Today the folks at Cotic Bikes have a new build option on offer, but it’s not merely a swap of component brands or spec. They will now offer mixed-wheel builds on their three full-suspension bikes that originally all used 29″ wheels: the RocketMAX, Jeht, and FlareMAX. The brand does have another full squish frame, but since it rolls on a pair of 27.5″ tires they won’t be making changes there.
In terms of advantages, Cotic says that the smaller rear wheel offers better butt-clearance while descending and makes the bike feel a little more maneuverable overall. In terms of rectifying the frames’ geometry, they mentioned that “when you fit a smaller rear wheel to a 29er bike, the BB drops about 10mm, and the head angle slackens nearly one degree. By installing the angleset to steepen the head angle again, this also acts to lift the BB up.” So the frame remains the same, and can easily be swapped back to a balanced 29er by swapping the rear wheel and inserting a standard headset.
The brand also said that they will install the angleset in frames for DIY builds, and some of their older designs will work with mixed wheels — though they ask that owners email them for details.
Check the Cotic Bikes page for specific details on mixed-wheel geometry, as the numbers do shift slightly despite the angleset.