bikemike73 

Hi
I live in an area with hardly any big long hills....

Mostly flat.

8 speed lightweight road bike


Which small chainring is better?

39. Or 42?

Appreciate any and all help

Thank you

Andrew R Stewart 

What's your favorite color? Now tell us why?

Gearing is like this, entirely personal preference. How low a gear do you need? Do you shift in the order of the numerical ratios or just leave the chain on one ring most all the time?

I completed a bike tour in Cambridge last week and rode down Strawberry Hill Td from Littleton. Even on this mostly down hill road I found myself in my 24x30 second to lowest gear a few times. But then my loaded touring bike weighed about 95lbs! BTW it's large ring is only a 444T.

Needs and preference, so what's yours? Andy

Iride01 

Better for you or better for shifting? Most of the ring combos sold together on a crank are optimized for the best shifting and capacity of the rear DR that is used with them.

I'd think only you could tell what gearing is best for you. I ride rolling terrain with a 52/36 and use to ride it with a 53/39 front and usually am in the big ring for most of the ride.

However whether that is best for you all depends on how cycling fit you are, how long you ride at a time and how much power you care to put out for your rides. As well are you going on a out and back ride just for fun or fitness or are you going on a week long tour carrying your own equipment for camping and all your other weekly needs?

And especially it depends on what rear cogs you pair with any of those front rings.

bikemike73 

Thanks for the replies

I have a 1990 Basso Loto


I am not into racing. I am a casual rider.

Cassette is a 14 /24 campagnolo

I guess the real question is.....
What is the advantage of one over the other ?

Thanks again

Iride01 

Specifically on the ring combos in your title, the one with the smallest ring will give you more lower ratios. Do you need any of the lower ratios it will give you for the riding you do? If not then you might benefit with the 42 small ring.

However in flat land, I wonder if I would ever need anything but the large ring for just a normal day out riding with no cargo carried with. So maybe a 1x will be better all around. Though I have 11 speeds and more choice ratios between the min and max of the rear. I think you only had 8 on the rear and you might want a specific gear ratio you can only get with the smaller ring

Especially when I'm trying to match speeds of others I occasionally ride with, it's nice to be able to find the perfect ratio for my cadence and power output to match their speed.

70sSanO

I think you need to look at this from how you normally ride, and what replacement cassettes are available.

First question, does Campagnolo, or Miche, still make any 8 speed cassettes with a 14t first position?

What chainring do you typically use the most now?

If you ride the inner ring a lot and you can’t get another 14-24 cassette, 39 might more sense.

But if you ride in the outer ring and are not looking for more speed with the 14t, neither a 52 or 53 are a good choice if you end up with an 11t or 12t 1st position cog.

John

Litespud

There's no inherent advantage one way or another - any more than one shoe size is inherently better than another. That being said, I would probably go with the 39, simply because it gives you a little low-end range that you wouldn't otherwise have, for no cost. Given that your terrain is largely flat, you'll probably be in the big ring routinely. However, the rare day may come when you're bonking up a hill into a headwind, and that 39 might be the difference between making it or walking. It may never happen, but there's no real downside to having that 39 in your back pocket.

icemilkcoffee 

42. I'll tell you why. It's easier to shift in the front when the small ring and the big ring are not too far apart in size. This is especially true for that 8 sp drivetrain. The 8 speed era chain rings were not as good as the 9sp and later chain rings.

Litespud

This is a valid point - I guess it depends on how much front shifting he's doing in his relatively flat terrain as to whether the ease in shifting outweighs the slight extra low-end range

bikemike73 

Thank you IMC and LS !!!

Those responses was what I was looking for.

All the other similar bikes I have from that era are 42/53. I bought the complete set up because the price was great !!!!.

Really did not need the chainrings. Just the crank arm assembly.

I'll switch it to the 42.!!!

I had to order a NEW chain today. A Campy 9 speed chain 6.8mm. Compatible for 8 speeds

I need 6.8mm and it was a Sram 830...... 7.1 mm that I put on, but rubbed the FD in certain gears. It did not do that before.

The old chain that was on there before is a 6.8mm.

Thank you again for all the help.

GREATLEY APPRECIATED !!!!!

squirtdad

personally I would keep the 39/53 so that if you ever need the lower gearing, like say against a head wind you have it. especially with a 14-24 range in back

I have had absolutely no problems with shifting between 39/53 so that in my mind is a non issue

44.5mph

https://sheldonbrown.com/gear-calc.html

bikemike73 

The Basso had a 42 originally , so I will put on a 42.

My other similar bikes have this set up and I have had no problem riding anywhere.

I am strong and powerful

Thanks again for all the VERY helpful comments, help, and knowledge !!

MUCH appreciated

Gonzo Bob

I prefer a 42-53 on my 6-speed road bike. The main reason is that the smallest cog I can fit on my freewheel is a 13, which means that the 2nd cog is a 14 which means that the biggest gear on the small ring is a 42/14 (I generally don't crosschain). That is big enough to use on the flat or even a shallow downhill grade (unless there is a big tailwind). I've swapped in a 39 inner ring (along with a larger freewheel) on my bike when I've taken it to the mountains, and I've tried that in my home terrain (flat to gently rolling with an occasional hill requiring some low gears), but I hate it. The 39 is barely usable, plus it has almost exact duplicates with a 53. Plus the shift between 39 and 53 is slower.