Author Topic: Largest Di2 chainring size? (Read 6929 times)

LittleWheelsandBig · « **Reply #25 on:** 15 August, 2018, 02:36:45 pm »

Not an option because that requires expensive 10t-up cassettes to get higher gears.

thing1 · « **Reply #26 on:** 15 August, 2018, 06:34:19 pm »

LwaB: get in touch if would you like to borrow a Di2 groupset to test anything out with. For complicated reasons we have an excess of spares now.

Brucey · « **Reply #27 on:** 15 August, 2018, 06:41:51 pm »

if there is an issue with knowing if it will work or not, is it possible to mock up the system using a standard mechanical front mech? IIRC the capacities of the (equivalent, much cheaper) mechanical mechs are near enough the same as the Di2 versions, so if it works with one, it ought to work with the other. This will give you the chance to experiment with adjusted/revised FD mountings etc without having to shell out on a load of Di2 kit first.

-just a thought-

cheers

PeterM · « **Reply #28 on:** 15 August, 2018, 08:08:06 pm »

Quote from: LittleWheelsandBig on 12 August, 2018, 01:48:19 pm

SRAM's eTap doesn't look to have long enough range between charges, beside an excess of batteries.

A spare eTap battery weighs 24g and costs around 30 quid. The eTap battery officially lasts 1000km (a conservative estimate, I strongly suspect) and is interchangeable between front and rear mechs. The CR2032 batteries in the shifters are supposed to be good for 2 years riding 15 hours a week. Or 65 days of riding round the clock, in HK terms. And eTap eliminates problems in separating the Moulton for travel.

I wouldn't rule out eTap.

LittleWheelsandBig · « **Reply #29 on:** 16 August, 2018, 07:51:15 am »

Apparently a German fellow managed to get a 61t ring working on his Di2 Moulton (different model) a few years back and there are several Asian Di2 Moultons. Obviously a 58t ring itself is unlikely to be a problem. The major thing is to check whether there is sufficient clearance between the Moulton swingarm and front mech when in the small ring. It was quite tricky setting up the Campag triple mech on HK's Moulton for that reason.

I'll have a second look at eTap as I am a little concerned at repeated plugging/ unplugging of Di2 wires when splitting the bike, which is a major reason for using Moultons for us. Carrying spare batteries would seem reasonable.

Is there some way of stopping batteries running down if the Di2/ eTap levers are bumped/ pushed during transport? I recall the things having their Di2 battery unexpectedly depleted by the shift levers being buffeted on a roofrack.

Torslanda · « **Reply #30 on:** 16 August, 2018, 08:59:20 am »

eTap allows battery removal.

Kim · « **Reply #31 on:** 16 August, 2018, 01:29:56 pm »

And presumably with DI2 you can unplug the levers, if not the battery. (Perhaps as a side-effect of splitting the bike?)

jiberjaber · « **Reply #32 on:** 16 August, 2018, 01:38:00 pm »

Quote from: Kim on 16 August, 2018, 01:29:56 pm

And presumably with DI2 you can unplug the levers, if not the battery. (Perhaps as a side-effect of splitting the bike?)

Yes - from Junction box A.

I have never come across any wind buffeting issues with the DI2 levers. I have had some mysterious flat batteries say 4 instances since 2015.

Bumped levers are always a concern. I have never left the DI2 in a position where the derailleur is straining due to a knock - I would like to think it is intelligent enough to recognise the strain due to not shifting and fail safe rather than sit there and burn out the motor or run the battery down

quixoticgeek · « **Reply #33 on:** 16 August, 2018, 02:19:31 pm »

Quote from: Kim on 16 August, 2018, 01:29:56 pm

And presumably with DI2 you can unplug the levers, if not the battery. (Perhaps as a side-effect of splitting the bike?)

Disconnect the cable that runs from junction a to junction b would be simplest, and represents a single disconnect, rather than disconnecting the shifters, which unless you are using Y cable, would be 2 disconnects.

J

chrisbainbridge · « **Reply #34 on:** 16 August, 2018, 07:21:14 pm »

Do remember that the Di2 connections are "fit once" and are not designed for repeated separation. many of the early complaints regarding failure and water ingress turned out to relate to multipledisconnections. You also need a special tool to safely disconnect without pulling on the wires.

I would definitely go for tap if I was looking at separating them. In addition taking a single extra battery allows on the go charging (although Di2 will charge and work from a dynohub)

grams · « **Reply #35 on:** 16 August, 2018, 10:35:49 pm »

Some Di2 connections are recessed and super awkward and are not easy to plug or unplug even with the tool (Drop bar shifters, front mech), with the usual result being chewing the plastic body of the plug. Some have good access and can be done (with care) with your bare hands (rear mech, internal battery). Junction A and B fall somewhere in between, depending a lot on if other connectors are in the way.

The connector itself is just a standard MCX RF connector in reverse (ie the Di2 plug is female MCX, socket is male) and I’d expect it to be robust to repeated connects / disconnects, within reason.

jiberjaber · « **Reply #36 on:** 16 August, 2018, 11:02:26 pm »

Quote from: grahamparks on 16 August, 2018, 10:35:49 pm

Some Di2 connections are recessed and super awkward and are not easy to plug or unplug even with the tool (Drop bar shifters, front mech), with the usual result being chewing the plastic body of the plug. Some have good access and can be done (with care) with your bare hands (rear mech, internal battery). Junction A and B fall somewhere in between, depending a lot on if other connectors are in the way.

