Replaced My Stromer ST2 S with an ST7

britannic

britannic

Member
I was able to pickup a demo Stromer ST7 (Gold), but sadly I have to sell my ST2 S.

The ST7 is a great bike! What I like so far:
  • Pinion Gearbox
    • Love the auto downshift to my chosen start gear when stopped
  • Super quiet drive train - the belt is a huge improvement
  • Stability at speed on the bigger tires
  • Omni touchscreen very responsive
  • Extended Range
    • The reason I really wanted this bike, was to go for longer rides
    • My ST2 S was pretty good, but with so many hills in Portland, I averaged around 40 miles
Cons:
  • Not as nimble
    • Definitely aware of the weight
  • It isn't stealthy :)
    • The ST2 S wasn't an obvious S-Pedelec at a glance
    • The ST7 gives it away with the meaty downtube
 
Last edited:
Lightspeed said:
I too just got an st7. I do love it. My major gripe is the tires. Even with tannus liners and goop in the tube I still got a flat. And the manufacturer says take it to the shop to fix! What if I’m 40 miles from civilization? Walk home? I need to be able to field fix a flat.
Click to expand...
Fair point. I carry a repair kit for tubes. It's a habit from when a bike was my only transport for the first 20 years of my life. I can remember bubbling tubes in a cow trough after a patch.
 
Some more observations, after some more riding miles:
  • Braking
    • I've had some white knuckle moments on downhill descents, with full recuperation (battery at 60%), where the disc brake stopping power just isn't as good as my ST2s
    • The additional bike weight is definitely a factor
  • Gearbox
    • Absolutely loving this, although the automatic downshift when stopped is often too slow, so manually downshifting in advance
  • Omni screen
    • Way more responsive and faster than the ST2s
    • Power level 2 tuning and updating is fast too
  • Bigger tyres
    • Grip is excellent and needed with the bigger weight
    • Definitely no need for a suspension fork (YMMV)
      • The Kinekt seat post is all I need
  • Rear wheel/belt removal
    • I wanted to see how easy it was to remove
      • NOTE: don't attempt to derail the belt like a conventional chain
        • Even with the tensioner disengaged, there isn't enough play to gently remove it without damage
      • Very straight forward, I used a dowel to lock the belt tensioner
      • Unscrewed and disconnected the power coupling
      • Pulled the axle whilst holding the wheel - it has some heft
        • Protect the belt from being twisted during removal
      • To completely remove the belt, the rear rack leg will also need to be unbolted along with the seat stay plate removal
    • Reassembly is a reversal
      • Be sure to align the reference spot
      • Double check the power cable clip is holding the cable away from the disc
        • IMHO its too close even with the retainer clip
      • 25nm torque for the axle bolt
 
Last edited:
Thanks, keep reports coming please.
I own a ST2-S and ST5 and am considering a ST7.
My ST2-S is totally silent. I heard one report of ST7 belt being louder. What is noise on your ST2-S? ST7 is quieter??

How fast/smooth is the Pinion shifting?
Di2 is so fast and smooth.

Enjoy your ST7!
 
MinnBobber said:
Thanks, keep reports coming please.
I own a ST2-S and ST5 and am considering a ST7.
My ST2-S is totally silent. I heard one report of ST7 belt being louder. What is noise on your ST2-S? ST7 is quieter??

How fast/smooth is the Pinion shifting?
Di2 is so fast and smooth.

Enjoy your ST7!
Click to expand...
The pinion is very smooth, but won't change gears under heavy load, so I need to shift early before climbing hills, unlike a derailleur. IMHO the ST7 belt is quieter.
 
Still loving my original 36v/500w ST1, but ready to upgrade to a 48v system. Which Stromer model to buy is the question...
IMG_1317.JPG
 
For my braking concerns, Tektro (TRP) are recommending 30-40 hard full stops to bed them in. I’ll report back on the results when I get an opportunity.
 
