Author Topic: Making an "adventure bike" from a Pompino, good idea?  (Read 1287 times)

Panoramix

  • 50 61 6E 6F 72 61 6D 69 78
  • Suus cuique crepitus bene olet
    • Some routes
Making an "adventure bike" from a Pompino, good idea?
« on: February 01, 2020, 12:09:11 am »
It looks like next summer I will be able to go on a touring ride in Colombia. I've wanted to do this for 10 years, my wife is Colombian and each time I fly over the country I wish I was a small dot on the ground cycling up and down these beautiful mountains. SWMBO finally agreed that it was safe.

So I am starting to think about the bike, I want something reliable with fattish tyres that roll well on less than ideal roads which can be unpaved. I need gears but I don't really want a derailleur as the bike may end up in a bus at some point.

My utility bike is a fixed wheel Pompino, it has served me well for 10 years now, I don't do much more than adding a bit of oil on the chain from time to time and it keeps serving me well! I am starting to think that may be it would be a good idea to use the Pompino as my touring bike, the plan would be :
  • Build 2 wheels with a gear hub and a dynamo hub
  • Fit as wide as possible tyres
  • Carry as little as possible to survive the long climbs

The advantages I see :
  • Simple bike
  • Relatively inexpensive bilke so won't pain me if I damage it
  • A bike I trust
  • Mrs P doesn't count an extra wheelset as a new bike and anyway I won't have touring opportunities like this every year, so one bike for rough touring + commuting is sensible

Now comes the technical part.

Is it sensible to run a gear hub on a pompino?
What kind of gear hub? Ideally, I would like to get 65(ish) gear inch in direct drive and the lower gear at about 27 gear inch. Top gear doesn't bother me.
I quite often ride fixed, so big spaces between the gears won't bother me. Nevertheless, I need this low gear as I will have to negotiate crappy and steep roads.
What gear hub do I want? If it could be cheaper than a Rolhoff, that would suits me, I can probably live with 5 well spaced gears or 7 more tighly spaced. It needs to be bomb proof, lighter is better.

bludger

  • Randonneur and bargain hunter
Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #1 on: February 01, 2020, 01:59:47 pm »
Sure why not? I know someone who happily used a SA 3 speed brompton for a South America tour. Ask your favourite bike shop if they have any hubs going spare, quite a few do as they're not in fashion.

You can also get a fixed 3 speed from SJS but might not be desirable for rock gardens and technical descents.
YACF touring/audax bargain basement:
https://bit.ly/2Xg8pRD


fuaran

  • rothair gasta
Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #2 on: February 01, 2020, 02:33:46 pm »
What width are the dropouts? That will affect what hubs you can use. If 135mm, could use a a Shimano Nexus/Alfine 8 speed.

The Pompino is a bit limited for tyre clearance. Might squeeze in 35mm. Can get a little more space if you put the wheel further back in the dropouts.
So depends on how crappy the roads are.

And I'd rather have discs brakes for any steep, rough stuff.  Could replace the fork, and have a disc on the front.

Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #3 on: February 01, 2020, 03:07:03 pm »
are you going to be alright on the (~35mm?) width tyres that will fit in that frame?

Re the hub gear if you use an old (non-NIG) 3s AW hub I would suggest that you carry a spare axle and a few other spare parts such as pawls and pawl springs, toggle chain, toggle key etc. You will need cone spanners, a drift (screwdriver bit?) and a hammer (rock?) to gain access to the internals if needs be.  If using a (secondhand) steel shell the wheel should be built using the original spoking pattern in the hub (the sharp edges on the drillings will be slightly rounded) and also use spoke washers.

To get low gears without a lot of extra complexity there is a cunning dodge which I have used which I call

'Magic Alpine Double'.

The idea is that you have two chainrings and two sprockets (which an old AW will accommodate quite nicely) and you use the inner ring with the inner sprocket when climbing hills and the outer ring with the outer sprocket the rest of the time. There are two things that make this easy to live with

1) that you run the chain slack enough that you can simply move it to the other combination (using a twig or something so you don't get oily fingers) without moving the wheel. If you get it just right the chain won't fall off when you are riding the bike normally, even if it is pretty slack and
2) that you use chainring/sprocket sizes which give an exactly identical chain length. (You can verify this in a chain length calculator)

For example I have used 46/19 and 36/30 combinations this way using a five speed SA hub

