Exzentriker 46mm shell eccentric bottom bracket

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VeloGiro
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Exzentriker 46mm shell eccentric bottom bracket

Postby VeloGiro » Tue May 02, 2017 12:33 pm

A couple of years back I converted my 2012 Vivente World Randonneur’s drive chain from its stock derailleurs, triple chainring and 9 speed cassette setup to a Rohloff internal gear hub. To tension the chain I initially used an old derailleur, set/locked to the correct chainline, which worked fine…then a single speed chain tensioner, which again worked fine.

All the time however I was really keen to ditch the tensioners. So looked at all manner of options but it landed on giving an Exzentriker 46mm shell eccentric bottom bracket a go, which I installed last weekend. Leaf T asked if I could report back to the forum on how I have found it so here goes…

For those that may not know about the thing it’s basically designed to allow a standard 46mm BB shell bike to run a single speed sprocket…or internal gear hub without having to use a chain tensioner. Most eccentric bottom brackets use a much bigger 68mm shell.

If you’re interested to find out more here’s a link that explains what it does and what it looks like… http://www.trickstuff.de/en/products/exzentriker_KL.php

Well, Its installed…and yep it does what it said it would very nicely. I now have a perfectly tensioned chain on my VWR!

The instructions on the Tricksuff website suggests there is the ‘capacity’ for a + or – 16mm adjustment with the thing…but to achieve this you may need to use a half link or play with sprocket/chainring combinations. With a standard 68mm eccentric BB there is no such rider (or need) for half links etc.

I reckon I was lucky that the chain length on my setup was close to being rideable with the eccentric set at its shortest pitch, so in the end it was really easy to achieve a tensioned chain without having to muck around with half links (which are supplied with the BB) or changing sprockets/or the chainring by one tooth to find the sweet spot.

The biggest challenge for me was making the installation tool. SJS cycles (where I purchased the BB) were out of stock of the Trickstuff installation tool…so I had a crack and making my own, which in the end worked a treat. I have attached a couple of images of the ‘tool’. Installation was fun. I really like playing around with new bits of kit.

Getting the chain line right was a matter of trying different spacer settings. In the end however; using no spacers on the drive side achieved the required Rohloff 53mm chain line almost perfectly. The crankset I was using was an old Sora road triple on the outside ring.

I did need to grind off the granny gear bosses for the crank spider to fit over the BB due to the Exzentriker being quite a deal larger in diameter than a conventional BB.

So the installation required some inputs. I wouldn’t say there was anything too technical (particularly if you have an angle grinder at hand – or a single speed crankset…and the installation tool!) but yes there were a few inputs required.

Lets see how it goes riding. I can’t imagine it’s going to do anything other than what a decent eccentric bottom bracket is supposed to do. Think I’m a fan…I’ll keep you posted with a few rides (and perhaps a rear wheel removal on the road) under the belt.

What I do like is that the bike now looks like an internal gear hub machine should – Its probably purely aesthetics…and a case of form over function but I’m happy to back my purchase in and to be both superficial and somewhat pleased about the look of the bike! Here’s what it looks like now and a couple of images of the BB in situ. Happy to field any questions if anyone has any...

Cheers

The bike
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The BB
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The tool - Mark 1 - I had to use high tensile bolts to stop them from bending under the force of tightening
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The 'tool' in action
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Last edited by VeloGiro on Tue May 02, 2017 5:36 pm, edited 1 time in total.
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find_bruce
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Re: Exzentriker 46mm shell eccentric bottom bracket

Postby find_bruce » Tue May 02, 2017 2:42 pm

It's a nice bit of kit & I'm looking forward to reading about how it works in the long term, especially on a touring bike - how easy it is to adjust for chain wear, does it become unadjusted, how well the bearings last etc.

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Leaf T
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Re: Exzentriker 46mm shell eccentric bottom bracket

Postby Leaf T » Tue May 02, 2017 5:12 pm

Thanks VG. Lots of good info there and good to hear it's working out well so far. It looks great on the bike too without the wheeled tensioner.