britannic said:
Some more observations, after some more riding miles:
  • Braking
    • I've had some white knuckle moments on downhill descents, with full recuperation (battery at 60%), where the disc brake stopping power just isn't as good as my ST2s
    • The additional bike weight is definitely a factor
  • Gearbox
    • Absolutely loving this, although the automatic downshift when stopped is often too slow, so manually downshifting in advance
  • Omni screen
    • Way more responsive and faster than the ST2s
    • Power level 2 tuning and updating is fast too
  • Bigger tyres
    • Grip is excellent and needed with the bigger weight
    • Definitely no need for a suspension fork (YMMV)
      • The Kinekt seat post is all I need
  • Rear wheel/belt removal
    • I wanted to see how easy it was to remove
      • NOTE: don't attempt to derail the belt like a conventional chain
        • Even with the tensioner disengaged, there isn't enough play to gently remove it without damage
      • Very straight forward, I used a dowel to lock the belt tensioner
      • Unscrewed and disconnected the power coupling
      • Pulled the axle whilst holding the wheel - it has some heft
        • Protect the belt from being twisted during removal
      • To completely remove the belt, the rear rack leg will also need to be unbolted along with the seat stay plate removal
    • Reassembly is a reversal
      • Be sure to align the reference spot
      • Double check the power cable clip is holding the cable away from the disc
        • IMHO its too close even with the retainer clip
      • 25nm torque for the axle bolt
Click to expand...
Do you know how to do an oil change for the gear box? or would you get it service by the dealer?
 
I’ve bedded the brakes in using TRP’s instructions (30-40 full stops). However, the front brake isn’t able to normally stop the bike from 20mph (note, normal = not actuating ABS). This is in comparison to my ST2s.

Blu Brake states the front braking should be normal force, unless ABS is actuated.

Additionally the front brake is really noisy just before a stop, which is usually cured by bedding in. I don’t believe the front brakes are getting enough pressure to be properly bedded in.
 
britannic said:
I’ve bedded the brakes in using TRP’s instructions (30-40 full stops). However, the front brake isn’t able to normally stop the bike from 20mph (note, normal = not actuating ABS). This is in comparison to my ST2s.

Blu Brake states the front braking should be normal force, unless ABS is actuated.

Additionally the front brake is really noisy just before a stop, which is usually cured by bedding in. I don’t believe the front brakes are getting enough pressure to be properly bedded in.
Click to expand...
So I switched the rear brake pads with the front pads. For the first 4 full stops, the rear brake screeched some, then was silent thereafter. The rear has the same full brake force as before the pad swap. The front brake was silent, but still not strong. In fact on a moderate downhill descent at 15mph, it cannot stop the bike by itself, only slow it down to 5mph.
 
britannic said:
…... In fact on a moderate downhill descent at 15mph, it cannot stop the bike by itself, only slow it down to 5mph.
Click to expand...
That is too weird as the front brake should be able, on a downhill descent at 35 mph/ 55 kph,
to stop the bike, no problem whatsoever.
A stop from 15 mph should be like no effort!

On 35 mph stop, the only concern should be … the brakes are so powerful that deceleration can cause a front flip. Thank you Stromer ABS.

Could it be misalignment of the front brake disc and caliper? The pad would only contact on the edge, with almost no surface area.
As that edge wore, a little more surface would be added.

All my Stromer brakes are super powerful and yours should be too. Sorry to hear , please let us know what happens.
 
Alignment is correct and the pads are showing full contact. I’m convinced the front brake needs bleeding, there’s a smidgen of sponginess compared to the left. My LBS had difficulties with the front and explained the challenge is with the convoluted routing of the lines through the ABS. If anyone has a technique or information on how to bleed the BluBrake ABS/front brake, I’d love to learn it!
 
Last edited:
Hi, I read somewhere (another european forum) that a special machine ( pump ?? )is required to bleed the Bluebrake ABS brakes . Hopefully your dealer is equipped with such a device.
Maybe check out this thread. Use Google translate feature if you don't speak dutch.

Bleedin' ABS - Speed Pedelec Review

speedpedelecreview.com speedpedelecreview.com
 
I was able to solve my issue by setting the bike and FB vertically in my bike stand for 2 days. This allowed the trapped air in the convoluted ABS hydraulic lines to travel up to the FB reservoir. Periodically pumping the FB lever during this time did the trick.

The LBS had already tried to bleed the brakes, but told me they use this technique for stubborn setups.
 
britannic said:
I was able to solve my issue by setting the bike and FB vertically in my bike stand for 2 days. This allowed the trapped air in the convoluted ABS hydraulic lines to travel up to the FB reservoir. Periodically pumping the FB lever during this time did the trick.

The LBS had already tried to bleed the brakes, but told me they use this technique for stubborn setups.
Click to expand...

So how are they now?
Can you do a huge deceleration with two fingers?
 
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