Some might ask why I would even care what the Polaris Slingshot drives like from the point of view that it is unlikely to ever be sold in Australia and it's a production vehicle not a kit like the Tri Pod 1 I have designed and put into limited production. Curiosity is perhaps one of the main reasons I wanted to drive it on a recent trip to the USA, but also because I up until trying the Slingshot out I had only ever driven three wheelers of my own design. Well actually that's not quite true as I have had a few goes on Can Am Spyders but they are an all together different animal having handlebars and saddle seating rather than a 'chair'. The curiosity aspect is about how they have handled various aspects of three wheeled design and have they found a magical recipe as outwardly they have perhaps not fully taken advantage of some of the reverse trikes advantages such as a simple driveline and potentially very light weight. Advantages that when exploited also help to balance some of the deficits of a three versus four wheeled layout.
Before I ramble on too much about my thoughts on Polaris's effort to make a 'fun' driving machine (according to Polaris you actually ride it rather than drive it, but this would be more about the necessity of registering this three wheeled car as a bike to avoid a barrage of testing etc. More power to them in an effort to avoid over the top safety regulation) I will layout my thoughts and therefore my criteria on what fun actually is when driving. There is a chance that my idea of fun while driving is not yours so here goes.
I am looking for more than a show off appearance or unusual nature of the vehicle I am operating (ie. Latest Lambo or rusty VW Combi). I am after raw driving appeal. A seat of the pants positive vibe where all sorts of information comes to me through the wheel and the chassis and allows me to place the car precisely on the road at just the right speed for any given steering angle giving me a certain 'buzz' from dabbling with the limits of adhesion or at a more leisurely pace just reveling in the car feeling alive and accurately responding to my inputs at the tiller, brake, throttle, gear lever, and clutch. What the vehicle may look like to other road users or in fact how fast I am travelling are secondary to this potential driving pleasure. On the road, driving pleasure these days simply cannot be about the adrenalin generated through outright speed and risk. This desire for driving gratification at sensibly legal speeds is a big part of what my design philosophy behind the Tri Pod 1 is. Enough power to provide an enjoyable thrust and require a delicate touch at the throttle to avoid sloppy wheelspin. A low, open air experience not dissimilar to a Go Kart on the road with a tonne of feedback from the chassis. An engine noise, a layout and a set of closely stacked gear ratios that makes you think you are steering a high performance racing car. Responsive handling as closely replicating the "think me through a corner" performance of an open wheeled racing car. These were the thoughts and the objectives I had when I set about drawing up the original Tri Pod. These are the aspects of driving I enjoy. These are the things I looked for when driving the Slingshot over 5 hours recently in and around Phoenix in Arizona, USA.
Polaris have made a few claims for the Slingshot. Low height, light weight, huge fun in corners. Car and Driver magazine in an online review stated the following - "Forget what’s going on behind the seats and it’s easy to pretend that you’re piloting your own open-wheel Formula car since the Slingshot is so low, elemental, and raw". Owners on the Slingshot forum seem to be pleased with their fun car (bike) even though they have suffered a re call and a small handful of 'known issues' that need fixing in many cases all in the first 6 months of the vehicle being available for sale. Anyone can as I did look at the actual facts and make up their own mind about how accurate these claims for automotive nirvana might be. Facts such as you sit in it on a normal looking seat and the vehicle has a ride height the same as any other lowish sedan so why the claim for it being so low. My best guess is that you sit somewhat higher in it than say a Lotus Elise or Mazda Miata/MX5, let alone a Clubman style sports car. Facts such as the weight is actually more than any clubman and 250kg heavier than a Morgan three wheeler. Facts such as 'electrically assisted steering'...? Not sure any real sports car needed or was improved by that technology. Facts such as the engines model name is Ecotec, not Speedtec, Racetec, Funtec or any other name that might imply fun or performance. As for Car and Drivers quote re Formula car likeness....? It was as much because of the obvious jibes one can make about the Slingshot versus its marketed pretensions as a drivers car that I needed to drive it.
It took me three cracks even to see a Slingshot in the flesh (2 visits to dealers and one to a rental bike company) as they sell easily and also rent regularly it seems. First time I saw it before me I was slightly taken a back by the scale of the machine. The professionally drawn angles that look fine in a photo now took on a slightly jarring appearance. The height is striking as well. This is a big car! No fake test drive was in the offing so I chased down another rental mob (the first was in San Diego and the Slingshot was booked ahead for a while), which in this case was in Phoenix which would not be too far out of our way later in the trip so a booking was made.
