Trower

I am planning on doing a bit of a rual road with some dirt trails bikepacking trip this summer. I want to do it with my monster cross fixed dingle speed I'm building. I building it primarily to be able to bike to some single track (5 miles away) and then hit the trails there. I thought it would also be fun bike for this trip. The only option for a dingle cog with a decent range range is Surley's 17&21 tooth combo. Planning on trying it with a 42 and 46 tooth chainrings, which would give me 54.56 & 73.82 gear inches respectively. Do you guys think that gearing is doable? I will have a frame pack with my hammock, rain jacket, food and cooking supplies, my small down sleeping bag on the handlebars and some cloths, tools and odds & ends in a seat bag. I could drop the chainrings down to 40 & 44, and get 51.96 & 70.61 gear inches. I know I may have to just try it, but figured I see what you guys thought

Spoonrobot 

I'd recommend you start with the 40/44 combo. 73.82 is a tall gearing for dirt/gravel/crusher run type roads, 70 would be much better. I've noticed that when fixed gearing it too tall for a given ride it feels hard at the start and stays that way all ride. But when you're undergeared you feel slow and spinny for the first few miles but after that it's fun and feels normal.

That sounds like an awesome trip, this forum generally throws up a lot of flak at fixed gear riders but please let us know how it goes.

Are you planning on using a quick-release rear wheel?

Trower

Ya I had a feeling Ide probably go lower, you talked me into it

I figured I might get some flac, but I wanted to hear opinions and have really enjoyed running fixed in the winter for better control on the snow and ice. I am taking a week off for my cousins wedding that's going to be in western Maine, and for 4 days Im going to bike out in nomans land right off the boarder with Quebec. I will take lots of pictures and for sure let you guys know how it goes!

I am planning on making and welding on a tensioner with an idler that is attached via wingnut to keep the gear change easy and simple.

Roughly what I was thinking with braces on both sides of the chainstay.


Thanks for the input!

-Nick

Spoonrobot 

I'm not sure that set up would be durable enough to work. You'd probably be better off with a quick-release rear wheel and a lacrosse ball.

(Loosen quick release, adjust chain, slide lacrosse ball between tire and seat tube, rotate to achieve desired chain tension, tighten quick release.)

Or even just regular chain tugs+QR would probably work fine.

Other than that you sound pretty set.

fietsbob

You could do a Double- Dingle set ... the chain ring for the bigger rear cog total the tooth count less
but equal to the combination of smaller cog + Bigger chainring.
then the chain length required is the same for both

Buy a Swiss made Schlumpf Speed drive crank to mount your 2 chainrings, and then the gear in the outside is an overdrive by 1.6X
for 4 speeds, but still Fixie.

Then again a single gear low enough, x 1.6 should do for a cruising gear ,

if young, and strong, and commited to Fixies.

Theres a Guy that has done international Tours on a replica Highwheeler , only 1 gear, the wheel size ,
but He did do a fair amount of hill walking.

Trower

I think I could get the tensioner to function, just gave you a really crappy drawing with no detail. I was running a job with a long cycle time today so I had some time to think about how it could work I would have to weld it to both sides of the chainstay and support it on the underside a bit as well, so I don't know if I would want to to that and lose clearance. I I'll probably just bring a wrench and use nuts, as I already have a Surly Wheelset thats solid axle. I'm not really a weight weenie, and I will pack quite lite so the extra weight of a wrench won't bother me! The tensioner would probably weigh alot more anyhow if I made it Whatever I do I'll make sure and give a plenty of weighted testing before I set out.

Trower

Wow thats pretty cool! Never heard of anything like that before, though I don't think I would spend that much on one, I'de just use my winter commuter Sturmy Fixed gear 3speed S3X hub with the dingle setup, but I don't think Ide need that many speeds!

fietsbob

Quote:

I'de just use my winter commuter Sturmy Fixed gear 3speed S3X hub with the dingle setup, but I don't think Ide need that many speeds!

Internal Hub mix and match..
FWIW, Sturmey makes a 3 by 2 hub for Brompton, the Driver uses the Splines like Shimamo Or the S3X,
but doesnt thread it, instead they made it wide enough fo 2 cogs 2mm thick, and use a snap ring to hold them on
and the chain-tensioner ,that Brompton designed, also shoves the chain back and forth..

The 2 cog driver & bwr core may be substituted replacing the one in the regular 36 hole AW shell ..

at least in theory..
the ratios are a bit wider , with the 13 ,15t cog set brompton uses, they half step the 3 internal gears.


Anyhow

FWIW its not the 'How many Speeds', My AW3 Mountain Drive crank only has 6, but they are all usable .
the big reduction gear in the Crankset is as if a 50;20t crankset,

low in high range is followed by high in low range as I go down through the gears .. and so the spread
between the lowest and Highest is pretty big..

And because they are both Planetary gears the double shift in the middle works well
even bogged down in the middle of a hill, to go from 4th to the 3rd.

love.the.smell

Why is the chain tension device needed at all? If your chainrings differ by the same number of teeth that the dingle cogs differ by then chain length should remain the same if you only run big/little or little/big, right??

fietsbob

Or a Dos - Dingle .. 2 cog Freewheel on the other side ..

Put a 4 bolt chainring on in place of the Brake disc on a Rohloff Hub, and it's a Fixie, too .. flipped over..

nun

Yep, and if you have track ends you can take up chain slack too. I do this with a "multiple single speed" I have. I use 40x32 on the front and at the back I have 2x freewheels; on one side I have 16x18 and on the otherside 23

fuzz2050

just a reminder (because it's one of my pet peeves), if you have a hammock, and you expect temperatures below 50 degrees or so, it pays to have insulation underneath you. Your choice if this is an underquilt or a sleeping pad, but something can make the difference between a night spent awake and shivering and a good night's sleep.