Optimised For Inline is our new frame layout which we're introducing on the Soul275. Up until now, we have used our original Ultra Compact Geometry approach for all our hardtail frames. We've spent a lot of time over the years comparing different approaches and trying different things, particularly on the 26” bikes, but we kept coming back to our original layout being our preferred compromise for the riding we love to do. Have a read of the launch story for the latest Soul26 on 18/7/2012 for the lowdown on what we tested (www.cotic.co.uk/news/archive2012#newsoulthinking).
That feeling and handling is still the basis on OFI, but two big changes since our last Soul update influenced the design philosophy:
We, and most people we know with 26” Cotic hardtails, use layback seatposts to get a good position. Inline seatposts shortened the position, put a lot of weight on our wrists, and made us feel a little cramped. Also, the legacy of our long lived Ultra Compact Geometry is that is was designed around 100mm forks initially. When you put longer forks on the frame the reach reduces (you effectively swing the head tube up and towards the bottom bracket). This double hit of reduced reach due to longer forks and shortening of the position with an inline seatpost left us with a much reduced cockpit area using our original sizing. We realised that with the new frame we had to make our bikes more suitable for use with inline seatposts.
The solutions to this were to optimise the geometry of the new bike around 120mm forks to preserve the reach in the most commonly used configuration, and to slacken the seat angle so that the clamp on inline seatposts meets the saddle rails approximately where a layback post would sit on the original geometry. With the added effect that the first frame we applied this to is a 27.5” wheel (with higher front end), the effective top tube lengths on the new bikes look very long. However, as you can see from the table below, the reach (the BB to head tube top horizontal distance) is virtually identical to our 26” bikes.
|Soul275 (120mm Fork) reach||411.6mm||425.6mm||439.5mm|
|Soul26 (100mm Fork) reach||411.4mm||425.6mm||438.7mm|
|Soul275 Effective Top Tube Length||597mm||614mm||631mm|
|Soul26 Effective Top Tube Length||577mm||593mm||610mm|
With the slightly longer back end (430mm vs 420mm) due to the 27.5” wheel, and a touch slacker head angle, and the forelengthening effect of the longer 27.5” fork, the weight distribution is identical to the classic Cotic hardtail layout, simply with a slightly longer wheelbase.
The saddle, cranks and your handlebars are therefore in exactly the same place as we have placed them on all our hardtails, but we have simply joined the dots differently in order to fit the parts, forks and wheels you want to fit on a modern bike.