calling Brucey.. SA touring potential

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nat
Posts: 4
Joined: 6 Dec 2018, 1:04pm

calling Brucey.. SA touring potential

Postby nat » 6 Dec 2018, 3:05pm

Hello all, a question for Brucey if I may. Of course, no-ones input is ' out of bounds'! I will shortly be starting to tour, my first area concerns Spanish mountains. Now, I have a choice of cycles to use. The thorn, though built for the purpose in every way, is a mite heavy and, has 27 spd derailleur. Yes no great issue, bar the input of grinding paste via granite (around here) but, will always be so via some medium. Which brings me to my point-
SA hubs on two other bikes. One, the venerable Aw. Two, a 7 spd sprinter. Raleigh twenty/ Moulton apb respectively. No problems with maintenance/ mods etc etc but, what I wish for is a ' trueism' on touring with minimal gears. I read your 30 yrs SA story and, to be honest, I'd buy the book if that story were expanded. Well done to you. I've swopped cog, running 46/ 21 on a 451 rim atm. Thing is, though legs can get me up most in Cornwall, my (old)hernia starts to winge a touch!!
Clearly, that's not good.
So, carry on modding R20 / add SA fw 5spd conversion x2 sprockets and braze in horizontal dropouts, so as to be able to go more than 3 teeth difference, and kick in the granny sprocket for the hardest stuff. Or, use APB and hope hub holds up, potentially add sprocket again. Lastly, give up on the love of classic/ 'it stuck around as it works ' hubs/ a nice chainline , and go derailleur ( living with the grinding paste mix, plus it's not KISS principal any more) or indeed, new igh?? Though cvt was nice in principal, I didn't get on with nuvinci.
Fwiw, I've spent my life restoring classic cars/ building historic racers, hence my love of old gear. Design classics, will always be ' my thang'. Theft, will also be dialled down with older gear, is the assumption.
I thank anyone who chimes in with constructive replies,in advance.

Brucey
Posts: 31553
Joined: 4 Jan 2012, 6:25pm

Re: calling Brucey.. SA touring potential

Postby Brucey » 6 Dec 2018, 4:03pm

sprinter 7s hub is not especially reliable in hard use and suffers the disadvantages that spares are now getting incredibly difficult to find and (AFAICT) other SA internals don't fit into that hubshell. On the plus side with small wheels it sees an easier time of it (lower torque) and if it has lasted this long it can't be too badly suited to your use.

The 'old' twin toggle SA 5s hubs (converted FWs, S5s, but not the 5-star) have the killer advantage that if the centre claps out, you can whack an AW internal into the same shell and be on your way. Thus with that style of TT5s or an old AW, major blow ups are not such a concern; most places in Europe will have old AWs lurking about the place. New AW internals fit too, BTW.

I have always carried enough tools (a couple of spanners plus a drift that I can hit with a borrowed hammer or a rock) to strip an AW or a TT5s hub. If I wanted to be really well prepared I'd carry a spare axle, spare pawls, toggle key and spare pawl springs.

The latter parts are not very likely to fail but are easy to carry. However a broken axle is a real possibility and more of a show-stopper; this eventually failed in my highest mileage hub, cracking across the toggle key slot. Had I had my wits about me, I wouldn't have ignored the loud crack sound that preceded the final failure; that sound was the first side of the crack near the slot breaking through to the slot, about a week before the end. 'Old' AW axles can have sun pinions that fail or the axle can crack where the sun pinion rivet goes through it.

With any SA hub you can fit more than one sprocket, use a derailleur and have an extended gear range that way. If you don't want a tensioner at all, you can run a second sprocket and chainring (leaving the chain slack enough to be manually derailed into low range) such that it makes what I call a 'Magic Alpine Double', i.e. so that the chain is equally tight on either chainring/sprocket pair. For example 46/19 give the same chain length (magic gear) as 36/30 and with a 5s gear you can have ratios from about 22" to about 100" this way.

So I'd happily tour on a modern NIG AW because the axle is (QA concerns asides) stronger built. However I'd fit the Rh tab washer than is now omitted by SA and I'd be careful that the actuator plate was in good condition though. A simple way of fitting multiple sprockets to one of these is to use a Brompton BMW driver; (the standard NIG driver isn't quite long enough to accept multiple sprockets easily, eg without losing the dust shield over the ring bearing).

