I just modified my Merida Race Lite 903 which has a similar off the store set up like yours a week ago, the hills here are tough (Sangklaburi, Kanchanaburi, Thailand). I changed the Cassete that was 11/28T to 11/34T and it worked without replacing the rear derailleur with a long cage (XT Deore). did this by turning all the way to the bottom the screw of the tiagra short cage RD to adjust the pull of the spring on the chain... noticed that the upper pulley chain guide space is just a few millimeters but not hitting the large cog as i change gears... I did not change the chain either, but i cannot use the large chaining on the largest cog... this combination not a good combination anyway...

i hope this helps...

Richard Baan Dada Children's Home and Community Services www.baandada.org

I just modified my Merida Race Lite 903 which has a similar off the store set up like yours a week ago, the hills here are tough (Sangklaburi, Kanchanaburi, Thailand). I changed the Cassete that was 11/28T to 11/34T and it worked without replacing the rear derailleur with a long cage (XT Deore). did this by turning all the way to the bottom the screw of the tiagra short cage RD to adjust the pull of the spring on the chain... noticed that the upper pulley chain guide space is just a few millimeters but not hitting the large cog as i change gears... I did not change the chain either, but i cannot use the large chaining on the largest cog... this combination not a good combination anyway...