The gear ratios that you get this way are represented here (for both S5 and AW 3s hubs)

http://ritzelrechner.de/?GR=SAS5&KB=46&RZ=19,39&UF=2170&TF=90&SL=2.6&UN=MPH&DV=gearInches&GR2=SAAW&KB2=46&RZ2=39,19&UF2=2170

(note that to represent the 36/30 combination I have used a 'proxy sprocket of 39T; 46/39 is almost identical ratio to 36/30; the gear calculator otherwise gives you 46/30 and 36/19 gears which you won't be using, if you enter the chainrings and sprockets 'as is'. )

In both cases you get two ranges of gears; one of which is useful on the flat and one of which is useful for longer/steeper hills. Obviously you need to dismount to change ranges, but other than that it is a very simple (and almost idiot proof) method of obtaining a good gear range on a bike which is only a little more complex than a singlespeed. In both cases gear range (total) is from the low twenties to about 90" or so.

I modified a 30T cassette sprocket to fit onto a standard 3-lug driver; standard IGH sprockets don't come bigger than about 26T or so IIRC.

cheers

Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #4 on: February 01, 2020, 03:29:46 pm »
IIRC the Pompino frame was sold in two dropout widths, but I suspect you have the narrower one if running fixed. I had a narrow Pompino which I spaced out to fit a SRAM Spectro 7-speed hub. It was a tight fit, but doable. The cable runs were clumsy, as there are no braze ons, IIRC, but that's more of an aesthetic thing.

I can't recall which tyres I used, but they wouldn't have been <32mm. Probably Marathon Plusses. I also ran those with mudguards, so there was plenty of clearance for my needs.

Brucey is the fount of all knowledge in this respect. What about an Alfine 11-speed hub? Would that offer a wide enough spread of gears?

As for braking, perhaps consider an IGH with a coaster brake or roller brake option, but I suspect that rules out the 11-speed Alfine. One of my steeds has a coaster brake that I hated at first, but I now realise it's a very useful regulating brake in addition to the v-brakes I have F & R. The advice of fitting a disk-brake-compatible fork is sound.
Haggerty F, Haggerty R, Tomkins, Noble, Carrick, Robson, Crapper, Dewhurst, Macintyre, Treadmore, Davitt.

Panoramix

  • 50 61 6E 6F 72 61 6D 69 78
  • Suus cuique crepitus bene olet
    • Some routes
Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #5 on: February 02, 2020, 09:55:01 am »
Thank you very much, as usual the knowledge here is amazing!

I had forgotten about the spacing, Mine is indeed a 120mm. So I imagine that I need a sturmey archer, they seem to be the only ones offering this (Correct me if I am wrong). Are the new ones reliable? As I will gear low, lot of torque will get through the hub. On their website they seem to have a few of them in 120mm OLN spacing, including the 8 speed one which has got a 325% range which is more than good enough for me as I don't mind sacrificing top gears. I don't really want to respace my rear triangle as I will keep using the bike as a utility bike afterward.  I am not used to gear hubs, is a 5 speeds one more reliable than a 8 speeds? Finally I hadn't thought of having disc forks but that makes sense.

The 2 speed ranges option might work well, in the Andes you have to cross ridges so when it starts going up you are in for several hours of climbing. Little of this British thing of going constantly up and down....  ;)

As for road quality, I think that it will range from pot holed in places roads to unsurfaced that looks like our bridleways. I might have to go through "camino reales" to avoid dangerous roads (on main roads traffic is mad), but not being a mountainbiker, I will mostly push the bike in those.

LittleWheelsandBig

  • Whimsy Rider
Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #6 on: February 02, 2020, 11:17:58 am »
My 120 OLD Pomp is a very snug fit between the chainstays with 35mm tyres. I can’t use the front half of the dropout slots because the 35mm tyre jams. I use 32mm tyres in back to give a bit of mud room and more chain adjustment. Readjusting the rear cantilever brake pads is then an issue, because of the small frame size.

People do all sorts of things with unsuitable bikes but I don’t think the Pomp is the right bike for the job you want it to do.

I’d be careful touring the SA8 hub with 700C wheels and low gearing; it is very sensitive to cable adjustment and a bit delicate. The SA5 isn’t much better. I’d prefer a bombproof F&S/ SRAM 3sp or 5sp cargobike-rated hub but they are long out of production. The SA3 is pretty good, provided the axle doesn’t flex too much = not excessive baggage weight and stiff dropouts.

I’d bite the bullet with a proper bike for the job but you know your constraints better than me.
Wheel meet again, don't know where, don't know when...