I can see the appeal of an IGH for touring in mucky conditions but there is more than one way to skin a cat and all that; if you are worried about wear on a derailleur transmission, you can address this in various ways. An easy way is to carry a spare chain and to fit that when the original one gets too dirty/slightly worn. The old chain can be cleaned and reused or binned. With an 8s system reasonable chains are cheap enough to throw away, more or less.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Greystoke
Posts: 111
Joined: 8 May 2018, 7:41am
Location: Lincolnshire

Re: calling Brucey.. SA touring potential

Postby Greystoke » 6 Dec 2018, 6:02pm

Brill. Planning a similar commuter/tourer project of my own with SA plus a few cogs.
Just got a few old technology rally cars to finish first :D

robc02
Posts: 1565
Joined: 23 Apr 2009, 7:12pm
Location: Stafford

Re: calling Brucey.. SA touring potential

Postby robc02 » 6 Dec 2018, 7:10pm

I've done a few camping tours using a late '80s spec SA 5 speed / drum brake. The bike was geared 32x17 on 700c wheels, so had gears from about 33 to 76 inches. The first trip was Lon las Cymru for which my bottom gear wasn't really low enough - and I swore "never again"! The other trips were much less demanding and the setup was perfectly OK.

I have also done a couple of two or three day camping trips on a 1950s Humber roadster with a four speed dynohub. Direct drive was 46x20 on 26 inch (590 ETRTO) and was OK on gently undulating stuff.

nat
Posts: 4
Joined: 6 Dec 2018, 1:04pm

Re: calling Brucey.. SA touring potential

Postby nat » 7 Dec 2018, 8:55am

Great. Thank you to all thus far. Brucey, I have no major aversion to derailleur, bar the noise/ maintenance / replacement. I do a fair bit of off roading and ( along with rim brakes) can just hear grinding! To my mind, cycling was never meant to include constant cleans/ adjustments/ replacements. I'm sure you know how granite+ water = constant brake block adjustment ( angular) plus replace / constant chain clean ( never perfect) etc. If I hit the trails at 50% every day, I'd be buying cassettes/chains/ derailleur jockeys/ chainring/ brake blocks consistently.
The igh approach, though not perfect, aligns fiscally with the initial ethos. Or succinctly letting you in on my brain, I tune engines via sound/feel ( after using 'proper' stuff) , also pick up most other problems via the same medium....sound, with a touch o feel. Therefore, it's the knowing side of wear that- pun intended... Grinds!
Don't think I'll hit the 15.8 gi that thorn gives though. The fw conversion is more than tempting at this juncture. Still, I remain open the chimers. Cheers again, very much appreciate all the time spent.

nat
Posts: 4
Joined: 6 Dec 2018, 1:04pm

Re: calling Brucey.. SA touring potential

Postby nat » 7 Dec 2018, 8:58am

....I felt the almost perfect chainline when I replaced all gearing. It was quickly lost, and I've never felt it again. Strange, but true.

User avatar
Tinnishill
Posts: 103
Joined: 15 Sep 2013, 9:58am

Re: calling Brucey.. SA touring potential

Postby Tinnishill » 7 Dec 2018, 2:13pm

About your APB; it’s hard to beat a Moulton for quality of touring ride. I had an APB which I regret parting with. The SA 7 speed Sprinter hub was never very good. I currently run a Tern Node which I fitted with a Sturmey CS-RF3 3 speed/8 speed combo gear and I reckon that that would have been pretty OK for the APB. I can’t remember the OLN size of the APB, but the CS-RF3 is optimized for 135mm.

Regards.
Agitate, educate, organise.

Brucey
Posts: 31553
Joined: 4 Jan 2012, 6:25pm

Re: calling Brucey.. SA touring potential

Postby Brucey » 7 Dec 2018, 5:03pm

Just in case it wasn't clear, the Magic Alpine Double keeps a perfect chainline in either primary gear combination and doesn't use a tensioner. It is just as silent and efficient as a standard IGH drive is.

Smaller chainrings with the same sprockets can give gears from about 15" to about 80" this way. I don't think many IGHs are rated for the high torque that results from such a low input ratio though.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

1066enthalpies1939
Posts: 34
Joined: 16 Jul 2018, 10:33pm

Re: calling Brucey.. SA touring potential

Postby 1066enthalpies1939 » 7 Dec 2018, 5:15pm

Brucey wrote:sprinter 7s hub is not especially reliable in hard use and suffers the disadvantages that spares are now getting incredibly difficult to find and (AFAICT) other SA internals don't fit into that hubshell. On the plus side with small wheels it sees an easier time of it (lower torque) and if it has lasted this long it can't be too badly suited to your use.

The 'old' twin toggle SA 5s hubs (converted FWs, S5s, but not the 5-star) have the killer advantage that if the centre claps out, you can whack an AW internal into the same shell and be on your way. Thus with that style of TT5s or an old AW, major blow ups are not such a concern; most places in Europe will have old AWs lurking about the place. New AW internals fit too, BTW.

