Home » Gear » Frames » Mountain » Pronghorn PR6-SW (2010)

Pronghorn PR6-SW (2010)
Speed and endurance in a blistering light-weight package
40
Price: £2300
Unapologetically fast and uncompromising.
It's unapologetically fast and uncompromising!
Contact: Surf Sales
Tel: (01303) 850553
www.pronghornracing.com

Words and Photos by Gary Lake - posted 23/05/2010

Pronghorn Racing is a Danish company specialising in high-end, (mostly) carbon MTBs. Named after a lesser know member of the Antelope family, Pronghorns can outrun a Cheetah, yet show incredible endurance. That's quite a name to live up to as we take a look at the PR6-SW, the carbon full-suspension xc/race bike in the Pronghorn line-up.

Handbuilt in Denmark, the carbon construction utilises Pronghorn's patented Smooth Wall Construction. A latex rather than plastic mold is used and ensures a smoother inside to the frame's surface - something that Pronghorn claims to offer more strength, less risk of internal stress points and an overall lighter construction. Pronghorn offers a 99 year warranty on their frames!

The PR6-SW offers up 100mm of rear travel via what it calls its Anti Power Loss System (APLS) - basically it's a good old fashioned Horst Link arrangement, only the rocker and shock work above the top tube rather than down inside the main triangle. Pronghorn claim that by mounting and driving the shock in this way, all forces through the shock are driven horizontally and this is supposed to eliminate pedal-bob.

overall it was surprisingly pretty in the end, in a kind of purposeful and carbon smut-fest kind of way...

Continuing around the frame, it is a slightly awkward looking machine. Some of the tube profiles look quite nice but with the top tube dipping sharply to accommodate the shock, and the rather brutish arrangement around the rear dropouts, it just looks a bit funny whichever angle you look at it. Internal cable routing goes someway to tidying things up and the DT Swiss XR rear shock minimises the visual impact of its placement. That said, our bike came built with a smattering of carbon including the sublime DT Swiss XMC 100 fork. Overall it was surprisingly pretty in the end, in a kind of purposeful and carbon smut-fest kind of way anyway.

Chain stays are asymmetric and bridged for stiffness, the seat stays are also bridged to the chain stays to further beef things up at the back. The seat stays connect to a carbon rocker link which bridges either side of the seat tube and pivots on the top tube. Construction isn't completely carbon though, the chain stays are alloy, presumably a decision made as a nod towards durability. There's not a whole lot of tyre clearance in there though and the fitted 2.1 Schwalbe Nobby Nics were about the limit. However, with the PR6-SWs racing intentions, most eventual owners will be thinking skinny and light anyway.

gents, you're not in anyway going to get your knackers caught in the shock/linkage arrangement...

Final features of note are a semi-integrated seat mast and a single set of bottle cage bosses - perhaps a minor faux pas but it's possible that there simply wasn't room for a second set. The PR6-SW is finished in a clear coat revealing the rather tasty carbon weave below. Those decals are actually the tube dimensions, a unique idea for sure but it at least looks smart!

Oh, and let's dispel the one thing that nearly everyone says upon seeing the Pronghorn - gents, you're not in anyway going to get your knackers caught in the shock/linkage arrangement - end of!

Pronghorn claim a weight of 3.7lbs including the shock for a 16" frame - that's pretty much up there with the very lightest on the market and the £2300 price tag for the frame puts it right in there alongside class leaders such as the Specialized S-Works Epic and the Santa Cruz Blur XC carbon to name a few. Our build was a little more practical and everyday coming in at 23lbs - Pronghorn claims their racier off the peg builds are around 21lb - featuring flat carbon bar, Rocket Ron tyres, carbon seatpost and a Sella Italia SLR saddle. So, the PR6-SW adds up on paper then but how does it ride?

you're all but guaranteed to be leading the pack up the first climb...

