How low can you go? Gears.

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cycle tramp
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Re: How low can you go? Gears.

Postby cycle tramp » 16 Feb 2020, 8:51am

LittleGreyCat wrote:
Well, yebutt...

6 mph is a 10 minute mile which is a relaxed running pace.
Assuming your legs, knees and feet are up to even relaxed running.

I've used walking to increase fitness in the past, but 4 mph is about as fast as I can comfortably go after some building up days.
I have difficulty visualising walking at that pace pushing a loaded touring bike up a steep hill!


No.. definitely not running - if both feet are of the ground at the same time then you are exercising a different technique to the one to which i refer...
...stand up, swing first leg forward to only to the point where the heel of your first foot swings past the toe of the foot on which you are standing...
...very small leg stride, hardly and movement in the knee or upper leg, now repeat. See how much faster you are? Feel that you are not using the same amount of energy as with long strides? When the ground goes up, shorten your stride even more.
...its like cycling cadence. Not pushing your legs around in a high gear, more like spinning them in low, but achieving the same speed or greater as muscles are not tiring as much with each movement...

cycle tramp
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Re: How low can you go? Gears.

Postby cycle tramp » 16 Feb 2020, 9:09am

How long is big hill which you climb? In 2014, I was part of a group cycling from Lands End to John O'Groats, it was day 3 and we had Dartmoor to climb, the day was unseasonably warm and there was no wind..
At the very bottom I got of to walk... wishing my fellows a good days ride.... half way up the hill, I passed some of them, who had used all their energy and were now having to push and stop every 100 yards. Once at the top, I mounted and was on my way...
....half way over Dartmoor I was caught up by the fast bunch of the group, who on reaching the top decided to refuel at the first food stop....
... the day continued with me pushing my bike at every hill and I reached the destination as part of the middle group.

jimlews
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Re: How low can you go? Gears.

Postby jimlews » 16 Feb 2020, 9:50am

How low can you go?

Pretty much as low as you want. So how low do you need to go?

eg. I used to tow a log hauling trailer around the Haldon hills (just west of Exeter). My bike had a Sturmey Archer 3 speed gear and to get a gear low enough to climb the frequent one in three hills with a load on board, I fettled the cottered cranks to accept the 22 tooth chainwheel from an abandoned kiddies trike. With a 22T sprocket on the end of the Sturmey, I had a low gear of something like 17 gear inches. I was making up a 28T sprocket for the Sturmey when the bike was stolen.The bike had roller lever brakes which made going downhill interesting. They were disconnected at the time of its theft.

edit

At around the same time Pete Tansley, the local Exeter frame builder was constructing a hand cranked trike that used two SA Three speed hubs; one driving t'other, driving ( if I remember correctly) a seven speed wide ratio freewheel. I don't remember what the bottom gear was but it must have been extremely low.
Last edited by jimlews on 16 Feb 2020, 10:29am, edited 1 time in total.

Brucey
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Re: How low can you go? Gears.

Postby Brucey » 16 Feb 2020, 10:01am

the tortoise and the hare....? Hairy tortoises...?

There is more than one way to skin a cat (even if it is a hairy tortoiseshell). Walking up hills, in touring circles, is/was a widely accepted practice, especially when gearing isn't low enough. But if you are young, fit, obstinate and wearing cleated shoes, you are more likely to struggle on than get off and walk, and it isn't always the right decision.

At one time I was young, fit and daft (instead of old, unfit and still daft in plenty of ways) and I would struggle up hills on clearly unsuitable gearing, possibly spurred on by Neitzsche-esque thoughts of 'whatever doesn't kill you must make you stronger'. I also couldn't imagine ever needing gearing lower than about 27", even when packing a load in the Alps.

These days -rightly or wrongly- I take a slightly more nuanced view that 'whatever doesn't kill you might be doing you in anyway, in a different, slower, less obvious fashion'. And I welcome ever-lower gearing.

cheers
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whoof
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Re: How low can you go? Gears.

Postby whoof » 16 Feb 2020, 10:25am

cycle tramp wrote:How long is big hill which you climb? In 2014, I was part of a group cycling from Lands End to John O'Groats, it was day 3 and we had Dartmoor to climb, the day was unseasonably warm and there was no wind..
At the very bottom I got of to walk... wishing my fellows a good days ride.... half way up the hill, I passed some of them, who had used all their energy and were now having to push and stop every 100 yards. Once at the top, I mounted and was on my way...
....half way over Dartmoor I was caught up by the fast bunch of the group, who on reaching the top decided to refuel at the first food stop....
... the day continued with me pushing my bike at every hill and I reached the destination as part of the middle group.

This is two sides of the same coin. My bottom gearing was too high so I felt it was easier to get off and walk. My companions bottom gear was too high so they struggled riding up a hill and burnt themselves out. Nothing wrong with getting off and walking but engineering in a gearing that compels it isn't always necessary.

cycle tramp
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Re: How low can you go? Gears.

