A few weeks ago I’ve ordered a carbon bike on the Internet. Now, I’ve found out that the frame is not accurately centred. The wheel is about 1.5 millimetres offset from the centre. I’ve already tried to turn the wheel, but the result is the same. This means that the wheel is symmetrical. Then I’ve measured the frame with a stretched line: I’ve guided the line through both drop-outs and tightened it around the head tube. The measurement on the seat tube shows an offset of about 2.5 to 3 millimetres. Various measurements had the same results. Do you think it’s still within tolerance or a reason for complaint? My ten year old alu frame has an offset of 4 millimetres.
Reply by Dirk Zedler, TOUR Technology expert and bicycle expert
One typical feature of carbon frames is that they are optimally centred. They do not even distort after they come out of the manufacturing moulds. It may be possible that the measured distortion is due to asymmetries in the area of the seat tube or the like. Apart from that there are no hard borders from which the frame is still accurate or not. We assume that in the case of road racing bikes a lateral distortion of more than 2.5 millimetres from the centre is not accurate. Without having seen the frame I would therefore assume that the measured offset is still within the range of tolerance.