I have always carried enough tools (a couple of spanners plus a drift that I can hit with a borrowed hammer or a rock) to strip an AW or a TT5s hub. If I wanted to be really well prepared I'd carry a spare axle, spare pawls, toggle key and spare pawl springs.

The latter parts are not very likely to fail but are easy to carry. However a broken axle is a real possibility and more of a show-stopper; this eventually failed in my highest mileage hub, cracking across the toggle key slot. Had I had my wits about me, I wouldn't have ignored the loud crack sound that preceded the final failure; that sound was the first side of the crack near the slot breaking through to the slot, about a week before the end. 'Old' AW axles can have sun pinions that fail or the axle can crack where the sun pinion rivet goes through it.

With any SA hub you can fit more than one sprocket, use a derailleur and have an extended gear range that way. If you don't want a tensioner at all, you can run a second sprocket and chainring (leaving the chain slack enough to be manually derailed into low range) such that it makes what I call a 'Magic Alpine Double', i.e. so that the chain is equally tight on either chainring/sprocket pair. For example 46/19 give the same chain length (magic gear) as 36/30 and with a 5s gear you can have ratios from about 22" to about 100" this way.

So I'd happily tour on a modern NIG AW because the axle is (QA concerns asides) stronger built. However I'd fit the Rh tab washer than is now omitted by SA and I'd be careful that the actuator plate was in good condition though. A simple way of fitting multiple sprockets to one of these is to use a Brompton BMW driver; (the standard NIG driver isn't quite long enough to accept multiple sprockets easily, eg without losing the dust shield over the ring bearing).


I can see the appeal of an IGH for touring in mucky conditions but there is more than one way to skin a cat and all that; if you are worried about wear on a derailleur transmission, you can address this in various ways. An easy way is to carry a spare chain and to fit that when the original one gets too dirty/slightly worn. The old chain can be cleaned and reused or binned. With an 8s system reasonable chains are cheap enough to throw away, more or less.

cheers


Do have any photographs of your magic drive with the Brompton BMW driver?

Brucey
Posts: 31553
Joined: 4 Jan 2012, 6:25pm

Re: calling Brucey.. SA touring potential

Postby Brucey » 7 Dec 2018, 5:36pm

with an older (pre NIG) hub the driver is long enough to accept two sprockets, so I modified a 30T cassette sprocket to fit a standard IGH driver and used that. I have used the BWR driver in other SA NIG hubs, including X-RF5 (for a 10s Brompton); it is a straight swap for the standard NIG one. The chainset at the front is a standard double chainset. The only thing that looks a bit weird is that the chain has a fair amount of slack in it; enough that the chain will derail to a smaller sprocket/chainring With the right chain and sprockets etc the chain doesn't unship in normal road use.

In its final form it was to have a pair of derailleurs so that the high/low range shift wasn't manual; an osgear type RD and a modified FD. Neither will contact the chain in normal running. However that hasn't happened yet; too many projects on the go.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

webber
Posts: 225
Joined: 2 May 2012, 3:48pm

Re: calling Brucey.. SA touring potential

Postby webber » 8 Dec 2018, 10:47am

Brucey wrote:sprinter 7s hub is not especially reliable in hard use and suffers the disadvantages that spares are now getting incredibly difficult to find and (AFAICT) other SA internals don't fit into that hubshell. On the plus side with small wheels it sees an easier time of it (lower torque) and if it has lasted this long it can't be too badly suited to your use.

The 'old' twin toggle SA 5s hubs (converted FWs, S5s, but not the 5-star) have the killer advantage that if the centre claps out, you can whack an AW internal into the same shell and be on your way. Thus with that style of TT5s or an old AW, major blow ups are not such a concern; most places in Europe will have old AWs lurking about the place. New AW internals fit too, BTW.

I have always carried enough tools (a couple of spanners plus a drift that I can hit with a borrowed hammer or a rock) to strip an AW or a TT5s hub. If I wanted to be really well prepared I'd carry a spare axle, spare pawls, toggle key and spare pawl springs.

The latter parts are not very likely to fail but are easy to carry. However a broken axle is a real possibility and more of a show-stopper; this eventually failed in my highest mileage hub, cracking across the toggle key slot. Had I had my wits about me, I wouldn't have ignored the loud crack sound that preceded the final failure; that sound was the first side of the crack near the slot breaking through to the slot, about a week before the end. 'Old' AW axles can have sun pinions that fail or the axle can crack where the sun pinion rivet goes through it.