Panoramix

  • 50 61 6E 6F 72 61 6D 69 78
  • Suus cuique crepitus bene olet
    • Some routes
Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #7 on: February 02, 2020, 12:02:35 pm »
Yes, I haven't made up my mind yet. I run 28mm tyres on my pomp, I was under the impression that I had a lot of space left.  One of the new gravel bikes would be neat but I find a €2000 bike a bit too fancy for one that will have to endure planes and buses. If there was a frame like the Pompino but with the right clearances, that would be perfect for me.

These guys (https://www.facebook.com/BamboocyclesColombia/) offer a workshop in Bogotá where you build a bamboo bike and end up as the proud owner of a frame at the end. On one hand that would seem appropriate but on the other hand, building from scratch a bike 2 weeks before touring is asking for troubles...

LittleWheelsandBig

  • Whimsy Rider
Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #8 on: February 02, 2020, 12:06:53 pm »
I have a green Pomp and there are detail differences over the years. The Pomp fork allows much bigger tyres than the chainstays; the seatstays to a lesser extent.

I think it would be fun to take a 2 week old bike on a tour but then I rode a brand-new bike for PBP07 (picked up from fidgetbuzz the night before bike check) that I hadn’t assembled. I was quite comfortable with diagnosing and tightening loosening bolts, etc. along the way. If I’d assembled the bike from scratch, that running-in period would have been a non-existent issue.

You could try using a SA BWR 3sp hub with top gear around 67” on your Pomp, if you want to go that way. The low gear would be pretty low and most of your climbing would be done in direct drive. I’d mount a guard over the index chain though, because it is not a rotary gear change hub. 34t chainring and 19t cog gives 67”, 49” and 35”.

Alfine 8sp hubs are pretty tough and can cope with chainring:cog ratios below 2:1. The same chainring and cog sizes get below 26” bottom and 80” top. No direct drive though. The hub can be modified to get sub-130mm OLD but I’m not sure how easy it is to get to 120mm, probably not practical.
Wheel meet again, don't know where, don't know when...

zigzag

  • unfuckwithable
Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #9 on: February 02, 2020, 01:19:48 pm »
i'd get a cheap used flat-bar bike (hybrid/trekking or similar) off the internet and build it up with 1x, 36t and 11-42 cassette. pack a spare mech hanger and a another rear mech with the cage removed, to save space. sell the bike after the tour. i've tried most gear hubs in the past and none of them were actually good (i was really committed to finding the one i could use!..).

Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #10 on: February 02, 2020, 03:04:20 pm »
As it happens I'm taking my pompino to Colombia later this year. I'll be running it with 68"/74" fixed/fixed and 28mm tyres. Don't overthink it, if the bike fits you and rides well, just ride it. Or do what zigzag suggests.
Quote from: tiermat
that's not science, it's semantics.

Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #11 on: February 02, 2020, 03:11:17 pm »
IIRC you can't quite build a N8 hub down to 120mm. I think Sheldon built one as narrow as it could be, practically, and the width is listed on the SB website. ~124mm from memory.

The 'new' (NIG) versions of the AW 3s gear are OK but they

a) lack the cone lockwasher on the RHS of the hub and
b) the actuator plate fails occasionally

either thing can cause the hub to fail; if the RH cone is not properly locked and decides to precess into the hub it causes absolute carnage.  There are occasional lapses in SA QA, such that some parts are found which are just not durable/hard like they should be. Pot luck on that one really. None have enough grease inside them when they are new, and the grease itself is not the best grease for lubricating the hub with either.

I'd rate an old AW (non-NIG) internal as being significantly more reliable than a new NIG one, better yet with a new axle in it.  SA make axles for old style AWs and when they are good they are better (stronger) than the ones from Nottingham, because they are solid and don't have a riveted sun pinion. However any axle with a slot in it can break; I've only seen this a few times myself but one such breakage was mine (took about 80000  miles though).

Obviously the BWR hub is only available in 28h drilling so you would need to install the BWR internal into another hubshell if you went down that route. Simply because the cone cannot be accessed inside the BWR driver, the BWR hub has a RH cone lockwasher. It still has an actuator plate though.

Any NIG type 3s or 5s hub with a toggle chain can be fitted with the BWR driver and this allows an easy way to fit two sprockets onto these hubs (the driver is otherwise too short for two sprockets unless you are happy without the dust shield - bad idea).

