easy gearing combination question
 

I'd appreciate some opinions regarding gearing on my orange '72 Super Sport rebuild:

I bought a 14-38 Suntour Perfect freewheel from that-(C&V)-guy-zach.
The front double right now is a pair of Superbe Pro rings, on Sprint arms...53t and 39t.
Derailleurs are both Suntour Sprint, shifters are Suntour barcons.

Would I be better off with a 53/42 front chainring ring pairing?
I'm a "vintage" guy, riding on mostly flat terrain.

Thanks!

The 53/39 combo doesn't bother me at all. However, I'm wondering will your RD throw to the 38 in the rear?

I assume it's a 5-speed freewheel. If the gearing progression is even, it's about a 22% gap between cogs.

If keeping the 53 is important to you, I'd recommend a 48t chainring to help make up for those huge jumps. That'd be half-step gearing giving you 11% jumps between 10 evenly spaced gears.

That would be 34 to 102 gear inches, which is quite a wide range.

Me too. It also sounds like alot of chain wrap for a corsa deraileur.

Thank you for figuring that out for me! (And yes, it's a 5-speed freewheel)
I suspected the 39 was too small, but never thought about going up to a 48.
Looks like I will continue shopping!

Shifting half-step gearing is a little funny. If you go through all the gears in order, you have to shift both front *and* rear every other gear.

Another way is to remember which front chainring you're on, and bias your rear shifting accordingly. (i.e. if you're on the big ring now and shifting to go faster, go to a rear gear that's maybe a little to hard, knowing you can fall down to the small ring.)

Just something to think about -- some people adore half-step gearing but others can't stand it.

53 and 48 are pretty big gears for a double, especially for someone who claims to not ride very fast.

Two things you might consider:
(A) smaller chainrings (46/30 maybe?) and a normal-size freewheel (like a 24-14 or something),
(B) getting a triple with something like a 53/48/34. You could climb walls with a 34T chainring and 38T cog, if you could keep your balance that slow! :-D

Jan Heine has written this better than I can: http://janheine.wordpress.com/2012/1...ur-chainrings/

Yeah — 48 does not give you much of a break — I would guess for criterium racing on the flat with a close ratio cluster. I don't claim any athletic status as a cyclist, but I am happy most of the time with 52/39 on 14-28T. Finding RD's to change on that combo is not difficult. If the OP wants to go with 52/42 on his 38T "perfect", I think that he needs to think about finding a SunTour Xc MTB RD. Nice piece of gear and not too heavy.

Well, I'm officially a dumb-sh_t, as my original post is wrong!
My freewheel is a 8.8.8 Maeda Perfect, in a 5-speed format: 15, 17, 19, 21, 24.

So, would that work well with a 53/42 double?

This should work fine it is pretty close to what was stock common for this bike and the components you have. Also the 53/39 should work on this set up. The previously stated concerns were based on the mega range 38tooth freewheel.

wow, that's much more conventional! Sounds totally normal, go with the 42 or keep the 39, depending on whether or not you want the slightly lower low gear of the 39.

If you don't have hills.

+1. I run a similar configuration on one of my bikes and I seldom leave the 42 ring.

I built a bike for a friend last winter and gave him a 24T rear cog and a 39T inner. He is happy. I am planning a build that may end up using almost the same combo as you have: 15-24T/ 52/42T. I intend to use this for my workouts along the river and marsh — basically flatlands. (I need some gearing cuz of fierce headwinds.) For marching up and down hills I'd elect for either a 28T or dropping your 42 to 39.

And just in case you missed this — Maeda Industries was the maker of SunTour. I believe that I have exactly the same freewheel in my bins.