Di2 for e-bikes? Really?

Redsrider

New Member
Looking at a new purchase and am considering an e-Genius, Shuttle, or perhaps a custom build of a Wire Peak. The Shuttle is obviously the fanciest choice but I really have to wonder - is there any point at all to Di2 for an eBike (other than: it's super-cool)? Anyone with experience have some thoughts?

And to go one step further I really wonder if (for my use-case anyway) there's much point in anything more than a 1x10 drivetrain. I mostly climb as a means to getting to the downhill. I couldn't really care less what speed I'm climbing at, it's more about making sure I get to the top fresh enough to really pin it on the DH, and maybe have another lap afterwards. And using e-assist to go faster on the flats isn't something that interests me, so it doesn't really matter if I don't have a high top-end gearing. I prefer to go fast with the aid of gravity.

To me, an electric motor with a good torque sensor and software is sort of a tool to make you not have to shift as much, e.g. if you're pedaling along at whatever cadence is comfortable and whatever (human) power output you're comfortable at and you come to a slightly steeper section, where you'd normally shift down on your regular bike you (momentarily) apply a little more torque to your pedals and the software+motor responds and gives you a little more assist, and up you go without ever touching the shift lever. So in that sense you really don't need as many gears, or as close a range of ratios.

Soooo... am I missing anything? Or do I have it right and spending money on the fanciest of drivetrains for an e-bike is a bit of a waste (ignoring quality/reliability)?
 

Johnny

Well-Known Member
Your question is ambiguous.

The point of Di2 to any ebike is the same as of it to any bicycle. Not necessary but feels amazing. If price difference is reasonable I would always get di2.

Is 1x10 sufficient? Yes especially with the new 11-46 cassette Shimano offers.
 

Nova Haibike

Well-Known Member
is there any point at all to Di2 for an eBike (other than: it's super-cool)? Anyone with experience have some thoughts?
You never have to worry about gunk in the cables screwing up the shifting. But you do have to worry about a flat battery (although to be fair a charge will last quite a long time.)
I really wonder if (for my use-case anyway) there's much point in anything more than a 1x10 drivetrain.
The component manufacturers have rather dictated how many gears bikes have, with higher-end bikes having 11, 12, or now 13 gears. SRAM does make an e-bike specific group with 8 gears, but I personally am not aware of any bike manufacturer actually spec'ing it on one of their e-MTB's.
 

opimax

Well-Known Member
Have a Stromer with DI2, enjoy it a lot, a luxury for me, a requirement for my wife’s thumbs, very reliable. If it was the only replacement for a twist grip on a bike it would be a requirement for my wrist.
 

Deacon Blues

Well-Known Member
I have Di2 on my Giant Defy road bike and love it. It shifts like a dream and never needs adjustment.
I'm in the process of converting my Cannondale Topstone Neo Lefty 3 from drop bars to flat bars. To do this I'll need new brake levers, a gear selector, and a new derailleur.
I looked into going with electric shifting, but compared to Shimano Deore XT (what I'm going with) the Di2 was crazy expensive.

As for number of gears, I'm happy with my 1x11 speed setup.
 

PDoz

Well-Known Member
Nah, you need a synchronused shifting 14 speed https://www.rohloff.de/en/products/speedhub

Ummm....that's a joke, but with a frightened dose of reality. It took me 2 cassettes and 4 chains to improve my technique enough that I no longer think a di2 would have been a good investment. But perhaps 2/3 times each ride I'm not really sure. There's a new xt in a box waiting to go on when my next cassette needs replacing because the last xt is looking just a little battle scarred. Perhaps a rohloff might have been worth the $/ weight?
 

linklemming

Well-Known Member
I rode a Bulls FS bike in late 2018 with Di2 for a few weeks as a loaner bike while by other ebike was being serviced.

I really liked it, best shifting bike I have ever owned (to be expected).

