Review of the Slappy ST1 Hollow Inverted: Skate Trucks with Maximum Grind Clearance for Smiths and Feebles

Slappy is a newer skateboard truck brand that started during the pandemic by skate industry veteran Mike Sinclair with the goal of creating trucks that turn better, weigh less, and have the most grind clearance.

Lately, I’ve been trying to relearn how to feeble grind, so the thought of having a generous amount of grind clearance in a lightweight truck sounded really helpful to me. I bought a pair of the Slappy ST1 Hollow Inverted skateboard trucks to see if the extra kingpin clearance would help me, and here is what I thought of them.

The Main Benefits of These Trucks

The Slappy Inverted ST1 Hollow Trucks have a hollow inverted kingpin that sits 9mm down into the body of the truck, hollow axle, polished silver hangers, and polished silver baseplates. From the outside, it looks very similar to a typical skate truck, but it’s got these primary benefits.

• Added Kingpin Clearance for Smith Grinds: The unique kingpin design offers a generous 9mm (.345 inch) grind clearance. This extra kingpin clearance helps with Smith, Feeble, and Hurricane grinds.
  
  
• They weigh 10% less than a standard non-hollow truck (like the Independent Stage 11) and match the weight of a standard hollow truck (Independent Stage 11 Hollow), but offer the benefit of a unique kingpin design for added kingpin clearance.
  
  
• The trucks come pre-broken in with 90a bushings.
  
  
• New 20-degree geometry for tighter turns and better control. The updated angle of the baseplate and kinpin allows for tighter, more responsive turns, and that makes setting up for tricks and slappy grinds feel easier.

What Is the Grind Clearance in Your Skateboard Trucks?

Your skateboard truck’s grind clearance, or kingpin clearance, is the distance between a truck’s hanger, the part between your wheels that you grind on, and its kingpin, the central bolt that runs vertically through the truck’s baseplate and hanger and often has a nut that sits prominently in the middle of the hanger.

Why is Grind Clearance Important?

Grind clearance is important because it affects how smoothly the skateboard truck grinds for off-angled grind tricks like Smiths, Feebles, Hurricanes, Overcrooks, Bennett, and Barley grinds.

When a skater leans their weight in to pinch or lock into these types of angled (or off center) grinds, the truck’s kingpin nut can gouge in or catch on the surface they’re grinding on. This catching makes angled grind tricks extremely difficult, or even impossible, to balance the grind in the right position.

By having a higher level of grind clearance, your kingpin stays out of the way, allowing you to grind easier. To put it simply, the more the grind clearance you have, the easier it is to smith or feeble grind with your trucks.

How Does Slappy’s Grind Clearance Compare to Other Skate Trucks

Here’s Slappy’s Grind Clearance Measurements compared to other brands.

*Grind Clearance is the distance from your truck’s kingpin to the top of your hanger.

**Grind Angle is the degree of angle your trucks provide from catching on Smiths, Feebles, Hurricanes, Bennett and Barley Grinds. The larger the degree the less kingpin catch you will have.

Overall Impression of the Slappy Hollow Inverted Trucks

Overall, I am really enjoying my Slappy trucks and plan to continue skating them as my primary set of trucks after this review. I typically skate Independent trucks, and these feel a lot like those, but with a few added benefits.

Here are some of the highlighted notes I have for how my Slappy Inverted trucks feel to me.

They Feel Very Similar to Independent Stage 11 Hollow Trucks

When I first stood on these trucks, I noticed that it didn’t take me long to get used to them because they felt so similar to the Independent Stage 11 Hollow trucks that I was skating right before them.

• Same Turning & Response: Slappy’s turning experience and level of response feel so similar to an Indy Stage 11 truck. Slappy’s have their kingpin at an updated 20 degree angle to promote a tighter feeling turn, but if there is a difference in its turning over an Indy, it is so subtle that I haven’t noticed it. (These trucks turn exceptionally well, and so do Independent trucks.)
  
  • Both have stock 90a Bushings.
    
    • Slappy’s bushings feel a little more broken in right out of the gate.
      
  • Both have a similar-shaped hanger.
    
  • Both have a similar weight.
    
  • Wheelbase is similar – Independent Trucks add 3″ to your wheelbase while Slappy adds 3.06″. (I didn’t notice the 1.524mm difference.)
    
• 5050 Grind Feel: Both trucks have an identical feeling grind on curbs or on coping for linear grind tricks like 5050s or 5-0s.
  