The big day came and we appeared at the rental company (Street Eagle in Scottsdale, great bunch of people) filled in the paperwork, swiped my card and drove off in Polaris's idea of three wheeled heaven and only my second experience of what 'driving' on three wheels can be like. Lets cover the positives first. Storage areas behind both seats are easy to get to and quite cavernous. Probably fairly watertight as well! There was also a very roomy glove box in the traditional location as well. I also was impressed with the adjust ability between steering, seat and pedals. As much as the driving position is no different or any lower or more sporting than driving most sedans it was at least as adjustable as most sedans.
While we are on the steering wheel and its position it really does look like and feel as if its off a lawn mower or maybe a basic runabout speed boat. ie water proof, cheapish and skinny rimmed. In general though the steering is what you would expect. Unlike some reviews I have read I thought it steered a pretty straight line up the freeway although this example had the updated steering rack so maybe there is something in that. Turn in to corners is quite good as well (perhaps not as exciting as Car and Driver suggested but adequate). Grip is quite good and there was certainly no terminal understeer and when pushed to the limits of adhesion there was a similarity to what the Tri Pod does. What was different was the complete lack of any information coming at me via the electrically assisted 3.5 turns lock to lock rack. You just apply force to the wheel and make guess's about whats going on based on whether the car is out of shape or not. The enjoyment factor I mentioned earlier is simply not there as instead there is just a rubbery numbness. A functional, professional design that works - yes! Fun factor? Zero.
The chassis set up and the way it feels is similar to the steering. Yes it turns in largely as you would expect, yes it grips agreeably, yes the rear end moves out quite controllably (assuming the traction control is switched off and excessive power is applied) but then it gets all a bit messy and wasn't even that much fun before things got ugly. The lack of any real communication from the chassis to your backside via the loosely constructed seat (slideable base and reclineable back) that is rubbery and not at all grippy (due to slippery waterproof finish mostly I suppose) combined with the slow steering rack means it's a hamfisted affair to balance the rear end slip and one that again offers no real fun. Sure with practice one could lay long stripes up the road with the Grand Ma steering all crossed up but would it be fun? For me, no!
Brakes? Spongy, long travel and innefective. I'm not sure if they are boosted but they certainly feel like it. Maybe the example I drove needed a good bleed or perhaps more likely the flexiable hoses need changing to premium braided numbers (I am assuming they are rubber, certainly the brakes 'feel' rubbery). Some on the Slingshot forum suggest different pads improves the brakes. I'm not sure why Polaris didn't get this fairly simple task right first time.
While you drive onto the next corner one wonders about the suspension set up and why so many modern ordinary cars have that weird rubbery jiggliness that to me seems like a combination of an overweight chassis, high spring rates to control its movement combined with cheapy shock absorbers that don't quite offer the right damping. Maybe all that combined with unnecessarily low profile tyres? Unfortunately the Slingshot has this feel as well...not diabolical but its there. One also has time to wonder about why we are sitting so high up. There is nothing low or sporty feeling about the driving position at all. Why also is there a radio. It sounds like actual crap and is just one more thing the weather is going to kill sooner rather than later. Oh and while I'm on a roll, the windscreen for anyone slightly shorter than myself is going to be a real pest too as you will both look through and over it at the same time creating a nasty 'step' in your vision due to the optics of the polycarbonate. From what I could tell it is not adjustable. On a positive note though the screen stops the cockpit from being overly turbulent and even on this fairly warm day in Phoenix for the time of year (91 F) I felt the heat from the front mounted engine wasn't too bad and found the whole thing quite comfortable temperature wise. The wind and engine noise is a whole different story though and I will come to that shortly.
First lets talk about the other noise. There is a lot of talk on the forum about the final drive and how the whine from it is a bit loud and annoying. Some have not gone ahead and bought the vehicle because of this once they have had a quick test drive. The 5000 mile example I hired certainly had a driveline noise and it wasn't quiet but maybe compared to the other racket going on it wasn't too bad. To me it sounds like a straight cut gearbox whine. Most say its down to the rubber drive belt in the final drive. Whatever the cause maybe it settles down a bit after quite a few miles. Its worst when on a balanced throttle setting such as down hill when it whines away with just a whiff of throttle. When under even a small load it goes away. Moving on to the real noise issue though...
