skibunny

Hi,
I am new to the forum. I recently moved from the UK to France with my Pashley Britannia. In the UK we lived in a reasonably flat area. We now live on the edge of the Pyrénées which means it is much more hilly. The Britannia has 5 speed Sturmley Archer gears. I have read various places that I could consider getting either a bigger back cog thingy (chainset?? don't know official name) or a smaller front one which would shift all the gears lower making it easier to get up hills but less power downhill (which would be fine as I don't like going fast and never use 5th and rarely 4th anyway)
Does anyone have a view about which would be better thing to do or can anyone explain what if any the difference in performance/feel would be between the two options? Also how much bigger or smaller should I get??

T-Mar

How big or small you go depends on the terrain and your climbing ability. It's going to be a bit of trial and error. However, I supsect that neither option is going to be entirely satisfactory. The main reason is that your shifting the entire gearing spectrum to the low end. To obtain gears that are low enough for the hills, will probably result in your spinning out on the flats (i.e. you can't turn the cranks fast enough to obtain your normal crusing speed).

A rear cog change is certainly cheaper but I don't believe the cog selection is big enough to make the type of difference you'll probably need. Depending on your crankset design, you may not be able to get a small enough chainring for those hills.

Basically, rather than shift the entire gearing spectrum you want to broaden/widen the spectrum, retaining the current gearing for flats and downhills while adding lower gears for the climbs. There are a couple options that retain the current 5 speed internally geared hub but they are much more expensive. First is to perform a mutiple cog conversion to the existing hub and add a rear derailleur. The second is to convert to a mutiple chainring and add a front derailleur and chain tension device. However, these options are fairly costly and still a compromise. Of course, you could always do both. The best solution, certainly the easisest, may be a new bicycle with suitable, wide range gearing.

skibunny

You are probably right that a new bike is the most sensible answer in some ways. But I love the Pashley and am hoping I can find some solution that lets me keep it. Perhaps taking it in to the shop and seeing what could be done re changing the front or back cog (I am not really a bike expert and cannot tell what might be possible) and then try it out for a while.
I have been reading this blog https://lovelybike.blogspot.fr/ and the writer things that the Princess (which is the same as the Brittania) isn't ideal for going up hills even with better gearing. She has various lovely vintage bikes which made me think about buying some oldish steel frame and putting some suitable gearing on to it (it may be obvious I don't know too much about bikes... but I can learn right?)
There are a couple of bikes advertised close to me https://www.leboncoin.fr/velos/343785943.htm?ca=16_s and https://www.leboncoin.fr/velos/343791476.htm?ca=16_s which look interesting. However it seems that (and it makes sense) the conformation of the frame is important to whether the bike will go up hills well or not. How can one tell this? It is hard often to try older bikes as they are a bit knackered and need work before they can be used.
Where do I start in my ambition to restore a vintage bike**********

Grand Bois

It would not be expensive to try a larger cog. It would just be the cost of the cog and a chain. I live in the hills and I was able to make a SA 5 speed work for me by gearing it down.

conspiratemus1

When all is said and done, the only things that matter a lot in hill climbing are your own muscle stamina and how low a gear you can bring to the task. From the link you included I'm gathering your Pashley weighs just below 30 lb. That is on the heavy side to be sure, but while you would probably notice it if it weighed 6 lb. less, you wouldn't really climb all that much faster since the weight of bike and rider together dictates how fast you climb.

Frame conformation, which I interpret as geometry?, doesn't make all that much difference in climbing ability per se. There is a lot of mumbo-jumbo about stiffness and compliance affecting energy conservation but this is more something to get interested in if you are already shopping for a new bike, and should not be seen as a reason to become unhappy with a bike you already own, and enjoy.

I agree the best thing to start with in the foothills of the Pyrénées -- lovely country! -- is to try to put a larger sprocket on the rear hub, to give a lowest gear of about 40 inches. In Europe and UK, this would equate to a "development" -- the distance the bike rolls with one complete revolution of the pedals -- of about 3.2 metres (if I've done the conversions and multiplication by pi correctly.) This will help you decide if your flatlander bike is going to be versatile enough for its new home. You may find that you need higher gears as well as lower, once you start to get confident with the speeds you can make downhill. And then it's time for a new bike with 18 to 30 gears.

zukahn1 

+1 normaly to change to lower gearing on a bike like this you change to larger cog on the hub. I would definetly try this and see how it works before resorting to the much more pricey options. If you want to keep the bike and leave it basically intact you could also change to IGH hub with more gears, but this is a really pricey option.

skibunny

So how would I work out how many teeth I need (or how are the cogs sized?)

jrecoi

We really can't determine anything about changing the gearing without knowing what gearing you have, that is to say how many teeth you have in the front chainring and in the rear sprocket.

The usual method of comparing gearing is by gear inches, which are calculated by multiplying the number of teeth in the front chainring by the diameter of the rear wheel in inches (since it is a Pashley Britannia, we'll go for 26") and the result divided by the number of teeth in the rear sprocket. Since your bike has an internal gear hub, the other ratios are calculated from published information from the manufacturer. There are online gear calculators have options for internal gear hubs.

Sheldon Brown has a wonderful gear calculator that works with gear inches as well as meters of development as well as an option for internal gear hubs https://sheldonbrown.com/gears/

Since you mentioned that your top, fifth gear is uselessly high, with the fourth being so high that it is rarely used, lowering the gearing is perferable. The eternally informative Sheldon Brown has an article with some reccomendations on this topic: https://sheldonbrown.com/internal-gears.html#sprockets

I'm not sure about current Sturmey Archer hubs, but the old AWs had cog drivers long enough to stuff in two cogs and shifted with a derailer. This was a hack used from the 30s up to the early 60s, and there is enough of a demand for this for both SRAM and Sturmey Archer to sell dedicated hubs for this kind of gearing. In your case, this is a last resort, for mysterious reasons, manufacturers set up bikes with very tall gearing, and lowering it usually resolves things.