The Kneeslider

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Polaris Slingshot Bolt On Quad Conversion Kit

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Polaris Slingshot quad conversion kit from Bullet Speed and Design
Polaris Slingshot quad conversion kit from Bullet Speed and Design

If you’ve seen a Polaris Slingshot on the road, you have to admit, it looks pretty radical. The low profile and angular style is almost guaranteed to attract attention, but what if you swapped the single back wheel for a real push rod/rocker independent rear suspension with a limited slip 3.53:1 differential? You end up with sort of a Lotus Seven or Caterham roadster, but with radically updated styling. Now there’s two wheels to get the power down along with lots more grip in the rear for high speed cornering. Pretty cool.

Polaris Slingshot quad conversion kit from Bullet Speed and Design
Polaris Slingshot quad conversion kit from Bullet Speed and Design rear view

The whole conversion is a bolt on. No cutting and chopping to make it happen so the original Slingshot is still intact. Bullet Speed and Design in Holiday, Florida builds the kit and, at least for now, it’s only available if installed at their location. You need six weeks lead time for them to build all the parts and then your Slingshot will spend two days in their shop getting the work done. The kit comes in a base version for $10K or an R-spec version for $12.5K.

Closeup of the conversion in place
Closeup of the conversion in place

Any good looking 3 wheeler with decent performance is always a potential 4 wheeler for someone with the right skills and tools. These guys couldn’t resist the temptation and the result looks mighty fine. They don’t provide any performance figures so it’s not clear what it will do compared to a stock Slingshot, but I’m guessing it beats it without too much fuss.

Polaris Slingshot quad conversion kit from Bullet Speed and Design
Polaris Slingshot quad conversion kit from Bullet Speed and Design

Licensing for the road? Since it’s a bolt on, it could be just like the Q-Tec conversions and legal in most states. We’ll see, but it sure looks like a lot of fun to me.

Posted on Filed Under: Motorcycle Kits, Three Wheel Vehicles Tagged With: , ,

Comments

  1. Finally, something that makes a Slingshot worthy of consideration. That kit looks extremely well done, and turns an odd toy into a serious road machine. I’m impressed.

    • Bovine defecation. It makes the Slingshot unregisterable because installing it means it’s no longer and motorcycle and it won;t meet automobile regulations.

    • The world is full of four wheelers. Why screw up such a lovely road toy? It doesn’t make any sense.

      • How cool is that? And with four wheels it is even more stable.
        But just think of the savings,…motorcyle plates and insurance. Even if you lost your driving privileges, you might be able to use your motorcycle license to drive a four wheeled slingshot.

  3. Problem is in most states the emissions are different for four wheelers and three wheelers. While it may be cool, it also may not be legal because of the change in vehicle status. Check first. It varies state to state.

    • Unfortunately with 4 wheels it is now officially a car and therefore must conform to DOT standards and can no longer be registered as a motorcycle. Air bags, seat-belts, crash ratings and all other automobile restrictions are now enforced.
      It’s a neat mod but trouble in the legal department

  4. “They don’t provide any performance figures so it’s not clear what it will do compared to a stock Slingshot, but I’m guessing it beats it without too much fuss.”
    I have a hard time believing that adding extra weight and extra rolling resistance will improve performance. Fuel efficiency will definitely go down, and in my opinion, so will the performance. Hope to see a proper race between two machines (without any engine mods/upgrades).

    • I ran over a blurb that has a supercharger for the Polaris ” coming soon”, but I don;t remember what company it was……..

      • Seems like the lateral g performance would improve greatly while sacrificing some acceleration.

        • Well when the inside rear wheel is lifted in hard corners I seriously doubt that lateral “g” performance would improve.

  5. I’m not sold – look at that suspension geometry, there is none. Equal length double wishbone means that there will be no negative camber gain in roll, which means that, as the Slingshot rolls towards the outside while you’re cornering, the inside tires angle up onto their inside edge and the outside tires angle up onto their outside edge, significantly reducing your contact patch in an extremely quick amount of time. I bet it has some pretty wicked snap oversteer due to this.
    They could’ve at least just copied the front geometry, but then they would have to calculate CV shaft plunge, and they were likely too lazy to properly account for this(independent suspension geometry of driven or steered wheels is VERY complex, a LOOOOT of variables to account for). To be fair, they probably went into this knowing that 99% of their customers will be the show n’ shine mall crawler crowd, while the track hounds will be rare. Still, it’s unfortunate to see such a great concept in half baked execution.

    • Keep in mind that the stock/single rear tire setup has no camber change, either – this setup at least doubles the amount of tire edges on the road. And with the fairly high roll center at the rear, I’m guessing the back end depends even more on having a lot of front bar to keep the rear tires planted – and since the stock 3 wheeled setup requires all of the roll behavior determined by the front end anyway, well, there’s the reason why it’s that way, or at least why they can get away with it.

      If maximum performance for this platform mattered, it would have been front wheel drive, along with a lot of other differences. I get the impression that it was designed just to be fun, (I.e., a 3 wheeled motorcycle) anyway.

  6. eh there guys how are ya doin? i bought my 2015 slingshot its awesome i was in a bike collision 2005 when i was on my GSXR 600 had to right that bike off but eh I’m still kicking right any ways guys becouse of that half my head works and my right hand is metal and my right leg had eh poll from my knee to my foot hahaha any who I’ve been looking into making my slingshot eh 4 wheeler can you guys help me out any thanks guys eh

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