So yes you can tour on anything, but if it breaks you are gonna have to fix it, and for that you need to be prepared. Above I posted the spares list I would carry with a non-NIG AW to which I'd add a new actuator plate, and driver pawls/pawls spring if you are thinking of a NIG type hub. With any SA hub  I'd also carry new axle nuts if you expect to have to move/remove the wheel often; these are soft enough that they are basically consumables.

With almost any SA IGH you can add a shaped washer between the LH cone and locknut and this will allow 'one spanner' adjustment of the bearings with the wheel still in the frame.

I would not consider the SA 8s hub sufficiently strong for the sort of jaunt you have in mind. Even if they don't break they just wear out; 20000 miles is enough to see off the planet pinion bearings in the first gear stage.

cheers



Kim

  • Timelord
Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #12 on: February 02, 2020, 06:01:35 pm »
I’d be careful touring the SA8 hub with 700C wheels and low gearing

That's almost an oxymoron, given that it's 1:1 in bottom gear and you'd need fairly silly chainring/sprocket combinations to achieve a low gear with a 700c wheel in the first place.

(It's a reasonable hub for small-wheeled bikes, where it avoids the need for enormous chainrings, as long as you're not too bothered about efficiency.)
Careful, Kim. Your sarcasm's showing...

Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #13 on: February 02, 2020, 07:22:04 pm »
SA8 isn't desperately silly. I run one with 26" wheels. It takes a 33T chainring, but I'm not as loaded as I think you're going to be. It's been golden once dialed in (half an hour), and max efficiency in bottom has helped me out a few times. I'm only at 4k miles because all I really do is commute, and it isn't that far in this job.

You're probably in the 28-30T range, so hopefully there's something reasonably priced. I did try to set 1/8" chain and sprockets but couldn't get a matching set so running with normal rings and cheap chain I can replace whenever. I also have a chain tensioner.
Cruzbike V2k

Panoramix

  • 50 61 6E 6F 72 61 6D 69 78
  • Suus cuique crepitus bene olet
    • Some routes
Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #14 on: February 02, 2020, 08:42:48 pm »
i'd get a cheap used flat-bar bike (hybrid/trekking or similar) off the internet and build it up with 1x, 36t and 11-42 cassette. pack a spare mech hanger and a another rear mech with the cage removed, to save space. sell the bike after the tour. i've tried most gear hubs in the past and none of them were actually good (i was really committed to finding the one i could use!..).

I have an old steel Raleigh hybrid that could have a new life (it was the utility bike before the Pompino), nevertheless if I abandon the idea of a gear hub, I might go for this frame : https://www.planetx.co.uk/i/q/FROOBZ650/on-one-bootzipper-650b-mountain-bike-frameset

IIRC you can't quite build a N8 hub down to 120mm. I think Sheldon built one as narrow as it could be, practically, and the width is listed on the SB website. ~124mm from memory.

The 'new' (NIG) versions of the AW 3s gear are OK but they

a) lack the cone lockwasher on the RHS of the hub and
b) the actuator plate fails occasionally

either thing can cause the hub to fail; if the RH cone is not properly locked and decides to precess into the hub it causes absolute carnage.  There are occasional lapses in SA QA, such that some parts are found which are just not durable/hard like they should be. Pot luck on that one really. None have enough grease inside them when they are new, and the grease itself is not the best grease for lubricating the hub with either.

I'd rate an old AW (non-NIG) internal as being significantly more reliable than a new NIG one, better yet with a new axle in it.  SA make axles for old style AWs and when they are good they are better (stronger) than the ones from Nottingham, because they are solid and don't have a riveted sun pinion. However any axle with a slot in it can break; I've only seen this a few times myself but one such breakage was mine (took about 80000  miles though).

Obviously the BWR hub is only available in 28h drilling so you would need to install the BWR internal into another hubshell if you went down that route. Simply because the cone cannot be accessed inside the BWR driver, the BWR hub has a RH cone lockwasher. It still has an actuator plate though.

Any NIG type 3s or 5s hub with a toggle chain can be fitted with the BWR driver and this allows an easy way to fit two sprockets onto these hubs (the driver is otherwise too short for two sprockets unless you are happy without the dust shield - bad idea).

So yes you can tour on anything, but if it breaks you are gonna have to fix it, and for that you need to be prepared. Above I posted the spares list I would carry with a non-NIG AW to which I'd add a new actuator plate, and driver pawls/pawls spring if you are thinking of a NIG type hub. With any SA hub  I'd also carry new axle nuts if you expect to have to move/remove the wheel often; these are soft enough that they are basically consumables.

