dezzie

Seen a few folk doing conversions and thinking of doing it on my old mk2, now i have read lots of confusing things regarding what hub to get, drum, disk etc, folk i know using drum version, now what would be the best for gearing, wheels are 349 size so what would be best chainring size? read stuff saying a small chainring is better, some say larger, then same again with rear sprocket? What the hell is better before i spend the cash and building one into a new rim etc, stories of the old 8 speed hubs disintegrating so who has the latest and is it worth it?

rhenning

Do some research on your own. Find out what the gear multiplications are in the SA hub. Then run a gear inch chart to see what gets you the best compromise. You want to try to get something that gives you about 30 gear inches in low and about 100 gear inches in high. Gear inches is diameter of the wheel times the gear ratio times the multiplication in the hub. If you have a 16 inch wheel tire combo and a 54 to 18 sprockets plus an internal hub with a 1 to 1 would have a gear inch of 48. That is 54 divided by 18 times 16 times one. The are so many possiblities that I wouldn't want to even start telling you what to use. My F frame has the 4 speed with a 52 to 14 and seems to work fine. Roger

12boy

there is an excellent tool provided by the Great Sheldon, RIP, you plug in your stuff and you can choose between gain ratios and gear inches, my preference. it creates a little chart you can cut out and paste on your handle bar if wished. For my part mid eighty gear inches on the high side and 30 low will allow me to climb and zip around with a tailwind. You haven't said what it is like where you live, however. the 8 speed first gear is direct drive so choose a chain ring and cog that establishes the lowest gear inch you want. this is why the chain ring will be pretty small and the cog can be larger.
[h=2]Gear chart using Gear Inches[/h][h=3]For 16 x 1 3/8 / 35-349 tire with 170 mm cranks[/h][h=3]With custom sprocket(s)[/h][h=3]With Sturmey-Archer 8-speed wide-ratio (2009-) X-RF8(W) Rear Hub[/h][TABLE]
[TR]
[TH="bgcolor: yellow"]1.0 (Low)[/TH]
[TH="bgcolor: yellow"]1.3[/TH]
[TH="bgcolor: yellow"]1.48[/TH]
[TH="bgcolor: yellow"]1.68[/TH]
[TH="bgcolor: yellow"]1.93[/TH]
[TH="bgcolor: yellow"]2.19[/TH]
[TH="bgcolor: yellow"]2.49[/TH]
[TH="bgcolor: yellow"]3.24 (High)[/TH]
[/TR]
[TR]
[TD][TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]34[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]18[/TH]
[TH="bgcolor: white"]30.4[/TH]
[/TR]
[/TABLE]
[/TD]
[TD][TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]34[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]18[/TH]
[TH="bgcolor: white"]39.6[/TH]
[/TR]
[/TABLE]
[/TD]
[TD][TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]34[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]18[/TH]
[TH="bgcolor: white"]45.0[/TH]
[/TR]
[/TABLE]
[/TD]
[TD][TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]34[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]18[/TH]
[TH="bgcolor: white"]50.9[/TH]
[/TR]
[/TABLE]
[/TD]
[TD][TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]34[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]18[/TH]
[TH="bgcolor: white"]58.6[/TH]
[/TR]
[/TABLE]
[/TD]
[TD][TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]34[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]18[/TH]
[TH="bgcolor: white"]66.4[/TH]
[/TR]
[/TABLE]
[/TD]
[TD][TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]34[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]18[/TH]
[TH="bgcolor: white"]75.4[/TH]
[/TR]
[/TABLE]
[/TD]
[TD][TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]34[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]18[/TH]
[TH="bgcolor: white"]98.3[/TH]
[/TR]
[/TABLE]
[/TD]
[/TR]
[/TABLE]
[h=3][/h]