Would I pay the extra $$ for it, not just for di2 only.
 

Stefan Mikes

Well-Known Member
Region
Europe
City
Brwinów (PL)
I agree, I don't need 13 gears... especially on ebikes.

What I care about is gear range, but not how many gears I have in between.
The competing cyclists on traditional bikes might disagree but indeed the market seems to be gone overboard.
 

Deacon Blues

Well-Known Member
About a third of my rides is on my Giant Defy road bike, with a 2x11 (11-32) Di2 setup. I've found that on a 60km ride the only time I switch to the smaller chain ring is when I'm climbing steeper hills. 95% of my ride in is the larger chain ring.
An interesting feature with Di2 is I can't use the two smallest cassette rings (11 & 13 tooth) when the chain is on the smaller front ring.
 

Lightning P38

Active Member
Doesn't the chain get narrower as number of cogs increases!?!?

Probably not the best match for an ebike
The good news is I have ridden my ebike 1,000 miles this year....the bad news is I need a new $65 chain, said my buddy. I have only ridden 500 miles this year on my 9 speed ebike with about 15% wear on my chain....but my recumbent takes 2.25 chains to replace, so about 65 bucks.
 

LimboJim

Well-Known Member
Someday I hope to test ride an eMTB with e-shifting, but my 2017 Haibike Xduro Allmtn 8.0 and 2018 Commencal MetaPower Race Fox both came with SRAM's ebike-specific EX1 drivetrain and I love it! As smooth shifting as any I've experienced, and EX1 chains last twice as long as any brand did on my previous 11-speeds. Commencal and Haibike have since dropped EX1 for the trendier 12-speed setups, but Greyp is using it and I think Frey is too, at least on a couple models.

In the UK, Commencal still has a 2018 model in L & XL for 27% off: https://www.commencal-store.co.uk/Mobile/meta-power-29-2018-c2x25577876
 

DouglasB

Active Member
Doesn't the chain get narrower as number of cogs increases!?!?

Probably not the best match for an ebike
Yes, you buy your chain has to match your gear count. More gears, narrower chain. Not sure if it is weaker but it certainly is narrower to accommodate more gears.
 
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RabH

Well-Known Member
My last road bike had Ultegra Di2 and I loved it, it was super smooth and easy on the wrists! The battery lasted a very long time, from memory I only had to charge it twice a year! I actually thought about converting my Giant Road E+1 Pro at one point but I decided against it as the shifting is very smooth and I really don't think it would be worth the expense!
 

Luto

Active Member
Interesting question about number of gears. Before I bought, I thought about it a lot, even considered replacements cassettes etc. Then I got my bike, and yes I was correct, the ebike assist make the top three (42-40-38) unnecessary. Then I started riding without the assist, because I can and it extends my range indefinitely. Then I DID NEED the extra low gears in the back, crawling up hills with a 40 pound bike. Now I think I would take a 13 speed for sure for two reasons. One, the narrow chain gets me less cross over. Two, I have gearing for essentially two bikes (e-bike and regular).

As for the Di, I hear it is more precise. I got the Shimano GRX 810 but they now have a Di. If it were available back when purchased, I would have gone for it after I thought hard about the price. In other words, I think the GRX 810 could be better. Specifically, the paddles need to 100% clear back before it can re-engage, and sometimes it does not. I suspect the Di does not have that issue. As for the shifting, it could be better too.
Hope that helps.
 

Luto

Active Member
Doesn't the chain get narrower as number of cogs increases!?!?

Probably not the best match for an ebike
Yes, And I will go out on a limb here: I want a narrower chain so I can get more "direct drive" front to back and more gears.

Yes it will be:
  • more fragile by being thinner, but I trust the materials will hold up.
  • Ok with my style of riding, which is low or no assist high cadence for old joints.
  • maybe, a bad choice for a TURBO, LOW gear style riding that stress the drive train a lot.
But sorry off topic.