Technical & Reference Section > Tech and Restoration
Sturmey Archer Gearing on a BMX.........I'm not crazy BTW!!
moley:
--- Quote from: Dark Diggler on October 30, 2010, 09:10 AM ---Moley.....your a mong
--- End quote ---
I thank you for your encouragement and support!!
--- Quote from: Badbaldie on October 30, 2010, 11:55 AM ---hills are no problem to a mole ...... they just tunnel threw. :LolLolLolLol:
--- End quote ---
It could take weeks to tunnel through!!! :idiot2:
--- Quote from: Jon The Bassist on October 30, 2010, 11:13 AM ---For fitness you should keep it single speed :smitten:
Unless you've got a seriously steep hill that's impossble to get up. On my ride to work I go from the lowest point in Harrogate to the highest, which is a decent climb. It's only about 4 miles but it really gets your heart rate up as you're out of the saddle for a lot of the way.
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Why keep it singlespeed? The rohloff system is good but expensive but think about the system. Its clean. No derailleurs, No slack chain that needs tensioning, no trailing chain under the freewheel that you have worry about clearance. Sturmey Archer are taiwanese now so the tolerances on the machinery are far better than the English made ones (from the 60's when the quality went downhill) because they ended up chucking out all of the machinery because it was so out of tolerance and built their own. If 44/16 is your neutral gear then with a 3 speed the lowest gear would be -25% and the highest would be +33% above 44/16. For spinning exercises you could knock it into low gear and for power you could knock it into high gear when your sprint training. Feel that burn. And you could also use it for general cycling. With 5 gears I reckon it could be used for the lake district and the big mountains. Just set the neutral gear so that the lowest gear (62.5% of neutral ) is suitable for the steepest hill you'll encounter and the highest (160% of neutral) should be fine for any decents or on the flat.
5 Speed Gear Calculation Chart Based on 44/16t Gearing 20x175 180mm Crank (51.4" Travel Distance)
S/A Gear BMX Gear (closest) Distance Ratio Inc/Dec % Gear Inc% 128/1632.1"62.5%-37.5%Gear 1233/1638.5"75%-25%Gear 1 +20% 344/1651.4"100% NeutralDirect DriveGear 2 +33%459/1668.5"133%+33%Gear 3 +33%570/1682.2"160%+60%Gear 4 +20%
I think a normal 27 Speed 26" MTB gearing is 44/32/22t Sprocket and 9 Speed SRAM (12/13/14/15/17/19/21/23/26) giving low gear of (22/26t) of 21.9" and high gear of (44/12t) of 95.1" distance travelled!! Sturmey Archer 5 Speed with 44/16t gearing would give 32.1" (Low), 82.2" (High) and normal 44/16t Neutral middle gear.
It should give some usable gears!!
--- Quote from: James Nada on October 30, 2010, 08:24 AM ---Moley - I have an old folding bike with 20" wheels and 3 speed Sturmy Archer (or some kind of copy). I think it the rear wheel would fit a BMX.
Anyway, it's yours if you want it (it may be useful on a prototype at least).
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Is it fully operational with gear selector, cables etc, etc? Also how is the cable gear selector mounted to the frame? Metal clips or welded mounts or neither?
The big point is hub width. It would need to fit into a 110mm frame!! ???
I think a prototype made out of a Falcon Pro Flyer is on its way!!! :daumenhoch:
Diggler wont be laughing when he hits a steep incline on MTB and I wizz pass on my 20" Falcon Pro Flyer!! Take that Diggler and stick your negative energy where the sun dont shine!!! :LolLolLolLol:
Jon The Bassist:
I suggested keeping it single speed purely from the point of view of givng you a good workout, not to get you there quicker or owt. In my experience you get a good burn in the muscles going uphill, then practice your spinning when going downhill.
I totally understand about not wanting deraileurs with all the crappy angles for the chain, difficulty in maintaing it all etc and it generally being a rubbish, flexy system. If a hubgear works for you then go for it. Most of my fitness gains this year have been from commuting, so I highly recommend it :daumenhoch: .
For informaton my OM Flyer has a rollout of 60" which is hard work up the steeper hills but great on the flat and downhill.
griff:
go for it moley! not like you don't have other bikes to play on :daumenhoch:
look forward to seeing the results!
cheers
griff
PS you should put a twist-shift & some grifter decals on it 8)
James Nada:
--- Quote from: moley on October 30, 2010, 01:52 PM ---
--- Quote from: James Nada on October 30, 2010, 08:24 AM ---Moley - I have an old folding bike with 20" wheels and 3 speed Sturmy Archer (or some kind of copy). I think it the rear wheel would fit a BMX.
Anyway, it's yours if you want it (it may be useful on a prototype at least).
--- End quote ---
Is it fully operational with gear selector, cables etc, etc? Also how is the cable gear selector mounted to the frame? Metal clips or welded mounts or neither?
The big point is hub width. It would need to fit into a 110mm frame!! ???
:daumenhoch:
Diggler wont be laughing when he hits a steep incline on MTB and I wizz pass on my 20" Falcon Pro Flyer!! Take that Diggler and stick your negative energy where the sun dont shine!!! :LolLolLolLol:
--- End quote ---
Yep, proper gear selector and cables attached etc. It prbably needs a lube up though.
I think the cable gear selector is mounted via clips rather than welded mounts - not sure though. Dunno about the 110mm frame either -the bike is under a pile of shite at the moment. I'll find out.
moley:
--- Quote from: James Nada on October 30, 2010, 02:19 PM --- I'll find out.
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:LolLolLolLol:
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