LarrySellerz not everyone has the same motor, some of us don’t need the low-low gears to up hills, and some of us spin out 50x11. BEar that in mind before you offer
advice opinions about gearing based on your abilities. I admittedly struggle with this when people ask how to build a Franken-geared bike with sub-20 gear inches on the low end.
Originally Posted by
dirtydozen
Hello,
I currently have a shimano 105 5700 triple chainset 50-39-30 with an 11-34 cassette.
According to the derailleurs capacity, i should have for a maximum a 32T cassette but this 34 worked well the few times i had to use it.
I would like to be sure that if I buy a 53T and a 34T chainring to make a triple 53-39-34, it wouldn't cause any problem in the capacity side of things.
I could change the 39T in something like a 42T to match the wears and to have a consistent spacing between each rings if that can help the FD.
I could also later on when changing the cassette (i believe i can get more km's out of this cassette) go for a 11-32T one
Thanks for your attention
Capacity is NOT the largest cog your derailleur was designed to accommodate (which for Shimano is ALWAYS conservatively spec’d).
Addressing the largest cog issue first, turning the b-screw will often allow use of a slightly larger cog, just how much larger is not universal from RD to RD, so you really need to do some research and/or experimentation. One word of caution, a tooth or two larger is usually not an issue, but 3 or more than lead to shift issues, first smoothness and potentially also skipped or missed cogs especially as you get into the higher end (smaller cogs) of the cassette.
Capacity is a function of how much chain the derailleur can wrap (rear), or how large of a gap between chainrings it can manage (front). The wrap on the rear is a combination of tooth difference from large to small on the cassette and the difference between large and small chainring. So, going to a 53 and 34 (from a 50 and 30 respectively) should be no issue, though you may need a slightly longer chain.