1 x 10 mega cassette 29er build Di2

Discuss light weight issues concerning mountain bikes & parts.

Moderator: Moderator Team

motorapido
Posts: 332
Joined: Fri Jul 30, 2010 7:08 pm

by motorapido

Finally got my 1 x 10 Di2 setup finished, although i've still got some ideas for some tweek's

Notsure if anyone else has tried this but the standard Ultegra 6770 Di2 rear mech can be controlled by the new Alfine SW-S705 flat bar shifter, and having just bought a One Up 42 tooth cassette ring i started plans to mod the rear mech to cope with a 11-42 cassette.
heres some pics of the finished build, it looks a bit tight on the 42 tooth ring but its set up as OneUp recommend and shifts fine.

the Cassette is a 10 speed XT 11-36 with the 15 &17 tooth sprockets removed and replaced with a Dura Ace 16 tooth sprocket, and the OneUp Components 42 tooth sprocket.
With a Hope 34 tooth chainring up front and Dura Ace chain.

the Alfine SW-S705 shifter has had its clamp machined off and the remaining stub machined to replicate the shape of a Sram matchmaker to fit the R1 brake lever. The shifter wire is then plugged into what is normally the output end of the SM-EW67 control unit which means i can still trim or reset the rear mech, with one of the wires that normally would connect to the shifter cropped and the other extended and routed inside the frame to an internal junction where the battery and rear mech wires connect up. With a direct external battery mount bolted to a custom bracket secured to the down tube bottle bosses so it lays flat on the tube.

The rear mech took a few goes to sort out a good shape, but i ended up with something close to the Sram XX1 or K-edge cage with an offset top pulley, and an MTB mid cage length. So the same cage length as the new Ultegra Di2 GS mech. I've used a modified Ultegra long cage rear plate and Ultegra 11 tooth pulleys, i'm going to try a 13 tooth upper pulley to see if i get a better chain wrap on the smaller cassette sprockets.
The outer cage plate is 3mm thick laser cut aluminium hard black anodised with a brass threaded insert and aluminium spacers for the correct pulley offsets, this is to match up with a standard Ultegra cage so there is no setup problems with shift alignment. This was an easier option than machining the whole cage from 5mm aluminium plate. The P spring is increased in tension and B spring plate is modified as well to increase the spring tension and force the mech to pull in closer on the small sprockets.

having tried a few rough cage plates to sort out the best tension and pulley positions, it was pretty much a case of bolt the whole mech together, fit it to the frame and the indexing was spot on, and just needed the limit screws setting.

One thing is, you must use the PC link and E-tube to update the firmware or the whole lot is dead and won't work, even then it pings up a shifter error in red on the road bike connection check, but it still lets you alter the shifts available and select muti-shift. (Alfine is 8 or 11 speed only)

Next stage is to make the rear mech Shadow+ by fitting a clutch in it, so i can get away without running a front chain device, i've got a trashed Di2 mech of ebay, and have got hold of a needle roller clutch the right size to suit the Shimano rear mech, and i think i've found a clamp that will give me the an adjustable degree of slip to alter the tension for the clutch.

its been foggy all weekend so the photos aren't too hot, but i will get some better ones taken soon, and i got a few spare mech cage plates made if there's any interest.

[img][IMG]http://i63.photobucket.com/albums/h159/MotoRapido/IMG_4440_zps080ee4da.jpg[/img][/img]
[img][IMG]http://i63.photobucket.com/albums/h159/MotoRapido/IMG_4425_zps43cb26dc.jpg[/img][/img]
[img][IMG]http://i63.photobucket.com/albums/h159/MotoRapido/IMG_4431_zps147ae8de.jpg[/img][/img]
[img][IMG]http://i63.photobucket.com/albums/h159/MotoRapido/IMG_4436_zps595c5856.jpg[/img][/img]
[img][IMG]http://i63.photobucket.com/albums/h159/MotoRapido/IMG_4427_zpsd6a03486.jpg[/img][/img]
[imgImage][/img]

commendatore
Posts: 273
Joined: Mon Dec 30, 2013 1:51 am
Location: North Carolina

by commendatore

nicely done. fitting a clutched pulled to the road derailleur interests me for a 1x cx setup.

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



Tazzy
Posts: 165
Joined: Wed Apr 09, 2008 10:55 am
Location: Netherlands, The Hague

by Tazzy

amazing :)

tonytourist
Posts: 1426
Joined: Sat Oct 10, 2009 7:13 am
Location: 90039

by tonytourist

Please keep us updated on your progress, what a cool project!

Jrock831
Posts: 25
Joined: Fri Aug 02, 2013 11:41 pm

by Jrock831

Plus +1
2004 trek carbon 9.8
2013 giant talon 29er
2001 mongoose XR-500

motorapido
Posts: 332
Joined: Fri Jul 30, 2010 7:08 pm

by motorapido

A quick update on the rear mech, well i now have the clutch sorted, having bought a Deore shadow + and had it apart. Basically when its locked down the clutch needs 3Nm torque to make it slip.I will take some photos tonight but it consists of a needle roller clutch operating on a hardened pin which is the mech cage pivot, and a steel band spring is clamped onto this by the cam.

