenience of a mid-storm breakdown.

Each Season

Walk the Driveway Before First Use

Clear rocks, garden hose ends, extension cords, and stakes before snow covers them. Stake out the driveway perimeter with marker stakes so you know where the edges are — and where the lawn begins — after heavy snowfall.

As Needed

Flip or Replace Worn Skid Shoes

Skid shoes are reversible — flip them when one side wears down. When both sides are worn, replace them before starting a new season. Worn-down shoes cause the housing to drop lower over time, eventually letting the auger housing itself contact the ground.

Snow Strip Questions

The most common causes are: a worn or misadjusted scraper bar sitting too high off the ground, skid shoes set at the wrong height, a slipping or worn auger belt reducing impeller speed, a broken shear pin leaving one auger section idle, or operator technique — passing too fast or too wide for the snow conditions. Start by checking your scraper bar height and skid shoe adjustment before assuming a mechanical failure. These two causes alone account for most strip complaints.

A strip specifically down the center often points to a scraper bar that has bowed slightly — worn more at the ends than the middle, so the center no longer contacts the ground. The fix is to shim both outer ends of the scraper bar when adjusting skid shoes, rather than the center. If the bar is bent or worn unevenly beyond adjustment, replacement is the correct solution. Also confirm both shear pins are intact — a broken pin on one side can create patterns that look like a center strip depending on the machine's auger configuration.

For paved driveways: place a 1/8-inch spacer (coins or a paint stir stick) under the scraper bar on a flat surface, then loosen the skid shoe bolts and lower the shoes until they contact the ground. Hold each shoe down firmly while tightening. Both shoes must be adjusted equally — use a tape measure to confirm. For gravel driveways, use a 1/2-inch spacer to raise the housing enough to prevent the auger from reaching the gravel. Always check tire pressure before adjusting — uneven pressure throws off the whole process.

Most steel scraper bars on two-stage machines last two to four seasons under typical residential use. Concrete is harder on bars than asphalt; frequent use wears them faster. On single-stage machines, the rubber paddle/scraper bar wears faster — often needing replacement every one to two seasons on heavy-use machines. Many bars are reversible: flip the bar over when one edge wears to extend its life before replacing. When the bar can no longer be adjusted low enough to maintain the proper gap, it's time for replacement.

Yes — and it produces a specific, recognizable symptom. On two-stage snow blowers, a broken shear pin on one side leaves that auger section spinning freely around the shaft without engaging. The other side continues turning normally, creating an uneven intake: the machine clears well on one side and leaves a strip on the side with the broken pin. With the engine off and key removed, grip each auger section and try to turn it. If one section rotates freely without resistance — without turning the shaft — the shear pin on that side is broken. Replace it with the manufacturer-specified pin only.

Yes, especially in heavy or wet snow. Moving too quickly limits how long each section of snow is in contact with the augers, and the impeller can't throw what it can't fully process. Overflow spills back over the sides or isn't picked up at all. Manufacturers consistently recommend taking passes at one-third to one-half the machine's clearing width in heavy conditions, with a slower ground speed — while keeping the engine at full throttle. If the strip problem only appears in heavy or deep snow and not in light, dry conditions, technique is almost certainly the primary factor.

More Snow Blower Troubleshooting

Won't start after sitting? Chute keeps clogging? Not throwing snow far? We've covered the other common problems too.

Won't Start → Chute Clogging → All Snow Blowers →