Anyone using an 11-speed 11-42t (or similar) with a triple chainset?

[Tigerbiten]

As the gears get silly low, not only does it get harder to balance side to side on a bike but the front-back balance gets more critical as well.
The lower the gear, the more torque there is trying to lift the front wheel.
If you sit to upright on a steep hill in a very low gear then the front wheel will lift.
This effect is one downside of a single wheel driven delta trike.
The front wheel becomes light enough so the sideways force from the single driven wheel causes it to bounce sideways across the road and you lose all steering.

So you lean forward a bit to increase the weight on your front wheel to keep it down.
This lightens the load on the back wheel and reduces the amount of friction between the tyre and the road.
Lean forward too far and the amount of friction drops so low that the back wheel just spins and you don't go anywhere.
This effect is one downside of a tadpole trike due to naturally lower loads on the back wheel.
I can climb any hill on mine as long as I can keep traction.
But once the back wheel starts to spin due to loss of grip due to water, mud, dead leaves, etc on the road then I have to get off and walk.

So silly steep hills in silly low gears can be more of a balancing act than you'd think.

Luck .....

[Manc33]

The lower the gear, the more torque there is trying to lift the front wheel.
If you sit to upright on a steep hill in a very low gear then the front wheel will lift.

Yep. You'd have to ride it strategically and get a good, smooth cadence up, as opposed to any sudden kicking.

Lean forward too far and the amount of friction drops so low that the back wheel just spins and you don't go anywhere.

I remember going up a steep hill (just doing a recreational ride) and although it was about 4°C at the bottom of the hill, there was ice on the hill itself, but I didn't know that and could feel the rear wheel slipping. I carefully got off the bike and walked back down, since going down the other side on ice (on 700x25c) didn't seem like anything I wanted to be risking. The gradient was about 9%.

I think the trick would be to pedal fast in a gear as low as the above. It's hard to balance if you're fatigued though as well, it can be hard at 22x32t.

The thing is with the above setup, you could just never use the granny - but know it's there with three "super bailout" gears, if needed. Arguably a 34+50t double would be the best bet on it. Then you have still got 18.3" as the lowest gear (34x46).

[Bmblbzzz]

[quote="Manc33"It's a challenge staying balanced yes but what's harder is pushing off again up a steep hill if you stop. It sounds like it would be a laugh having gearing this low.[/quote]
The point at which a gear becomes too low to start off is higher, for me at least, than the point where it becomes too low for continued climbing. I think 12" is probably below both. But perhaps this is the sort of laugh you meant?

[Tigerbiten]

I'm looking at this from a recumbent trike standpoint where a wide range with an ultra low first gear is reasonably standard.
An 11-42 with a triple is well over limits of the range a derailleur setup so you won't get the full benefits from it.
If the maximum overall range is 50 teeth then going roughly 30-20 front-back with the SA 3 speed hub probably the way to go.
Because you're basically working with 5 chainrings with the SA hub option then it's a lot easier to fine tune the gears.
Going with a rough 30-30 split means you're really only working with roughly 2.5 chainrings so it will be a lot harder to fine tune the gears.
Both options may give you the same gear range but the 11-42 setup may only give you half the gear options.
The only way I could see it as a viable option is if you modded the rear derailleur cage so the overall range is somewhere around 65 teeth, then would you get a simple sistem with all the gears usable.

[Manc33]

Modding the swingarm length could be an option but on 26" wheels the rear mech swingarm on the M8000-SGS is already only a few inches off the ground. It's 107mm between the jockey wheels giving a total capacity of 47t. Older mechs like the 9-speed M772 SGS are 100mm so, they are getting longer. I don't know why Shimano doesn't just make all different swingarm lengths, it's not that hard to swap a swingarm. The only problem would be it getting too close to the ground. On 29" wheels or 700c it's probably doable.

[StephenW]

The only way I could see it as a viable option is if you modded the rear derailleur cage so the overall range is somewhere around 65 teeth, then would you get a simple sistem with all the gears usable

Perhaps you could have a sprung return idler that helps to take up the slack in addition to the rear derailleur?

[Tigerbiten]

The only way I could see it as a viable option is if you modded the rear derailleur cage so the overall range is somewhere around 65 teeth, then would you get a simple sistem with all the gears usable

Perhaps you could have a sprung return idler that helps to take up the slack in addition to the rear derailleur?

