unbelievably

Opinions on both...
Pros, cons...Whatevers...

Moose

Well the Elliptical BB is only a choice if you are getting a new frame, but they are quite nifty. The chain tensioner is good for conversions. Given the choice between an Elliptical BB and a frame with track ends, I'll take the latter.

Edit: unless you want disc brakes, then go with the Elliptical BB and vertical drops, easier to remove the wheel.

mosplat

you mean eccentric bottom brackets?
i'd say only if you can't adjust at the dropouts.
keep in mind an EBB will also adjust your bottom bracket height a little.
it's much easier to tighten a tensioner.

dirtyphotons

i've heard a few people now complain about persistent creaking with eccentric bottom brackets. maybe they got cheap ones or didn't install them properly though.

i think its a great idea if you're running disc brakes.

Aeroplane

I love my EBB.

But if you don't want to have to think about stuff, and don't mind messing around with disc brakes, track ends are stupid simple and cheap (relatively).

coelcanth

eccentrics are bit heavy and a bit complicated..
it's not uncommon to hear about slipping or creaking problems (people seem to find the binder bolt type shells more secure though)
adjusting the tension means you are effectively changing your bb height/seat tube length/angle/relationship etc.

when i pondered the same debate recently my impression was that most builders recommend ebb's only for tandem applications and for mtb/disc brake applications they like the paragon sliding dropouts

https://www.paragonmachineworks.com/

bellweatherman

Ditto that. If you are like me, then after adjusting the tension on your EBB just right, now your seat height is off. So, you end up fiddling with adjusting the seat height and the fore/aft. It's a pain. Plus, you got that creaky thing going on at the BB shell.

I'd get either standard track dropouts if you don't plan to use a rear brake, or the picture of the sliding dropouts posted above.

mintyai

I heard that because an eccentric bottom bracket is basically a smaller bottom bracket that you can rotate inside the frame, the bearings are smaller and don't work as well. On most tamdens with eccentric bottom brackets, they have a much bigger shell so you can put a standard bottom bracket in.

If you could get a special frame with an over-sized shell that would work, but probably easier to change the dropouts than the bottom bracket shell.

My bike has vertical drops and an ENO eccentric hub, I really love it. It takes less time to set the tension on this than it does with track ends. Much neater than an eccentric bottom bracket or tensioner. It did cost a bit, but eccentric bottom brackets aren't cheap.

dirtyphotons

the prevalent eccentric bottom brackets that are on the market today are inserts that go in to a larger-than-normal bottom bracket shell. the accept any standard english threaded bottom bracket, and i don't think the inserts themselves are very expensive.

there were some grumblings a little while ago on mtbr about an ebb that fits in a standard shell, but that seems to have fizzled for the time being.