What is the lowest gear inch possible on a trike?

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Trikeyohreilly
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What is the lowest gear inch possible on a trike?

Postby Trikeyohreilly » 11 Dec 2014, 1:17pm

Hi.

I am in the process of changing my rear end on my ICE trike from 20" wheel to 26". I'm going to be running the same crankset and cassette (lowest I know of) so it will have the effect of gearing up my trike. Problem is I already wanted to lower the gearing, but I have gone as far as I know how to with basic running gear. Iirc it was about 11gear inches with the 20" wheel.

What do you think is the most cost effective way of going way lower than 11" with a 26" wheel?

How low is too low? Following the brief of: A set of gears usable as crawling gears off road with full camping gear and supplies (about 25kg) for a rider whose legs can spin all day but rarely put heavy loads into the pedals and wants to push limits of riding steep and or very muddy and or rocky terain slowly.

Thank you. Ed

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Tigerbiten
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Re: What is the lowest gear inch possible on a trike?

Postby Tigerbiten » 11 Dec 2014, 1:47pm

The easiest way to get a mega range with a 26" back wheel is probably a 48-36-22 triple in front and a 12-32 cassette on a SRAM dual drive on the back.
Total range is 13"-141".
Going lower than that is harder/more expensive on a 26" wheel as you start looking at Schlumpf drives and/or Rohloff's.
A 48-36-22 front to a 16 sprocket Rohloff is 10"-114"

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[XAP]Bob
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Re: What is the lowest gear inch possible on a trike?

Postby [XAP]Bob » 11 Dec 2014, 1:50pm

I have an SA 3 speed in my rear wheel, which gives a normal SA decrease on top of the 32 tooth sprocket I have there.
Added to a 22 tooth front and it gets low...
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

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yakdiver
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Re: What is the lowest gear inch possible on a trike?

Postby yakdiver » 11 Dec 2014, 1:54pm

I don't know how to do inch gears, but my lowest is chainring 22 rear 32 with a wheel size of 24 inch
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Tigerbiten
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Re: What is the lowest gear inch possible on a trike?

Postby Tigerbiten » 11 Dec 2014, 2:01pm

yakdiver wrote:I don't know how to do inch gears, but my lowest is chainring 22 rear 32 with a wheel size of 24 inch

24" wheel x 22 chainring / 32 sprocket = 16.5" gear.

I've probably got the lowest to highest range at 9.5" - 172" but my setup wasn't cheap.

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[XAP]Bob
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Re: What is the lowest gear inch possible on a trike?

Postby [XAP]Bob » 11 Dec 2014, 2:10pm

I don't go quite as low, nor nearly as high.
22/32*.75*20" = 9.6"
48/11*1.33*20" = 108.7"
But mine is all standard, except the SA CS-RK3 hub in the rear wheel. Means that the Capreo cassette isn't needed, so I don't think it's a more expensive option (new wheel cost £160, as opposed to £75 being asked for the new cassette) and I had a couple of 9 spd cassettes around anyway.

Shlumpf + Rolhoff + double sprockets on Tiger's trike is awesome, but seriously expensive.

At ~10" you are still pedalling at ~40rpm at 1mph, which is happily tolerable on a trike.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

Trikeyohreilly
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Re: What is the lowest gear inch possible on a trike?

Postby Trikeyohreilly » 11 Dec 2014, 2:23pm

Right. Thanks

I'm currently running 22,32,44 up front with 36-12 at the rear. Though that I rarely use the 44. Once i get to "cruising speed" of about 16mph im happy. Rolling down steep hills glad of the rest.

Its going lower that I'm interested in. Sounds like its going to be expensive.

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[XAP]Bob
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Re: What is the lowest gear inch possible on a trike?

Postby [XAP]Bob » 11 Dec 2014, 2:26pm

The CS-RK3 isn't *too* costly - I'm happy for people to come and have a look (in fact last time I did that we worked out that SA made a batch with the wrong axle length).

It doesn't double the cost of the trike at least ;)
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

Trikeyohreilly
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Re: What is the lowest gear inch possible on a trike?

Postby Trikeyohreilly » 11 Dec 2014, 3:17pm

Bob, am I right to assume from your figures above that the lowest gear on your hub drops your gears by .75 and the 3rd raises them by 1.33 (2 being direct drive I.e. 1)? Leaving lots of gears over lapping but effectively giving you an extra lower chainring and an even higher one. This might do the trick and as you said at £160 for the wheel not brake the bank.I think I'm going to have to get to grips with Sheldons gear calculator. Hopefully your hub is on there.

Trikeyohreilly
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Re: What is the lowest gear inch possible on a trike?

Postby Trikeyohreilly » 11 Dec 2014, 3:33pm

Its ok thanks Bob. I just saw from the calculator that it is what I thought it was. Cheers

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[XAP]Bob
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Re: What is the lowest gear inch possible on a trike?

Postby [XAP]Bob » 11 Dec 2014, 4:29pm

Exactly that, I use direct drive mostly, but have a 0th and a 4th chainring. So I hat a 22*.75=15.5 tooth granny ring onto a large sprocket.

Additionally I can drop a gear range when stationary (after a hard stop at lights for instance)
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

Trikeyohreilly
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Re: What is the lowest gear inch possible on a trike?

Postby Trikeyohreilly » 11 Dec 2014, 4:55pm

I'm going to have to look at the gear calculator again. Your hub was on there but didn't seem to drop it that much. In hindsight I think I was wrong with what I thought I had in gear inches in the first place. A 15.5 tooth effective bottom chain ring sounds like just the ticket! Leaving it in direct drive most of the time sounds like less wear on the hub too.

Besides I think it may be the only option. Half hour reading schlumpf's FAQs has left my head spinning and my wallet in palpitations.

Cheers

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[XAP]Bob
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Re: What is the lowest gear inch possible on a trike?

Postby [XAP]Bob » 11 Dec 2014, 4:59pm

If you're around rugby then drop in
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

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[XAP]Bob
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Re: What is the lowest gear inch possible on a trike?

Postby [XAP]Bob » 11 Dec 2014, 5:36pm

Gear inches is the size of the virtual wheel you have - so your actual wheelsize multiplied by the ratio provided by the gearing.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

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Tigerbiten
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Re: What is the lowest gear inch possible on a trike?

Postby Tigerbiten » 11 Dec 2014, 5:59pm

eddiewalkling wrote:Besides I think it may be the only option. Half hour reading schlumpf's FAQs has left my head spinning and my wallet in palpitations.

Cheers

The easy one to remember is a cadence of 100 rpm in a 100" gear will see you doing 30 mph on the road.

I love my Schlumpf HSD and Rohloff combo.
I took me a couple of years to get the right combo of chainrings and sprockets.
Normal range 38/21 and 53/21 lets me pedal up to 14 and 20 mph.
Then I kick it into overdrive which lets me go 2.5x faster ..... :lol:
Downside is that it set me back around £2k :shock: when I had the trike built by ICE.

If you want to see/try my setup I based between Northampton and Wellingborough.