Marin's Mount Vision has become almost ubiquitous. And deservedly so. Its simple but effective single-pivot suspension design is well-suited to UK XC conditions (unsurprisingly, as Marin designer Jon Whyte is based here) and it was one of the first accessible full-sussers. After the launch of the Whyte PRST-1 with its unusual linkage fork, rumours abounded that Whyte was going to do something similar for the back end. The new Quad design is the result. But is the extra complexity worthwhile? We've been riding the top of the range Mount Vision Pro to find out.

Frame

Now with extra pivots!

At first glance you wouldn't notice that the Vision has an entirely new suspension design. The general profile of the bike is exactly the same as the old one, with the front end being of identical semi-monococque construction and the swingarm almost identical. There's no real reason to change the front end. Those big tubes are formed in two halves then welded along their length to form the frame. The front end of the shock is mounted to another semi-monococque piece that bridges the top and down tubes, while the back end mounts to the swingarm in a familiar fashion.

While the swingarm may look almost the same, it's actually slightly lighter than last year's. Now that it's attached to the frame at two points rather than one it doesn't need to be quite so meaty at the front, so Marin have slimmed it down a bit. Impressively, the whole frame is actually slightly lighter than before, coming it at just under 6lb including the shock.

This is the forward linkage. The other one's the same

But it's between the front and back halves that the real new stuff goes on. Instead of one big pivot the Quad design uses four. You could probably guess that from the name. The design uses two short forged linkages, one under the down tube ahead of the bottom bracket and one on the back of the seat tube above the front mech. Just above the second one is a 'notch' in the back of the seat tube for clearance under full compression.

At this point you may well be rubbing your chin and muttering about loads of pivots and unreliability. Although there are now eight bearings rather than just two, they're the same sort of bearing. So you've got the same loads spread across four times as many bearings so each one doesn't have to do quite as much. With more bearings you've got more potential sources of looseness, and a little bit of slop across more bearings adds up, but these bearings have proven reliable in a single pivot application and we really wouldn't expect any problems here.

Plenty of space for clarts

At the other end of the swingarm are forged dropouts with a replaceable hanger on the drive side (which is quite thin and, erm, bent quite easily. Ahem...) and a disc brake mount of the other. There are no V-brake bosses on the swingarm (although the cheaper East Peak and Rift Zone come with them as standard), trimming a bit more weight.

There's an impressive amount of mud room around the rear tyre. The swingarm doesn't have any bracing between the two sides behind the seat tube (except for the upper linkage) and there's plenty of space either side of the tyre even with proper tyres in (more on that later...).

Cable routing will be familiar to any existing Marin sus bike owners, as will the bottle mount positioning. One's under the downtube (dirty and difficult to access but good for light batteries), the other's on top of the top tube, good for access but not so good for 'nad (or your nearest gender equivalent) clearance.

A quick word on sizing. If you've ridden Marins before you'll know about this, but their sus bikes are quite generously sized. Our test bike was a 19in with a rangy 23.6in effective top tube. You'll want to be at least 6ft to be comfy on this one.

Components

SID World Cup fork

The Quad bikes are designed for fast cross-country riding, and with the MV Pro at the top of the tree it's no surprise to see the pick of top-notch XC gear adorning the frame. Up front we've got RockShox's 80mm travel SID World Cup, complete with carbon fibre crown/steerer and funky remote lockout lever. We're not usually huge fans of suspension lockouts, but we can see the logic on an XC race machine like this. And the SID lever is really neat, featuring a spring and a release button that you press to return immediately to full plushness.

Performing springing duties out back is a Fox Float RL with compression lockout and tricky-to-reach rebound adjuster. It's fine in the workshop, but tweaking it while riding is an acquired skill.

Shimano XTR throughout

Hung off the frame and fork is a complete Shimano XTR groupset. There's been plenty written about this already, but the highlights are the dinky one-piece forged disc brake calipers, all-new bottom bracket/crank design and integrated brake lever/shifter pods that use the brake lever blades moving up and down to change gear. It's all very sleek looking (except the shifters which we haven't quite grown to love the looks of yet).

