Howdy.
A budding mechanic here. I have a ~1990's Bianchi Boardwalk hybrid whose freewheel I'd like to upgrade from its current Shimano HG-37 7-speed 14-28 to a Shimano Megarange 7-speed HG-50. This is what I know about my bike:
Chainring: Suntour Powering 48-38-28
Freewheel cogset: as listed above HG-37
Dropout spacing: Well, my cheap ruler says 129mm, but I'm guessing that's really 130mm (or is it possible it's 129.....?)
F/R Derailleurs: Unknown make/model. Identifying markings long gone.
Dropout type: vertical
I'm confused about a couple of things:
-According to Sheldon Brown's website, the Megarange 7-speed (and most other 7-speeds) is for a 126mm spacing. And 130mm spacing is typically for >=8. Why, then, do I have a 7-speed freewheel on a 130mm spacing?
-Is it true that not only must I have a 7-speed rear derailleur, but one specifically able to handle the 34T on the Megarange? If so, can someone suggest a rear derailleur which I might use, given all the other specs I've provided?
-Is a rear derailleur dedicated to a certain number of speeds or can it typically handle a range (e.g., does "9-speed" mean "up to" 9 (but including 7 and 8) speeds?
-If I haven't provided/considered all the specs needed to decide on this freewheel (and, potentially, rear derailleur) can someone recommend a 7-speed freewheel cogset which would improve (as in 13 or 12 T) on my 14-28 and be compatible with my current setup, i.e., so's I don't need to change anything but the freewheel cogset?
Thanks
Peter
A budding mechanic here. I have a ~1990's Bianchi Boardwalk hybrid whose freewheel I'd like to upgrade from its current Shimano HG-37 7-speed 14-28 to a Shimano Megarange 7-speed HG-50. This is what I know about my bike:
Chainring: Suntour Powering 48-38-28
Freewheel cogset: as listed above HG-37
Dropout spacing: Well, my cheap ruler says 129mm, but I'm guessing that's really 130mm (or is it possible it's 129.....?)
F/R Derailleurs: Unknown make/model. Identifying markings long gone.
Dropout type: vertical
I'm confused about a couple of things:
-According to Sheldon Brown's website, the Megarange 7-speed (and most other 7-speeds) is for a 126mm spacing. And 130mm spacing is typically for >=8. Why, then, do I have a 7-speed freewheel on a 130mm spacing?
-Is it true that not only must I have a 7-speed rear derailleur, but one specifically able to handle the 34T on the Megarange? If so, can someone suggest a rear derailleur which I might use, given all the other specs I've provided?
-Is a rear derailleur dedicated to a certain number of speeds or can it typically handle a range (e.g., does "9-speed" mean "up to" 9 (but including 7 and 8) speeds?
-If I haven't provided/considered all the specs needed to decide on this freewheel (and, potentially, rear derailleur) can someone recommend a 7-speed freewheel cogset which would improve (as in 13 or 12 T) on my 14-28 and be compatible with my current setup, i.e., so's I don't need to change anything but the freewheel cogset?
Thanks
Peter