Hi, I just fitted some new wheels to my hybrid. Originally, this had none-too-impressive 10 year old STX-RC hubs with Alex rims. I replaced these with Shimano XT hubs and Mavic rims weighing about the same. Really nice quality and feel bombproof - just what I needed. However with the same tyres and tubes the bike really feels a lot slower. I thought quality, modern hubs would run better. Is it just because the hubs are new and take a time for the bearing to "bed in" (I thought XT surfaces were pe-pollished) or is it becase the rim is slightly wider and this seats the tyres differently? I'm really quite annoyed at such a big noticeable difference after spending quite a lot of money on the new wheels. Any advice?