As mentioned our build was a little more everyday - we had a decent width riser (Pronghorn's own carbon number), Nobby Nic tyres and a more all-day friendly saddle and beefier seatpost. That said, despite being a little more user friendly, the Pronghorn was still unapologetically fast and racy.

With a 71 degree head angle and 73 degree seat angle the geometry was a little old school with only the addition of the riser bar and slight rise in the stem preventing it from feeling completely head-down arse-up. It's worth noting that the PR6-SW is warranted for 120mm forks which should bring the head angle up to a more trail friendly 70 degrees, and with 120mm Rock Shox Sids on the way in 2011, that's a very interesting prospect!

It's worth noting that the PR6-SW is a pretty compact bike. We had the 20.5" frame on test and riders from about 5'8" up were perfectly happy on this largest size - in fact it's hard to imagine anyone above 6'0" getting on with this largest size unless you like a smaller sized bike. Female riders however might well find the Pronghorn a great fit as it's proportions seem to have more in common with many women specific designs! The 16" is positively tiny in the top tube!

Bursting out of the car park you're all but guaranteed to be leading the pack up the first climb, whether it's fireroad or techy singletrack, you'll be motoring. The APLS rear arrangement works pretty well and while you'll see the shock bobbing around between your legs a little, you certainly don't feel it. Claims of it climbing like a hardtail are a little far fetched on any full suspension bike, but that's not a bad thing - it actually climbs better than a hardtail on everything except maybe a smooth fireroad climb. It doesn't totally lockout under pedaling and it gives when you need it, but otherwise you just knuckle down and get on with thrashing your mates to the top. Even if you're not that fit, you'll find yourself cruising in the middle and big rings a lot more than usual, it really rewards you for just getting on with it and turning the cranks over quickly.

It's not all roses though; on really techincal and loose sections it does tend to spit out a little, especially if you're tired later in the day and resort to crank mashing rather than maintaining a highspeed cadence. And even worse, on those long all day epics when you can't help but reach for the granny ring, the PR6-SW exhibits some disturbing amounts of pedal feedback. It's possible that some tweaking of the shock pressures could help here but the Pronghorn felt spot on in every other way. We'd be reluctant to tweak any further and just try and stay out of the granny ring.

a direct but light touch and caffeine fuelled reactions are what's needed...

When it comes to singletrack, you definitely need to be on the ball with the Pronghorn. It's devastatingly quick and razor sharp, it doesn't really leave you anything in reserve. A direct but light touch and caffeine fuelled reactions are what's needed. But if you commit to it, you'll be showing everyone a clean set of heels as you whip between the trees in a speeder bike like frenzy. It really comes together if you pick your line right first time, it'll just carve round corners perfectly. Get all twitchy and keep making adjustments and you'll be heading for the outside of the bend, scrubbing speed and panic braking.

It's taut under pedaling though, letting you really crank the power down. And the back end is just about stiff enough to cope with serious big ring abuse. Stand on the cranks and pump it through sections and it carries speed well, the rear suspension feeling more open and supple. The 100mm of travel feeling just about enough - not too little, not too much - as is the way with the Pronghorn.

you'll be whipping down the trails at speed...

Point it downhill and the story is much the same. It shouldn't descend that well looking at it on paper but it can make very rapid progress downhill in the right hands. Once again, get your line right first time and you'll be whipping down the trails at speed, and much to the disbelief of your more overbiked riding buddies. Get it wrong, ride nervously or passively, and it's going to be a slow and long skid-fest to the bottom. The wheel base is pretty short even in the largest size so it feels nippy and flickable at slow speeds - it just needs a little care and confidence in rougher high speed sections.

A particular test ride took us on some of the mini downhill runs in the Mendips, ok it's not going to do road gaps or clear big doubles, but taking the occasional chicken run in order to preserve bike and rider, it was mighty quick to the bottom each time, just a little white knuckle is all!

