Originally Posted by
waddo
There are no bikes of any size in the shop so we cannot tell which would be better. Her Sirrus has a sloping top tube (?) so hard to compare; but measuring straight accross the LHT is shorter, so I guess would give her a more upright position which would be more comfortable. But I dont know much about bike fitting so I can only guess.
Look at online geometry for the Sirrus and LHT. Compare the effective top tube lengths. Also compare stack height and reach measurement.
Those 3 measurements will give you a level set between a sloping tube bike and a level top tube bike.