If you read between the lines of the Car and Driver online review the real noise issue is mentioned but unless you are familiar with the sound of "mixing cake batter with a Bell Huey II helicopter" which I am not (well maybe now I am) one cannot be sure what they are driving at with that description. Okay so this hasn't been the most positive review so far of this new wonder trike but what would you prefer I do? Make it all up? Write the same marketing tainted crap that most reviews out there consist of (in fact most just regurgitate the press release from Polaris) or tell it the way it is or at least the way I found it. Yes it could be suggested that this whole review is biased based on my involvement with the three wheel car industry but hang on I make a kit. not a production car and in such small volumes as to have no relevance versus Polaris's might. So here goes... The sound of the engine in the Slingshot can only be described as sounding exactly like flogging the crap out of an old Toyota Hilux 2WD utility. Its got the same course, nasty, seemingly gutless sound that an old rusty shitbox ute has. In fact coupled with the inert high ratio steering and general lack of any feel through the seat of the pants the whole driving experience is a dead ringer. This came as a great shock to me and caused bizarre high volume laughter as a I realised where I had heard this noise and experienced this handling quality before. If it wasn't for the fact that if you put up with the hideous racket long enough the thing eventually drags itself up to a speed slightly beyond that of your average trayback you could be forgiven for thinking you were taking a load of palm fronds and broken masonry to the local dump. Too harsh? Drive it and you will know what I mean. No four cylinder high revving whine like a great Japanese superbike engine, no rorty V twin noise caused by an open pipe no this thing just sounds dreadful. It feels oddly gutless too at anything under 4000rpm. When I say gutless I mean lethargic to rev and maybe this feeling is made worse by the noise versus acceleration ratio 'cos its incredibly loud as well as nasty. Also making this whole excersise worse is the incredibly heavy and short throw throttle pedal. Couple this with Camry style wide ratios in a gearbox operated by a not altogether pleasant H pattern and this is the least fun I've had in a car for a while.
Zooming along the open road and the chorus of hoarseness from the front and the whine from the rear mixed with wind noise and this is strictly a ear plug vehicle for anything more than a trip to the boozer for a six pack. If wearing a helmet as many states require (states in USA) you won't need plugs so badly I suppose.
Back to some positives for a second. This is quite a well screwed together unit and Polaris have obviously put in a huge effort to bring such a complete design to market quickly and for the most part reliably. Their design goals were obviously thoroughly middle of the road and 'safe'. By safe I mean not offering a diminished feature set that would stop some folks slapping down the cash. Examples being a radio with Bluetooth capability (couldn't live without that for a second!), ergonomics and a size that can obviously fit all comers, and styling set to attract lovers of Hollywood rather than fans of Bertone or Pininfarina. Part of this mainstreaming is responsible too I suppose for the numbness of the chassis as is a certain amount of cost cutting on componentry to get the retail price to the incredibly sharp sub USD$20k. Choosing the hoarse sounding engine they used rather than something more musical no doubt also a cost cutting measure.
To sum up though, I say well done to Polaris for building a high volume sales production three wheeler and a professional looking effort it is too. For me though as a machine for driving pleasure it is a long way away from being the hoot that it could potentially have been. Sensible and reliable (as far as any trike can be) yes it is. Huge fun and a design likely to ultimately be as highly regarded for handling quality as a MX5/Miata, Lotus Elise, Renault Clio or Clubman style sports car, ergh no chance.
The passengers thoughts...
