Converting derailleur to hub gear other than Rohloff

[PAB855]

As the years roll on, I am gradually changing the spec of my 10 year old CUBE Cross Road Trekking bike to help me with my slow reduction in ability, fitness etc.

First was a retrofit Cytronex edrive.

Second a dropper seatpost.

Thirdly I am considering a hub gear, having been a user many years ago and never really liked dérailleurs despite thousands of miles ridden.

Why?

Being able to change from top to bottom gear while at a standstill is my main mission in view of the current trend and I don't want to do a Joe Biden although I don't have foot withdrawal symptoms yet.

I know a number of factors need to be considered such as a new wheel and a change lever, but if I need to obtain a similar gear range to what I currently have,, could I retain the rear derailleur in order to take up chain tension on the front triple chainrings? 48,36,26 and 11- 34 . Why not use them?

Maybe more knowledgeable cyclomathematicians could tell me how I could obtain a comparable range with minimum overlaps or what my options are. Am I flying a kite here?

I have long envied the Rohloff owners, but I'm not doing many round world trips these days !!!! and they are a bit pricey, but the Rolls Royce of gears no doubt.

I'm thinking, SA, Nexus, Shimano etc

PS I was here before so it's still a bee in my bonnet and at that time Brucey contributed in his remarkable way, a brilliant guy.

Hopefully I've not been too unrealistic this time, I don't wish to waste any body's time

Cheers

[Jupestar]

I don't see why that wouldn't work.

You would need to make sure the rear cog could take the chain size needed for the front. If the recall the original cogs with guard use a 9s. But a 1/8 doesn't fit.

Also you need a way to fix the RD. Either with the H and L screw, or under tension.

I'm sure others have tried it.

[slowster]

The link below illustrates and compares a standard Shimano Nexus 8 speed set up with what you are suggesting, i.e. using your triple with a hub gear (a Sturmey Archer 3 speed for the sake of this example). The latter would give a poor range of gears and a number of duplicated gears. One of the advatanges of a hub gear is the longer lifespan of the chain, due to the straight chainline and the tolerance of the set up to wear of the chain, sprocket and chainring, which would be negated or reduced by using a triple chainset.

http://www.ritzelrechner.de/?GR=SAAW&KB ... 8&UF2=2185

[Carlton green]

An answer of limited help, but maybe some.

Hybrid gearing have been around for many decades, so what the OP proposes to do will have been done / sort of done before.

I love SA three speed hubs (IMHO they’re undervalued and I wouldn’t be without mine) but the rest of SA hubs are, I think, a bit doubtful. The three speed hubs have wide gaps between ratios and using small chain wheels with them goes well beyond what they’re designed to cope with.

Why still such a wide gear range? Electric assist has to cut out at say 15 mph and electric assist (front wheel in this case) is there to get you up hills so there’s less need for very low gears.

To my mind the best way forward is to simplify things. Let the hub motor take the strain and fit a reasonable low geared hub gear - the Shimano 8 and 11 speed hubs seem popular - with a single chain wheel.

[PH]

I don't know about using a triple, I can't see why not, though it isn't something I've looked into.
You can, I have, use a Alfine tensioner and a double chainset (I used a triple with a bashguard fitted in the outer position) the capacity of the tensioner is 16T,
It does offer the range you're looking for, though I'm not sure it answers your other questions. I found it took a bit of getting used to, I couldn't really use both rings to get sequential gears so there's still the same irregular jumps of any Alfine. Instead I'd use it as two ranges, I might spend 95% of a ride in one ring or the other depending on what sort of ride it was.

EDIT - cross posted with Carlton green, I hadn't picked up the E assist element, so yes I'd also question the need, My E-bike is 1X9 and I could manage fine with less.

[PAB855]

All very useful and to my relief encouraging suggestions.

The other flaw I have found with dérailleurs in my experience is that when they're new, the changing is by a single click, which is as expected, but as time goes on the two up one down or two down one up repeated attack on selecting a gear gradually becomes the norm. It's not a lot better than the old down tube friction levers, or am I just not looking after my bike properly. Don't blame the tools!!!

I'm going to take time to study all this and who knows, maybe return to a single chain wheel and a hub gear.

Happy (?) memories of grinding up the A9 in either bottom or middle gear, leaving top until over the Drumochter summit, on a Raleigh All Steel ( you've said it) 3speed AW(?) bicycle with full STEEL chain case complete with screw in oiling cap, hub dynamo and 5p diameter rear light! Fantastic.

What am I thinking about?

[jimlews]

As a first port of call, I would be looking at one of these:

https://www.sjscycles.co.uk/hubs-intern ... e-hub-36h/

Doesn't get your top to bottom gear in one go at a standstill, but worth consideration.
Potentially, it gives 81 ratios; but that's a bit of a red herring.
Effectively, it gives an extra low gear and an extra high gear.
So the Sturmey would be kept in 2nd gear most of the time. (1:1)

[Jupestar]

Also missed this is ebike.

Always thought an ebike and IGH would be a good mix. (Maybe not for a dedicated road ebike). But for the majority of ebikes.

