Market / Spectrum / Test: A growing number of mountain bikers in particular are deciding to build their own dream bike. Frame, fork, components, wheels - you can choose everything yourself and adjust it to your own preferences. However, this requires a certain know-how and a lot of perseverance in the search for the right components. In our new series of articles we accompany the construction of a complete bike from individual parts.
The first and decisive question before building your own bike must of course be: What do I want? What do I need? In our case, on the one hand we wanted a mountain bike that can be used universally, from a leisurely tour to trail banging, but on the other hand something 'special' that you can't get in every shop - otherwise you could take the trouble with your own assembly also save.
We decided to build a trail hardtail: universally usable with simple technology, inexpensive and robust. For many people, such a hardtail should be exactly what they are looking for: It doesn't climb quite as willingly as comparable XC hardtails that you often see as a complete bike, but it has significantly more reserves in the field. Up until a year or two ago, this type of bike was one of the exotic ones in the MTB sector, but now larger manufacturers such as Specialized, Trek or Ghost have also recognized the advantages of these simple fun machines.
We spent some time looking for a good basis, suitable components, so that in the end we could get a technically and optically well-rounded bike. Over the next few days, we will briefly present the selected components to you in a total of three parts, before presenting the final result. It starts with the frame and the drive.
The frame: Dartmoor Primal 27.5
The Polish bicycle manufacturer Dartmoor will probably only be known to a few people in this country. Founded more than ten years ago in a small town near Warsaw, the roots of the manufacturer lie in the dirt and pump track area. Even if the passion for this niche of MTB sport continues to this day, Dartmoor 2016 serves a much wider range of bikes for different purposes. From Dirt/Street to FourCross to Downhill and Freeride, the Poles now have suitable bikes and frames on offer.
A few years ago, Dartmoor recognized a trend that really only really caught on with the masses of mountain bikes this season. In 2011, the first version of the Dartmoor Hornet was launched - a hardtail for the rough, with flat angles and for long booms. Some time later, the Primal, a slightly more moderate variant, was followed by Dartmoor's interpretation of the trail hardtail that was so popular at the moment. This is exactly the frame we chose for our bike.
The frame is available for 27,5″, 29″ and also for the new 27,5+ standard. We chose the 'classic' 27,5″ size. The frame is made for suspension forks with a spring travel of 130-160mm and largely dispenses with modern, new standards such as PressFit inner alger or the Boost axle standard. It may not quite be able to keep up with the most modern of the moderns, but such a frame is a blessing for many hobbyists: Parts and components can also be taken over from other bikes or the leftover box can be plundered a little.
The geometry of the Dartmoor Primal 27.5 is reminiscent of that of current trail fullies: A moderately slack head angle of 67° (with 140mm travel) meets a steep seat tube angle, short chainstays and a wide reach. This should ensure a lot of safety even on more demanding trails. A nice detail is the ISCG5 mount for chain guides - more and more manufacturers are now doing without it, but depending on the application, installing a fixed chain guide still makes sense.
Geometry Dartmoor Primal 27.5
| Size | S | M | L | XL |
|---|---|---|---|---|
| Seat tube length (mm) | 430 | 457 | 480 | 485 |
| Top tube length (mm) | 581 | 606 | 631 | 656 |
| Head tube length (mm) | 120 | 120 | 120 | 120 |
| Steering angle (°) | 67 | 67 | 67 | 67 |
| Seat angle (°) | 73 | 73 | 73 | 73 |
| Chainstay Length (mm) | 425 | 425 | 425 | 425 |
| Stacks (mm) | 625 | 625 | 625 | 625 |
| Reach (mm) | 390 | 415 | 440 | 465 |
The RRP for the frame is an extremely reasonable €259,90 and it comes in four different colors – our choice fell on the plain, reserved black/grey finish. Incidentally, our scales remain at 2,2kg for size L. So the Primal is not a lightweight, but given the area of use the weight is quite appropriate, after all the frame will have to cope with one or the other fall.
The drive: Shimano XT 8000
In addition to the frame, performance, appearance and driving experience are primarily determined by the drive group used. Here we opted for the proven XT group from Shimano in the current M8000 version. There is currently no other drive group that combines the three important factors of durability, performance and weight as well as the proven XT group - at an extremely attractive price.
For the crank, we chose the variant with just one chain ring - thanks to the 11-speed cassette with up to 46 teeth, the bandwidth is sufficient for most applications even without a front derailleur. The 32 teeth of the chainring are significantly wider than their geared counterparts and thus always keep the chain securely on the ring - even without a chain guide.
At the other end of the chain is an XT cassette with 11-42 teeth - when we built the bike a few weeks ago, that was the variant with the widest range. In the meantime there is also an 11-46 cassette which, in combination with a chainring at the front, almost comes close to the range of conventional 2-speed drives. The hub, which is compatible with conventional freewheels, weighs 447g.
The XT rear derailleur with a medium-length cage ensures crisp shifting operations, which, thanks to the 'Shadow+' damping, reduces chain slap to a minimum and always keeps the chain securely on the ring. It is operated via the XT trigger on the handlebars, which, thanks to the multi-release, allows several switching operations at once in both directions. By the way: It is often assumed that the rear derailleur is crucial for good shifting performance - the shifters play a much more important role here - so keep your eyes open when buying a complete bike.
With that we already have the frame and the drive together - in the next few days the second part of our assembly story will follow, in which we will deal with the suspension fork, brakes and wheels.