With almost any SA IGH you can add a shaped washer between the LH cone and locknut and this will allow 'one spanner' adjustment of the bearings with the wheel still in the frame.

I would not consider the SA 8s hub sufficiently strong for the sort of jaunt you have in mind. Even if they don't break they just wear out; 20000 miles is enough to see off the planet pinion bearings in the first gear stage.

cheers


Thanks, for all this info. I am in France, so finding a second hand SA will be pretty difficult, if I go this way, it will be a new one. In term of durability, do you think that the 5 speeds NIG will be more durable than the 8 speeds? I think that it has just enough range for me as I can happily spin my legs. If I do the 2 pinions trick with the direct drive at about 65-70'' it will even be pretty comfortable.

As it happens I'm taking my pompino to Colombia later this year. I'll be running it with 68"/74" fixed/fixed and 28mm tyres. Don't overthink it, if the bike fits you and rides well, just ride it. Or do what zigzag suggests.

Brilliant! Sadly I probably don't have the stamina for this. Altitude is hard on my system!

Where are you going?

That's a route I was plotting yesterday :

http://brouter.de/brouter-web/#map=10/4.4723/-73.7402/OpenTopoMap,HikeBike.HillShading,route-quality&lonlats=-74.062958,4.72759;-73.611789,4.76296;-73.381805,4.586513;-73.786068,4.477732;-74.064932,4.726778

Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #15 on: February 02, 2020, 08:59:24 pm »
Got a 3sp Torpedo hub with a coaster brake 36h drilling doing nothing if you want it. Takes 2 sprockets (it was a 2x3 hub but who the hell runs a dérailleur with a coaster brake  :facepalm: ) You'll probably want to get one of Mr Thorn's cheap triggers as the 2x3 shifter is a twin lever thing mounting on the stem. You can have it if you want it, postage from Limoges to Rennes won't be a deal killer.

LittleWheelsandBig

  • Whimsy Rider
Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #16 on: February 02, 2020, 09:15:25 pm »
F&S did a couple of hybrid hub/derailleur systems back in the early ‘80s (and possibly ‘70s). The 2x3’s 2sp derailleur locked the (steel) chain tensioner when backpedalling, so the coaster brake worked without chucking the chain off.
Wheel meet again, don't know where, don't know when...

Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #17 on: February 02, 2020, 09:53:53 pm »
F&S did a couple of hybrid hub/derailleur systems back in the early ‘80s (and possibly ‘70s). The 2x3’s derailleur locked the (steel) chain tensioner when backpedalling, so the coaster brake worked without chucking the chain off.

So that's how they did it. The only photo I have seen had the short cage version of a cheap steel Huret mech (I have a long chain version acquired elsewhere) which certainly would not have done this. i didn't acquire the mech with the hub although I was given the shifters which are marked Huret. I assume therefore that mine is post '85 as I think Sachs bought Huret/Maillard/Sedis about then. There is a spacer to go between the sprockets that is slightly thinner than a standard SA one. The circlips doesn't seat well with the wrong spacer.

2x3 is quite fun but I never got into changing between the sprockets to split the gaps on the 3sp. I prefer the 5sp now but it doesn't give the impression of solidity of a 3sp.

LittleWheelsandBig

  • Whimsy Rider
Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #18 on: February 02, 2020, 10:16:04 pm »
F&S bought Huret in 1980, according to http://www.disraeligears.co.uk/Site/Fichtel_Sachs_derailleurs.html My vague recollection was that it was a modified Huret mech.

The other system was the Orbit with 6 derailleur gears on a 2sp hub. I first saw that system on a Roulandt recumbent.
Wheel meet again, don't know where, don't know when...

Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #19 on: February 03, 2020, 02:46:25 pm »
FWIW the SA NIG 5s hub eg S-RF5(W) is both
a) slightly flawed and
b) no longer in production

It is super-sensitive to cable adjustment (a 0.8mm cable setting error is enough to cause problems) and it has (IMHO) inadequate bearings on the planet pinions too.

I don't think it is as durable or as efficient as a 3s hub. The replacement SA 5s hub is a much heavier arrangement with rotary shifting and the suns lock a but like 8s suns. Reliability is unknown

NB I forget to mention that there is an additional parasitic loss in all NIG toggle-operated hubs; essentially the load from the clutch spring is borne via the (turning) sliding clutch all the time, so causes about 1W of parasitic drag all the time you are pedalling. It also causes at least one flavour of hub blow-up in the 5s hub.  The old (non NIG) AW hub had the clutch on a carrier, where it could rotate freely without any drag from the clutch spring.

