So 12 speed is not enough for you

02gf74

How about 13 speed
10-52 cassette
.

https://singletrackworld.com/2018/07/ar ... e-too/amp/

steve_sordy

I'm not impressed. I'm an old git with dodgy knees and even I am happy with a gear range of 5:1

10-52 is only 4% more range from the "standard" 10-50 offering from SRAM Eagle. That in exchange for the complexity of a 13-gear cassette. Unless they make the hub wider, the shifts have to be smaller and therefore even more precise. I have Eagle 12-speed on both my bikes, one is XO1 and the other is GX. Whist I'm not considering going back to 11-speed, the 12-speed exhibits problems of a kind I've ever had before and with a relatively rapid frequency. The gear cable needs changing more frequently, the mech alignment and mech hanger alignment needs checking at the first sign of shifting problems. That long mech arm is in the danger zone. If it's not alignment, then I'd change the cables. I have learned not to start adjusting the cable tension (once it was properly bedded in) or the limit screws as they have never been the problem.

Whenever a bike mechanic has been anywhere near my rear mech, I always check the B-gap. I have discovered that despite SRAM's instructions on how to set the B-gap correctly (they even proved a setting gauge), no mechanic that has "set up my shifting" ever set the B-gap correctly. The upper jockey wheel frame always ends up catching the 50t. Why do I let them near? Warranty claims!

The good news is that the SRAM Eagle kit seems to be lasting very well. I'm on target to get 5 to 6 times the mileage out of a chain. My assumption (hope!) is that this extra life is also a feature of the ring and cassette gears.

02gf74

steve_sordy wrote:

. Unless they make the hub wider, the shifts have to be smaller and therefore even more precise..

They can do that ad boost rear hub has extra 3mm each side or thy can dish the largest sprockets, just had a look at my 11 cassette and there is easily room for two more sprockets.

I'm not upgrading to 12 nor 13 but will wait when 15 speed comes out.

steve_sordy

02GF74 wrote:

steve_sordy wrote:

. Unless they make the hub wider, the shifts have to be smaller and therefore even more precise..

They can do that ad boost rear hub has extra 3mm each side or thy can dish the largest sprockets, just had a look at my 11 cassette and there is easily room for two more sprockets.

I'm not upgrading to 12 nor 13 but will wait when 15 speed comes out.

But will the chain run in those two extra sockets without hitting anything? Frames might need to be of a different design.

I suspect that when you suggest a 15-speed gearing, you are only joking. There are practical difficulties to take into account.

The main factor against going bigger is just that, the size. By bigger I mean a bigger range.

The 12 speeds of the SRAM Eagle cassette are distributed over a 5.0 to 1 range, which is an average 15.7% shift each time. If we do this three times more to give a 15-speed cassette, we'd end up with a 77.6T gear, lets say 78T.

If we use the same basic design as the 50T, it would be more than twice as heavy (not forgetting the weight of the two intermediate gears). The 50T gear is 8" diameter and the 78T would be 56% more, ie 12.5", and the mech arm would have to be 4.5" longer to cope. I just measured where the end of the jockey wheel frame is when in the 50T and it is at a 10" radius from the hub. Add 4.5" onto that and you would get 14.5". That's right a radius of 14.5" or a diameter of 29". So no 15-speed gearing for 26ers, 27.5ers, or 29ers for that matter!

So there is a practical limit. On my 27.5" wheels (radius 13.75"), the outer reach of the jockey cage is 10", so I only get 3.75" clearance. No wonder I keep having to get my mech alignment checked!

I accept that you don't have to have 15.7% average ratio between gears, you could go for less to keep the size of the big gears down. But when that ratio is pretty much a universal standard for gearboxes (give or take a few % to provide whole numbers of teeth), then why would anyone want a lower average % unless it gave weight or significant cadence benefits. I suspect that gearing higher than 12 will be the economic and practical limit except for specific uses.

JGTR

I have SRAM 12 speed, has been bullet proof, ultra reliable and maintenance free.

They squeeze in the 13 speed by reducing the width of the hub, which kind of defeats the object of Boost surely?

steve_sordy

JGTR wrote:

I have SRAM 12 speed, has been bullet proof, ultra reliable and maintenance free.

.................

We must ride different kinds of trail. I am not saying I ride harder or anything sneery like that. Just different.

JGTR

Maybe you just need a better mechanic

Chain gap is 15mm so god knows how they adjust it so that it contacts the 50T :shock:

mediamonkey

02GF74 wrote:

steve_sordy wrote:

. Unless they make the hub wider, the shifts have to be smaller and therefore even more precise..

I'm not upgrading to 12 nor 13 but will wait when 15 speed comes out.

Pah, I had 15 gears on my Raleigh Mustang in 1988.

OK, it had three chainrings, but...

steve_sordy

JGTR wrote:

................

Chain gap is 15mm so god knows how they adjust it so that it contacts the 50T :shock:

It looked as though it was set by eye to be a similar gap to what I used to do my 10-speed set up. That gap is not enough for 12-speed. And that was from a well known bike retailer that was selling lots of Whyte bikes. (So it wasn't Halfords!)

The Rookie

steve_sordy wrote:

So there is a practical limit. On my 27.5" wheels (radius 13.25")

erm, two errors in one... 27.5 wheels are actually 27” (using the measuring system that started MTBing with a 26” wheel being the diameter with a two inch tyre, 27.5 actually having a rim diameter 25mm larger than a 26”) and half of that is 13.5” or half your 27.5” is 13.75” anyway!

