Thru Axle and Quick Release Fork/Frame Compatability?

I've never seem an adapter for either of these situations. I doubt one would fit.

That said, a lot of manufacturers use the same hub body on their through axle and QR wheels and are more than happy to sell you the bits that are different.

I had this problem when I got a pretty good deal on some wheels with a 15mm front hub. In the end, after a month or two of looking, I found somewhere with a non tapered 15mm fork in stock and bought that over rebuilding the hub.

The best way, is to choose wheels that fit out of the box!

PS I found this adapter for a 15mm QR on a roof rack, not sure I'd like to ride it...

Only with manufacturer-specific parts, and only with hubs that were designed to be adapted (e.g. you could probably adapt a 15mm bolt-thru hub to 9mm, but not the other way around).

For example, Hope will sell you adaptors to let you use Pro 2 Evo hubs with these drop-outs:

• Front QR
• Front 9mm
• Front 20mm
• Front 15mm
• Front Maverick fork
• Rear QR
• Rear 10mm Saint
• Rear 12mm (135)
• Rear 10mm Bolt in (135)
• Syntace X12 142mm

You might get lucky and find adaptors from one brand of hub will work in another, but in general that isn't the case.

Simply for your two points:

• For a front wheel you can buy or machine a part that will allow you to run a smaller axle on the front than the hub is equipped with. This an adapter to run a 15mm TA hub in 9mm drop outs.

The rear is more difficult as hub sizes get wider with larger diameter thru axles. You couldn't make a 12x142 thru axle hub fit in a 10x135 QR dropout even if you shimmed the space at the end as the chain line would be off.

• In terms of frame/ fork design, the design form for through axles offers no backwards compatibility with QR drop out design. I haven't seen and can find no evidence online of an adapter that allows you to run a 9mm hub in 15mm TA drop outs. That being said it could be possible to engineer something that created the required tension to hold the hub in place, but I wouldn't trust a home made solution.

Can I use a wheel with a thru-axle hub on a standard quick release fork or frame dropouts (with an adapter)?

Through-axle hubs have a larger inner diameter to accept a 15mm or in some cases 20mm spindle, so many of them can be purchased with adapters that accept a 5mm spindle and fit in a 9/10mm dropout (QR usually have a 5mm spindle and fit a 9/10mm dropout).

For example Hope have conversion kits for their hubs that allow you to use their hubs with an older quick release (QR) fork http://www.hopetech.com/product/axle-conversion-kit/

Can I use a wheel with a quick release hub on a thru-axle fork or frame dropouts (with an adapter)?

If the quick release hub is truly a 9 or 10mm quick release hub then no. The diameter of the internal hole where the spindle goes through on these hubs will not accept anything larger than about a 5mm spindle, which means it is not possible to use them with a 15mm spindle that threads into the fork or frame.