BB and dingle cog
 

So I have a dingle cog ready to install, and I just ordered new cranks that call for a 110mm bb. Should I get like a 107mm bb to offset the difference between the two gears on the dingle cog? I'll be using both gears pretty equally so it would seem going in the middle would be the best bet.

I would assume when designing the cog, they compensated for the offset.

I wouldn't do anything different.

It's surly we are talking about here....

Double dingle cog on a flip/flop would be pretty awesome. 15t-18t.

/end random thought

or use a road double crankset. i have a 42x16 and 39x18 setup on the same bike. one is great for road and the other is great for offroad. both use the same chain length.

I've played with the though of two rings on the cranks and a dingle cog, still playing with the idea.

whaaaaaaaaaaa, that'd be even better. That white industries double crankset thing, and double dingle flip/flop.

8 speed fixed.

Unless you used two different length chains, you'd also need to use a chain tensioner (which wouldn't work fixed). It could happen with a White Industries Dos freewheel though.

I've used a Surly dingle cog, 17/20 paired with a Sugino RD-2 crank with 42 and 39 tooth chainrings on a 103mm BB (recommended width for fixed used on the RD-2). It depends on your dropout length and chainstay length, but I was able to use 3 of the 4 gear combinations with one length of chain. 39/20, 42/17 and 39/17 or 39/20, 42/17 and 42/20.

Make sure you use a 9 speed chain to avoid rubbing on the dingle cog. This of course will mean you'll need a 3/32" chainring.

BB width depends on your cranks, whichever gives you a track chainline is what you should use.

Alright thanks. I guess I could run dual chainrings, might be a bit excessive for around here but having the option would be nice. The Sugino Mighty Comp cranks I just picked up have tabs for two chain rings.

Well this is proving harder than I thought. So I can find that a Sugino Mighty Comp crank used a 114mm spindle stock, but it was a road crankset so I'm not sure what kind of chainline that give it. And to top it off the bb taper was old campy, which seems to be neither iso nor jis, but closer to jis. So I'm all confused as to what bb to get to match up to this thing. Anyone running this crank that can help? I might just have to wait until it gets here and try it out on my 107mm iso miche bb to see how it fits, but that means waiting a week longer to order a bb and get riding again.

i don't know where you got your info re mighty comp cranks using 114mm spindle but sugino themselves publish that it is meant for jis 110 mm as double/103 as single, just like their couple other road double cranks that have become commonly used for ss/fg.

i used a surly dingle cog on my bike in combo with a fsa gimondi crank with the chainring on the outside & 103 mm tange bb, chainline was close enough with 3/32 ring & 9-speed chain & it was trouble-free for the short time i had it on. took it off when i realized that i never switched between the 2 cogs. but i will use it again to have the additional ratio available if i go through with a several day tour i am contemplating.

I might have used confusing terms. I have the sugino mighty competition cranks, not mighty comp, which I guess is different even though comp is just short for competition. Anyways they're the ones from the 70's, not the modern ones you might be referring to.