Not easy or simple on a bike.
It would not only have to move up and down to keep the chain tight.
But also move side to side to keep the chain line straight.
Otherwise you'll get too much sideways bend in the chain.

Quad chainrings where only a passing phase due to the range limitations of the cassettes at the time.
Now with range of modern cassettes there isn't really the need for a fourth chainring.

Luck .......

[NickJP]

My touring bike with Rohloff hub, 38t chainring, and 17t sprocket, has a low gear of 16.9". I've been quite thankful for that a few times when touring in Switzerland, where I went up several climbs with average gradients over 10% and max gradients over 20%. I carry most of my touring load in front panniers so that I don't have problems with the front wheel lifting off the ground. I find I can comfortably climb steep gradients at around 6kph without having problems keeping the bike stable:

[Manc33]

16.9"

That's about the same as 22x36 on a 700c wheel (25c tyres) and from experience is about as low as it gets without it becoming a balancing act, unless you go at a high RPM, but I never like doing that uphill.

I have thought many times about getting a Rohloff hub, but I am not sure about the high gears if I have my lowest set at something like 17".

On my current triple with a MTB cassette it's got a range of 793%

That's another thing I made a calculator for

Code: Select all

https://www.sendspace.com/file/upoq6c

[Tigerbiten]

I have thought many times about getting a Rohloff hub, but I am not sure about the high gears if I have my lowest set at something like 17".

On my current triple with a MTB cassette it's got a range of 793%

That's fairly easy to do.
Just run a 15t sprocket on a Rohloff with a 50/34 compact double.
That will give you 17 gears and a 772% range.

Luck ........

[Manc33]

That's so tempting.

I have found that a few 11-speed cassettes with a 34t or 36t low sprocket can be used on a standard (9s/10s) freehub body.

The SunRace MS8 in an 11-36t will fit on the old hubs. I quite like the spacing on those since they start with 11-12-13t.

The 11-speed Shimano CS-HG700 11-34t starts off with 11-13 sprockets so it has that awful gap between the 2 smallest sprockets!

Shimano, why you do this when you've got the luxury of 11 sprockets to play with!



The solution then seems to be the SunRace MS8 (11-36t) that is priced reasonably and it starts off with 11-12-13 - meaning yes OK it fans out more towards the bigger sprockets as a result, but those are the sprockets where you want it to have bigger gaps, if anywhere, not where the 11-12-13 is (those are always used on the middle chainring on flat roads!)

No one is using a 25t or bigger unless they are going uphill and when a sprocket is bigger than 25t you don't want it going to a 27t, that's just absurd to me, it's a jump of just 11.1% where you'd want it to be more - Shimano messed up doing it that way IMO.

[Samuel D]

The 11-speed Shimano CS-HG700 11-34t starts off with 11-13 sprockets so it has that awful gap between the 2 smallest sprockets!

Shimano, why you do this when you've got the luxury of 11 sprockets to play with!

I think this gap is in recognition that the 11T is intended for optional pedalling, not hard, sustained work for which precise cadence is desirable.

But when you use a smaller chainring than Shimano intended, in order to make the 11T a working gear rather than a gee-whiz range extender, the gap makes less sense.

[CXRAndy]

I have Kinesis Tripster ATR V2 which I have fitted a Deore Triple crankset 48/36/26 and I either use a 11-32 cass or 11-40 for mountains. This is shifted with XT/XTR Di2 front and rear on road shifters. I developed the setup from using a 44/28 mtb crankset.

I use syncro shift to limit cross chaining. I tend to use the 36t for upto 8% long climbs and drop into the 26t inner ring over 12%

I can climb 40% gradients seated(albeit wheel lifting) and cycle over 50mph on the 48-11 gearing.

I like having the 26t, allowing me on those occasional times where I just want to keep going but drop into zone 2 HR on a climb.

[Samuel D]

I can climb 40% gradients seated(albeit wheel lifting) and cycle over 50mph on the 48-11 gearing.

… at 143 RPM and lower road speed than tucking and coasting in the same conditions. So why do you prefer pedalling at 143 RPM to coasting at higher speed?

You’re not alone in this preference, but it intrigues me because of the seeming contradiction: pedalling as if wishing to go fast, but ending up going slower.

[CXRAndy]

I was giving the example of range the gearing offers.

You are right, if I remember correctly, I hit 145rpm at 53mph coming down Mt Teide chasing down my pack. I would usually coast above 35mph, but I was having a bit of fun that day