Picked up a mostly original 82 Trek 720 for $40. What I'm wondering is would a 1st generation Suntour cyclone or VX GT be a better choice considering the 720's long chainstays. Have both parts already & both are in good shape.

Both are fine choices and will work. The problem with the long chainstays is that you likely need the entire length of chain. The other thing you want to pay attention to is max cog size and chain wrap but the two RDs are probably pretty similar in that regard. Personally I'd lean to the VX GT but that's a matter of taste.

Velobase is a good source of technical info on this:


VeloBase.com - Component: SunTour Vx-GT

VeloBase.com - Component: SunTour Cyclone GT

The two RDs vary a bit but in the real world, I doubt there's much difference between them.

Thanks, bikemig. Considering the points you made, which would you go with?

Sorry edited my first response. Personally I'd go with the VX GT as I think of it as more of a touring derailleur but really that's a matter of personal taste.

I'm running a suntour xc sport 7000 rd on my '82 Trek 720 which is wrong I guess age wise since it dates from the late 80s but it's what I had in my parts bin when I built the bike and it takes up a lot of chain.

https://velobase.com/ViewComponent.aspx?ID=e0fa65ea-0433-4725-921f-1cf39f2b9f7b&Enum=108