Assembling a single speed: I got my rear wheel onto the drop out, and now it is leaning to the left a lot (almost touching the frame🥴). What part(s) needs to be adjusted to center the wheel? (Pictures may be hard to see—it’s a confusing perspective) grateful for all your help.

Horizontal dropouts yea? Is this a new bike?

The chain tension needs to be set, your wheel shouldn’t be slammed all the way forward.

Check out this park tool video/website page: https://www.parktool.com/en-us/blog/repair-help/chain-replacement-single-speed-bikes. I’m assuming you can skip the chain sizing bit in the first minute.

Also tried to write out what I would do, but the video is easier to grasp with the visuals.

Axle bolts should be loosened. Pull back the wheel until there is tension in the chain, and tighten the axle bolt on the drive side (right side) just enough so it doesn’t move. Check the chain tension. Center the wheel, and tighten (but not fully tighten) the non-drive side (left side) axle nut. Check chain tension.

The correct chain tension is achieved when the chain has about a half inch vertical movement at the middle point of the chain between the front and rear sprockets.

Adjust the chain tension by loosening the drive side axle nut only, and shifting the drive side forward or backward to change the tension. The wheel won’t be centered when you’re doing this. Tighten the axle nut at the new position for the new chain tension. Loosen the left side, recenter the wheel, re-tighten the nut.

When you are satisfied with chain tension and the wheel is centered, then you can fully tighten the axle nuts.

I highly recommend [chain tugs](https://www.ebay.com/itm/314052057807?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D262356%26meid%3Dd260277ceaba4d3581e74145f404287b%26pid%3D101429%26rk%3D1%26rkt%3D12%26sd%3D174804111641%26itm%3D314052057807%26pmt%3D1%26noa%3D0%26pg%3D2332490%26algv%3DSimPLMWebV1CPCAutoManual%26brand%3DUnbranded%252FGeneric&_trksid=p2332490.c101429.m2460&itmprp=cksum%3A314052057807d260277ceaba4d3581e74145f404287b%7Cenc%3AAQAJAAABAOfK84Ydv1r5uz9ZG%252BtRiRxp0TbjGeNVW3z9ywv7hy6%252BT2%252FmBMThs5fJAQcbuPzx9rebloKUXynH35gjoSvbESjWc%252FeU%252Blpna72Hwai6k7YMtTLytUqh2rb%252BQ8drijmLoONVUxawEAo7VinPoA56buMoX%252FY3f3NzhAuw%252BVxDDtrtpyvRwJ5L37bku2t1wcSfK9W6O1R%252FF1hbw0jBrBLQrAfMfTOqCc1ZyXayNsJ%252FsZQjY3KEZwbjldNWEeNnQQFgQMFMQVXPNpyRgfzT3fVQL7HvrLgbDdQWURmEeh%252BMszbng0VVue3gIBD5qR%252By25BiscMVYniP6JADM9RqYm%252BXNXs%253D%7Campid%3APL_CLK%7Cclp%3A2332490&itmmeta=01HT6VF1NTVT9VZF6W3FJZS1WX) for setting the wheel in the frame/chain tension. I work in a shop and love every single speed/fixie/bmx frame that has them, it makes it way easier. The frames with integrated ones are the best. The other guy nailed the issues.