MrRider

I'm converting my 2x road bike to a 1x. Is the optimal chainline for the 1x exactly halfway between the inner and outer chainring positions on the 2x setup?

As well, I'm aware narrow-wide chainrings and chains are best for 1x setups due to chain drop, however will the 2x-designed chainrings and chain still hold ok using them as 1x for the short-term?

fietsbob

Yes.. parallel to centerline, aligned Center cog of the rear cassette... its just like middle ring of the triple crank

BITD single ring (cyclocross) used a toothless ring on either side of that 1 toothed chainring...


shifting aids not on that inner chainring? full height teeth? (indexing cuts the teeth shorter to shift on/off it easier)




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Bill Kapaun

I tend to use the smaller cogs more, so I favor the chain line a bit in that direction from "normal".

MrRider

Thanks mate. Regarding the chainring position, I'll probably put the ring on the inner chainring position. My 30 tooth won't go on the outer chainring position anyway. If I do that, do you know if it's feasible to put a washer/shim on each side where the cranks connect on, to move the cranks out a bit more so that the inner chainring position moves out to that centrelink position?

Your second and third paragraphs went over my head unfortunately.

MrRider

Ah that's a good way of looking at it! And how about using normal chainrings (not narrow-wide), does that work alright?

fietsbob

Surly Stainless steel chainrings are made for being the only one.. I use a 110-38t with my IGH 26" wheel bike.
https://surlybikes.com/parts/drivetr...eel_chainrings

an older pre re engineered for indexing chainring is similar
30+ years ago I built up a triple with older steel chainrings , I have been using friction bar end shifting for 40+ years..

those steel chainrings are not only long wearing... but Surly's are flat,
so you can flip them over.. extending the wear life..




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DrIsotope

This. I've never used a 1X-specific crankset, so I just run my narrow-wide in the big-ring position on 2X cranks. Never had an issue.

OP, if you're riding primarily on pavement, the 2X chainring will be fine, if a little clickety-clackety in the smallest and biggest chainrings. Any issues will show themselves in big-big, when the chain will want to drop off to the inside. Do yourself a favor and pick up a narrow-wide. They're cheap from guys like USA Made and DECKAS.

fietsbob

30 tooth ?this the granny bgear of a triple? its way too far inboard.

MrRider

This is very informative, I understand a lot better now,

Cool I will then look to get a narrow-wide as soon as I can. I've just ordered a Sunshine 11-42T cassette and Roadlink so will have a cool-as setup! I hate my front deraileur, if I can figure out how to get the cable out of the STI lever I'll be one step towards the 1x!

MrRider

I know, outrageous isn't it?! And what's better is I just realized I can actually get it on the big-ring position. All systems ahead! Another advantage of flat chainrings besides flipping them over is that they would then be closer to the centreline.

I was thinking of putting 26 inch wheels on my road bike to get thicker tyres on, however it only gives me an extra 2mm over 650b wheels, and the 650b wheels give me 6 mm over the 700s I'm currently running. I suppose your 26 inch wheels are running on a mtb? My concern is 26 inch might be too small to be road-efficient.

fietsbob

I have a Folding bike with 16" wheels it has 1 54t chainring
and a 15t cog on the 3 speed..

my 26" wheel bike is a Touring/Trekking bike ... Rohloff hub ,bike bought used 10 years ago when it was already 4 years old..

another clever bit Efneo GTRO Efneo shop 1 28t chainring with a gearbox
offering 2 overdrive gears as if a 28 , 40 & 50t.
the chainring thru the gears in it turns faster than the crankarms.. but physically is just 1 chainring..

MrRider

My bike is also being converted for trekking as well as light on-off-road bikepacking/touring, that's what all this gear and wheel conversion stuff is all about.

I've heard of Rohloff hubs, you're doing well to have one of those! How thick are your tyres on the 26 inch touring wheels? What's it like on the road, much more inefficient than larger wheels?

fietsbob

fietsbob

It's fine, I don't go OCD on efficiency.. there is graphs published online if you want to geek out on that.

Used, whole bike was reasonable especially since you cannot buy them in the US.. to buy new see ;
https://www.koga.com/en/koga-signature

someone brought it back from Europe. seller even paid shipping, NC to OR. [I've had it since 2008]

Bill Kapaun

To me, going to a 1X would be a worst possible choice for those choices.
Limiting yourself to wide steps between gears, instead of a closer spaced, more efficient gear for the specific condition.

fietsbob

FWIW, because the hub has been engineered to increase by 13.6 % going up from first the gears get closer together giong down..

inverse fraction? math specialists can answer that.
A-W 3 speed has a 3/4 low sand a 4/3 high.., and Rohloff is 3 speeds ..
used 2 X




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MrRider

That's a gorgeous touring setup. I've now got the 1x going, it's working really well. Still only using the 11-32T cassette though, the 11-42T is on order.

And it does feel good to ride, cleaner, simpler. I like it so far. And I can always put the 2x system back on if I want.