Following on from the previous part where I talked about tyres, this chapter covers the wheel components. I normally choose the rims and hubs first so I can measure them to then be able to order the correct length of spokes. The intent of this build is a 1,800g dynamo hub disc wheelset which is tubeless compatible and with a wide profile to better support the tyres I want to run.
RimsThe rims had to serve several criteria, they needed to be tubeless compatible, lighter than what I used before on Phil and preferably meant for disc brakes (no brake track). The rims I considered were Stans Crest, Velocity Ailerons and DT Swiss RR411. However each of these had a compromise, the Stans Crest had a reputation for being light but a bit too fragile, the ailerons were a bit too heavy and the DT Swiss were a little too narrow at 19mm internally.
Eventually I stumbled upon a brand I never heard of before at a German bike shop website. BOR Germany is a wheel/rim manufacturer not well known outside of continental Europe but used often by pro racers. They are not cheap however they are very light and they have lots of great features such as eyelets, tubeless compatibility and asymmetric spoke holes.
Eyelets are seldom seen on many modern racing rims but they help distribute the load from the spoke nipple which prevents cracking, the asymmetric holes help build a stronger wheel by creating a more evenly dished wheel. I went with the XMD-366 29er model which is meant for XC riding. At 380g they are on par with the Stans Crest and about 100g lighter than the H Plus Son Archetypes I used before! The width is 21mm internally which should give a more supportive base for wider tyres.
They are quite pricey at 99€ per rim however I managed to find them for 70€ each, although with the plunging value of the £ this is still expensive. Nonetheless despite the seller sending me one wrong rim, I got a pair of them eventually. They came in at exactly 380g which is extremely light and comparable with carbon fibre rims!
The construction is beautiful, very nicely finished with a subtle laser etched logo on them. The valve hole somewhat misleadingly says Max pressure 3.0bar despite their website saying it could handle about 5.0bar (~80psi). I emailed BOR about this and they confirmed that the 3.0bar warning only applies to very wide tyres and that 5.0bar was fine for narrower tyres. Surprisingly the rims are not welded at the joint but instead are pinned/sleeved, however the joint appears to be of very high quality as I could barely see it compared to other pinned/sleeved rims I've seen before. Typically a lot of manufacturers use welding at the joint of the rim as it creates a seamless appearance, this is also usually used on more high end rims as well. However what I've read is that in practice it makes no difference.
They came more or less bang on 380g for both rims, again the quality of these rims is fantastic... I guess you get what you pay for.
The hub choice came down to several factors. As the frame utilises a 15 x 100mm thru axle on the front and a 12 x 142mm thru axle on the rear (standard on better MTB's). Both hubs would need to be compatible with this. The hubs also needed to have mounts for disc brakes and the rear hub would need to be 11-speed road compatible. Lastly the front hub would have to be a dynamo hub.
The front hub was a relatively easy choice as there are only really two dynamo hubs on the market that are compatible with a 15mm thru axle, there is the SON 28 15 disc and the SP Dynamo PD8X. The SON model, as with all their hubs is very expensive at about 270€, the SP Dynamo is about €120 or so... less than half the price but still quite expensive.
Funnily enough the SON dynamo is not only twice the price but also weighs 40g more. The SP-PD8X Dynamo hub came in at a light 423g and also comes with a 9mm quick release adaptor axle.
Next part I'll cover the wheelbuild itself when I put these bits together with some spokes, thanks for reading!