So to reverse engineer it, and fit it into a Di2 or road P knuckle is a bit tricky but not impossible. The hardest bit has been trying to find a clamp mechanism to replicate the steel band of the shadow +. The answer to this was simple in the end, a spring hose clamp, this locks onto the outside of the needle roller clutch, with the advantage that the 2 ears of the clamp can be loaded up by a locking screw.

i've tried it in the wrecked mech i got of ebay and it seems to work just waiting for a new rear mech to turn up so that i can modify it. I'm thinking i will just swap the P knuckle over with the one of the wrecked mech so i can put it back to normal if it doesn't work.

Just for info 'Rose Bikes in Germany are selling off Ultegra 6770 Di2 mechs and shifters at half price' and have been for a while.

motorapido
Posts: 332
Joined: Fri Jul 30, 2010 7:08 pm

by motorapido

Here is a photo of the standard shimano clutch,
the piece around the outside of the roller clutch is the band spring which is compressed by the cam to load it up.

My version of the same thing, in pieces, Custom cage, standard shimano P pivot pin, its hardened and ground where the roller clutch fits so it seemed easier to buy the part than attempt to replicate it. Needle roller clutch, spring clamp, and a new bearing piece for the P knuckle as this is fixed on the clutch mechs rather than be part of the cage as on a standard road mech.

Now to fit all these bits into the P knuckle.
[img][IMG]http://i63.photobucket.com/albums/h159/MotoRapido/IMG_4442_zps737a93a1.jpg[/img][/img]
[img][IMG]http://i63.photobucket.com/albums/h159/MotoRapido/IMG_4444_zps24d92346.jpg[/img][/img]
[img][IMG]http://i63.photobucket.com/albums/h159/MotoRapido/IMG_4445_zps34a843a0.jpg[/img][/img]
[img][IMG]http://i63.photobucket.com/albums/h159/MotoRapido/IMG_4447_zps107bcdb1.jpg[/img][/img]

User avatar
eliflap-scalpel
Posts: 870
Joined: Sun May 25, 2008 10:12 pm
Location: italy
Contact:

by eliflap-scalpel

well done.

my compliments
http://eliflap.it/

User avatar
hjb1000
Posts: 265
Joined: Wed Sep 16, 2009 10:25 am
Location: Australia

by hjb1000

Please keep us updated with mounting your custom clutch- awesome job!

User avatar
hjb1000
Posts: 265
Joined: Wed Sep 16, 2009 10:25 am
Location: Australia

by hjb1000

Also I wanted to ask a question- I am thinking of building a similar setup. If I purchase the 6870 RD mid cage GS, do you think it will be able to handle a 11-36T? The GS is made for 11-32. I guess it depends on the derailleur hanger, I've got a Scott Scale.

motorapido
Posts: 332
Joined: Fri Jul 30, 2010 7:08 pm

by motorapido

You will need to wind the b tension screw right in, and it may still struggle to get into the 36 cog.

Also the original Scott derailleur hangers aren't the strongest and are a bit prone to bending when slightly overloaded, so after a couple of rides you may find your gears start to play up, so check the mech hanger is still straight.

I had one bend half way through a muddy 24 hour race, luckily i had a spare.

warx
Posts: 20
Joined: Sat Jan 03, 2015 1:45 am

by warx

Building a new cross/adventure bike and have the R785 shifters and brakes. For the moment I am moving my current cross bikes' Zee 1x10 setup (40-11 wolftooth cassette, Zee RD and thumb shifter, 42T chainring) while waiting for the XTR Di2 RD. I would like to be able to run a 1x11 setup for cross races and a 2x for 4hr mixed/gravel races (smaller jumps). Also that RD is like $650 and with road shifters will only do 1x since you can't use the XTR Di2 FD or use ultegra FD mixed (come on Shimano!) I suppose regular 6870 setup would work for all but the bumpiest stuff. How much does just a P spring upgrade give you in terms of reducing chain slap and drop?

User avatar
eliflap-scalpel
Posts: 870
Joined: Sun May 25, 2008 10:12 pm
Location: italy
Contact:

by eliflap-scalpel

you need a xx1 style narrow-wide chainring and you'll ride in safety
http://eliflap.it/

warx
Posts: 20
Joined: Sat Jan 03, 2015 1:45 am

by warx

My current cross bike has either a 38T and 42T wolftooth chainring (130bcd, 38T took a bit of filing to fit on the RED crank). I also race this bike single-speed using a BEER eccentric BB which is why I have a choice of two sizes. I've been using my roadbike (Cannondale EVO, U-Di2) for some mixed offroad stuff like the Sonoma Grasshoppers and on the dirt descents the chain flaps like crazy and often falls off the chain ring without even any pedaling but otherwise is excellent - I love Di2. Cross bike is rock solid on the rough stuff with the Zee RD clutch engaged. I know I can do electronic MTB 1x11 (XTR) but the 2x is the part I just don't know how I can figure out. It definitely can not use narrow-wide chain-rings. Maybe I need to get the Shimano software and "see" why it does not allow mixing the the Ultegra FD with XTR RD. But if I could just go all 6870 Ultegra with a spring mod and perhaps even a clutch too it would be perfect!!

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



motorapido
Posts: 332
Joined: Fri Jul 30, 2010 7:08 pm

by motorapido

Well after a couple of months of trials and discussions with warx, i've finally got a Di2 mech design up and running with a clutch, its taken a bit of work but it uses a modified Sram type 2 P knuckle with a Nylon rapid prototype component to get the arm take off angle correct, and its then mated to an Ultegra Di2 mech with my own custom cage. will post some pictures in the near future. As i have also changed to the Absolute Black 40 tooth cassette and a 34 tooth oval ring.

Post Reply