Market / Spectrum / Test: Second part of our big mountain bike construction story - after we dealt with the concept of the bike, the frame and the drive in the first part, today the suspension fork, wheels and brakes follow.
Product news: We build a bike #1 - an all-round mountain bike that you can build yourself
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 […]
The suspension fork: Rock Shox Pike DPA RCT3
The importance of the suspension fork to the overall performance of a mountain bike can't be overstated - even more so on a bike like the Dartmoor Primal we're putting together. Due to the lack of suspension in the rear triangle, you are all the more dependent on a powerful fork at the front. According to Dartmoor, the geometry of our frame is designed for forks in the range of 130 to 160mm - depending on the length installed, the geometry of the bike then changes slightly. More spring travel means more installation height, which in turn results in a slacker head and seat angle. To put it simply: the longer the fork, the more descent-oriented the bike.
Our choice fell on one of the really big hits in the MTB sector in recent years: the Rock Shox Pike. With the powerful Charger damping, a sensitive response and a good balance between weight and stability, it is not too surprising that the Pike has been THE suspension fork par excellence in the trail/all-mountain/enduro sector since its rebirth a few years ago.
But Pike is not always Pike - as usual from Rock Shox, there are different versions of damping and spring travel. We opted for the DPA RCT3 variant, where DPA stands for Dual Position Air and describes the suspension and RCT3 is the designation for the built-in damping. The DPA air spring can be lowered by 30mm to the fork crown with a quick movement of the hand - the spring travel can be adjusted from 160 to 130mm - perfect for our setup! The RCT3 damping is the most advanced of the Charger dampers currently available and offers the driver a wealth of adjustment options. In addition to an open and closed setting and an adjuster for the rebound - this is what the RCT3 has in common with the simpler RC version - you can also use platform damping and also adjust the low-speed compression to your own needs. Experienced trail pilots who already have basic knowledge of the suspension setup or who are not afraid to deal with it, the RCT3 damping offers real added value.
The wheels: Crankbrothers Iodine 2
Opinions have always been divided on wheels from US manufacturers: some dismiss them as "ice cream parlor parts", while others appreciate the smart technical solutions and the unmistakable look. We would count ourselves in the latter group and chose the all-mountain set Iodine 2 for our setup. The bare data is easy to read - but it doesn't set the wheels apart from the competition: 23mm inner width at the rims and a total weight of 1845g.
But even the eye-catching look reveals: The Crankbrothers Iodine 2 are anything but ordinary. 24 spokes front and rear, arranged in the Crankbrothers-typical twinpair-spoke technology: The spokes are arranged in two pairs in parallel and are attached to the rim. With this construction, there is no need for holes for spoke nipples. This not only makes the rim stiffer, but also simplifies tubeless mounting of the tires considerably.
The hubs are also made in-house: conversion options to quick releases, 15mm and 20mm thru axles on the front and 142×12 on the rear wheel make the wheelset flexible to use. When it comes to freewheeling, you rely on proven technology with pawls and 21 locking points - that doesn't seem like much to us; the space could be a bit big. The test will show whether this is noticeable in practice. However, one thing is already clear after the dry test: the rear hub has a crisp sound.
The brakes: Shimano XT BR-8000
We rely on Shimano for the brakes and for the drive - components from the XT group are also used here. The M8000 brakes are the successors of the very popular and successful M785 - with a significantly slimmer encoder unit, from which the unloved chrome finish of the previous model was banned and instead comes in plain anthracite.
The technical features remain largely unchanged: servo wave in the lever for a small lever travel and strong braking power, simple venting via a funnel and ceramic pistons in the brake caliper for greater resistance to fading.
We combine the brakes with IceTec pads and brake discs - IceTec is Shimano's name for those products that are intended to ensure better heat dissipation in the braking area. The pads are equipped with small cooling fins on the top and the discs have an aluminum core between a hard outer layer of steel, which is supposed to distribute the heat quickly over the entire surface. In terms of size, we opted for 203mm on the front wheel and 180mm on the rear wheel - we now appreciate the advantages of a large disc on the front wheel, especially on longer descents. We are happy to accept the few grams of extra weight.
Website
www.shimano.com
www.paul-lange.de
www.crankbrothers.com
www.sram.com/rockshox
Paschal says
According to the manufacturer, the frame of the Primal 27,5 has an installation dimension of 135 × 10 mm on the HR. I ask about the Crankbrothers wheels with the 142×12 mm hub. Greetings Pasquale
Michael Faiss says
The Crankbrothers hubs in the wheelset used can be easily converted to quick releases with the appropriate conversion kits and thus also fit easily into the rear triangle of the Primal.
Peter says
The project sounds exciting, but how did the construction proceed?
Is there a #3 ?
I would be interested in the following:
Could the frame also be ridden with 26″ wheels and fork?
(these would certainly still be available with many self-builders)
Which handlebars, which stem length, which headset?
how hard is it ?
How is it driving?
Isn't the drive with 1×11 geared too short?
Can the frame also be used with a 2×11 front derailleur?
Is there an overall assessment of the structure with your parts?
Also toying with the idea of building a bike with this frame.
Best regards
Peter