I'm having trouble trying to understand this whole hub measurement to order a new one since it's my first time doing so. It's hard to measure the hub with the freewheel and rotor on but I came up with 177mm the same as my dropout on the bike (diamondback said it's 150mm but the tape measure reads 7inches which it 177mm). My axles are the cheap bolt on 10mm axles. I wanted to buy a new wheel with a cassette so I could switch to 9speed instead of 7speed. So would that mean if I purchased a 177mm rear wheel with QR it would fit into it? Or if I got a 170mmx12 thru axle and got a 12mm to 10mm axle and a few spacers it would work for it? Any help is appreciated thank you.

A. What model DN you got?

1. You can get 9 speed freewheels. May require respacing the rear hub a bit, but cheap and usually easy.

https://www.universalcycles.com/shop...&category=1665

2. 170mm is the nearest common size for plus/fat bikes. You really need to remove the rear wheel to get a good measurement.

3. Some bikes come with solid axles and freehubs, so make sure it's freewheel and not freehub.

I just went out to re measure with a micrometer I bought and it seems the dropout of the frame is 180mm. And sorry it's a diamondback El Oso gordo. And yes it's a freewheel I want to switch to cassette for more options on gearing. So my question is if I buy a 180mm x10mm QR will it bolt right up to the bike I have? Thanks for your response.
It won't let me post pictures yet I'm new here.

Are you measuring to the inside faces of the rear dropouts? That's where the measurement's taken, measuring to the outside of dropouts might put you at 180 on a 150 OLD frame.

Yes that's a measurement from the inside, I'm not sure which but to measure to on the hub since there's 2 on each side but also a spacer on the drive side for the freewheel. Just trying to upgrade the rear wheel. I'll attach a picture. It's all really confusing to me and I just want to order the parts so I can get started haha.

3mm isn't much I wonder if I could buy a 177mm wheel and squeeze it in there with a QR? I just put hydraulic brakes on the bike so hoping to get the right size hub so the rotor lines up.

150mm is likely the common standard for the fork, but it is not QR and instead thru axle (the manufacturer's info there is confusing)
The most popular fatbike axle width is now 197mm for thru axle and 190mm for QR to accommodate larger tires
I suspect you have 170mm QR on your frame since it is not thru axle. The fatbike standard for thru axle in that range is 177mm and won't fit your frame.
Snap a few pics and we can probably be more sure and more details on the bike as well.

found more info on this bike, and believe it's the one offered at Costco a few years back for $350
It is indeed a freewheel and oddly spaced at 150mm. Here's a snip of someone else's post
I don't know if the 150mm DH standard was ever made in QR. Even if the frame is steel, I wouldn't want to try a 135 or 170mm QR hub. If aluminum, just ride it as is.

Quote: With a 150 mm rear hub, and a 7 speed freewheel (not a freehub) it greatly lacks the ability to be upgraded. This is where the similarly priced Mongoose Vinson excelled. Still, as long as youre not going to upgrade (or break) anything, and only need it for some light duty riding, youre out of options at the price point. Vinsons are hard to come by, and certainly arent selling for as cheap as they did black friday 2015. So you may well be right, youre not going to find anything else for this price. Unfortunately the smarter move may be to hold out until you can push the budget a little higher (Framed / bikes direct)

What pictures should I be taking so you can see? I can take some today, it is the cosco bike, everything has been upgraded over the past few years on the bike except for the rims I left them for last cause I could never figure out how to measure it right lol.

The hub with the freewheel on measures 180mm from nut to nut. With the freewheel off and measuring from the inner lock nut on the rim itself it's 150mm. So I would think I could just buy a 177/180mm hub with cassette and throw it right in there? Or a 170mm hub with 2 5mm spacers?

the hub standards we are referencing are measured same as how you measured the inner nut of the existing hub.
What is the frame made of, steel or aluminum?

The frame is a steel frame I'd think it would be no issue to make up the 1.5mm each side if I put a 177mmx10QR hub in. My current hub has a cone nut and another nut on each side. The drive side has a cone nut, spacer, and a lock nut where the freewheel slides over to attach to the hub. It is a 150mm hub with 30mm of spacers to make the 180mm spacing for the dropout. So that's why I'm assuming a 177QR or 170mm bolt on hub would work as long as there 10mm axle.

A 9-speed freewheel? WOW! What are the chances of breaking or bending the axle on a wheel with one of those on it?

Cheers

read up on cold setting the frame, I've never tried beyond 10mm. 20mm or more is fairly extreme. Expect potential alignment issues and cracking the welds on the stays. I'd still recommend against it, but it's your bike afterall, good luck