Di2 cable length to aid seatpost removal, should I go long?

daniel_b

Morning all,

so soon I should finally begin to get my new bike assembled and ready to ride.

At some point, once again, i will buy a bike and ride it as it came off the peg!

Tyres were partially fitted to the new 2nd hand wheels, and are hopefully stretching nicely to make fitting with tubes a doddle - haha.
Rotors will be going on once that is completed, as I wanted to minimise the chance of bending them whilst wrestling with the tyres.

So on my Synapse, the Di2 battery is installed in the too short seatpost - I now have a 350mm one, and need to swap the battery out, hoping that will not be too traumatic.
I have also bought a little ant sender unit, which I am hoping will also post down the seattube, but I need to buy a second power cable, so I gather, to daisy chaing it inbetween the Di2 'network' and the battery.

I tend to like to ride my bike 50-100 miles if we are visiting relatives, whilst my gf drives with our daughter in the car.
Then I drop two seats in the back of the car, whip the front wheel and seatpost out of the bike, and pop the bike upright in the car, securing it to the grab handle and a suitable internal mounting point with bungee cords.

Now what occurred to me, is that I am now going to have a power cable attached to the battery that is in the seatpost, so what are my best options?

I assume frequent plugging and unplugging is not recommended?
Would I be better to purchase, perhaps a 1m long cable, so I have enough leeway to rest the saddle\seatpost on the floor of the car, or should I keep it uber short (15cm) and just disconnect it each and every time?

This 'issue' had not even occurred to me when I asked for the upgrade option.

I do have one of these:

But haven't got hands on enough yet to figure out how to use it :oops:

Thanks

Dan

bernithebiker

Could you not just push the seatpost right down into the frame? Does that not give enough clearance to get the bike in?

Otherwise, I see no reason why you couldn't use the longest Di2 cable, just it's more expensive!

Don't lose that tool, it's pretty useful; hook up the cable in the left end and pull it out, and push in with the other (although I tend to use the left for both), and make sure you hear the click when pushing in, you need to push harder than you think.

daniel_b

bernithebiker wrote:

Could you not just push the seatpost right down into the frame? Does that not give enough clearance to get the bike in?

Otherwise, I see no reason why you couldn't use the longest Di2 cable, just it's more expensive!

Don't lose that tool, it's pretty useful; hook up the cable in the left end and pull it out, and push in with the other (although I tend to use the left for both), and make sure you hear the click when pushing in, you need to push harder than you think.

I probably could do, but I have a LOT of seatpost showing, and it would scratch it up probably to a worse level than the first synapse seatpost I had delivered:
Scratched seatpost of wrong length by Daniel 2009, on Flickr

I like to try and keep my stuff in good nick :oops:

When I have looked online, the cables seem to be the same price irrespective of length, which I did find a bit surprising.
ie: http://www.chainreactioncycles.com/shimano-sd50-di2-electric-wire/rp-prod85149

And thanks for the tips on the tool - surprising how little advise\guidance there seems to be out there on using Di2, basics like connecting cables, and charging etc, perhaps I am just not looking hard enough.

janwal

https://carltonbale.com/shimano-di2-eve ... d-to-know/
This may be worth reading for di2 info.

daniel_b

janwal wrote:

https://carltonbale.com/shimano-di2-everything-you-need-to-know/
This may be worth reading for di2 info.

Wonderful stuff, that looks like a wealth of information, I will check that out tonight, post rotor and tyre work - 3 year old daughter allowing!

I have ordered 4 cables from CRC, free returns so will return what is not needed - went for 250mm, 400mm, 700mm, and 1200mm - thought that should cover it.........

dag_on_a_bike

Daniel B wrote:

...Then I drop two seats in the back of the car, whip the front wheel and seatpost out of the bike, and pop the bike upright in the car, securing it to the grab handle and a suitable internal mounting point with bungee cords.

