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

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Manc33
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Anyone using an 11-speed 11-42t (or similar) with a triple chainset?

Postby Manc33 » 15 Jun 2018, 9:34pm

The low gears would be absurdly low but is anyone running a 11-speed MTB cassette with a 42t low sprocket and a 22t granny ring?

You could carry an elephant on your back and still get up the steepest hills.

This would give about half a turn of the rear wheel for each full turn of the crank (0.52).

The chain would need to be so long it might not work on middle>small even on a SGS derailleur :|

The thing is there are triple 11-speed MTB groupsets with low sprockets at this size, or there used to be.
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Re: Anyone using an 11-speed 11-42t (or similar) with a triple chainset?

Postby Brucey » 15 Jun 2018, 11:50pm

back in the 1970s you could buy freewheels with ~38T sprockets. These were meant for half-step systems and I think some folk used them with triple chainsets. For a solo this is probably overkill but for recumbent machines maybe it has something going for it.

I think you will run out of total derailleur capacity with most derailleurs.

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

Postby horizon » 15 Jun 2018, 11:59pm

I'm currently running a 22T front with a 32T rear for camping trips on my Sardar which I think is fairly common. That's a 17" and I would like to get it lower at 34 on the rear, which again isn't that rare AFAIK to give me 16.26".

The problem then is that either the bike becomes generally difficult to handle (because you are using the gear to get a very heavy bike up a hill) or it becomes impossible to balance at that speed (it already zig-zags a lot). In any case, you can at that point get off and push with little loss of speed (I know we have discussed this on the forum - not everyone agrees!). But for me, after 34/22 it's time to reduce weight on the bike, push or avoid that hill.

But with a recumbent, all that changes ....
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Re: Anyone using an 11-speed 11-42t (or similar) with a triple chainset?

Postby Valbrona » 16 Jun 2018, 3:11am

Yeah, but who rides up steep hills with an elephant on their back?
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Re: Anyone using an 11-speed 11-42t (or similar) with a triple chainset?

Postby brynpoeth » 16 Jun 2018, 10:22am

Fit fold-down stabilisers like on a kiddies bike :wink:
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Mick F
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Re: Anyone using an 11-speed 11-42t (or similar) with a triple chainset?

Postby Mick F » 16 Jun 2018, 10:27am

Manc33 wrote:The low gears would be absurdly low but is anyone running a 11-speed MTB cassette with a 42t low sprocket and a 22t granny ring?
My arithmetic suggests that the gear with a 22/42 would be about 14" depending on tyre size.

Bottom gear on my Moulton is 16" so 14" is fine by me.
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horizon
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Re: Anyone using an 11-speed 11-42t (or similar) with a triple chainset?

Postby horizon » 16 Jun 2018, 10:53am

Mick F wrote:Bottom gear on my Moulton is 16" so 14" is fine by me.


It won't be - you'd overbalance.
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Re: Anyone using an 11-speed 11-42t (or similar) with a triple chainset?

Postby Mick F » 16 Jun 2018, 11:32am

Why?

16" will get me up anything I've ridden so far, but there is one hill (off-road) I'd like to try, and 14" would be better.

http://www.cyclingweekly.com/news/lates ... ide-352571
Scroll down to Kit Hill, but that climb is easy peasy done it many many times all the way from Lucket to the summit.
I'm suggesting the incline. Very steep, long, and a bit rocky.
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horizon
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Re: Anyone using an 11-speed 11-42t (or similar) with a triple chainset?

Postby horizon » 16 Jun 2018, 11:45am

Mick F wrote:Why?

16" will get me up anything I've ridden so far, but there is one hill (off-road) I'd like to try, and 14" would be better.



Except that you would be going so slowly so you would fall off your bike. A recumbent, a cargo bike, a trike, a bike with stabilisers (as suggested above) would be fine. But I reckon there is also a danger point around 16" when you need to zig-zag and on a narrow road with traffic that can be tricky. Maybe that's just my front panniers but to need that gear you would probably have them.

PS I'm sure there are people who swear they can cycle up a hill on less than 14". :shock:
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Re: Anyone using an 11-speed 11-42t (or similar) with a triple chainset?

Postby tatanab » 16 Jun 2018, 11:53am

horizon wrote: I'm sure there are people who swear they can cycle up a hill on less than 14".
About 30 years ago I met a chap whose preferred touring region seemed to be the deserts of Africa. He had a bottom gear of 11" and said that he had proved to himself many times over that it was more efficient to ride a very low gear under such circumstances than to push the bike for what could be hours.