Wheels use XTR hubs laced to Mavic X317 rims and shod with remarkably light and narrow Kenda Klimax Lite tyres. And Lite they certainly are. Narrow too, with a very shallow tread. If you're thinking they don't quite look like the tool for the job in the UK most of the time, well, you'd probably be right...

Finishing kit features a neat FSA stem (zero rise, naturally) and carbon Esaton bar (flat, naturally). A WTB saddle sat on a USE Alien carbon post on our test bike, but bikes in the shops will have an Easton EC70 carbon post to go with the bars.

Ride

The first thing to say about the ride of the Mount Vision is that it's intended as an out-an-out XC race bike. If you're after an all-day big terrain ride or a big hitter, you're looking in the wrong place. The MV is all about speed...

You only have to get on it to notice that. The long frame and flat stem and bars give the bike a proper old-school XC head-down-and-hammer riding position that's frighteningly effective on climbs and the flat and, er, just frightening on steep, slippy descents. Actually it's fine, you just have to pay more attention than on a shorter, more upright machine. The tyres don't help. While they're very fast rolling on the right surfaces, the right surfaces are hard to come by, particularly in November. We were surprised at how well they coped with the slime, as it turned out, but they wouldn't be our first choice. But again, this is XC race spec. The bike isn't designed as an all-rounder...

Let's talk suspension first. While the design is conceptually similar to Santa Cruz's VPP design in that it hangs a one-piece swingarm off a pair of non-parallel linkages, the design intent is quite different. While the VPP Blur has an axle path describing a kind of S-shape, the Quad is an arc, but not an arc that you could get out of a fixed pivot. As well as modifying the axle path, the Quad design varies the amount of leverage on the shock through its stroke.

One of the things that Whyte's linkage fork does well is take out pattery little bumps. This is thanks to the initially rearward axle path, a trait shared by the Quad design. In the first part of the travel the suspension is pivoting around a point somewhere near the front tyre, with the axle initially moving slightly back and up. This, combined with smaller shock movements for given wheel travel, makes the bike very sensitive on the small stuff. At the other end of the travel the swingarm's pivoting about a point down near the bottom bracket, minimising chain growth (and hence pedal feedback) on the big hits. The other thing it does is develop a fairly steep rising rate towards bottom out.

So what does all this mean in practise? Power delivery is impressive, although you'll experience more rear suspension movement than on a Blur. The rising rate stops things getting out of hand, though. The overall effect is almost the reverse of the old single-pivot Mount Vision. The single-pivot bike had a falling rate suspension and fairly substantial chain tension effects. The significant extension of the suspension under power, and effectively harder springing in the early part of the travel, contributed to a fast feel but hampered plushness. And the falling rate meant a tendency to blow through the travel over the big stuff. The new Quad bike has reduced chain tension effects, although still enough to prevent unpleasant wallowing, while the rising rate tames the worst bob and prevents you running out of travel on the big stuff.

If anything, the progressive nature of the suspension is possibly too much. You have to hit things really quite hard to approach the limits of the suspension. And there's a noticeable threshold between the plush bit at the beginning of the travel and the firm bit at the end, with some hits being too much for one but not enough for the other. The trick seems to be to keep some weight on the saddle even if you're tempted to stand up. If you stand up, there're some mid-sized hits that'll kick the back end, but stay seated and things are handled with more aplomb. On the upside, the lack of chain growth at full travel stops the pedals kicking back over big hits. Again, this is an XC bike. The intention is to take out the stuff that hampers pedalling and have some life-saving travel in reserve when things start getting out of hand. And it does that very well.

That's the thing with the Mount Vision Pro. It's rather more single-minded than the old one. Marin have the TARA range of adjustable travel single-pivot bikes for the big country enduro/light freeride boys, and have exercised their freedom to make the Quad bikes more XC speed oriented. We don't have anything against single-minded bikes as long as they're fit for purpose. And the MV Pro certainly is...

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