With any SA hub you can fit more than one sprocket, use a derailleur and have an extended gear range that way. If you don't want a tensioner at all, you can run a second sprocket and chainring (leaving the chain slack enough to be manually derailed into low range) such that it makes what I call a 'Magic Alpine Double', i.e. so that the chain is equally tight on either chainring/sprocket pair. For example 46/19 give the same chain length (magic gear) as 36/30 and with a 5s gear you can have ratios from about 22" to about 100" this way.

So I'd happily tour on a modern NIG AW because the axle is (QA concerns asides) stronger built. However I'd fit the Rh tab washer than is now omitted by SA and I'd be careful that the actuator plate was in good condition though. A simple way of fitting multiple sprockets to one of these is to use a Brompton BMW driver; (the standard NIG driver isn't quite long enough to accept multiple sprockets easily, eg without losing the dust shield over the ring bearing).

I can see the appeal of an IGH for touring in mucky conditions but there is more than one way to skin a cat and all that; if you are worried about wear on a derailleur transmission, you can address this in various ways. An easy way is to carry a spare chain and to fit that when the original one gets too dirty/slightly worn. The old chain can be cleaned and reused or binned. With an 8s system reasonable chains are cheap enough to throw away, more or less.

cheers

im very interested in this magic gear i have a condor tempo that i pick up off ebay (£150 bargin) that i love riding in single speed still not sold on fixed which i would like to do some fast touring multi day events on and would i be able to use a double chainset and keep a good chainline and just move the chain or would i have to swap chainrings ??

Brucey
Posts: 31553
Joined: 4 Jan 2012, 6:25pm

Re: calling Brucey.. SA touring potential

Postby Brucey » 8 Dec 2018, 11:02pm

yes in principle, but details of exactly which chain and sprockets you use can affect chain retention when you use a 'magic double', if you use it as described, i.e. with the chain slack enough to derail by hand if required.

However if you run with the chain tighter, you will only be able to change gear by disturbing the rear wheel. Some folk will ask 'well what is the difference between that and just running a flip-flop hub?' and in truth 'not much' is the answer. But the magic double does not require long droput slots to work and two gears (achieved by changing the sprocket only) which are different enough to be worth having for long climbs etc does usually require a lot of rear wheel movement.

It varies a bit (with exact chainstay length, gear ratio, and absolute chainring sizes but there are broadly two (useful) types of closely matching 'magic gear' that give identical or near-identical chain lengths, assuming one of the gears is about 2.5:1 or 3:1 (as might be required for tapping along on a ~27" wheel)

a) 'similar size' where both chainring and sprocket are within one or two teeth of the other gear, eg high gear might be 44/17, low gear might be 43/18. This is never 'perfect' with actual chain length differences being about 1mm at a minimum. It works OK if you have just a short dropout slot to play with only, or you are happy to run more slack than is absolutely necessary.

b) 'very different sizes'. This means if the chainrings differ by 'n' then the sprockets differ by 'n+1'. This seems to work if n ~ = 10 or so. Hence chainrings of 46,36 (n=10) usually work OK with sprockets of 19,30 (n +1 = 11). This gives a big difference in the two gears.

You can work out chain lengths (and therefore how 'magic' the gears really are) easily using an online calculator, eg

http://www.machinehead-software.co.uk/bike/chain_length/chainlengthcalc.html

If you choose carefully and keep the chain length constant (eg by mixing up parts of two slightly differently worn chains) you can run a 'magic double' using vertical dropouts.

Another way of achieving two gears simply is to use a scheme called 'retro-direct'

Image

this uses a fixed tensioning sprocket on the chainstay (pref on a brazed on bracket) or a spring loaded tensioner as above. You need to engineer two independent freewheels on the rear hub, (of which one or the other is running, potentially noisily, all the time) and accept that in one of the gears (usually the low one), you need to pedal backwards.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

nat
Posts: 4
Joined: 6 Dec 2018, 1:04pm

Re: calling Brucey.. SA touring potential

Postby nat » 9 Dec 2018, 12:42pm

Thank you Brucey et al. Yes, I do realise chainline would stay correct with aforementioned ' alpine double ' seems a good way to go. Have a double wending it's way, as I write :).
As for touring a la apb, I've just gone for a good old ride out. Yes laterally stiff, no doubt. How much exactly has to do with 406 rims/ 36 spokes is open to debate. Suspension does take the ' sting' out though. Mmm, feel you're right on hub all round, caveat being mildly sticky cable. It's a recent purchase, and based on design/ aesthetics too if honest. I was wrong on gearing ( R20) it's 39 GI , not so good for hill climbing methinks. Experiment time.....