Not for me though in my preferred touring territory where a bottom gear of 22" works well enough hauling camping kit.

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

Postby pwa » 16 Jun 2018, 11:56am

The length of the arm on the rear mech is going to be the limiter (as Brucey says), with a huge range cassette and three rings I think you will end up with too much chain for the mech, and the mech folding up on itself with chain flopping between mech and chain ring.

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

Postby Mick F » 16 Jun 2018, 11:57am

I have no problems at all with 16" bottom gear, so I doubt 14" would be much different.

Biggest problem I have with Moulton, is that the steering is very light and twitchy at low speeds irrespective of gearing. The slower you go, the harder it is to steer a steady course. It's all to do with the small wheels being easier to steer as there's not much weight to turn left and right. I doubt I anyone could do a trackstand with a Moulton.

There's a road near here that is 25% and is ok to climb, but due to stones and gravel and grass in the centre of the road, there's only about a foot width to cycle on. Going slowly up there is difficult on Moulton, but easy on Mercian.

Given a wide enough bit of road, 14" wouldn't be an issue.
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Re: Anyone using an 11-speed 11-42t (or similar) with a triple chainset?

Postby RickH » 16 Jun 2018, 3:31pm

I've found that at very low speeds in a low gear it helps to get into the practice of balancing by weight shifting your upper body rather than trying to steer - that's how these trick riders, like Danny MacAskill, do it on very narrow objects such as riding along a handrail. :shock:

+1 for the derailleur capacity being the limiter. It might work but you'd probably lose use of the top half of the block, at least, in the granny ring with a big-big length chain length setup.

Manc33
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Re: Anyone using an 11-speed 11-42t (or similar) with a triple chainset?

Postby Manc33 » 16 Jun 2018, 5:02pm

The M8000 crankset from 2015 was a triple and it did have a 22t inner (40-30-22 I think) so presumably that had a 40t or 42t low sprocket and it was all officially sold as a groupset, meaning the corresponding XT derailleur in SGS must have been able to handle it.

On 9-speed there's a 12-36t I might try next, since the M772 can allegedly be pushed to 36t (it's arguably not close enough to the 32t even with the b-tension screw removed). Someone said you can run the M772 on a 36t but shifting around the middle of the cassette might be a bit laggy.

The 12-36t again puts a gap of 3t between 18-21 which is a pain, but there's a decent difference between 32t and 36t.

I found going to a 48t outer means I don't need an 11t (22-36-48 shifts fine at the front with the XT front mech) and if the 11t is scrapped, 12-36t (on 9-speed) is viable. There is only one 9-speed cassette with nice ratio's in 11-32t (that goes 11-13-15-17-19-21-24-28-32t) and it's unfortunately one of the cheapest cassettes going. :roll: All others have a gap at 18-21, or on 11-34t its 17-20. The 12-36t again has that gap of 18-21t.

2" at gear inches of only 16" or 14" is a lot :P it's 14.3% which is another full gear lower.

On 9-speed, I wouldn't bother with 11-34t when 12-36t are available. I did try the 11-34t and the 17-20 gap drove me mad. 32t to 34t is only a lower gear by 6.25% but from 32t to 36t it's 12.5% which is basically another gear. This is why I wouldn't mind seeing if 11-speed triple works, although I have not even looked at the ratio's and bet it needs to be 11-40t to not get that 3 tooth gap around the 17-21t range.

EDIT: The 11-speed 11-40t cassette is 11-13-15-17-19-21-24-27-31-35-40

That's alleviating the awful 17-20t or 18-21t gaps found on 9-speed, but 40t comes perilously close to 36t which can be had on 9-speed (sigh, with a 18-21t gap). 36t to 40t is 11% so on MTB its sort of 2/3 of a gear. This stuff drives me nuts. :lol:

I have tried cassettes with the 18-21t gap and that too drives me nuts. I think I'd rather just stick to the magic/unique cassette thats both 11-32t, 9-speed and doesn't have a big gap in exactly the place you don't want it.

Another option is a 20t inner chainring, but after seeing you'd have to file down the crank arm and the bolts as well, it's not worth it to get it only 10% lower.

My dad used to say "If your gearing is lower than 1:1 you might as well get off and walk" but I like not doing and staying on the bike. :oops:
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Re: Anyone using an 11-speed 11-42t (or similar) with a triple chainset?

Postby pwa » 16 Jun 2018, 6:37pm

I have walked up steep hills pushing the bike, and I have cycled up them. Cycling is the least uncomfortable if you can manage it. So there is a reason to want the lowest gear you can cycle without toppling sideways.