Now what occurred to me, is that I am now going to have a power cable attached to the battery that is in the seatpost, so what are my best options?...

All I do when transporting 2 bikes upright in the back of the car with front wheels out, is remove the seatposts. On mine with Di2, rather than try & let it all hang out, or replace with a longer cable, is tie the saddle/seatpost to the top tube. Works just fine.

daniel_b

DAG on a bike wrote:

Daniel B wrote:

...Then I drop two seats in the back of the car, whip the front wheel and seatpost out of the bike, and pop the bike upright in the car, securing it to the grab handle and a suitable internal mounting point with bungee cords.

Now what occurred to me, is that I am now going to have a power cable attached to the battery that is in the seatpost, so what are my best options?...

All I do when transporting 2 bikes upright in the back of the car with front wheels out, is remove the seatposts. On mine with Di2, rather than try & let it all hang out, or replace with a longer cable, is tie the saddle/seatpost to the top tube. Works just fine.

That's not a bad call at all, I could take something to wrap around the top tube, and use a pair of old toe clip straps or something to secure it.

optrexeyedrops

If you push the battery all the way down the seat tube you shouldn't have a problem pushing the seat post as far as it can go.

daniel_b

optrexeyedrops wrote:

If you push the battery all the way down the seat tube you shouldn't have a problem pushing the seat post as far as it can go.

The battery lives IN the seatpost - but I don't want to push the seatpost all the way down, as it will scratch the living daylights out of it, and additionally I won't be able to have a nice easy marker on the seatpost (Usually a strip of electrical tape) to make it easy to reset the height when I re-assemble the bike.

optrexeyedrops

Daniel B wrote:

optrexeyedrops wrote:

If you push the battery all the way down the seat tube you shouldn't have a problem pushing the seat post as far as it can go.

The battery lives IN the seatpost - but I don't want to push the seatpost all the way down, as it will scratch the living daylights out of it, and additionally I won't be able to have a nice easy marker on the seatpost (Usually a strip of electrical tape) to make it easy to reset the height when I re-assemble the bike.

I know the battery lives in the seat post, as thats where Ive got mine. But i can push my seat post all the way down. No scratches, can still see the marks for adjustment.

Maybe you're making a mountain out of a molehill? :roll:

daniel_b

optrexeyedrops wrote:

Daniel B wrote:

optrexeyedrops wrote:

If you push the battery all the way down the seat tube you shouldn't have a problem pushing the seat post as far as it can go.

The battery lives IN the seatpost - but I don't want to push the seatpost all the way down, as it will scratch the living daylights out of it, and additionally I won't be able to have a nice easy marker on the seatpost (Usually a strip of electrical tape) to make it easy to reset the height when I re-assemble the bike.

I know the battery lives in the seat post, as thats where Ive got mine. But i can push my seat post all the way down. No scratches, can still see the marks for adjustment.

Maybe you're making a mountain out of a molehill? :roll:

Ah apologies, I misunderstood - and yes I may well be doing that, but may I refer you to exhibit A - the seatpost that came on the first bike, I rightly or wrongly assumed that this was caused by jamming it down into the guts of the frame.
I can also never properly see the marks on my seatpost, and reply on a bit of electrical tape (Sometimes covered by a Fizik seatpost ring) to inform me where I need it set when re-fitting - really bugs me if it is not quite right.
Also pretty sure in my estate car, that even with the saddle all the way down, there is no room for the bike to stand up, without the saddle hitting the roof lining.

dazz_ni45

Daniel B wrote:

optrexeyedrops wrote:

Daniel B wrote:

optrexeyedrops wrote:

If you push the battery all the way down the seat tube you shouldn't have a problem pushing the seat post as far as it can go.

The battery lives IN the seatpost - but I don't want to push the seatpost all the way down, as it will scratch the living daylights out of it, and additionally I won't be able to have a nice easy marker on the seatpost (Usually a strip of electrical tape) to make it easy to reset the height when I re-assemble the bike.

