50-34 w/28T cassette vs 1x42 with 40T Chainring

[Defy The Odds]

I recent purchased the new 2018 Giant Toughroad SLR GX 0 with a 1x42 cassette utilising a 40T Chainring.

I'm trying to work out how this will compare to my current Defy gearing of 50-34 chainrings and 11-28 cassette.

If I am not mistaken, the 34-28 cassette will give a ratio of 2.5 - on a 42 Cassette this would be the third last sprocket which is a 32t and on the 1x it goes down 1.9 on the 42T sprocket therefore the 1x with the 42t cassette actually has a better climbing set up .... this sound right?

The Defy runs SRAM Apex 10 speed 10-28

Thanks in advance

[2wheels_mond]

Here's a link graphically showing the difference between the two setups.

http://www.gear-calculator.com/?GR=DERS ... 2&UF2=2220

[Defy The Odds]

Here's a link graphically showing the difference between the two setups.

http://www.gear-calculator.com/?GR=DERS ... 2&UF2=2220

Thanks mate !

That's actually awesome to see visually.

So from what I can interpret, it seems that I will lose a bit in the top end but essentially climbing will be easier... does this sound about right ?

[bychosis]

And the jump between gears will be a little bigger.

[find_bruce]

So from what I can interpret, it seems that I will lose a bit in the top end but essentially climbing will be easier... does this sound about right ?

That is a feature of the front ring you have chosen. The 11-42 will actually have a slightly bigger range, as the same site with a 50t front ring shows - I also made the tyres the same size. It also clearly shows the point bychosis makes - 50-34 & an 11-28 gives you effectively 13 gear ratios compared with 11 for 1x & an 11-42. Where the difference shows up is that an 11-28 has 11, 12, 13, 14, 15 ... The 11-42 skips 2 cogs & has 11, 13, 15 ...

The downside to that site is that in the real world you don't step up speed - your cadence has to vary within a range until you get to the next gear. Lets just say you like to keep your cadence above 90. You won't change to the 13T until you are doing 44.7 km/h. If you have a 14T, that is a cadence of 97 & is an easy change within a fairly tight band. If you only have a 15T, you need to have a cadence of 104, still achievable, but harder.

Pros want close gears at the top end because they ride at those speeds for extended periods of time. At the other end of the spectrum is an old fat slow bloke like me for whom it doesn't matter much.

[RonK]

So from what I can interpret, it seems that I will lose a bit in the top end but essentially climbing will be easier... does this sound about right ?

That is exactly what I would expect from this type of bike. Actually I wouldn't consider buying it if it didn't have a good climbing gear.

[Derny Driver]

So from what I can interpret, it seems that I will lose a bit in the top end but essentially climbing will be easier... does this sound about right ?

That is exactly what I would expect from this type of bike. Actually I wouldn't consider buying it if it didn't have a good climbing gear.

If you look at the graph, apart from the bail out gear (a six tooth jump to the 42) all other gears are within the range of the double chainring gearing. And a double chainring allows for closer ratios.
I wouldn't consider buying anything with 3, 4, 5 or 6 tooth gaps between cogs.

[singlespeedscott]

On my road bike I have found that once my speed has dropped below about 22km/hr I am happy to accept jumps of 3 or more teeth as it usually means I am going up hill. Faster than 40km/hr I do prefer jumps of only 1 tooth. Any where in between 2 tooth jumps seem fine for me.

[RonK]

So from what I can interpret, it seems that I will lose a bit in the top end but essentially climbing will be easier... does this sound about right ?

That is exactly what I would expect from this type of bike. Actually I wouldn't consider buying it if it didn't have a good climbing gear.

If you look at the graph, apart from the bail out gear (a six tooth jump to the 42) all other gears are within the range of the double chainring gearing. And a double chainring allows for closer ratios.
I wouldn't consider buying anything with 3, 4, 5 or 6 tooth gaps between cogs.

You might not, but close ratios don't matter a fig to people who ride off road. This type of gear progression works well for riding hilly back roads and trails. And plenty are only too happy to get rid of the front derailleur.

[Defy The Odds]

So pretty much what I gather with my limited knowledge is this:

1. I will have better climbing gears (ie 42T bail out gear) - this is what I want as with this kind of bike I obviously heavily favour climbing over outright speed

2. Due to the larger jumps between gears I will have to change my cadence and basically have a different approach to how I change gears now

With the second point, I don't have a real issue with this because I came from a Giant Roam to the Defy and so had to swap MTB gears for road and learn that.

Given the nature of the bike I feel much better. It will definitely be a different riding experience overall but I think for its purpose as a bit of an off-roader/part time road bike the 1x42 will work superb.

I still have the Defy for the bunch rides.

Besides, there aren't many times I'm maintaining 40km/h for long periods of time unless in a bunch, so not too fussed there

[uart]

On my road bike I have found that once my speed has dropped below about 22km/hr I am happy to accept jumps of 3 or more teeth as it usually means I am going up hill. Faster than 40km/hr I do prefer jumps of only 1 tooth. Any where in between 2 tooth jumps seem fine for me.

Same here s.s.scot. Remember however that when you are up around 40 km/hr you are most likely down on small cog (typ 11T-14T) on the cluster. Here a one tooth jump is a much larger percentage change than is a one tooth jump at say 20T. That's at least part of the reason.