Does anyone know, offhand, what the outside diameters are of 53, 52, 51, 50 tooth chain rings? I'm fine tuning a derailleur fit. I'd like to get the tail of the derailleur dropped a couple of mm to keep the chain from dragging one rear cog smaller than it does now (currently 53 on the front).
-Jim
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Does anyone know, offhand, what the outside diameters are of 53, 52, 51, 50 tooth chain rings? I'm fine tuning a derailleur fit. I'd like to get the tail of the derailleur dropped a couple of mm to keep the chain from dragging one rear cog smaller than it does now (currently 53 on the front).
-Jim
Each tooth is a half-inch. Diameter = circumference / pi.
On Mar 6, 12:49 pm, Dan Connelly <d_j_c_o_n_n_e_l@y_a_h_o_o_._c_o_m>
Quoted message said:
James Fitch said:
Does anyone know, offhand, what the outside diameters are of 53, 52, 51, 50 tooth chain rings? I'm fine tuning a derailleur fit. I'd like to get the tail of the derailleur dropped a couple of mm to keep the chain from dragging one rear cog smaller than it does now (currently 53 on the front).
Quoted message said:
-Jim
Each tooth is a half-inch. Diameter = circumference / pi.
Dan
Plus a skosh for the points of the teeth. The formula you posted describes the diameter through the pins of the chain- the chainrings' actual diameter is a little larger than that.
In my experience, fine-tuning front derailleur fit is best done once the bike is completely assembled. If you need a front derailleur with a longer cage, maybe you should indicate what kind of frame and front derailleur you have currently.
"JeffWills" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
On Mar 6, 12:49 pm, Dan Connelly <d_j_c_o_n_n_e_l@y_a_h_o_o_._c_o_m>
Quoted message said:
James Fitch said:
Does anyone know, offhand, what the outside diameters are of 53, 52, 51, 50 tooth chain rings? I'm fine tuning a derailleur fit. I'd like to get the tail of the derailleur dropped a couple of mm to keep the chain from dragging one rear cog smaller than it does now (currently 53 on the front).
Quoted message said:
-Jim
Each tooth is a half-inch. Diameter = circumference / pi.
Dan
Plus a skosh for the points of the teeth. The formula you posted describes the diameter through the pins of the chain- the chainrings' actual diameter is a little larger than that.
In my experience, fine-tuning front derailleur fit is best done once the bike is completely assembled. If you need a front derailleur with a longer cage, maybe you should indicate what kind of frame and front derailleur you have currently.
Jeff
Its on a long-assembled bike with a Campy triple front derailleur. I recently put on a smaller inner chain ring, which caused the dragging when on the 5th cog. I'd like the lower gears more than the higher ones, so the simplest solution seemed to be to simply put on a smaller large chain ring and lower the derailleur. A longer derailleur cage would work, too. Dan's formula (and I'm a little irked I didn't think of it myself) is probably accurate enough to tell me what I need to know.
-Jim
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