uprightbent

My 78' Grand Prix doesn't shift that well, specifically from the smallest cog it wants to skip to the 3rd cog on a 5 speed original freewheel. And getting it into the very big 34 tooth first cog is anything but smooth.

Reading on the Harris site about modern chains & teeth with ramps, etc. I'm wondering how much improvement I'd feel with a modern freewheel and new chain. If it's not going to improve smoother shifting I guess it's not worth the hassle?

My real question since I'm still new to this addiction is if there's a true design difference in today's minute gear and tooth patterns (and chains) vs. what's on this bike from 31 years ago?

Thanks in advance.

USAZorro

Yes. The difference is quite significant. Some derailleurs mask the difference better than others.

Chombi

The variety of gear and chain profiles have constantly changed in the last 30 years, but I would not say there has been any revolutionary developments that will set one design way above the others. The mechanics of gear and chain drive is just to rudimentary that you can't do to much modifications on them. But there were standouts that provided smoother quicker gear changes. One that stood out for me was Sedis Sedisport chains. It was the benchmark standard for chains that shift well because of their then unique, inner side plate design that help catch gears earlier and more positively. I noticed now though that after so many years dominating the chain market, Sedisport is gone. haven't tried the newest stuff from SRAM or Shimano that seems to be biggest(?) suppliers of chains today, but I suspect the improvements were enough to kill off Sides/Sedisport chains off the market. Sedisport chains might not have worked with the narrower gear profile format that they use in bicycle drivetrains today

Sci-Fi

Consider an IRD Defiant Freewheel if you want to try a modern ramped design. They make 'new' 5-speed FW's as well as 6-7 speed FW's and offer you have more choices in gearing/cog sets. Uses the Park FR-1 FW removal tool. But you need to check the condition and adjustment of the rest of your drivetrain. Might need more than a FW and chain (worn chain rings, weak dérailleur spring, worn out dérailleur jockey wheels, bent hanger, worn cables and/or housing, shifter, etc) and/or parts need to be serviced/oiled/greased.

tatfiend 

Sachs bought Sedis and SRAM bought Sachs bicycle parts division so the current SRAM chains are basically the Sedisport design with continued development. Not just sideplates but Sedis also developed the bushingless chain design which has become practically universal for current chains. Shimano adopted it as soon as the patents expired.

tatfiend 

Harris Cyclery offers the IRD freewheels in 5 speed. Not inexpensive though. Their freewheels page also has quite a bit of information.

https://sheldonbrown.com/harris/freewheels.html#5

The modern ramped freewheels make a considerable difference in shifting in most cases per posts on the C&V forum. Also fit a modern chain and make sure that the chainwheels and derailleurs are in decent shape. 8 speed chains are supposed to work well with 5 through 8 speed freewheels.

stausty

Anyone here ever tried Sheldon's "Sheldo-glide" modification to improve freewheel shifting?

Chombi

Thanks for the clarification on this tatfield! I'll check out the SRAM chains then when I wear out my old Sedisport silver chain on my PSV, if it does work well with 6 speed clusters.