Of course a 29er is actually 28.5” but for marketing the ‘roughly half way size’ of 650B I was called a 27.5......

Chain and lots of Whytes sounds like LLC!

steve_sordy

The Rookie wrote:

steve_sordy wrote:

So there is a practical limit. On my 27.5" wheels (radius 13.25")

erm, two errors in one... 27.5 wheels are actually 27” (using the measuring system that started MTBing with a 26” wheel being the diameter with a two inch tyre, 27.5 actually having a rim diameter 25mm larger than a 26”) and half of that is 13.5” or half your 27.5” is 13.75” anyway!

Of course a 29er is actually 28.5” but for marketing the ‘roughly half way size’ of 650B I was called a 27.5......

.............

I own up to the simple maths error I divided 27.5 by 2 and got it wrong! As you say it should be 13.75" not 13.25". I have corrected my original post. Thanks for that. However, the error doesn't alter the conclusion that I came to.

But the rest, about wheel sizes, we are going to have to disagree.
It very much depends upon what tyres you have fitted. I just measured the 27.5 x 2.4" HRII on my Capra and they measured at a small fraction under 28". When my mate and I were on 26ers with 2.2"Conti Trail Kings, he bought a new bike, one of them new-fangled 650b jobbies with the 27.5" wheels. On our first ride together I asked him what difference he could feel. When he said zero, I got my tape measure out (I was experimenting with sag that day). His wheel diameter with Scwhalbe (2.25 Rapid Robs I believe) was 27.25". But my 26er was 26.75". No wonder he couldn't tell the difference, the diameter was less than 2% different!

I have never owned a 29er, so I never had cause to measure the wheel diameter, but until I do I'm happy to accept your statement about their true size.

02gf74

steve_sordy wrote:

I have never owned a 29er, so I never had cause to measure the wheel diameter, but until I do I'm happy to accept your statement about their true size.

25" without tyres.

jamski

11 or 12 speed is the limit for me. It’s more about range than increments in between top and bottom. Happy with my 11 speed Shimano, a 32t chainring and 10-46 cassette gives me enough range.

roger_merriman

Personally I’d be more interested in the lack of maintenance, that hydraulic systems give, than the 13vs 12 speed etc.

The Rookie

steve_sordy wrote:

But the rest, about wheel sizes, we are going to have to disagree.
It very much depends upon what tyres you have fitted.

The 26" was defined with a 2" (carcass not knobs) tyre, the wheel size can't change with the tyre or you'd never know what you needed to buy, but yes a 27.5 with 2.4" tyres will measure up about 27.8" to the carcass or about 28.2" with a reasonably normal 5mm knob height. Doesn't change the fact a 27.5 rim is only 25mm bigger diameter than a 26" one.

I do agree its acedemic though, the darn derailleur is going to be rather close to the ground (although won't be pointing straight down on the biggest sprocket as you intimated but rather when about 1/2 way down the cassette).

steve_sordy

The Rookie wrote:

..............

I do agree its acedemic though, the darn derailleur is going to be rather close to the ground (although won't be pointing straight down on the biggest sprocket as you intimated but rather when about 1/2 way down the cassette).

Hmm, I must go have a look next time I'm in the garage. It is not something I have paid much attention to until now. It shows what assumptions can do! :oops:

I wonder what gear choice does give the lowest ground clearance for the mech? I will report back.

(I'm Iceing my knee at the moment.)

supersonic

So 11 speed (1x) was introduced by SRAM to remedy the shortcomings of the front mech, and 2/3x systems. They then introduced 12 speed Eagle to remedy the shortcomings of the range of 11 speed. Rotor have introduced 13 speed this to fix shortcomings in the steps between gears of 12 speed systems... Maybe Shimano's original 14 speed patent may actually be waiting in the wings!

I remember the first time I saw a 7 speed 'MegaRange' 14-34 freewheel lol, and being amazed at that dinner plate out back.

Is interesting though that, alsongside their new 1x 12 speed stuff, Shimano still have an XTR front mech and shifter. It looks pretty well refined and usefully light. I still think that there is a place for it for certain riders and bikes. I probably wouldn't run a double with the large range cassettes available - but on an XC bike, a 10-30 cassette with say a 21/37 double would interest me.

02gf74

supersonic wrote:

. Rotor have introduced 13 speed this to fix shortcomings in the steps between gears of 12 speed systems..
.

I have to say with my style of pedalling off road I'm not too fussed about the steps, I reckon I can get way with 2 gears for extreme uphills, 2 for level ground and 1 or 2 for downhill or flat on road, that is 6 in total. Id rather have cassette biased to the low gears so I don't have to walk uphills as I can always freewheel down hill.

On road is is different story where my cadence is kept constant so I'm forever changing gear.

The Rookie

steve_sordy wrote:

Hmm, I must go have a look next time I'm in the garage. It is not something I have paid much attention to until now. It shows what assumptions can do! :oops:

I wonder what gear choice does give the lowest ground clearance for the mech? I will report back.

On a 1x with correctly sized chain (big sprocket and plus 2 links (at max chainstay length on an FS) the lower run is almost straight and the mech pulled right forward. If its spot on on capacity it will be doubled right back on the smallest sprocket which means around the middle of the cassette it will be pointing straight down but the parallelogram action to follow the cassette profile will have lifted the upper jockey and therefore the cage.

Example of correct chain length and mech on a 1x, apologies I couldn't find a picture with wheel and tyre logo's aligned as they should be!