jetignacio

I have an old school Shimano 105sc 7 speed. The combination is 53/42 (cranks) and a 13/23 (cogs). Would this be a match or a good combination? My rinding is a mix from flats to rolling terrains. Hope to know your thoughts. TIA

veganbikes

Best answer: Maybe? It is not a great ratio for hills for average riders but those who can climb they could do it I am sure. Granted with older parts running wider ranges can be tough on a 130bcd crankset the lowest you could go is maybe a 38t chainring and cassette you might get lucky and a 28t could fit but it might be more than that derailleur can handle.

jetignacio

Make sense. I'll just have to makes some adjustments on the areas where I ride, as retro parts don't come easy nowadays. Or maybe, choose climbs that are somewhat bearable with the kind of combination I have.

veganbikes

Or replace parts. Get an old XT derailleur and run a wider range cassette (or freewheel) or swap cranks to something compact. If you love the bike make it work for you. If you are trying to keep it 100% original or stick with a pure vintage theme I get it but also do a little to make it work well for you so you can actually ride it where you want. My Phil Wood Apple VeloXS bike has a WTC Roadlink (so I could run a larger 6 speed freewheel) and a 38t Dimension inner ring so it still looks pretty classy but actually works a little better for me. At some point in the future I want to strip and polish the Roadlink but not anytime soon.

jetignacio

Yes, actually I want it to stay as a retro bike. Maybe for starters, I can look for a 38t chainring and replace my 42t, or if I can find a same model and year as mine but with a 52/38 combination (if there is).

canklecat

If you're younger and strong, sure. That's a typical old school gear combo.

Over the years I've made a few changes to my '89 steel road bike to accommodate age and loss of power:

• The original 52/42 chainring and 7-speed 13-24 freewheel
• Then to 52/42 and 13-25;
• Then 52/39 and 13-25;
• Then, after being hit by a car in 2018 and losing some fitness, 50/38 and 13-28;
• And, now, 52/39 and 13-28. I tried 52/42 again from January-April but couldn't quite get along with the 42T chainring on some days with climbs into headwinds. I was straining my knees trying to mash slower than 60 rpm.

For a 130 BCD crank spider, you can get a 38T chainring (Vuelta are very good). At a glance it looks fine on a classic bike with 50, 52 or 53 big ring. Even the 52/42 or 53/42 chainring combo wasn't always the standard. With ye olden 5-speed freewheels some riders used half step gearing with smaller differences between big and small chainrings, to avoid tiring herky jerky large jumps in gearing, at least for some terrain and stages.

tcarl

Would this be a good combination? Well, it's perfect for me, but I'm a fairly strong rider who rides in relatively flat terrain.

jetignacio

Great suggestions, thanks. I'll try the 52/39 chainring combinations first and go from there.

Miele Man

I just used Sheldon Brown's Gear Calculator to show the difference in Gear Inches between a 42 chainring and a 39 chainring (which isn't much) and the differrences between rear cogs up to 28 teeth. I'm pretty sure that an Old School Shimano 105 rear derailleur will handle 28 teeth.

Cheers

jetignacio

Nice illustration of ratio difference, this is helpful. Thanks!

tkamd73 

Had that exact set-up on my PDG series 5, did not work for me, but I live on top of a large hill, and I’m old. Changed out the cassette for a 13-28t one, works a lot better on the hills.
Tim

Retro Grouch 

How long have you had the bike? Ride it around for awhile to decide how well you like it. What you have doesn't have any very easy hill climb gears but, if you live someplace where there aren't any very big hills, you might not care. If you decide that you'd like an easier hill climb gear, for example, ask. There are at least two or three quite different options that you might find interesting.

jetignacio

Honestly this is a project bike. What I'm currently using is a Brompton. My area has more flats that rolling ones, and was thinking of a way for the bike to be flexible in any situation. But yeah, I'm gonna ride it first until I adjust to the bikes gearing then decide from there. Thanks!

PoorInRichfield

Best gear calc web site ever...
BikeCalc.com - Bicycle Gear Speed Chart

jetignacio

I’ve found gooold! Never thought I can still find one! Bought myself a 11/28 Shimano 7s cog in fair condition as replacement for my 13/23...yes! This will certainly do me good now on climbs!