ST1 Replacement Bottom Bracket/Crankset alternative

KidWok

Member
Hey all,

My ST1 Limited Edition is coming up on 9k miles as I also am nearing my three year anniversary with it. Did about 4k miles in year one, but got and sold a GoCycle G3 in year two and got a Tern GSD last year that have brought my annual mileage on the ST1 down a bit.

I have been planning a major overhaul at 9k miles as it seems time to replace the OEM chainring and freewheel. I had rotated two chains, taking the first one out at 50% worn, running a second one until 50% worn, then the first chain going back on until 100% worn, and now using the second chain until it is also 100% worn. The OEM Big Ben plus tires also look like they're due for replacement and I've got some Maxxis Gypsy e-bike tires ready to go. Had also planned on replacing the crankset and bottom bracket at the same time as the crankset was slightly bent after I went down on some ice last year.

Had all these parts ready for the big overhaul, but was just riding along last month when my bottom bracket spindle snapped in between the bottom bracket cups. I suspect this is due to me standing on my cranks often over bumps, which probably causes a lot of torsional shear on the BB spindle. The OEM BB spindle also does not appear to be hardened steel.

This meant I needed to do the BB and crank replacement ahead of schedule. I had decided that I didn't want to use the same FSA made RPM BB with the OEM crankset as they seemed pretty cheap. However, there really aren't many other BB's out there that are wide enough (OEM IS 138 mm spindle). I saw Phil Wood makes something special order at 135 mm. In my parts stash, I had a custom 129 mm spindle Ultegra Octalink BB with 73 mm BB shell spec that Shimano had custom made for my Santana tandem, as well as the 6500 crankset to match. The shorter spindle length would mean that the ST1 LE's single chainring would sit 4.5 mm further inboard, which it looked like there was enough chainstay clearance handle that.

Replacement was pretty straightforward as the ST1 BB shell is standard 73 mm spec. It all works well. The BB spins very nice and I know from my experience with my road bikes that it's a durable unit. The OEM 52t chainring mounted in the inside position, with the OEM chainring guard still on the outside, clears the chainstay by a couple of mm. I had made a custom chain keeper out of some stainless steel rod salvaged from a collapsible laundry basket that you can see in the first pic below. That had to be pulled off and put into a vise to bend it a bit to accommodate the new chainline. It is held onto the seat tube with a couple wraps of innertube and a zip-tie. Has worked beautifully since I put it on in the first year.

Rest of the overhaul will happen in about 200 miles with this last chain eeking out what remaining miles I can get out of the drivetrain. The freewheel has some pretty ovalized teeth, one chipped tooth, and I think the freewheel mechanism is making some clunky noises. OEM chainring is steel and I had flipped it about halfway through to get more miles out of it...it has started to slip under heavy acceleration. I'll do another post about the overhaul later.

Pics attached. Snapped BB spindle with both crank arms pointing down. Parts pulled off showing the BB spindle snapped on the inside of the non-drive bearings. Replacement crankset installed with OEM chainring and chainguard.

Tai
 

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per-larsen

New Member
Hi. Last week I dropped my Stromer ST1X 2019 taking a turn too fast on a wet road. The right crankset got bend in the crash and needs to be replaced. I would like to order the part myself online and replace it. According to the Stromer spec sheet it should be a FSA Omega 52T, but a google search on this part does not seem to bring anything that resembles what is currently on my bike. Do you know if I should look for it under a different name or is it a speciel Stromer parts that can only be bought through them? Maybe I can replace it with something else if this is the case?
Thanks
Per Larsen
Denmark
 

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KidWok

Member
Sorry...I can't help you there. I didn't much care for the FSA parts on my bike so I replaced them.

Tai