Postby cycle tramp » 16 Feb 2020, 4:39pm

whoof wrote:Nothing wrong with getting off and walking but engineering in a gearing that compels it isn't always necessary.


Absolutely... whenever I build I bike, it's based around both its use and the conditions and topography in which I expect to use in (within 20 mile radius of my home) and I would imagine that would be the same of all thinking bicycle users....
...what we all should be aware of is the amount of pressure that the cycle industry applies in order to sell expensive transmissions which run from 19" to 129" when infact the conditions that we find ourselves mostly riding in every day may require a simpler and less costly (in both initial outlay, maintenance time and part replacenent) which may cover a range of 24" to 85"
There is an under current in advertising that seems to suggest that if your bike doesn't have the correct gearing for every conceivable condition, you will not enjoy cycling as much... ..not only is that not true, but it also means that the bicycle rider is actually paying for equipment that they may never even use...

whoof
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Re: How low can you go? Gears.

Postby whoof » 16 Feb 2020, 6:00pm

cycle tramp wrote:
whoof wrote:Nothing wrong with getting off and walking but engineering in a gearing that compels it isn't always necessary.


Absolutely... whenever I build I bike, it's based around both its use and the conditions and topography in which I expect to use in (within 20 mile radius of my home) and I would imagine that would be the same of all thinking bicycle users....
...what we all should be aware of is the amount of pressure that the cycle industry applies in order to sell expensive transmissions which run from 19" to 129" when infact the conditions that we find ourselves mostly riding in every day may require a simpler and less costly (in both initial outlay, maintenance time and part replacenent) which may cover a range of 24" to 85"
There is an under current in advertising that seems to suggest that if your bike doesn't have the correct gearing for every conceivable condition, you will not enjoy cycling as much... ..not only is that not true, but it also means that the bicycle rider is actually paying for equipment that they may never even use...

I don't know where you are seeing bikes advertised but the vast majority of bikes are not touring bikes and the majority of these have gearing of 27" or greater very few with 20". A quick look at some shops selling touring bikes and even some of these have a bottom gear of 30 & 32" which would have many walking on the hills if loaded up.
As to costs my current tourer came with a bottom gear of 28/32 (26" wheel) giving a gear of 23" . For fully loaded camping I wanted 20" x so £11 for a 9 speed cassette with a 34 sprocket and £7 for a 26 tooth chainring. If someone finds this expensive they must live extremely frugally, I can't believe such a person would for instance ever drink a point of beer.

Brucey
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Re: How low can you go? Gears.

Postby Brucey » 16 Feb 2020, 7:30pm

If you can get by with a modest change in chainwheel and sprocket size (as per the post above), fitting lower gears need not be a major expense. However it all depends on the bike you start with; all too many OTP bikes come with the smallest chainring possible (on that chainset) and a RD that is already 'maxed out' which greatly limits the scope for cheap upgrades to give lower gears.

For example a road bike with a (typical) 'compact double' and a Shimano 11s 'road' groupset is stuck with 34/34 bottom gear. You can't fit smaller chainrings or larger sprockets without problems; the only 'cheap option' is a larger cassette and a gear hanger extender, but IME the shifting on the small sprockets goes to pot earlier in the life of the chain, and there are obvious problems that are likely to crop up if you run big-big or small-small in terms of total capacity of the RD.

All of which explains the enthusiasm with which the Shimano GRX groupset has been welcomed; the GRX RDs allow much lower gearing to be installed on such a bike, without too many compromises, and without buying half a bike's worth of parts. It still ain't cheap (you are in for a chain, cassette and RD), but it is a lot less expensive than it used to be to get lower gearing on such a bike.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

whoof
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Re: How low can you go? Gears.

Postby whoof » 16 Feb 2020, 8:04pm

Brucey wrote:If you can get by with a modest change in chainwheel and sprocket size (as per the post above), fitting lower gears need not be a major expense. However it all depends on the bike you start with; all too many OTP bikes come with the smallest chainring possible (on that chainset) and a RD that is already 'maxed out' which greatly limits the scope for cheap upgrades to give lower gears.

For example a road bike with a (typical) 'compact double' and a Shimano 11s 'road' groupset is stuck with 34/34 bottom gear. You can't fit smaller chainrings or larger sprockets without problems; the only 'cheap option' is a larger cassette and a gear hanger extender, but IME the shifting on the small sprockets goes to pot earlier in the life of the chain, and there are obvious problems that are likely to crop up if you run big-big or small-small in terms of total capacity of the RD.

