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Talked to Kevin. Called him back on <2026-06-16 Tue> when I was supposed to come see it, having just crashed. As of <2026-06-29 Mon>, still need to make it out there. Would be great to do while the kids are gone! But I need to be in riding condition.

So far so good! A learning curve on how much battery I can use but this is fun. It's about as fast as ripping intervals/tempo on the road bike, but takes the edge off the difficulty.

I can make the trip to work in Eco (50/50) with the latter half on Sport (75/75), which is decent speed. I'm pushing ~200w by the bike's measure, so that does mean the motor is working at nearly the max capacity for the mode.

On the way home I can do eco and then sport on the hill.

From my ledger (~/finances) and the eBay order. The Wolf Tooth 46T ring ($138.07) went back, so it is not counted.

Rack was $129.99 plus shipping; delivered [2026-07-27 Mon].

An immediate upgrade. Got from specialized, pretty cheap ($70.49, see Cost).

Came with 44T. Would like to go to 48 (or 50?). The "SRAM X-Sync Eagle, 107 BCD, 44T" is only sold up to 46… so the only option I'm seeing is the Alugear. These go allll the way up in size, but I have to more closely measure for any offset, and see exactly how big I could go.

I should be able to take the exact diameter of the existing one, and add X% based on the ratio 48/44, 50/44, etc, to figure out exactly how much bigger those ones are. I could also try to 3d print a test for size: remember the chain needs to fit on as well.

Bought this one and it doesn't fit:

https://www.wolftoothcomponents.com/products/aero-107-bcd-chainrings-for-sram?variant=40430218346531&country=US&currency=USD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&tw_source=adroll&tw_campaign=[ADROLL:CAMPAIGN_EID]&utm_term=[ADROLL:AD_GROUPEID]&tw_adid=[ADROLL:AD_EID]&tw_source=google&tw_adid=&tw_campaign=23862604931&tw_kwdid=&gad_source=1&gad_campaignid=23857398423&gbraid=0AAAAACraZvt376qS0iiNo8mb6z6KdCdno&gclid=Cj0KCQjwlNPVBhCMARIsAPZ5RqjTzQnzzTXuTzwJjLDfUXHrNgCUEXDQDIIIsD9zP43F5lC2ZXRgBQAaAk_AEALwwcB

The aero 46T I think. Need to send it back <2026-09-24 Thu>. order 397859. Needs to be received in 90 days…did I miss the boat here? Emailed them, found the purchase on my card statement the day after I bought the bike. Should be good, mailed <2026-09-25 Fri> via USPS. Photo of the mailing info. They responded with the date which matches - let them know it's route.

Here's one that would work:

• https://alugear.com/products/round-aero-for-107-bcd-sram-asymmetric-road-gravel
• https://djcbikes.com/products/stone-round-chainring-107bcd-for-sram-rival-crankset-107-bcd-road-bike-34-36-40-42-44-46-48-50-52-54-56-58-60t-axs-flattop?VariantsId=38384

Here's the OEM one for reference "SRAM AXS X-Sync 1X 12 Spd 107BCD Chainring":

• https://www.jensonusa.com/sram-axs-x-sync-1x-12-spd-107bcd-chainring-5

Only goes up to 46T.

With more battery, I could ride turbo more, which I think I need to go that way. The 160Wh extender is only 50% more though, how much would it help? 160Wh for $400 is also a terrible deal: I'd expect less than a dollar per Wh. There are a couple third party ones, but none in the US it seems. I do think this is just "what you get" being inside the ecosystem.

Looked into bigger-than-160Wh options <2026-10-07 Wed>: a few DIY efforts, and the only bigger finished pack is from Europe. Considering buying a pack and modifying it for more capacity, but not until it is well used.

Quote from Specialized <2026-10-07 Wed> for the stock SL1-160 extender, shipped to 01072:

That is $2.72/Wh, and would push the mile-per-dollar goal out to ~7162 miles. Shipping is a lithium hazmat surcharge (160Wh > the 100Wh parcel limit); ship-to-store on specialized.com only cuts it to $50. Used on eBay <2026-10-07 Wed>: $308 shipped, seller reports 12 cycles and 100% health. That is $128 under new, ~$100 under ship-to-store, and no warranty.

Part numbers:

• 98920-5640: the RE battery itself, with Zee cage and retention band. This is the right one; all Creo 2 models take the same SL extender, but the battery firmware has to be current or the bike may not give full power (dealer update).
• 98920-5655: the 220 mm "Road" cable (Creo / Vado SL / Como SL), sold separately. Check whether the eBay listing includes it.

Rated 160 Wh = 3.35 Ah x 46.8 V, so 13s1p of ~3350 mAh cells (likely 18650s). If a 21700 cell fits the housing, 13s1p of 5000 mAh cells would be ~240 Wh; that is the modification to look at once the pack is well used. Open question: does the bike gauge the extender by voltage, or by coulomb counting (current in/out)? If it is voltage, a bigger pack at the same nominal voltage should just read correctly; if it counts current, the TCU would need to know the new capacity.

Goal: a mile per dollar spent, so the goal is the total from the Cost table (bump COST when it changes). Nothing else was bought for this commute: shoes, lights, jackets were all already here. Pulled from the local Strava database (~/projects/2026/strava-database/strava.db), which the daily health routine refreshes. The blog build re-runs the block on every publish; C-c C-c to refresh it here.

[████████-----------------–—] 1879 / 6726 mi

Parts logged with strava-db component (chains, cassettes, wheels, tires, …). Miles are reconstructed from the Strava rides on this bike while each part was mounted; indoor trainer rides only count toward the trainer and what is mounted on it.

Current setup on Turbo, as of 2026-11-09: