EBB for standard thread
 

Hello all,

The story: I have a Salsa Vaya with a Nuvinci N360 rear hub. I run the configuration with a single speed chainline, one chainring and one sprocket. My frame has vertical drop outs, and a standard British threaded bottom bracket.

Current setup:
48T chainring
22T sprocket
Sugino RD2 175mm long cranks
Phil Wood 110.5mm square taper JIS bottom bracket
450mm chainstays
Surly Singleator chain tensioner

I want to lose the tensioner, and use a chainring in the 46-48T range with a 22T sprocket. I have achieved magic gear in the past, 38 x 20 & 42-22 w/ a halflink. I am against using smaller sprockets/chainrings because in the past I have put enough pressure on the chain at a dead stop to cause it to skip, and I like the increased wear time for larger parts.

I am considering using an eccentric bottom bracket and a 47T chainring to take up the chain slack. According to FixMeUp! using a 47T chainring gives me a little slack in the line, and the Phil Wood EBB provides 1/4" of eccentricity so it should be fine. I can use the tensioner I have, but honestly the thing is a huge PITA. Removing the rear wheel is a serious chore. I have to unbolt the tensioner and remove it completely to allow for rear wheel removal.

I'm looking for advice on components. I've never before used OBB cranks so I don't know where to start. All eccentric solutions for standard threads use OBB cranks. I'm willing to lose the square taper cranks and bottom bracket that I already own if necessary. Nuvinci requires a 49mm chainline. I know that OBB cranks have a fixed spindle, but I'm curious to know if any standard cranks with a Phil Wood Philcentric will give me a 49mm chainline. Any advice is appreciated.

So how are you going to get an EBB to fit into a standard shell? An EBB requires an EBB shell, which is larger than a standard BB shell which the Vaya has, unless you get the BB shell of the Vaya changed, you need a different frame.

Phil Wood makes this:
http://www.philwood.com/products/bbp...hilcentric.php
It's a EBB for standard threaded frames. I can use my existing shell. Accepts OBB cranks except for Truvativ/SRAM & Campy cranks.

likely to need to half link for the chain too.. there are 1/8 & 3/32 wide ones
to get chain with in 1~1/2" range

Nice, except for the price

As per my post I have experimented with half links, with mixed success. Unfortunately sometimes it's too short or too long even with the half link.

forward component ebb

No longer produced :( I would prefer this bracket but Phil has never let me down before, and it's currently manufactured. Still leaves the question of what cranks I can use.

^ I think the Forward Components EBB is out of production. There is the Trickstuff Exzentriker, however.

i think this means that you might need a half link even WITH the PW EBB.

I saw this option as well. Even more expensive than Phil. Looks like it allows for infinite adjustability instead of discrete 15* positions. This option leaves the question of which OBB crank to use. I am not particular to what crank it is or what type (1,2,3 speed) as I will only be using 1 chainring position at the 49mm chainline. OBB cranks have fixed spindles, and I would prefer to avoid offsetting the spindle from center and get one that will just 'work'

Ah, I misunderstood. Well, I have no problems running a half link, Phil also says a half link may be necessary. It only offers 1/4" of eccentricity so it makes sense you need a half link.

anyhow, there are some 1/8" wide chains that are composed entirely of half links,
too..

Can't use 1/8" wide links, and I don't see the need for a half link chain... I already have a ton of half links, full links and master links.

they're mostly showing off what you can do if you got a chain-making machine,
for the Fixie bike and BMX type..

KMC supplies a normal steel 3/32 half link , i've got one I put on my Brompton
chain
certainly can find the pin to press out, when time comes
to pull it off and soak it clean.

anyhow, 1/8" is just 4/32 after all .. :rolleyes:

Sure, but a whole chain of half links doesn't give you more adjustment than a single half link.

Lets move the discussion from chains to cranks ... I've already selected my chain of choice and I'm using half-links. This is a discussion about chainline and cranks

I would expect the chainline with the PW EBB is the same as the chainline of whatever crank you are using would be with its stock BB. Phil Wood will have the definitive answer about this.
Most 'single speed' cranks, like the Truvative Stylo 1.1, have the same 'standard' chainline. I do not know what chainline it is.

SS gearing on track bikes is usually 42mm, and 45mm for road frames (130mm O.L.D.) I need to hit 49mm, and 45 is just way too off.

Keep in mind that the adjustment tool isn't available to the public.

Phil Woods has a Square Taper standard shell EBB in the works for a year http://philwoodco.wordpress.com/2011...-phil-centric/ maybe if you give them a call they'll give you an idea of a release date. As far as the current OBB Philcentric chainline, the chainline of OBB is determined by the cranks not the bottom bracket. With a 135mm hub you going to need to go with a mountain bike crank and they average 51-52mm.

THAT would be nice.

It looks like some e-retailers are including the alignment tools now. Aspire Velotech sells the bracket with the tools.
http://www.aspirevelotech.com/Mercha...PW-OUTBOARD-BB

Doing some researching, this is the best advice I can give:

Outboard BB cranks are available for MTB, road and track cranks. 47T chainrings seem to only be available in 110, 130 and 144 bcd, which means no MTB crank would work short of getting some kind of custom ring. Track cranks are generally 42-45mm chainline, so skip that. Road double cranks are 43.5mm chainline, so that leaves out standard road cranks and compact doubles. This leaves 130bcd road triple cranks. Looking at some shimano techdocs, a tiagra OBB triple crank has a 45mm chainline to the middle ring. Generally rings are 5mm apart, so in theory, putting your 47T chainring on the outside of a road triple could potentially give you a 50ish mm chainline. Problem is, this depends on chainring thickness and tooth offset. I don't have any information on that. Hope this helps.

tl;dr: try a road triple.

Alternately, try contacting Nuvinci to see what cranks they recommend.