Groupset help please - all these numbers are baffling me!

sabian92

Über Member
Evening,

I'm currently in the process of deciding the components for my next bike (A Disc Trucker). I know I want Shimano 105 but there's a few different gearings for both the cassette and the chainset, and it's got me confused.

Do I want 11-25 or 12-27 for lowest gearing on the cassette, and 50-34, 52-36 or 53-39, for the chainset? I want the lowest gearing possible (mainly because I'm a fat sod :laugh:) and I can't work out which is the lower one.

I'm going for a triple if that makes any difference.

Ta.
 

SWSteve

Guru
Location
Bristol...ish
Evening,

I'm currently in the process of deciding the components for my next bike (A Disc Trucker). I know I want Shimano 105 but there's a few different gearings for both the cassette and the chainset, and it's got me confused.

Do I want 11-25 or 12-27 for lowest gearing on the cassette, and 50-34, 52-36 or 53-39, for the chainset? I want the lowest gearing possible (mainly because I'm a fat sod :laugh:) and I can't work out which is the lower one.

I'm going for a triple if that makes any difference.

Ta.
You want the 12-27 cassette an the 50-34 chainset then. Good luck with the purchase :okay:
 

Tim Hall

Guest
Location
Crawley
Lowest gear is a combination of the biggest number on the cassette and smallest on the chainset. So in your example the 12-27 cassette, which has a biggest sprocket of 27 teeth and a smallest one of 12 teeth, coupled with the 50-34 chainset. This has 34 teeth on the small ring and 50 on the big. I don't think it's a triple, as these are normally described as 50-xx-34, where xx is the number of teeth on the middle ring. Happy to be corrected though.
 

jack smith

Über Member
Location
Durham
As above it dosent sound like a triple chainset, just go with the largest number for the cassette and smallest for the chainset for the easiest gears
 

andyfraser

Über Member
Location
Bristol
They're all double cranksets. 105 cassettes are also available in 11-28 for 10 speed and 11-28 and 11-32 for 11 speed. There's a 50x39x30 triple from the 5700 10 speed range. Didn't they drop triples from the 5800 11 speed range?
 
OP
S

sabian92

Über Member
As is the 105. What I meant was the OP seemed to be listing doubles but had mentioned he was going to use a triple.

PS. Ribble have a 105 triple for 82 notes.
I realised that after I'd posted it :blush: apologies.

They're all double cranksets. 105 cassettes are also available in 11-28 for 10 speed and 11-28 and 11-32 for 11 speed. There's a 50x39x30 triple from the 5700 10 speed range. Didn't they drop triples from the 5800 11 speed range?
According to Google you can still get 50/39/30 triples from the 5700 range. Not sure if they still do it for the 5800 range but I'm not interested in 11 speeds anyway.

The facorty built Disc Trucker comes with a 48/36/26 triple chain ring.

If you are going you are own way and want a low first gear, you need to look for something with a smallest ring of 26, or maybe 24.

That will probably mean fitting a triple.

http://surlybikes.com/bikes/disc_trucker/bike_specs
I am indeed - buying a frame and building it up. I don't want a proper granny gear designed for spinning up mountains all day, not yet anyway as I've got no plans for touring at the moment - for now it'll be a commuter but I do want to do some touring at some stage, although it'll likely be somewhere flat at first!
 

andyfraser

Über Member
Location
Bristol
According to Google you can still get 50/39/30 triples from the 5700 range. Not sure if they still do it for the 5800 range but I'm not interested in 11 speeds anyway.
Sorry, I wasn't clear enough. Yes, you can still get the triple for the 5700 series but I believe Shimano dropped the triple from the 5800 series. If you went 10 speed 5700 you could get a low gear of 30x28. That's virtually the same as 34x32 with the 11 speed 5800 with the 50x34 compact crankset so the lowest gear with either the 5700 triple or 5800 compact is more or less the same.
 

lpretro1

Guest
Dont bother with 5700 - it is a bit draggy on the gears because the way the cable run. The 5800 is way superior. A compact 50-34 with a 32t lower cog cassette will give you almost same lowest gear as a triple with a 28t lowest.
 

Sharky

Guru
Location
Kent
Hi, if you are struggling to know which is the best gear combinations, Try studying a gear table http://www.bikecalc.com/gear_inches . I've spent hours comparing different combinations. Try mapping your current bike's gears and work out where your most useable ratios fall and you can compare what you would get with doubles, triples etc.
Good luck
Keith
 

raleighnut

Legendary Member
Location
On 3 Wheels
You can mix a triple from the earlier series with a rear from the later one, I would not use a double that had such a difference between rings but stick to a triple. You will need the longer variant rear mech though.
 
OP
S

sabian92

Über Member
Hi, if you are struggling to know which is the best gear combinations, Try studying a gear table http://www.bikecalc.com/gear_inches . I've spent hours comparing different combinations. Try mapping your current bike's gears and work out where your most useable ratios fall and you can compare what you would get with doubles, triples etc.
Good luck
Keith
I'm not entirely sure on my current gearing, will have to find out. Short of counting each individual cog, is there a quicker way?

You can mix a triple from the earlier series with a rear from the later one, I would not use a double that had such a difference between rings but stick to a triple. You will need the longer variant rear mech though.
Would that mean 11 at the rear and 3 at the front for 33 total? Not 33 ratios obviously, but 33 different selectable gears?
 

Pale Rider

Legendary Member
I'm not entirely sure on my current gearing, will have to find out. Short of counting each individual cog, is there a quicker way?



Would that mean 11 at the rear and 3 at the front for 33 total? Not 33 ratios obviously, but 33 different selectable gears?
You only need to count the biggest and smallest cog, so it doesn't take long.

As regards number of gears, it will be the number of rings at the front multiplied by the number of cogs at the back.

Eleven speed is relatively new, so you might be better to stick with the more common nine or 10.

That, with three rings at the front, would give you 27 or 30 gears.

More than you need, and there will be some overlap.

But as I mentioned earlier, to get a wide range you will need three rings at the front.

So while you might not use every gear, you will use every cog and ring.
 
Top Bottom