I would chuck an alfine on single chainring. Let the motor pick up the effort. And have plenty of spare chains to swap on at the first sign of chain stretch. If tensioner needed. I'd probably buy something solid which is designed for the job. Plenty of options out there and not that expensive.

With regards to your RD not working, you probably just need to adjust the cable to your RD. Pick up the slack as they stretch a bit. Cable adjuster should do that once the initial stretch has been taken out ..

[deeferdonk]

i've got a cytronex conversion on an brompton 6 speed - which has sturmey archer hub gears. Works fine, mine is slightly higher geared than standard which is nice - as i have a bit of assistance up hills so doesn't need to be too low but i have more of an option to give it some beans above the assistance speed if i am so motivated.

[Moser151]

I don't see why that wouldn't work.

You would need to make sure the rear cog could take the chain size needed for the front. If the recall the original cogs with guard use a 9s. But a 1/8 doesn't fit.

Also you need a way to fix the RD. Either with the H and L screw, or under tension.

I'm sure others have tried it.

Done this with a 1985 steel Moser frame but went for Shimano 11 speed Alfine with Di2 changers. I have been delighted with the result and ideal for winter, cleaning tiome reduced by 75%

[Brucey]

if you want Rohloff style efficiency, shifting and range, but at a lower cost, this is a tough ask, but not an impossible one. I would suggest that you get someone handy with a welding set to weld two sprockets together; then SG the pair until there is only one 3-lug mounting remaining. This 'double sprocket' should fitted to a shimano alfine 8s hub to give you 16 gears, with high efficiency. IMV the best pairing is probably 20t and 22t; and if driven with a ~52t chairing (on a ~26" wheeled machine) this gives a nice spread of gears from less than 30" to about 100", with no big gaps.

Obviously if you retain two chainwheels, this can give you 32 gears and so forth. In any case, I would most probably start with two SA sprockets, a 22t 1/8"one and a 20t 3/32" one. I would plan to weld them together at the cutouts, then retain the centre part of the 1/8" sprocket (it is stronger) and SG the teeth of the 22t sprocket until they accept a 9s chain. You will need two fixtures; one to hold sprockets concentric for welding and SGing of the 22t sprocket, the second for the SGing of the centre bore after welding. I think you can use an old SA driver for the former, and a simple wooden fixture for the second SGing operation. In both cases the fixture would be held via a piece of studding during SGing.
I think it might be best if the sequence went; a) SGing of the outermost part of the 22t sprocket, to allow the use of 9s chain, b) welding, c)
the second SGing operation, to remove the centre bore of the 20t sprocket.

[jimlews]

if you want Rohloff style efficiency, shifting and range, but at a lower cost, this is a tough ask, but not an impossible one. I would suggest that you get someone handy with a welding set to weld two sprockets together; then SG the pair until there is only one 3-lug mounting remaining. This 'double sprocket' should fitted to a shimano alfine 8s hub to give you 16 gears, with high efficiency. IMV the best pairing is probably 20t and 22t; and if driven with a ~52t chairing (on a ~26" wheeled machine) this gives a nice spread of gears from less than 30" to about 100", with no big gaps.

Obviously if you retain two chainwheels, this can give you 32 gears and so forth. In any case, I would most probably start with two SA sprockets, a 22t 1/8"one and a 20t 3/32" one. I would plan to weld them together at the cutouts, then retain the centre part of the 1/8" sprocket (it is stronger) and SG the teeth of the 22t sprocket until they accept a 9s chain. You will need two fixtures; one to hold sprockets concentric for welding and SGing of the 22t sprocket, the second for the SGing of the centre bore after welding. I think you can use an old SA driver for the former, and a simple wooden fixture for the second SGing operation. In both cases the fixture would be held via a piece of studding during SGing.
I think it might be best if the sequence went; a) SGing of the outermost part of the 22t sprocket, to allow the use of 9s chain, b) welding, c)
the second SGing operation, to remove the centre bore of the 20t sprocket.

SG ing ?

What is SG please, Brucey ?

[Brucey]

look for my post 'how to SG' . SG stands for 'SpinGrind',

[Jupestar]

to weld two sprockets together; then SG the pair until there is only one This 'double sprocket' should fitted to a shimano alfine 8s hub to give you 16 gears, with high efficiency. IMV the best pairing is probably 20t and 22t.

I love these sort of mods. Makes me want to try it even though I don't need it.

Have you ever tested this? Have you confirmed two sprockets fit.

Manual double double to widen the 16 range? Triple-double with FD,RD gives you 48 gears?

[jimlews]

to weld two sprockets together; then SG the pair until there is only one This 'double sprocket' should fitted to a shimano alfine 8s hub to give you 16 gears, with high efficiency. IMV the best pairing is probably 20t and 22t.

I love these sort of mods. Makes me want to try it even though I don't need it.

Have you ever tested this? Have you confirmed two sprockets fit.

Manual double double to widen the 16 range? Triple-double with FD,RD gives you 48 gears?

If you can find an old SA threaded driver, it is allegedly possible to screw a five speed freewheel thereon.
Up to 75 ratios available if using an S5 hub. 45 with an AW.
But if you can contrive a quadruple chainset...