The connector itself is just a standard MCX RF connector in reverse (ie the Di2 plug is female MCX, socket is male) and I’d expect it to be robust to repeated connects / disconnects, within reason.

Usually rated for 500 cycles

Zed43 · « **Reply #37 on:** 17 August, 2018, 08:23:09 am »

Quote from: PeterM on 15 August, 2018, 08:08:06 pm

I wouldn't rule out eTap.

Be sure to read this discussion before you spend your money.

thing1 · « **Reply #38 on:** 21 August, 2018, 10:28:32 pm »

Quote from: jiberjaber on 16 August, 2018, 01:38:00 pm

Quote from: Kim on 16 August, 2018, 01:29:56 pm
And presumably with DI2 you can unplug the levers, if not the battery. (Perhaps as a side-effect of splitting the bike?)

Yes - from Junction box A.

If you're doing this, also take care to cover up the disconnected socket if there's chance of water getting in. (Such as, if doing it because it's on the roof of a car...)

Quote

I have never come across any wind buffeting issues with the DI2 levers. I have had some mysterious flat batteries say 4 instances since 2015.

It only happened to us the one time.
We'd just driven from a friend's house to Wolf Creek pass and back (for a RAAM recce) about an 8 hour round trip drive. Said friend had kindly loaned a "bike thong" that goes over the bars to protect it from weather and bugs while on the roof of a car for so long. Problem was it spent 8 hours flapping against the levers shifting the mechs the whole journey. Damn lucky it didn't burn anything out.
We got to day 2 of the 1200km and had to do about 200km across the colorodo / wyoming snowy range mountains with no gear changes.... climbing .... on a tandem.... well that certainly built some character. Since then we've always carried the charger with us on long rides rather than rely on drop bags. (And also, learnt how to read the battery indicator properly)

jiberjaber · « **Reply #39 on:** 21 August, 2018, 10:39:46 pm »

Quote from: thing1 on 21 August, 2018, 10:28:32 pm

Quote from: jiberjaber on 16 August, 2018, 01:38:00 pm
Quote from: Kim on 16 August, 2018, 01:29:56 pm
And presumably with DI2 you can unplug the levers, if not the battery. (Perhaps as a side-effect of splitting the bike?)

Yes - from Junction box A.

If you're doing this, also take care to cover up the disconnected socket if there's chance of water getting in. (Such as, if doing it because it's on the roof of a car...)

Quote
I have never come across any wind buffeting issues with the DI2 levers. I have had some mysterious flat batteries say 4 instances since 2015.

It only happened to us the one time.
We'd just driven from a friend's house to Wolf Creek pass and back (for a RAAM recce) about an 8 hour round trip drive. Said friend had kindly loaned a "bike thong" that goes over the bars to protect it from weather and bugs while on the roof of a car for so long. Problem was it spent 8 hours flapping against the levers shifting the mechs the whole journey. Damn lucky it didn't burn anything out.
We got to day 2 of the 1200km and had to do about 200km across the colorodo / wyoming snowy range mountains with no gear changes.... climbing .... on a tandem.... well that certainly built some character. Since then we've always carried the charger with us on long rides rather than rely on drop bags. (And also, learnt how to read the battery indicator properly)

Yes - that makes more sense - something else being buffeted by the wind then hitting the switch...

FifeingEejit · « **Reply #40 on:** 03 September, 2018, 11:24:31 pm »

Tested it while charging the other day;
I couldn't change gear with the charging dongle connected at all; so no sneaky charging off the USB-Werk :-(

jiberjaber · « **Reply #41 on:** 04 September, 2018, 08:19:05 am »

Quote from: FifeingEejit on 03 September, 2018, 11:24:31 pm

Tested it while charging the other day;
I couldn't change gear with the charging dongle connected at all; so no sneaky charging off the USB-Werk :-(

What did you have the charging block plugged in to ?

I had no problem charging on the move on LEL.

If you have the charging block plugged in to a PC and the e-tube software running it will lock out the DI2 system. If you just plug the block in to a USB wallplug or USB powerbank / PC (with no etube running) is will still shft (we mine does)

FifeingEejit · « **Reply #42 on:** 04 September, 2018, 09:31:12 am »

That was with it plugged into any of:
The PowerMonkey
The wall plug

The only way I was changing gear with the charger in was if there was nothing in the micro-USB port.

Of course it's possible both the power monkey and the wall charger I use activated the USB data channels but seems unlikely; will do another test with a differeny wall charger when I get the dongle back from Portage Pete; which'll need to be today since my cortisoids are in the bag and I'll be a bunged up mess if I don't get them soon.

grams · « **Reply #43 on:** 04 September, 2018, 11:08:57 am »

I just checked both of my Di2 bikes and they both happily shift with the charger plugged into a power bank (and the orange charging light on).

FifeingEejit · « **Reply #44 on:** 04 September, 2018, 04:22:14 pm »

Which Junction A have people got?

Mines the bar end one; not gone to collect my bags yet so can't repeat the test until later.

jiberjaber · « **Reply #45 on:** 04 September, 2018, 04:58:02 pm »

I have the 5 and 3 way under stem ones

grams · « **Reply #46 on:** 04 September, 2018, 05:13:48 pm »

I have the SC-MT800 (XT) MTB display on one bike and the 5 way standard road A junction on the other.

chrisbainbridge · « **Reply #47 on:** 05 September, 2018, 06:40:04 am »

standard 3 way on this bike but it charges just fine with cache battery and dynamo. And i can still ride up and down hills