• Smith Grind Feel: Slappy trucks are noticeably easier to smith grind. As long as you’re locked in, it just goes without the kingpin catching.
  
• Slide Tricks: The baseplates of both Indy and Slappy trucks lock in similarly on nose and tail slides, so there was no noticeable difference for me.

This is all to say, both trucks feel incredibly similar, but the main benefit is that the Slappy ST1 Hollow Inverted trucks make it easier to Smith and Feeble grind.

Overall Review Rating of the Slappy ST1 Hollow Inverted Trucks

Editor’s Rating: 4.8 out of 5 stars

Pros of the Slappy Hollow Inverted Trucks

These were the things I love about my Slappy Trucks that you should know.

The Extra Kingpin Clearance Works So Well

I got these trucks to help me relearn how to feeble grind, and I am happy to report that feeble grinds are now back in the bag.

The extra kingpin clearance really does work to keep the kingpin out of the way, and that has made feeble and smith grinds a little easier to learn.

These Feel Noticeably Lightweight

These trucks felt noticeably light when I picked my board up. I really started to notice that the more I skated them. As I popped my board, the more I noticed my entire setup felt lighter and more controlled.  

I wanted to weigh them to get the exact specifications for comparison with my Indy Stage 11 Hollow Inverted trucks. It turns out that the Slappy ST1 Hollow Inverted trucks are actually 4.32% lighter than the closest comparable Independent trucks, the Indy Stage 11 Hollow Inverted trucks.

It’s also worth noting that the Slappy ST1 Hollows are very comparable in weight to the non-inverted version of the Independent Stage 11 trucks, so with the Slappy ST1 Inverted Hollows, you get basically the same weight as a plain old Indy Hollow Stage 11 along with the benefits of the kingpin clearance with the inverted kingpin.

They Have Such a Smooth Feeling Grind

A highlight of the Slappy ST1 inverted trucks is how incredibly smooth they feel to grind with. These trucks feel buttery smooth at the skatepark while grinding on steel coping and rails. However, they also work well to grind on gritty street spot ledges and curbs, too. The feel of their grind is noticeably similar to my Indy Hollows. I find that I grind just as far on the same gritty ledges that I do with my Indys, with no catching or unusual friction to slow me down.

I am starting to prefer my Slappy trucks over my Indys for the fact that the kingpin stays out of the way as I feeble and smith grind. So if Independent’s trucks are “Built to Grind,” then Slappy trucks could be considered to have the tagline, “Built to Grind a Little Easier.”

The Kingpin Really Does Stay Out of The way

Lately, I’ve been skating my Franklin Street Flatbar after work, and the noticeable detail about these Slappy trucks over my Indys is that I don’t see the visible gouging of my kingpin on the flatbar’s surface. This flatbar is made of a softer metal, so I can see visibly see when my kingpin digs into it, and I don’t have that issue with the Slappy Hollows. It really does stay out of the way and make Feeble and Smith grinds feel a little easier.

Cons of the Slappy Hollow Inverted Trucks

These were the things I didn’t like about my Slappy Trucks that you should know.

The Inverted Kingpin Loosens

One of the things I’ve experienced with my Slappy ST1 Inverted Hollow trucks is that the kingpin of my back truck has loosened dramatically, and if I don’t stay on top of it, the kingpin seems like it will unscrew altogether.

This GIF shows how loose my truck got. It took very little pressure to move, and if you look closely, you’ll see how much extra space there is above and below my bushings.

I didn’t loosen or tighten my trucks when I first got them either. They were perfect without adjusting them, so this loosening is just from the wear and tear on the threads from skating it.

I am pretty sure I fixed it, though. I was able to prevent it from loosening by putting some Loctite removable threadlocker on the threads of my kingpins.

Since adding the threadlocker, I rarely have to tighten my trucks.

They Still Get Wheel Bite

One of the selling features of the Slappy Trucks is that they are designed to get less wheel bite. I haven’t noticed that to be the case for me. Mine still gets wheel bite. It’s not terrible to the point of getting in the way of skating, though. I’d just say that if getting a truck that prevents wheel bite is your focus for your next set of trucks, just know that mine got the same level of wheel bite as my Independent trucks.

It’s worth noting that I tend to ride small wheels too. Right now, I am bouncing between 52mm conical Spitfire Formula Fours for park skating and 52mm Dragon Formula Wheels for street skating.

Bushings Are Blowing Out Quickly

This might be related to when my trucks were loosening, but the top bushing of my back truck looks to be tearing faster than normal.

