Going single front ring on Shimano

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jmaccyd
Posts: 120
Joined: Fri Nov 13, 2015 4:12 pm

by jmaccyd

Just some advice as I want to go single front ring on my CX bike and was wondering about the set up. I talked to a guy at a race and he had an AbsoluteBlack front chainring combined with a Di2 XTR rear mech and Di2 levers. This seems to be a fantastic set up for CX. Anyone running this and have any feedback on durability and how it rides?

Also is it possible to do this non Di2 with a standard, and therefore cheaper, set of say 105 levers and a SLX 11 speed shadow rear mech. Are cable pull ratios a problem?

What kind of gearing g do people run on this sort of set up. I live in the SE of England so not too hilly beyond the normal cross stuff.

by Weenie


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wpccrunner
in the industry
Posts: 429
Joined: Fri Dec 07, 2012 8:34 pm
Location: CO

by wpccrunner

The Di2 setup is a very good option for 'cross.
You will not be able to directly combine Shimano mechanical components as you have mentioned above. The cable pull ratio is different on 11 speed shimano road and mtb components. However if you want to use a mechanical 105 lever and SLX derailleur you can look into the Wolftooth TanPan. I don't not have any experience with the Tanpan but I have read reviews saying it does work pretty well. Maybe someone else can chime in on that.

http://www.wolftoothcomponents.com/products/tanpan

I personally am running a shimano 1x10 setup on my 'cross bike. 7900 shifter and rear derailleur. Ultegra 11-28 cassette. Wolftooth drop stop 40T chainring. I also have a cheap generic chain keeper to help prevent the chain from jumping off the top off the chainring. So far so good, once I got the chain keeper properly mounted.

jmaccyd
Posts: 120
Joined: Fri Nov 13, 2015 4:12 pm

by jmaccyd

Ah Ok thanks I wondered about the non Di2 set up. This guys Di2 rig just looked perfect, if expensive, set up for CX. he had also re programmed the Di2 levers so both buttons on the left lever shifted the chain left, and the same on the right. No problem with the shifter buttons when wearing gloves or with cold hands. Where do people put the charging box, I wouldn't like it under the stem as it looks a bit vulnerable to getting caught by branches?

he said his XTR rear mech was £400!! However, I see Shimano are bringing our an XT version this year that should be more palatable.

motorapido
Posts: 334
Joined: Fri Jul 30, 2010 7:08 pm

by motorapido

XT rear mechs are already available and can be got for about £225,
Dependent on if you can run internal cables or not, install options for the junction A charge port are, under the stem, there are alloy brackets that double as headset spacers, stronger than the rubber band. Under the seat, in the head-tube, some stems Pro Vibe i think that have an integrated mount or cavity for it, or you could just mount it to the back face of the bars up against the stem. There are a few other custom installs you can find on here such as in the end of the bars, which is a neat solution. Personally for the few times you will need to charge it a year i just use the older junction A and have to pull my seat-post out to charge the battery.

jmaccyd
Posts: 120
Joined: Fri Nov 13, 2015 4:12 pm

by jmaccyd

Thanks for that. How is durability, I understand it is an even more powerful motor in the MTB mech than the road one. Does it stand up to mud well? I can imagine racing it really is a top set up.

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mattyNor
Posts: 337
Joined: Wed Mar 19, 2014 3:18 pm

by mattyNor

even the road mech is more than powerful enough to shift through the worst mud/ice build up imaginable! Another option you could go with is just using the ultegra mid cage mech (di2 or mechanical) and one of the dozens of little chain guides to keep in on the front ring. the stock one will handle up to a 11-32 cassette and wolftooth makes an adapter thing so you can go to 11-40

CrossRob
Posts: 81
Joined: Tue Dec 14, 2010 9:18 pm

by CrossRob

Seeing the number of mechs ripped off at London League cross races, I've stuck with cheap but effective mechanical.

My set-up is:
- 40t RaceFace narrow wide chainring
- Ultegra 6700 shifters
- Ultegra 6600 short cage rear mech
- XT 11-32 cassette

I used to run an 11-28 cassette, but having switched to the 11-32, I'll probably get a 42t or 44t chainring to give a slightly higher top end.

Despite the mech's reported maximum of 28t, it has no problems handling the 32t cassette, and as it's a single ring at the front, the short cage mech is sufficient.

If you have a particularly short mech hanger, you may need the wolftooth adapter or similar to position the mech lower down.

No dropped chains in two years (I know - I'm asking for trouble).

jmaccyd
Posts: 120
Joined: Fri Nov 13, 2015 4:12 pm

by jmaccyd

Yes the cost of a rear mech is an issue. But have to say having had a gear change struggling with the general mud the idea of crisp and reliable changing in all conditions, all of the time, is the thing that attracts me. Rear mechs are a vulnerable point in CX, seen them getting destroyed in all sorts of ways in a cx race. Might be a cost bridge that I will not be able to cross

by Weenie


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