I know the battery lives in the seat post, as thats where Ive got mine. But i can push my seat post all the way down. No scratches, can still see the marks for adjustment.

Maybe you're making a mountain out of a molehill? :roll:

Ah apologies, I misunderstood - and yes I may well be doing that, but may I refer you to exhibit A - the seatpost that came on the first bike, I rightly or wrongly assumed that this was caused by jamming it down into the guts of the frame.
I can also never properly see the marks on my seatpost, and reply on a bit of electrical tape (Sometimes covered by a Fizik seatpost ring) to inform me where I need it set when re-fitting - really bugs me if it is not quite right.
Also pretty sure in my estate car, that even with the saddle all the way down, there is no room for the bike to stand up, without the saddle hitting the roof lining.

My wife occasionally uses one of my bikes for competitions and has to lower the carbon saddle. I couldn't believe how badly it has got scratched and scuffed after only 5-6 times doing this. It is probably much worse as she is using the bike with it lowered whereas you will just be lowing it for transport, but if you don't want it marked, then I wouldn't

stueys

I simply unplug thedi2 cable and take the seatpost out. No issues with the di2 connection from doing this frequently

daniel_b

Stueys wrote:

I simply unplug thedi2 cable and take the seatpost out. No issues with the di2 connection from doing this frequently

Perhaps I will just do that then - not knowing this system from jack, and having done zero research into it, I have no idea of the robustness of the system and connections.
Do you use the special tool to remove, and re-connect them?


It's the right hand\tube end you use to connect cables right, and the other end to help disconnect?

bernithebiker

Daniel B wrote:

It's the right hand\tube end you use to connect cables right, and the other end to help disconnect?

Yes and yes.

They're fairly robust, but it's not something I would want to be connecting/disconnecting once a week.

daniel_b

bernithebiker wrote:

Daniel B wrote:

It's the right hand\tube end you use to connect cables right, and the other end to help disconnect?

Yes and yes.

They're fairly robust, but it's not something I would want to be connecting/disconnecting once a week.

Cool, it wouldn't be that often, perhaps a dozen times a year would be my estimate.
I have all 4 cable lengths now, so will make a decision over the weekend - thanks for all the help guys.

stueys

Yep, I always use the tool to extract the cable. The way my seat post holder secures the batter I can't actually get at the connector with my fingers as it sits within the holder so I always use the tool to disconnect as the alternative is yanking on the cable to disconnect the connector, which I don't think would be a good long term practice. Reconnecting it together I'm less concerned about but I've found it far easier and more reliable using the tool to get a solid connection. When I just use fingers I don't alway get it connected well. You know when it's connected as you get a very solid click.

daniel_b

So I finally got around to trying to change the seatpost and battery etc today.

The law of sod however dictates I need another tool, some circlip pliers :evil:
So will need to find some and have another crack this week.

Anyway, I tied some string around the little ANT doobery, and prodded it down the seattube to see how it would fit, it did seem to fit ok, but there was a moment of panic when it got stock on something, I assume the sleeve for the seatpost, or some kind of lining, so I have quickly aborted that idea as just too damned risky, and with the room down there you would need to go with the shortest cable you could - so I will have to try and find somewhere else to stash it, or it might have to actually sit on the rear stay which would be a shame, or maybe I sell it.

I did see one youtube post where they stashed it in the top tube, doing this by removing the fork, but I don't think this bike has any suitable wiring there to tap into anyway - edit: Link found below, might be possible after all.

In fact, I think I will hopefully have my racetech Garmin and di2 junction box mount this week, which I gather has a go pro mount underneath as well, so will see if I can somehow fit it onto that, so it's not too ugly, either way, look like I need the shortest cable eh.

EDIT: here is the article on top tube fitting, not a video as I thought:
http://belgianwerkx.com/2015/06/installing-shimano-d-fly-internally/