Gear Ratio Question

[Banjo]

I have a friend looking at buying a new roadbike for fitness riding. No intention of joining clubs or doing sportives etc but just wants to ride.

We have some big hills locally so I recommended a Triple but we have also spotted the Specialized Secteur with SRAM Apex compact double with 34 front and 32 biggest cog on the cassette.

Does this compare similar to a 30 on the front with a 28 tooth cog on the cassette (this is on my bike and he wants something to compare it with.) He has been riding an old road bike with 34/25 and cant cope on long hills.

 

[MacB]

assuming 700x23 tyres then you get:-

30x28 = 28.2 inches
34x32 = 27.9 inches

just for comparison

34x25 = 35.8 inches

 

[Banjo]

Thanks Mac So the Sram set up would be a tiny bit easier/faster cadence than my Shimano Triple. And either would be far easier than what he struggles on now, cheers.

 

[marinyork]

Thanks Mac So the Sram set up would be a tiny bit easier/faster cadence than my Shimano Triple. And either would be far easier than what he struggles on now, cheers.

What's the second lowest gear on the triple and on the compact? That might be just as important. Or in other words how many gears below 35.8" and where?

 

[MacB]

if it's a 32t cassette then I expect the next ratio would be 28, just checked and yep it's:-

32 - 28 - 25 - 22 - 19 - 17 - 15 - 13 - 12 - 11

if it's the 11-32 Apex then the it spreads differently:-

32 - 24 - 21 - 19 - 17 - 16 - 15 - 14 - 13 - 12

with the first your bottom gears would be:-

34x32 = 27.9
34x28 = 31.9
34x25 = 35.8 so two gears below the existing compact

with the second it would be

34x32 = 27.9
34x24 = 37.3 so a big jump there

I can see the attraction in both, the first seems more suited to an endurance approach and the second to hard riding, with closer ratios, but giving you a really low gear if needed, just the one though and it's a big gap from 37.3 to 27.9.

Personally I think it would be easier if they weren't so hooked on a 50t big ring and the 34t limitation in the middle. Something like a 44/28 or 46/30 makes more sense to me for a compact. How often does your average rider use, and actually need, the top two or three gears from a 50t ring or bigger?

 

[2Loose]

Personally I think it would be easier if they weren't so hooked on a 50t big ring and the 34t limitation in the middle. Something like a 44/28 or 46/30 makes more sense to me for a compact. How often does your average rider use, and actually need, the top two or three gears from a 50t ring or bigger?

So very true.

 

[Alembicbassman]

If you're going to run a 28 or 32 sprocket it's a good idea to go for a 10 speed cassette or the gaps between gears will be a little on the big side.

New 2011 Shimano Tiagra ia 10 speed, otherwise Shimano 105 or SRAM Rival11-28 /Apex 11-32

 

[Garz]

The apex would be better, the only negative side is the closer gearing you would get with a triple. The weight saving, less faffing setting up indexing and lower overall gear would make it an ideal hill seeker for your friend.