The OEM rollers in my 2005 People 150 are 18 mm x 14 mm x 15 g. I replaced my OEM rollers with 13 g sliders and the top and bottom end is very similar to the rollers. If anything, I might have gained a little on the bottom end and lost a little on the top end but it is hard to tell. Acceleration is very smooth. I have put several thousand km on the sliders now and I have been very happy with them.....no problems to date. If you need to replace the rollers, you might consider going with the Dr. Pulley sliders.