Bicycle Mechanics - 3/8" rear axle to 11mm dia

My rear hub axle hole allows a 11mm bolt to clear.... would I gain much in strengh going to 11mm dia vs the 3/8" Assuming this is doable... solid axles for 126mm spacing.. 7 sp freewheel. Seem to remember seeing 11mm axles that were flat on the threads towards the end allowing insertion into the 3/8" dropout [?].

Thanks.

3/8"= 0.375 inch = 9.525 millimeter.. But Road bikes are commonly using a 10x1mm axle.

for strength What you should buy is a Phil Wood Freewheel hub, in 126.
I have used a Phil hub on my loaded camper touring bike, with out issues.

As fietsbob noted, the far more common axle for rear hubs is M10 x 1 mm threading which is already larger than 3/8". I'm unfamiliar with any 11 mm axles. Phil Wood does indeed make excellent, strong hubs but they are very pricey.

Plan B, lose the QR, buy a quality 10X1 axle, with Nuts..

My Light weight Classic uses Campag Hubs, I stopped having axle breaks
when replacing Campag rear with a 'wheels of Boulder' axle.

I believe the Campag axle was tempered a bit too hard-brittle
I think the replacement axle got a bit more ductility left in
by their tempering procedure.

Did it bend or are you just asking or ar you worrying about something that hasn't happened yet?

Solid axles aren't necessarily stronger than QR axles, there are a lot of factors that go into a good axe and whether or not you will break one. You also don't mention what kind of hub you are dealing with. Most 3/8 solid axle hubs weren't worth the material they were made from so it probably isn't worth it to upgrade an axle and try to find cones and locknuts (assuming loose ball design here) to fit when you can get a better quality NOS/used hub for pennies on the dollar for 126mm/freewheel use.

And I won't even go into a cold set and 130mm hub usage on old frames...