Living with the Pronghorn was on the whole very easy. The suspension layout isn't overly complicated so maintenance and cleaning isn't too difficult. We did get some creaking around the main pivot bearings in the very dusty, dry conditions we had - this was solved trail-side with a drop of dry lube. Perhaps a little less easy to live with is the cost of maintaining the pivots. The bearing kits alone are priced (sorry for Euro pricing) at €40, but a full Pivot replacement kit is €135! Let's hope they last at least a few seasons!

Also, while we dispelled the belief that the shock is going to castrate the gents among us at the first opportunity - the shock placement is a touch frustrating when it comes to baggy shorts of a certain length. Not everyone was affected but there was a tendancy for the various nipples and the schrader valve on the shock to catch and snag on the bottom of your shorts. One test rider in our group did scoff that it's hardly a baggy shorts kind of bike, and he might be right. We weren't going to start any fashion trends with our baggys turned up at the bottom anyway!

a real euro feel to the bike...

Our PR6-SW wasn't too dissimilar in spec to the off the peg offering. DT Swiss provides the fork and shock, the XMC 100 fork was a touch flexy in the tips and might have contributed to the 'get your line right first time or else' characteristic of the bike. But they're so buttery smooth, beautiful to look at and wonderfully light you tend to forgive them this. We regularly found the O-ring butted up against the crown on our little DH runs but we never noticed the fact we'd bottomed out and in normal XC riding conditions they feel wonderful. You could find a stiffer fork but you're only going to add weight in the process.

The DT Swiss XR shock doesn't feel quite as supple as a Fox unit but it's very light and contributes to the taut pedaling nature of the Pronghorn, which let's face it is more concerned about getting from A-B as quickly as possible, not giving a magic carpet ride.

DT Swiss also provide the wheels to complete a real euro feel to the bike - the XR1450 wheels are great value and at 1450 grams are only smuggling 100 grams over the rather more exotically priced carbon XRC1350s DT Swiss also offer. They seem tough enough as well, staying true despite our enthusiastic efforts to make them otherwise. Full builds will get Rocket Rons but the Nobby Nics our test bike came with are probably a more useful and still very light choice.

Our bike had a full SRAM X.0 gearset, Truvativ Noir cranks and Avid Elixir CR brakes, off the peg builds will get full XTR. Coming back to the Pronghorn's granny ring performance, we can't help but feel the PR6-SW is crying out for a 2x10 groupset. Even when we felt like we needed the granny ring, it was actually easier to keep turning the middle ring than try and battle the energy sapping tug on the chain when riding the granny.

In terms of finishing kit, off the peg bikes would get Pronghorn produced carbon bar (flat or riser), stem and seatpost - it's lovely stuff and makes for a very complete and integrated looking bike.

stick you on the podium with ruthless efficiency...

The Pronghorn is unapologetically fast, focused, light and uncompromising. Depending on your skill level the PR6-SW is either going to be a long, nervous day in the saddle, or it's going to stick you on the podium with ruthless efficiency. The fact that you can safely dumb it down slightly with 120mm forks does open up the Pronghorn to a wider range of riders. But in all honesty, we loved it the way it was! The high-maintenance personality, its constant demands for your full attention, and how rewarding it is to ride when you get things right really puts the buzz back into mountain biking!

Do you know what, the look of the Pronghorn even grew on us in the end!

Verdict

White knuckle racer, uncompromising performance for uncompromising riders, 120mm fork potential could open the speed up to everyone.

Specification

Sizes	16", 18" 20.5"
Colours	Black
Tubeset	Carbon
Weight	3.7lbs (16" manufacturers claim)

Geometry

Frame Size	16"	18"	20.5"
Head Angle	71°	71°	71°
Seat Angle	73°	73°	73°
Top Tube Effective	558	580	603
Bottom Bracket Height	330	330	330
Chainstay	425	425	425
Head Tube	110	110	110
Wheelbase	1042	1064	1087
Manufacturers Figures (measured static)