Following the recently published review of the Hemlock in MBUK and on BikeRadar we felt it was necessary to explain the situation from our point of view. There were two points of contention coming out of the test, regarding the chainstays and seatstays.
Firstly the chainstays: The failure experienced by the MBUK testers and a small number of other customers was due to an assembly issue which left some frames without a crucial spacer in the main pivot pinch arrangement. Once this was identified as the problem, we supplied all our customers with the requisite parts (either the spacers or complete new swingarms as appropriate) and we supplied Future Publishing with a correctly assembled part which they didn't break. We also put a procedure in place that ensured all frames dispatched since that time were checked for the spacers before going out to customers.
Regarding the seatstays, we actually refute this point. We got the bike back from Future and measured it ourselves, and it was possible, even using an accurate straight edge, to get a different view of the deflected shape of the seatstay depending on where it was measured. We even tried assessing it on the top side rather than the underside and this showed that piece was bowing very slightly in the opposite direction to the braking forces. We don't believe it was possible to measure accurately enough simply using a straight edge to draw the conclusion that they did. And to be clear, the maximum deflected shape we saw on the part in question was less than 0.5mm of bow relative to the straight edge in a part over 300mm long. This, as far as we are concerned, is acceptably straight for manufacturing tolerances for such a piece. To add to our point, the maximum measurements occurred at the bend in the tube where some deformation of the tube is inevitable due to the manipulation. Just to be completely sure, we have measured several of our own bikes and demo bikes and found them to all be similar, and therefore acceptably straight as far as we are concerned.
If you actually look at the rear brake under braking whilst on the bike, you will see some deflection of the seatstay. However, as we have argued above, we don't consider that this causes permanent damage and it's not possible to feel this on the bike in our experience. The arrangement at this point is designed that way for very good reason. Having the brake caliper mounted as far forward as possible minimises the effects of the brake forces on the suspension. It's one of the reasons the Hemlock rides so well, and the effects were proven during testing with several back ends which had different caliper positions. We have only had one failure of this design across all the frames we have supplied, which represents much less than 1% of the total.
It's also worth mentioning that following some recent lab testing for the latest CEN safety regulations (BS EN 14766), the existing Hemlock frame was found to be fully compliant to these new and quite onerous requirements for testing frontal fatigue, pedaling fatigue, vertical fatigue, frontal vertical impact and horizontal impact.
The Hemlock is currently out of stock, and we will be re-stocked in June with some minor running changes to the chainstay design to eliminate the problem of how sensitive it is to correct assembly.