Sharron my other (and superior) half 'rode' with me on this test and as a regular in the passenger seat of the Tri Pod prototype was as interested as I was to the differences. Her immediate thoughts were where do I put my right arm and damn this seats incredibly hot! The Slingshot had been relaxing in the Phoenix sun for sometime before we jumped in and if you had shorts or a skirt on (I don't wear skirts much these days so I didn't notice) the skin removing temp of the mostly black in colour, vinyl (or similar) seats is an issue you probably need to plan ahead for. Not sure where to place her arm she started off hanging onto the grab rail but its not in the right spot for everyone. This meant that driving around left handers at some speed to her felt like a recipe for falling out. This maybe unlikely but that is how she felt and she was no fan of seeing the road almost directly under her bluring past at 75MPH either. Perhaps her biggest compaint (I'll get to the positive in a minute) though was that at her height she was looking straight through the top of the screen and the optical issues that created for her (no doubt peoples annoyance at this will vary) ultimately (in combination with the harsh noisy environment) lead to a headache (which I ignored and kept on driving...). She liked the storage, liked the very useful glove compartment, liked getting out in the open air, but found the seat hot as mentioned and not supportive or particularly comfortable. She also commented that heat soak was an issue on her side, which makes sense I suppose with the exhaust being over there but it took an hour or so for the 'soak' to really heat up so short drives and winter won't be a problem. She didn't mind the look but thought it somewhat huge and high. Overall as a fan of open topped cars and motoring she scored it lower though because of comfort and noise issues and most particularly because of the screen ruining the view out the front. I think I enjoyed it more than she...
Does seat height matter?
Seat height is important for a few reasons but even more so in a three wheeler!
I was reminded while riding on a bus recently (that was seemingly being driven quite fast) why seat height is important in any car. Comfort as much as anything else. The further you get above the roll axis of any vehicle the further you are thrown from side to side and the greater that acceleration will be as well. The fact is the bus I was on was not being driven that quickly at all but sitting up as high as you do in a bus above what I guess might be the roll axis the roll is exagerated and the comfort reduced. I think without resorting to heavy maths that it is reasonably obvious that the perception of a roll free chassis and in turn the ability to control the car in question easily is more likely the closer you are sat to the axis with which the car rolls through. In most four wheeled sports style cars this axis is (subject to suspension design) probably 300mm to 500 mm off the road. In turn the height of the base of the drivers seat is somewhere in that range as well, most likely lower. I'm sure this helps make you as the driver feel more like part of the car and in turn gives you a more connected feel to the chassis.
The problem then with three wheelers and seat height and why I crap on about it to every builder that has thoughts of fitting higher car style seats for whatever seemingly practical reason is that three wheelers do NOT have a roll axis at some height above the ground. They by the very nature of only having one wheel at one end must roll through an axis at road level. The axis at the single wheel end (the rear in this discussion) will run through the centre of the rear tyres contact patch forward to a point most likely near the ground, and on any trike designed for benign break away at the limit of adhesion it will be on the ground based on the geometry of the front suspension design. Hence the seat in a three wheeler needs to a low as possible to help with the effect of feeling like you are sitting in the car not on it.
Of course the other very important aspect of seat design and a great driving experience is that it needs to be supportive and keep you locked in position. Sliding around and therefore having to hang on to the steering wheel to some degree is a recipe for a dodgy driving experience. Anyone who has ever fitted a race style seat to their car knows only how true this is.
Is traction control really necessary?
When I switched off the TC on the Slingshot I was surprised how little grip there really was in a straight line and how easily the grip of the rear tyre was overcome. There are many issues at hand as to how much grip can be generated by that single rear tyre and in turn how that available grip can be exploited.
The two key things I think that make the available grip more difficult to exploit than what I am used to is perhaps the lack of delicacy of the throttle in the slingshot (as mentioned in the review I found it very heavy and rather short of throw) making it more difficult to just sneak as much power on as the tyre will take and the fact that it weighs nearly double the three wheeler I am used to driving. For instance in regard to weight, sure you can just add twice the power and achieve the same acceleration in a vehicle of twice the weight of another but that assumes that the grip of the driven wheel to the road is infinite. Obviously grip from a rubber tyre is not infinite but to the benefit of the heavier vehicle the higher tyre loading (from the extra weight of the heavier vehicle) will generate quite a bit more grip but is this extra grip enough to offset the extra inertia of the heavier vehicle? I would say not. Another problem with higher vehicle weight is greater tyre wear. I suspect Polaris have used a somewhat harder compound in their tyre (than I generally suggest for the Tri Pod) to keep wear to a sensible limit (seems to be about 3000 miles per tyre on the rental unit I drove). This harder compound probably costs most of the advantage the higher tyre loading gives and makes for a not particularly grippy rear end. The extra torque of the car style, larger capacity engine in the Slingshot also does not help with the ease with which grip is lost in a straight line. The Slingshots rear end seemed to grip pretty well in corners suggesting this is the case.