View Full Version : Eccentric Bottom Brackets...
Loggahead
04-16-2009, 01:09 PM
I am wondering in general what you SSers think about Eccenctric Bottom Brackets?
The reason I ask:
Mark set my Cobia up SS a few weeks ago. I am loving it. SS fits me like a glove. He was able to get me in 32 x 18 with no tensioner! I really hate the look of tensioners... they take away "TeH S3X" appeal of SS. However, I have no options other than 32 x 18 to keep from using a tensioner. No biggie really but I was thinking it would be nice to have a dedicated SS frame bike and a geared bike as well so I have options.
I started looking for SS frames expecting all of them to have horizontal dropouts but am finding that more and more are using EBB's now. The Fisher Rig for example is my exact frame but with an EBB used for tensioning?
What are the pro's/con's to having an EBB for SS tension?
If I ever change gearing, should I look at getting an EBB instead of a tensioner?
Are EBBs compatible with XT externall BBs? Or will the EBB totally replace that and I just keep the cranks?
I found this cool tensioner that I find very intriguing... (http://forums.mtbr.com/showthread.php?t=408510) - One that hooks to the BB. any comments on that?
-g
i was scared of the ebb because they creak and weigh a lot plus it changes the geometry of the frame as you adjust the chain tension. i got a rig frame and the ebb is heavy but so far it works perfectly. i disassembled it when i got it, cleaned and greased it with heavy grease. so far no complaints. i bet there is an aftermarket ebb that is lighter but i haven't bothered looking. i have been using the external bearings with no problems. the geometry issue isn't that big a deal for me but i haven't changed gearing yet.
egordon
04-16-2009, 08:21 PM
Gaylen try a Surley singlanator tensioner, it pushes up on the chain for better tension, if not an ECC rear hub.. This one by White is only about 20 -30 grams heavier than Chris King rear hubs... http://www.whiteind.com/rearhubs/singlespeedhubs.html
Loggahead
04-16-2009, 08:42 PM
Now that is novel! I like that Eric!
-galen
donalson
04-16-2009, 10:27 PM
... you might be able to use a 1/2 link for different chain lengths...
but basicly eric covered it... the WI ENO does exactly what you need... keep your same frame (life time warranty is good)...
i hear mixed things on the EBB... some people have creeks all the time and others never have a problem... f
another option is paragon sliders
there are lots of options out there... but the 1/2 link and then eno would prob be the cheapest way to go... unless you are dieing for a change haha
the hub is $180 plus getting a wheel built around it. i got my frame off ebay for $200. scrounge some extra parts and then you'll have 2 bikes.
egordon
04-17-2009, 08:53 AM
Bens cycle still has 19.5 rita frames left for $200 free shipping. One thing to thing about even if you get a frame with sliders. Running a skewer on the rear hub doenst work very well.. I tried my mavics yesterday and the skewer wont hold the wheel tight enough to keep it from shifting..
brettk
04-17-2009, 08:54 AM
my cannondale has an EBB and i had to pull it apart and reinstall it at the very beginning. aside from that and some squeeks and pops i have had no problems whatsoever with it... yet.
i would say a dedicated ss frame with horizontal dropouts is the way to go. i have a surly 1x1 that i have never had a problem with as far as chain tension goes and you can experiment with gearing as much as you want. i have heard of people taking issue with horizontal dropouts when running disc brakes, but i have no first hand experience with that sort of thing.
just my two cents..
donalson
04-17-2009, 09:16 AM
eric what kind of skewer are you usiing?... basically for track ends you need to run a closed nut QR like a shimano http://sheldonbrown.com/skewers.html
when I ran a rear disc no matter how hard I put my hope QR's the rear brake at some point would slide the axle back... tossed on some old LX QR's I had laying around and never had another problem... if you use a good tensioner you shouldn't have an issue with the wheel sliding forward in the drop outs
that $200 rita frame would be a good way to go... only problem with that would be it's built around a 100mm fork and your fork is an 80mm... I don't think you can bump the fox up to 100mm (only down 100 to 80mm)... could be wrong though... but that being said mark was raving about running a g2 80mm fork wed
Loggahead
04-17-2009, 10:04 AM
Bens cycle still has 19.5 rita frames left for $200 free shipping. One thing to thing about even if you get a frame with sliders. Running a skewer on the rear hub doenst work very well.. I tried my mavics yesterday and the skewer wont hold the wheel tight enough to keep it from shifting..
I would have so jumped on that a few months ago if they had the 17.5" frame... That's what I ride in 29er...
egordon
04-17-2009, 10:23 AM
You can run 80 on the Rita.... Mark did it...
I had mavic skewers.. they get about as tight as any skewers going to... but not at tight as a ss specific bolt on hub.. Im just going to wait on my blunt rims..
egordon
04-17-2009, 10:24 AM
I would have so jumped on that a few months ago if they had the 17.5" frame... That's what I ride in 29er...
Why dont you buy my 17.5 rita , and buld your GF back up with gears..
Loggahead
04-17-2009, 10:52 AM
Why dont you buy my 17.5 rita , and buld your GF back up with gears..
dude... PM offer...
IMHO, I like the EBB's. On the plus side, they hold tension well and are easy to adjust. Minus points are heavier, creaking(more parts), and if ignored they might freeze in the frame. I have one on my tandem road bike. It has worked perfect for years. I did disassemble it when new and anti-siezed all it's parts. I would rather have an EBB than horiz. dropouts. As a compromise, I would run the Surly tensioner. I have never seen any problems with them. You gotta carry the narrow open-end wrench to adjust it.
donalson
04-17-2009, 03:24 PM
...galin... look at the ETT length... not the frame size... fishers have had long TT lengths sence they started the genisis geomotry back in the 90's or whenever it was... still holds true with the g2
also you have to learn that you can't just say "i ride a 17.5"... different manufactures meassure different... some measure it from center (of BB) to the top of the tube, others center to center (of the intersecting tube) or others center to top (of the intersecting tube)... just an example... my redline is a "21" and my karate monkey is a 20" because redline does C-T and surly does the "other" C-T... this goes into it pretty well under the "frame size" bit
http://www.surlybikes.com/spew17.html
all that being said... ETT (effective top tube length) is realy whats most important when fitting yourself to a MTB... ETT is an imaginary flat line (how old road frames top tubes used to be) from the center of the head tube to the center of seat tube (or post when using ETT)... most companies now use the ETT measurment... but back in the 90's a lot of companies where still posting the pointless real TT length
anyway your ETT is 601.90mm or about 23.7" so you'd want to look for other bikes with similar top tube lengths...
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