[h=2]Gear chart using Gear Inches[/h][h=3]For 16 x 1 3/8 / 35-349 tire with 170 mm cranks[/h][h=3]With custom sprocket(s)[/h][h=3]With Sturmey-Archer 8-speed wide-ratio (2009-) X-RF8(W) Rear Hub[/h][TABLE]
[TR]
[TH="bgcolor: yellow"]1.0 (Low)[/TH]
[TH="bgcolor: yellow"]1.3[/TH]
[TH="bgcolor: yellow"]1.48[/TH]
[TH="bgcolor: yellow"]1.68[/TH]
[TH="bgcolor: yellow"]1.93[/TH]
[TH="bgcolor: yellow"]2.19[/TH]
[TH="bgcolor: yellow"]2.49[/TH]
[TH="bgcolor: yellow"]3.24 (High)[/TH]
[/TR]
[TR]
[TD][TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]34[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]22[/TH]
[TH="bgcolor: white"]24.8[/TH]
[/TR]
[/TABLE]
[/TD]
[TD][TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]34[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]22[/TH]
[TH="bgcolor: white"]32.4[/TH]
[/TR]
[/TABLE]
[/TD]
[TD][TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]34[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]22[/TH]
[TH="bgcolor: white"]36.8[/TH]
[/TR]
[/TABLE]
[/TD]
[TD][TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]34[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]22[/TH]
[TH="bgcolor: white"]41.6[/TH]
[/TR]
[/TABLE]
[/TD]
[TD][TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]34[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]22[/TH]
[TH="bgcolor: white"]48.0[/TH]
[/TR]
[/TABLE]
[/TD]
[TD][TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]34[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]22[/TH]
[TH="bgcolor: white"]54.3[/TH]
[/TR]
[/TABLE]
[/TD]
[TD][TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]34[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]22[/TH]
[TH="bgcolor: white"]61.7[/TH]
[/TR]
[/TABLE]
[/TD]
[TD][TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]34[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]22[/TH]
[TH="bgcolor: white"]80.4[/TH]
[/TR]
[/TABLE]
[/TD]
[/TR]
[/TABLE]
[h=4]Gear Chart by Sheldon Brown[/h] The calculator is at
[h=3]Sheldon Brown's Bicycle Gear Calculator[/h]www.sheldonbrown.com/gears/

dezzie

i have, hence what i wrote in the first part of the page, their tends to be confusion regarding front chainwheel size as some say the sturmey is set up for small chainrings of 34 teeth approx, others are using 50 teeth, then there is the rear, its all confusing me hence why i am asking who has done it, i have the 4 speed sturmeys in both my Moultons already.

BruceMetras

40t in front 25t in rear .. will be wonderful..

dezzie

Have you done this Bruce?

BruceMetras

Sure I've run them on 305, 349, and 406 formats .. the good news, the X-RF8 can be had in 120mm OLN, so will fit the bike without too much drama.. and they have a good gear range of 325%.. the bad news is that they are really heavy at around 4lbs just for the hub, and the ones I've had were not quiet (like my SRAM P5) ..

tcs

The Sturmey 8 uses unique cogs available only in 20, 23 and 25T (unless you find a NOS 19t one).

dezzie

Latest purchase is a nicer mk2 Moulton Major, currently stripped and awaiting all this new bling i bought, 8 speed sturmey, sun rims, Brooks Flyer special and plump grips, new cranks, pedals, brakes etc and i think it will be lovely when finished!

edelay

Hi Dezzie.

I realize that you weren't asking about this but....I find the Sturmey Archer x-rf8 quite inefficient and noisy. Any chance you can test ride a bike with this hub in it to see if either of these properties are a deal breaker for you? The hub looks really nice on a bike and when properly adjusted shifts confidently. The spacing of the gears is nice except for that last big leap into 8th.

P.S. Was in Newcastle two summers ago to walk Hadrian's Wall. Beautiful countryside.

dezzie

Nope no chance of testing but my buddy in Florida has built his and loves it and the lady who built it has her own also, quite a few on some other forums have the same conversion, few say it takes a couple of thousand miles for the gears to settle and bed in before it runs smoother, some dealers fitting them to Bromptons in the UK also, so i guess it will be ok just a case of working out what chainring/sprocket combo works for me when its all built.

Yup we have some lovely countryside and beaches where i live!

