edelay

Hey folks.

For posterity, I thought I would let people know my thoughts on this hub after using it for a 2 weeks. Before doing this upgrade I was using a Shimano Nexus SG-8R30 for 1 year but on a different folding bike.

For my first two commutes on the Sturmey Archer X-RF8, I was steaming mad at how inefficient the gears are and how finicky the gear changes were. I swore I was going to do a mfr return on it. But I kept on pedalling. The hub seems to have broken in a bit and it pops into gear much more confidently. Previously it seemed to cling onto the previous gear a bit. I back off more on the power during gear changes and this seems to help to make the shifts more clean. Gear 4 is funny though... I have to do a little back pedal going up or down into that gear. The good thing is that on my commute I am mostly starting off in gear 2, then pop up into 5 when accelerating, then in 6 and 7 for cruising. I make it into 8 with a downhill or a tailwind. So 4 being fiddly isn't the end of the world. The gears are still make a very noisy whizz sound but I hope that decreases with time. Even though I'm still not happy with how inefficient the gears are, I do get a better workout, which is part of the reason why I bike to work.

The Dahon Curve D3 with 8 gears was going to be my ultimate dream bike, but I think now it really is just a pleasant stop on the road to buying a Brompton and then upgrading that to have a Shimano 8 speed.

April 21st Update:
Just an update on this. The hub went out of adjustment after another few weeks of riding. Adjusted them and now all gear (including the problematic #4 ) shift perfectly. I can shift while still pedalling, but I let off on the power. So the downsides are now
- harder to pedal than a Shimano Nexus
- noisy whizzing sound in all gears except #1 (direct drive)
My hope is that after a few thousand km's the hub will be easier to pedal and quieter. I will of course, update you folks on this.

elmore leonard

i have never ridden one but I believe you have to stop peddaling to shift gears and they need to be adjusted correctly. here all the manuals etc that may help if you do not already have them.
Sturmey Archer | X-RF8

leoho5

Thanks for the feedback edelay. I'm intrigued by the X-RF8 hub because of the higher gear inches for small wheel bikes but it's unfortunate that many owners are not satisfied with the efficiency and noise level.

I have been thinking about modifying a Curve D3 with an X-RF8 and Gates Carbon Drive. Do you think there would be enough frame clearance for a 12mm belt? Regular 8/9 speed chains seem to be around 6.5-7.X mm in width. I'd also be using a 46t chainring and looking at the pics you previously posted, I would think it would work but I'm not sure.

dezzie

I just ordered one for my moulton f frame, depending what chainring you use you can alter your ride to suit and the option of 3 different sprockets, maybe try a gear calculator and work out whats best for your needs, they are designed for smaller chainwheels but the folk who have done the moulton conversion seem very happy, they now do a conversion in the uk for Bromptons using a 36t chainring i have a 46t for now, will work it out after the bikes been rebuilt.

Winfried

Thanks for the feedback. Other riders have the same experience with the X-RF8.

Too bad the Curve won't take a Shimano Alfine 8, which is totally silent and very smooth.

tds101 

I had contemplated purchasing a Dahon Curve and doing this upgrade myself. I'm thankful for your user review. Now I know, said also prefer a Nexus 8 speed hub, to not go through with it. I had a bike w/the Sturmey-Archer 5 speed hub, and it's inefficient gear spacing & noisiness made me a bit crazy. I just wish the Curve was 135mm OLD instead of 120mm OLD.

BruceMetras

Hunt for SRAM/Sachs Spectro P5 ... high quality German hub .. dead quiet .. 256% range .. 5 speed .. reliable .. strong .. smooth .. efficient .. 120mm spacing .. standard 3 dog cogs .. run belt drive if you want ..

tcs

Interesting. How are you measuring efficiency?

tds101 

Nice,...but I'd only do an 8 speed. And Shimano Nexus is it. Especially since I'm not even a quarter as well versed in bike mechanics. I wish,...

edelay

>Interesting. How are you measuring efficiency?

Bike over the same route using a similar bike with a Nexus 8 vs a bike with Sturmey Archer X-RF8. The difference is quite dramatic.

edelay

I think there is only 2 or 3 mm's of clearance for the chain, so the belt may rub.
https://www.bikeforums.net/attachment...3&d=1457214035

I wonder if you could compensate with a narrower bottom bracket?

edelay

That is an awesome setup. I'll definitely keep that hub in mind. I found the SRAM i-Motion 3 closer to the Nexus 8 in terms of efficiency and soild gear changes. Another thing I could have down was keep the SRAM 3 speed and gear the bike up a bit.

P.S. That clickbox thingy on the outside of hub is a bit fugly.

tds101 

OK, I actually did a little more searching for the SRAM P5 hub,and all I can find is a shifter for sale. Anyone know where this hub can purchased?

BruceMetras

The hubs have been out of production for awhile, but show up on ebay worldwide all the time.. usually Germany.. sometimes they show on the US site .. worth hunting around for if you are trying to get a very nice hub into 120mm dropouts...

bargainguy

On hub efficiency, there was an article in A to B magazine awhile back that measured the efficiency of several hubs. I can't find the article online, but I remember being shocked that typical hub efficiency was around 85% compared to a derailleur system.

There were differences among hubs, but even the best hubs didn't come close to derailleurs. My takeaway is that there is a price to pay for internally geared hubs, and efficiency is one of them. No free lunch, unfortunately.

Winfried

Technical | A to B Magazine

BruceMetras

Here's a much more indepth testing/study... https://www.ihpva.org/HParchive/PDF/hp52-2001.pdf .. if one is to take the data presented, it is clear that some hubs are very efficient .. exceeding some derailleur drive trains .. in practice, I have found the Sachs 2 speed, 3 speed and 5speed hubs to be very efficient ..

BruceMetras

Yeah, the clickbox is a visual alright .. but it functions well .. as does the whole bike ... wanting a cleaner look also took me to a Sachs 3speed with pull chain.. that look I like a lot and the hub is a jewel..

tds101 

So sad that these hubs are so hard to get. It seems that when a good thing comes along it's always discontinued. Dang,...

smallwheeler

hoping to find a use for this sachs orbit 2 x 6 (!!!) 124mm OLD 12 speed hub:



(also pictured, hand-stitched cotton cycling cap by B.I.)

BruceMetras

Such a tease.. that thing is so pretty .. may have to look in the abandoned frame closet..

badmother

For shiny bike maybe?

OLD could be wrong..

jur

Should be able to space that out to 130mm... I would put that on a Ti Swift in a heartbeat.

edelay

That is a nice looking hub. Can you point me to do full photos of each of the bikes?

P.S. As much as the inefficiency of the X-RF8 irks me, it is a fine looking hub.
https://www.bikeforums.net/attachment.php?attachmentid=507986&d=1457214037

tcs

I'm assuming this is your Fiori, with ISO305 wheels & the same tires.

Fair enough. I've got an X-RF8(W) I've been riding for the last six years and it's noticeably freer running than another bike I have equipped with a Nexus 7.

I can't find the article in its German publication, but here's a chart they did on IGH efficiency. The bold lines are efficiency @ 200W input, the thin lines are @ 50W input. Setting the NuVinci (which doesn't have gear 'numbers') to the right of the chart is purely arbitrary. IIRC, the grafted 'efficiency' of the single speed was a SWAG.