I'm currently running a 50/34 with an 11-28 (105) on one of my bikes. On long, gradual descents I find that I'm starting to spin out, so I'm toying with the idea of swapping over to a 52/36. If I swap to a semi-compact, should I also swap the cassette to an 11-30 to keep the lowest gear relatively the same? I'm Bristol based, so while there are hills, it's not mountainous, so could possibly get away with keeping an 11-28.
Compact vs semi-compact
- Thread starter rivers
- Start date
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Racing roadkill
Guru
I moved from a standard 53-39 with an 11-28 cassette to a semi with an 11-30. I find that combo works well for routes with hills in them, better than a compact with 11-28 or the standard with 11-28.
Tigerbiten
Guru
What size wheel and what speed are you spinning out at ??
A 50/11x27 is around a 122" gear.
At around 90 rpm this will give you around 32 mph.
50->52 is only a 4% increase in speed or half a gear.
Top speed will increase by around 1 mph so probably not noticable.
But a work around.
Measure the gap the gap between the chain and the bottom of the front derailleur cage.
If it's bigger than 4mm you can probably move it up by that amount and swop in a 52 tooth chainring.
Only then if the front shift becomes bad, swop in a bigger small chainring.
A 50/11x27 is around a 122" gear.
At around 90 rpm this will give you around 32 mph.
50->52 is only a 4% increase in speed or half a gear.
Top speed will increase by around 1 mph so probably not noticable.
But a work around.
Measure the gap the gap between the chain and the bottom of the front derailleur cage.
If it's bigger than 4mm you can probably move it up by that amount and swop in a 52 tooth chainring.
Only then if the front shift becomes bad, swop in a bigger small chainring.
700c and around about 35-40mph (like i said, gradual downhill)
gavroche
Getting old but not past it
- Location
- North Wales
Why not keep everything as it is, cruise down the hills and start pedalling when it is flatter. 