If you want an old style AW hub IIRC SJS were selling them (with a 28h steel shell) NOS for buttons quite recently. 36h shells are easy to come by used.

cheers

bludger

  • Randonneur and bargain hunter
Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #20 on: February 03, 2020, 04:01:13 pm »
Would it be possible to fit the miche cog carrier system ( https://www.singlespeedshop.com/Single-Speed---Fixed-Gear/Single-Speed-Conversion-Parts/Miche-Cog-Carrier.html?language=en ) to a 3 speed IGH? Then you've got some flexibility on gearing without needing to mess around with any fettling longer than 5-10 minutes.
YACF touring/audax bargain basement:
https://bit.ly/2Xg8pRD


Panoramix

  • 50 61 6E 6F 72 61 6D 69 78
  • Suus cuique crepitus bene olet
    • Some routes
Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #21 on: February 03, 2020, 05:26:40 pm »
Got a 3sp Torpedo hub with a coaster brake 36h drilling doing nothing if you want it. Takes 2 sprockets (it was a 2x3 hub but who the hell runs a dérailleur with a coaster brake  :facepalm: ) You'll probably want to get one of Mr Thorn's cheap triggers as the 2x3 shifter is a twin lever thing mounting on the stem. You can have it if you want it, postage from Limoges to Rennes won't be a deal killer.

Thank you very much, that's very kind of you.

TBH, I am starting to abandon the idea of the Pompino. I've looked at routes options and I might have to do some proper rough stuff at times to avoid main roads (imagine a version of the Welsh part of the A40 with a mix of slow lorries, impatient drivers and mini bus drivers who seem to get bonuses for overtaking as many people as possible in blind curves!). That probably means 40 mm tyres.

My heart would like the bamboo bike self built in Bogotá with a gear hub but I might try to find a second hand rigid steel MtB and fit it with drops (flat bars hurt my wrists!) with either 1 (or 2?) chainrings and a "pizza cog" at the rear or a gear hub. Decatlon sold 10s of thousands of those frames in the 90's + early noughties, I can probably find a decent one second hand or possibly go for the on one cheap steel frame.

I am sorry for mobilising all this energy and changing my mind after!!! At least I've learnt about gear hubs.

Actually I have more questions, assuming that I don't have spacing issues and choose the frame, presumably the alfine hub is good enough for this kind of bike? It defeats a bit the objective of simplicity of the gear hub, but are these small tensioners any good? Would a hard tail mountain bike + gear hub + small tensioner be a "happy" combination?

I've never owned a gear hub bike, I am just trying to replicate as much as possible the robustness of the pompino with its "agricultural" design.

Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #22 on: February 04, 2020, 09:16:13 am »
I think you need a touring bike.  Not expensive new and lots second hand. 

If you are doing proper rough stuff you will want low gears as there will be steep bits.  I've never had a hub gear bike either (since I was 13 anyway) and if I was going to get one, I would get it for commuting at home, not an expedition like you are planning!

I've done that type of riding on my Super Galaxy lots of times, and would use it again for similar terrain.  I have 37mm Marathons on it, which are fine off-road (unless it is deep mud, sand, etc). 

Modern gravel bikes are basically a reinterpretation of that type of touring bike, but with disk brakes and a bit more clearance for bigger tyres.

Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #23 on: February 04, 2020, 10:15:04 am »
The SA 3sp is pretty bombproof. The middle gear is direct drive.

I used one in a track frame as my commuting bike, riding from Holmfirth over Saddleworth moor every day. 40 year-old gear with some parts replaced - no problems. It can take a lot of torque. The few spare parts that might be sensible to carry are tiny (they'd take up the space of two jockey wheels).

Surprised nobody has suggested singlespeed + triple up front with a chain tensioner. That would be a pretty bombproof setup as well.
<i>Marmite slave</i>

Karla

  • car(e) free
    • Lost Byway - around the world by bike
Re: Making an "adventure bike" from a Pompino, good idea?
« Reply #24 on: February 04, 2020, 10:43:01 am »
Byronius Maximus went touring in SA, I think including Colombia, and didn't Woolly and Peli go there too?  You might like to ask them what they think. 

Personally I agree with Frank.  There's a nice looking Super Galaxy going for £325 on the CTC forum at the moment.  It's 57cm so probably a size too big for you but it goes to show that these bargains can be had, and you'll then have the proper tool for the job.