My review of Haibike SDURO HardFour 4.0

Dmitri

Active Member
Recorded a video on Haibike HardFour, one of the few kids' ebikes out there. With some upgrades (as always)!

 

Dmitri

Active Member
Dude, I have a Bosch and pedal it without power just fine!
Err, Bosch is terrible to pedal. Don't take my word for it, here's what Bosch themselves say about the crank:

For 2018 the Bosch Active Line gets re-worked, with a new motor designed to deliver moderately dosed support for riders. The new motor design has reduced the overall size by 25% by going back to a big sprocket externally compared to being internally geared.
This allows less resistance and brings the size of the unit down for better integration.
(Emphasis mine). Later, Bosch mentions that:

The motor noise and resistance are also significantly reduced too, due to the new gearing set-up.
So Bosch themselves acknowledge that there's more resistance on a small crank. Of course, they are talking about electrical operation, but on mechanical, it's even worse. On a Rohloff, with a 27kg bike, that problem is compounded even more.
 

Fitzy

Active Member
I'll take my word for it; the resistance is insignificant, that or I'm in incredible shape.

P.S.: I'm not in incredible shape.
 

Dmitri

Active Member
The crappy Suntour fork on this bike gave out, oil leaked everywhere, it was rather unpleasant. And now Suntour is resisting on the warranty. Hey I know it's a $100 fork, but I want to think they'll honor their international warranty without claiming "you did it".

Meanwhile, I replaced the Suntour fork with RST F1RST. Dirt cheap (EUR150), oil/air, who knows how long it will last.

Some info for people wanting to upgrade:
  • The frame actually accepts a conical (1 1/2-1 1/8) fork, so you can install that instead of a straight one.
  • Removal of the straight-to-cone adapter required the use of an industrial fan. That's because the adapter is made of steel and wouldn't come off with just hammer&chisel. In fact, I broke the chisel.
  • You won't find any 24" forks apart from Suntour and RST.
  • A 26" fork with small travel distance would go well here.
  • You need 9mm QR unless you decide to rebuild the wheel with a TA hub.
Overall, looks pretty good. And btw those decals are not stickers, they are painted.

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