WeeBike

I noticed a call for experience advice for the Sturmey 8 speed hub on a Moulton. I have been running an 8 speed on a Brompton (16 inch 349) for 6 years and recently changed it up for another 8 speed but now with the drum brake. Works like a charm and I avoid the poor Brommie gears and worse brakes. The gears are a bit noisy but I always know what gear I am in by the unique sound from each gear. I use a J-Tek thumb gear changer (no space for a twist grip changer on a Brommie) which makes me think I have a Rohloff(what a dreamer) given how smooth it all works together. I use a Shimano Alfine 501 39 tooth crank set with the Sturmey 20T cog. This gives a range of 31 to 101 gear inches which works well in an environment without large hills (see Sheldon Brown's gear calculator if you wish to fine tune yours differently). On the Brommie you have to widen the rear triangle to 138mm (165mm initially to allow for spring back).

The Sturmey 8 speed gets a bad wrap on the net, however, I have had great success with mine. I use Jagwire cable adjusters at the hub(for adjusting on the work stand)and at the gear selector(for adjusting on the fly) in case I need to fine tune the adjustment which really only is needed for the fist week of setup and riding.

I also installed a Sturmey front dynamo/ drum brake combo. The drum brakes are weather proof, dirt proof, stop on a dime and are nice and smooth. The dynamo has you lit up at all times for safety.

Hope this helps!

WeeBike

I noticed a call for experience advice for the Sturmey 8 speed hub on a Moulton. I have been running an 8 speed on a Brompton (16 inch 349) for 6 years and recently changed it up for another 8 speed but now with the drum brake. Works like a charm and I avoid the poor Brommie gears and worse brakes. The gears are a bit noisy but I always know what gear I am in by the unique sound from each gear. I use a J-Tek thumb gear changer (no space for a twist grip changer on a Brommie) which makes me think I have a Rohloff(what a dreamer) given how smooth it all works together. I use a Shimano Alfine 501 39 tooth crank set with the Sturmey 20T cog. This gives a range of 31 to 101 gear inches which works well in an environment without large hills (see Sheldon Brown's gear calculator if you wish to fine tune yours differently). On the Brommie you have to widen the rear triangle to 138mm (165mm initially to allow for spring back).

The Sturmey 8 speed gets a bad rap on the net, however, I have had great success with mine. I use Jagwire cable adjusters at the hub(for adjusting on the work stand)and at the gear selector(for adjusting on the fly) in case I need to fine tune the adjustment which really only is needed for the fist week of setup and riding.

I also installed a Sturmey front dynamo/ drum brake combo. The drum brakes are weather proof, dirt proof, stop on a dime and are nice and smooth. The dynamo has you lit up at all times for safety.

Hope this helps!

badmother

I`d like to see pictures of your Brompton and I`d like to hear more but maybe make a new thread or find a thread with a Brompton topic to make it easyer for others to find your info when searching for solutions for Bromptons.

Your bike sounds interesting, thank you for posting!

dezzie

Has been in the shed 2 years, got sidetracked by my motorbike builds, so far all i have done is cleaned up and refitted the front suspension forks, so not even close to finished yet but once i am done i will let you know how i get on, i still run the Moulton F Frame group on facebook and some lovely builds posted recently have sparked my mojo again.

fietsbob

there is a 4 speed too, same 1:1 1st gear Sturmey-Archer | X-RF4
1.16 Kg rather than 1.8..
And uses standard 3 spline cogs 13 t and larger offered in 28 hole and 32 rather than just 36*

* have a Bike Friday with a 36 hole hub, laced in a 349 -- 24 hole rim 2X.. FWIW..

dezzie

The original is a Sturmey 4 speed so pointless going the same route, needed more gears hence the conversion, i cannot afford a spaceframe moulton but hopefully someday, an sst alfine 11 is on my wishlist.

fietsbob

The RX-RF5 .. 5 speed has 2 over 2 under .. 17t and bigger cogs..
Geared Cranks offer a front shift without the chain leaving the chainwheel..

Alfine 11 is a 135 wide hub, so a frame spread needed..

good luck with your decision..

dezzie

Getting there haha its taken years, sold the 8 speed wheels as i have been penniless for a good while but bikes almost there, just new wheels to build, also aquired a rough mk3 Moulton last week which needs a complete resto and possibly another today, mk3s seem flavour of the month so got the rough one very cheap and a better one for 6 times the price but still worth more. Will post pics later if it turns up. Here is where i am with the mk2 Major.