All of which explains the enthusiasm with which the Shimano GRX groupset has been welcomed; the GRX RDs allow much lower gearing to be installed on such a bike, without too many compromises, and without buying half a bike's worth of parts. It still ain't cheap (you are in for a chain, cassette and RD), but it is a lot less expensive than it used to be to get lower gearing on such a bike.

cheers

Absolutely, but the people having to replace half the components on their bike weren't sold a bike with unnecessarily low gears as the post above mine suggested. If fact it's the opposite.
Edit and if the solution to the lack of a low enough bottom gear was get off and walk then people wouldn't need to come on here and ask I'm sure they could work this out for themselves.

cycle tramp
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Re: How low can you go? Gears.

Postby cycle tramp » 16 Feb 2020, 9:40pm

whoof wrote:
Brucey wrote:Absolutely, but the people having to replace half the components on their bike weren't sold a bike with unnecessarily low gears as the post above mine suggested. If fact it's the opposite.
Edit and if the solution to the lack of a low enough bottom gear was get off and walk then people wouldn't need to come on here and ask I'm sure they could work this out for themselves.


You're right and I would like to apologise. I did use an unsupported example... what I should have stated was that we should be aware of the cycle industry selling expensive transmissions the range of which fails to met our requirements, whereas the transmission which suit own needs better may have less of an economic impact.
The example you gave of your own transmission seemed the perfect balance of cost and performance. Rather embarrassingly I use a IRD freewheel, it could well be that you'll have 'more bang for your buck'
If course it's not only the cycle industry which exterts this continual ideal of pressure of performance. Its prevalent in the cycle press as well. The idea that if you don't have the lightest bicycle, with the lowest and highest gears available or the highest performing brakes, that you are somehow missing out.
Well I for one don't and i am happy that I don't. Cycling is a fine past time. But the enjoyment of the journey relies so much more than the abilities of the bicycle.
.. if you enjoy the odd pint then the discovery of a fine public house is another aspect..

Sid Aluminium
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Re: How low can you go? Gears.

Postby Sid Aluminium » 16 Feb 2020, 9:47pm

LittleGreyCat wrote:It does beg the question, though, of how low you can go and still have a rideable bike.
What is the lowest gearing where you could expect to stay on the bike (gyroscopic action of the wheels) when climbing an extreme 1 in 4/25% gradient?



For your amusement - 1 in 3, 7.5 gear inches:

https://youtu.be/FgIL6eHHgZU

wheel71
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Re: How low can you go? Gears.

Postby wheel71 » 17 Feb 2020, 11:06am

Sid Aluminium wrote:
LittleGreyCat wrote:It does beg the question, though, of how low you can go and still have a rideable bike.
What is the lowest gearing where you could expect to stay on the bike (gyroscopic action of the wheels) when climbing an extreme 1 in 4/25% gradient?



For your amusement - 1 in 3, 7.5 gear inches:

https://youtu.be/FgIL6eHHgZU


That must be about as low as you can go. He must have good balance. :lol:
That hill looks fun too.

Brucey
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Re: How low can you go? Gears.

Postby Brucey » 17 Feb 2020, 11:15am

cycle tramp wrote:
whoof wrote:
Brucey wrote:Absolutely, but the people having to replace half the components on their bike weren't sold a bike with unnecessarily low gears as the post above mine suggested. If fact it's the opposite.
Edit and if the solution to the lack of a low enough bottom gear was get off and walk then people wouldn't need to come on here and ask I'm sure they could work this out for themselves.



.


I don't think I said that, did I? :shock: :shock: :lol:

cheers
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PH
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Re: How low can you go? Gears.

Postby PH » 17 Feb 2020, 12:13pm

whoof wrote:Edit and if the solution to the lack of a low enough bottom gear was get off and walk then people wouldn't need to come on here and ask I'm sure they could work this out for themselves.

Ha! I don't think anyone has posted that thinking it was going to be a revelation. I'll continue to say it, not because I think it hasn't occurred to anyone, but in an attempt to counteract the opinion that in doing so you have somehow failed.
Walk/don't walk, choice is yours. If you challenge yourself to ride up a hill and you don't, you've failed. Just don't let anyone else set those challenges for you, or think you have to follow someone else's rules.

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[XAP]Bob
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Re: How low can you go? Gears.

Postby [XAP]Bob » 17 Feb 2020, 1:39pm

Sid Aluminium wrote:
LittleGreyCat wrote:It does beg the question, though, of how low you can go and still have a rideable bike.
What is the lowest gearing where you could expect to stay on the bike (gyroscopic action of the wheels) when climbing an extreme 1 in 4/25% gradient?



For your amusement - 1 in 3, 7.5 gear inches:

https://youtu.be/FgIL6eHHgZU



I'm sure somewhere in this thread (haven't looked for the quoted section) someone will point out that the gyroscopic effect isn't what keeps a bike upright, and in fact at low speeds is negligible anyway.
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.