I am hopeful that now that my trucks aren’t overly loose, the bushings don’t get worse. In either case, Slappy keeps the cost of replacement bushings low. If you need a new set of bushings, you can get them for $7 here.

The New Geometry Took Some Getting Used To

When I first started skating these trucks, I noticed I was having a harder time locking into grinds on ledges.

That’s probably true with any truck, though.

Any time you’re skating brand new trucks, it can take a few days to begin to get their grinding grooves that help you to lock into the tricks you do most often.

However, there’s something slightly different with Slappy’s new 20 degree geometry of the baseplate and kingpin that took me a few sessions to get used to. I am not sure if this played a part too, but there is one visible difference to the hanger itself from the Indy hanger I was used to skating before this.

• Slappy trucks dont have an angle pointing downward where the hanger’s aluminum meets the wheel (where the axle is exposed). Instead, the aluminum in the Slappy Hanger is perfectly flat.  
  

Here’s a pic of an Indy so you can see what I am talking about. Look right next to the wheel, you can see how there is a slight curved dip in the aluminum before the wheel.

Now, compare that to the Slappy Hanger that is perfectly flat.

The difference is subtle, but noticeable at first.

After a few sessions, I got the hang of it, my trucks started to get their grooves, and there was no issue.

Image Gallery from the Review

Pricewise, How Do Slappy ST1 Hollow Inverted Trucks Compare vs. Independent, Thunder, or Ace Skateboard Trucks?

• They’re the same price as most other hollow (but non-inverted trucks)

The Slappy ST1 Hollow Inverted trucks come in at a price of $69.95, which matches the cost of Independent Forged Hollow Stage 11 and Ace AF-1 Hollow trucks. The main perk with Slappy trucks is that for the same price as these other hollow truck options, Slappy gives the added benefit of having an inverted kingpin design.

At the time of writing, compared to Thunder Hollow Lights at $65.95, the Slappys ST1 Hollow inverted trucks are just $4 (or 6%) more expensive.

• They’re $15 more than most non-hollow trucks.

Now, compared to a standard, non-hollow truck options like the Independent Silver Stage 11 ($54.95), the Slappy Hollow Inverted trucks are a $15 ( or 27%) more expensive, and I think that price increase is worth it given that they are 10% lighter and offer the added kingpin clearance.

My overall take is that it’s worth it to get the lighter-weight option with the most grind clearance.

So Are Slappy Inverted Trucks Worth It?

Yes, the Slappy ST1 Hollow Inverted trucks are very worth their price..

My Slappy ST1 Hollow Inverted trucks have become my primary go-to truck, but my main motivations are more around their weight and catch-free kingpin clearance than other selling features, like their resistance to wheel bite or having a tighter turn. If you’re looking to learn feeble and smith grinds and need a lighter truck that offers an exceptional value for its price, I highly recommend checking out Slappy Trucks.

Now for the million dollar question:

Did I Actually Relearn Feebles?

Yep, I’ve been able to get them more consistently thanks to the added kingpin clearance.

Where to Buy the Slappy ST1 Hollow Inverted Trucks

You can get these trucks at Tactics or Amazon.

And Check Out Our Other Skate Truck Reviews

• Comparison of the Lightest Skate Trucks
• Independent Titanium Trucks Review
• Tensor Mag Light Trucks Review: The Lightest Skateboard Truck
• Royal Ultra Light Skate Trucks Review
• Indy Hollow Truck Review

Steve Weber

Steve Weber is the passionate snowboarder, skateboarder, and author behind Board of the World. He understands that most gear reviews focus on having the perfect snow conditions, but his testing methodology is different. Living in Pennsylvania, Steve describes exactly how a board performs when the conditions aren’t perfect. His reviews cover performance on ice, hardpack, and flat-out brick conditions. In other words, he reviews boards for the conditions that East Coast riders actually face.

Bringing 27 years of East Coast snowboarding and 21 years of skateboarding experience, Steve is a 42-year-old intermediate park rider. His recommendations are informed by decades of battling icy conditions, ensuring every review accounts for the board’s performance on the roughest of terrain.

For the last five years, Steve has poured his passion into writing in-depth, unbiased reviews that help riders make informed decisions about the gear they’ll use. He also works part-time at a snowboard shop in Northeastern Pennsylvania, which gives him a direct line to learning about the new gear tech months in advance. When he’s not writing reviews, Steve is often found riding at Montage Mountain and testing out new boards.

Steve’s goal with Board of the World is simple: to help every reader find the right gear so they can have fun outside from the first time they use it.