I just had this discussion in another thread. I have a Walmart bike with a QR front and nutted rear. I thought it was impossible to replace the rear axle, so I thought I had to re-lace the rear wheel to a new hub just to get QR. Someone pointed out to me that I should be able to replace the axle. After some research, I discovered I need a Wheels Manufacturing part # Axle-12.

Anyway, from what I learned, you just need to determine 1) the diameter of the axle, 2) its thread pitch and 3) dropout space of your frame.

Axles seem to be 10, 9.5 and 9mm diameter. (Mine was 9 in the front, 9.5 in the rear). You can use a caliper to measure the diameter (across the thread ridges) and people here should be able to tell you which it is.

Threads are either 26 TPI, or 1 thread per MM (which translates to 25.4 TPI). Use a caliper to measure the distance of 10 threads, divide by 10, multiply by 26 or 25.4 and see which is closer to "1".

Measure the dropout space inside your frame. (For my bike it is 100mm front, 135mm rear). Add 10 or 11mm to allow for 5mm to 5.5mm inside each dropout. (I have a 110mm hollow axle in front, and need 146mm in the rear.).

Check the Wheels Manufacturing site to find the correct axle.

That should make it easy to go to your LBS and tell them what you need. If you take your nuts to them, they should be able to easily tell you the diameter and pitch (saving you some time).

But, it's been my experience that LBSs aren't too eager to help with changing solid to hollow axles. They don't stand to make much money relative to all the potential follow-up that could occur if it doesn't work right. They'd rather sell you new wheels.

So, you have to use some finesse if you ask them to tell you the diameter and pitch of your axle nuts. If you can figure it out yourself, it eliminates the potential to get off on the wrong foot with the LBS. If you have all the info, you can just go to them and ask them to order the specific part numbers (if they don't keep those in the shop).

If you buy the axles from your LBS, they might give you free skewers from their spare parts box. (Mine did.). Otherwise you're looking at least $15 each for skewers. (The hollow axles should be about $15 each too.).

If you need help determining the diameter of your axles, PM me. I just went through that and have a pretty good idea of what's what.