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baabaa
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Re: Exzentriker 46mm shell eccentric bottom bracket

Postby baabaa » Tue May 02, 2017 9:00 pm

Yeah, thanks a good report and a bit of a EBB fan here.
Nothing wrong with 16mm adjustment, a bushnell only gives 13.2 mm.
Also, re shell size yes 66 mm width to run a 68 or 68/73mm bottom bracket but a pretty standard EBB bb internal diameter shell is around 54 to 57 mm. With grub screws, I think the standard is 60.3 mm and 65 wide?
http://www.bushnelltandems.com/articles ... _size.html
The Bushnell eccentric is designed to fit in a bottom bracket shell that has an internal diameter of 53.8mm to 54.0mm (or 2.120" to 2.125"), or can be shimmed to 55 and 57mm sizes for just $20.
and for shell diagrams http://www.bushnelltandems.com/eccentri ... specs.html

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Warin
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Re: Exzentriker 46mm shell eccentric bottom bracket

Postby Warin » Wed May 03, 2017 8:38 am

The 'special tool' looks like a 'pin spanner'... adjustable ones can be had for not much money.

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VeloGiro
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Re: Exzentriker 46mm shell eccentric bottom bracket

Postby VeloGiro » Thu May 04, 2017 7:51 am

baabaa wrote:Yeah, thanks a good report and a bit of a EBB fan here.
Nothing wrong with 16mm adjustment, a bushnell only gives 13.2 mm.
Also, re shell size yes 66 mm width to run a 68 or 68/73mm bottom bracket but a pretty standard EBB bb internal diameter shell is around 54 to 57 mm. With grub screws, I think the standard is 60.3 mm and 65 wide?
http://www.bushnelltandems.com/articles ... _size.html
The Bushnell eccentric is designed to fit in a bottom bracket shell that has an internal diameter of 53.8mm to 54.0mm (or 2.120" to 2.125"), or can be shimmed to 55 and 57mm sizes for just $20.
and for shell diagrams http://www.bushnelltandems.com/eccentri ... specs.html


Ahh yes Baabaa your right on the diameter of a full sized eccentric. Thanks for the correction. I'd assume the Bushnell wouldn't require a half link to get that level of adjustment? Cheers
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VeloGiro
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Re: Exzentriker 46mm shell eccentric bottom bracket

Postby VeloGiro » Thu May 04, 2017 7:52 am

Warin wrote:The 'special tool' looks like a 'pin spanner'... adjustable ones can be had for not much money.


Thanks for the tip Warin - I'll check them out...
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baabaa
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Re: Exzentriker 46mm shell eccentric bottom bracket

Postby baabaa » Thu May 04, 2017 9:21 am

Correct, no need for a half link as once loose you drop in your wheel with your new or changed ratio freewheel and chainring and then snug it up once you get the correct tension. Remove your wheel and drop off the chain and then just tighten the whole ebb and bb combo up.
Also worth pointing out the other weird thing about an ebb is it gives you options on bb drop so one frame gives you a whole heap of sizing options. I don't get that fixed into a certain on crank possi as I just find the right chain tension and then forget it, but do notice the difference when you put your crank axle at 12 or 6 o'clock....

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VeloGiro
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Re: Exzentriker 46mm shell eccentric bottom bracket

Postby VeloGiro » Thu May 04, 2017 2:01 pm

VeloGiro wrote:
Warin wrote:The 'special tool' looks like a 'pin spanner'... adjustable ones can be had for not much money.


Thanks Warin- An adjustable pin spanner would have been prefect! Should have come straight here seeking advice :oops: That said the home made job got the grey matter (and the hub) working. I am going to purchase a pin spanner now though for next time :D !

Cheers
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VeloGiro
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Re: Exzentriker 46mm shell eccentric bottom bracket

Postby VeloGiro » Thu Jun 08, 2017 5:20 pm

Quick update on the BB...just on 750k's ridden and it hasn't missed a beat - No adjustment needed - perfect chainline and without doubt the bike feels and runs smoother with the direct chain than it ever did with the tensioner fitted...the one downside is the 'dreaded' rotating cranks while walking the bike has crept in. It happened occasionally with the previous setup...Its happening almost all the time now :|

The BB is all i hoped it would be - Planning an Adelaide to Melbourne ride later in the year so it 'll be good to see how it fairs with touring weight and touring conditions...but for now I'm pretty happy :)
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