Hongfu FM079
Moderators: MrCurrieinahurry, maxim809, Moderator Team
On a test ride, the Di2 was absolutely fine. I still have to get used to new paddle locations - a lot of wrong direction shifts today - but I don't see going back to 11s mechanical on my Hongfu FM079. The only thing I didn't like much was lack of feedback on bigger paddle, it has no distinct click unlike smaller paddle, I really enjoyed throwing mechanical paddles with a "clunk" at the end.
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- Klaster_1's Hongfu FM079 (27.09.2020)
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- Klaster_1's Hongfu FM079 (27.09.2020)
Glad to hear the modded di2 worked without a hitch. Curious how long the smaller batteries last and how the charger works with the new setup. I'm considering a similar mod on my next disc build. Keep an eye on those exposed wires. I'd be thinking twice about keeping the outer shield intact outside the frame but that would have saved less weight. The things we do for shaving grams. 
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Get a load of this, Extralite sent me not one, but two CFRP Ultraspacers (15mm and 10mm) and a replacement regular 15mm Ultraspacer. The CFRP spacer are noticeably more grey, similar to Darimo UD matter.
- Extralite Ultraspacer CFRP 10mm
- Extralite Ultraspacer regular 15mm
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- Extralite Ultraspacer CFRP 15mm
Hah, for some reason I used to touch my left shifter a lot and when I switched to Di2 that made shift the FD by accident every couple of rides
Looks like my Vuma Quad is a toast, the drive side crank arm developed a lateral wobble, when you look at the self-extracting bolt outer washer it stays still and only the CF arm moves. Actually, I noticed this at least a year ago, maybe even two, but never looked into the issue afraid to discover uncomfortable truth. Several years ago, the crank used to unscrew even when torqued to a spec from the manual. Not sure whether this was caused by installation error (not a single 0.5mm shim installed, unlike in the video) or that's how I bought it or it just plain broke. I suspect the wobble was the reason behind crappy front shifting and two delaminated Fibrelyte chainrings (chain sliced through a tooth during a wobble). Until the Skypivot business is sorted - probably not until next year - I'll keep using the Vuma Quad as is on the trainer. If it breaks, I still have a spare FC-5800, but not sure if 36/52 can safely use whole cassette range or if there's a way to put 36t outside, the bolts look proprietary and I don't want to spend much on this. Any ideas?
A lot happened, but the stem has finally arrived. My original plan was to replace the IX2 bolts with J&L hollow T25s and save 2g, but you can't do that: while IX2 bolt heads are M4, both the bolt thread and stem bolt holes are smaller (didn't measure yet) and thread length is longer than J&L. Custom bolts won't fit. Oh well.
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- Darimo IX2 stem weight, 3k matte, 11cm, -12deg
The Darimo IX2 is on, installation was straightforward, especially with the video instruction. Sits really tight over the steerer. Just as I calculated, IX2 has a stack similar to a Hyperstem with 5mm spacers on top and bottom. With less stem spacers and bar wrap, a total of ~16g was saved. Still getting used to the boxy look. The IX2 bolts are M4 with 19mm of thread and weight ~1.5g , Hyperstem bolts do fit, but are too short, I believe there's an opportunity to save a gram or two, but am not sure where to source the replacements - J&L and TP carry nothing similar. I sent an inquiry to TP, but don't expect too much from them.
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- FM079 cockpit with Darimo IX2 stem installed
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- Darimo IX2 stem, installed
Never heard of them. There's only a single match which doesn't look lighter, no weight listed either. I sent a message to Extralite too, maybe they have longer Ultrastem bolts.
How are the new smaller batteries holding up? How long do the batteries last on a charge? Maybe it's too soon to ask? I'm about to mod a battery.
Mod it away, you can always solder bigger cells back, I don't see any significant drawbacks besides loss of warranty. Unfortunately, it's too early to tell since I only had a handful of rides before I put the bike on a smart trainer, which I use in ERG mode, so almost no shifting action.
In other news, I bought a chain length ruler and retired my first chain ever due to wear since I started cycling in 2012
At least now I know the stash of lightly used chains I have will serve me for a while. Also retired is the Vumaquad, it creaked horribly under standing trainer efforts, good thing I was too lazy to sell my FC-5800. How about a sub-6kg road disc bike with 105 crankarms 
My main concern was the on board BMS being able to manage the smaller capacity batteries. Sounds like it hasn't caused any issues for you. At least, not yet. Have you been able to recharge it? Maybe you haven't run out of battery yet.
Too bad about the Vumaquad. They used to be pretty reasonable and common on Ebay some years ago but lately, they are overpriced. I guess you'll be biding your time waiting for the skypivot.
Too bad about the Vumaquad. They used to be pretty reasonable and common on Ebay some years ago but lately, they are overpriced. I guess you'll be biding your time waiting for the skypivot.
Agree, this is a valid concern I forgot about. I did not charge the modified battery yet. From what I learned, the charging should be fine as long as current is not too high, which might be the case when downsizing the cells. I should drain the battery and charge to see how the modified battery behaves, no timeline on this though.
To be honest, the whole Vumaquad experience was a lesson, I kinda overpaid for it back then - 700USD for a crank, Zipp BB, Zipp 53/39 chainrings and non-damaged 50/34 Fibrelytes. Three additional Fibrelytes later, I might as well have bought a Clavicula SE from the start. Paying a larger sum from the start for a better, time proof product can sometimes be more economically viable. In a similar manner, I'm on a crossroads about the frame, the Aethos fits me perfectly, I can transfer all the WW parts I own as is (well, except for front brake caliper), but the price... Maybe a good deal on a used frameset, but this will take a while to find.
The batteries drained to 10% today, so I charged it for the first time, done surprisingly fast at ~1h. Nothing caught fire (unlike my Xshfiter battery...) or heated up, as far as I could tell with battery inside the seatpost. The shift budget the lower capacity battery allows for is hard to estimate, most of my rides since September were on ERG, a couple of shifts per ride at most.
Hey Klaster_1, thanks for the update. Glad to hear they're working for you. Sounds like they may have limited capacity but still enough.
I went ahead and did the mod. I did not charge the batteries before soldering so I can see how they charge. Everything seemed to work as intended. The charge light came on and charged for a couple of hours give or take. Did not get hot either. I ended up using EBL CR2/15270/RCR2 3.7v Lithium ion which is slightly bigger but still lighter than the original. We'll see how long they last. Bike is still unfinished. It's the Aethos in the gallery.
I went ahead and did the mod. I did not charge the batteries before soldering so I can see how they charge. Everything seemed to work as intended. The charge light came on and charged for a couple of hours give or take. Did not get hot either. I ended up using EBL CR2/15270/RCR2 3.7v Lithium ion which is slightly bigger but still lighter than the original. We'll see how long they last. Bike is still unfinished. It's the Aethos in the gallery.
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