Ordered some Sora 7 speed shifters today. Looks like I have commited to upgrading the Schwinn Tempo.

RD is a

Name: Shimano RD-1050, 105
Brand: Shimano
Primary Group: 105
Model: RD-1050
Years: 1987 - 1988
Country: Japan


It appears it has a maximum rear cog of 28 teeth and a max chainwrap of 26.

I need to get myself a 7 speed freewheel and want to maximize my gearing somewhat. At present the front rings are 52/39. I wanted to get a 14-28 rear freewheel, but Im one tooth over a 27 there.

So Im wondering if the RD will handle that out of spec wrap, or if I will need to change it out. I consdered changing out the big ring to decreaset he wrap (dont really need a 52) but then thought maybe I might be smarter to get another RD such as the Tourney TX51 Rear Der. This gives me the option of up to 34 teeth and I could even use the mega range freewheel if I chose.

Thoughts or suggestions?