190mm QR = 197mm thru-axle

 

The frame have a 12x197mm rear spacing and the wheels 12x190mm.

 

Depends on the hubs. Some brands have conversion kits that would allow you to change it to thru-axle.

 

I am running this set up, Chosen 190x12 thru axle hub, 197mm spaced dropouts. I have 2x3.5mm spacers that make it the right width.

 

Hi Jason,
Where did you get the spacers?

 

I have bought a 197 frame and I already had the 190 hubs. It can be done with spacers as mentioned by Jay_RigidRide. Just make sure the axle that came with the wheel is actually long enough - mine isn't or I could have also used spacers.

That didn't bother me because I had bought the wheels just for the rims, but that's when I discovered the next snag.

I bought a set Hope FatSno hubs (197mm and 135mm) to build up the wheels. I thought they would have come with axles, my fault, I should have checked.

They took 4 weeks to arrive, probably because my lbs didn't get round to ordering them even though they knew I was wanting them for the WEMBO World Championship 24 Hour Solos.

So anyhow, I got them with a week to go, discovered the lack of axles, and back to the lbs to urgently order them. (No problem with the front, the existing axle was ok).

And this is where the snag came up. Hope make 197mm hubs, but don't make 197mm axles! They were adamant that the axle should come with the frame because at that size they screw in to the frame. I explained, no, it is actually a through axle and is fastened with a nut.

So there we have it, if you are buying a Hope FatSno to build a wheel, don't assume axles are available if you have an actual through axle frame rather than one where the axle screws into the frame.

So my ultra light weight weenie carbon fat fantastic was sitting all ready for WEMBO, but lacking a back axle and not enough time to source one.

I rode my 29er in the race and now have a very shiny 197mm desk ornament.

 

Is this common for fat bikes? I've never seen a thru axle bike frame not come with the correct axle.

 

I can see why it's the frame manufacturer's responsibility if the axle screws into the frame, but I can see no reason why a proper through axle that relies on a nut at the other end should be the frame maker's problem.

After all skewers comes with wheels, not the frame, and a proper through axle is just a glorified skewer.

 

It is generally true that the rear thru axle should come with or from the frame manufacturers. They generally screw into the opposite side dropout and the manufacturers have been using differing thread pitch on the threaded ends, making it a frame specific part. Through axles for forks always come with the fork, right? hope doesn't ship its qr hubs with the QR either.

 

Some of the non-branded carbon fat bikes from China are shipping without axles. Because of this they require a through axle and bolt. Threading the axle into a replaceable dropout/hanger is superior. But that costs more.

If you need to buy a 197x12 axle, search ebay for 197x12 and the first result will be a $19.99 thru-axle/bolt combo. Same for 190x12 or any other variation of through axle sizes.

 

Hope doesn't make any axles, not even for non-fatbikes. Neither does chris king, i9, etc. In fact, most hub manufacturers don't make axles.

This is because most axles are frame or fork specific. Rockshox, fox, manitou, xfusion, etc... they all have different fork axles. The same is true for rear axles and frame manufacturers. Even within a single brand there are multiple axle types.

 

...This is because most axles are frame or fork specific...

I keep hearing this. What you are saying is there is a subset to which that applies, but the evidence of forks and frames that do not require specific axles speaks for itself, and I raised the point so no one else gets caught out.

It looks like the axle industry is lagging the hub industry.

But it is no longer a problem because I am making my own axle.

 

The distinction I was getting at is whether the axle threads into a loose nut or into a chip attached to the frame. A chip attached to the frame is functionally superior in every way but is more expensive to manufacture and stock because it is different for every frame.

Either way, whether threaded into a detached nut or into a frame chip, it can still be either quick release or merely screw in. Many frames have pinch bolts or collars that prevent a threaded axle from backing out. This is typically only used on a non QR through axle.

My preference is for a threaded chip and a pinch collar to prevent the axle from vibrating out. But other people prefer QR through axle or the low cost of a simple threaded axle and detached nut. Hence the existence of so many variations of axles.

Throw split pivots and floating brake mounts into the mix and things get even more complicated fast. Both require longer axles and occasionally low profile heads to prevent heel rub.