How do you measure rear axle width?

I ordered a rear wheel from online store and it appears my 142 mm axle is 5-6 mm too short for this hub when I try to screw it into my frame.

Which immedietelly made me suspect this is 148 mm boost hub.

If I insert this wheel into my gravel bike 142 mm frame, the brake disc sits at correct position. Also on cassette side everything seems ok ( but I cannot screw down the axle.)

I checked the hub which came with wheel to see if maybe some sealed bearings werent pushed all the way in on the cassette side, but everything seems ok.

Brake side rotor is in correct position like I mentioned.

Does this mean all the width is in the hub itself, not the spacing around the hub ( 148 mm boost wheel hub is wider than 142 mm hub?)

I dont know how to "prove" this is boost hub.

Wheel is Gurpil infinite 6b disc tubeless.
https://www.gurpil.com/es-ES/Catalogo/Index/RUEDA-GRAVEL-DISCO-6T-12X142-SHIMANO

Yes, its says 142 mm but like I explained my axle is 5-6 mm short for this wheel and have been using 12x142 wheels on my bike for years.

For a "standard" (old?) QR axle, the axle is typically 11mm longer than the drop out spacing.
You bought an axle for 130mm frame.
You need a 146mm axle for your 135mm frame.
Pic below is a 126mm spacing.
EDIT- I don't know about the 12mm or Boost or ?? (aka new stuff) but frame spacing will still be as below.

You sound like you are talking about a thru-axle. Thru-axles are specific to the frame, and a frame that takes a 142 hub could have a wide variety of lengths and threads depending on the drop out design.

Do you have to spread the frame apart to squeeze the new hub in?

Is the make and model of your bike a state secret? How about including that information

This isn't really making sense. As noted, the rear thru axle specs pertain to the frame. The thru axle is part of the frame, not the hub. As bboy314 asked, unless you're having to jam the new wheel into the frame and spread it a few milliimetrs (which would be an obvious incompatability issue), there's some missing or misunderstood info here.

This is a great article explaining the Boost hub width thing
https://www.mtbr.com/threads/tech-ta...ained.1170220/

(you have to click “see more” for the full post)

It seems unlikely this is a 148 wheel hub since it fits in his gravel bike dropouts. If the thru-axle screws in ok without the wheel there, maybe it’s just an alignment problem. I had to temporarily loosen the rear mech hanger (which effectively forms the outer face of the dropout) on my crappy Cube CX bike to be able to get the axle to screw in.

Cube Nuroad Pro 2021

Sorry, I dont understand. My bike accepts 142mm through axle.

Should any wheel with 142 mm through axle hub fit there?

I have alrady bought several different wheels through the years, plus even for test, put 142mm rear wheel from my road bike to my gravel bike and it fits fine.

Cant say really but like I explained, my axle is 5-6 mm too short to screw in. I have never experienced this while trying to put some other 142mm through axle wheel in my bike.



but what is there to say, I explained, my axle is 5-6 mm too short to screw in. I have never experienced this while trying to put some other 142mm through axle wheel in my bike.

Another thing completely makes no sense and this is, the tire is not centered in the frame.

I know how other wheels (which I own) look like in the rear triangle and the tire is centered.

How can the axle not fit, when it did before you tried fitting the new wheel?

Just to confirm, you are correct that the frame does accept 12 x 142 hubs.



So the next thing is to measure your new hub. Obtaining a measuring caliper is the easiest way, and ones with sufficient precision for this job can be cheap. Measure the "over locknut" distance between the surfaces of the hub which will contact the inside of your frame's dropouts (as shown at https://velo-orange.com/blogs/thevel...sure-your-hubs ).

If that distance is 148, you need a different hub or maybe different (replacement) end caps, if ones for 142 OLD exist for your hub. If it is 142, something else is wrong. Maybe posting a picture of the too-short axle install might help.

Are you certain the hub is the proper OLD. You aren't wedging it in there and widening the spacing are you. If this is a new wheel, then it probably isn't the first time that a wheel hub came with the wrong spec'd OLD. (Over Locknut Dimension) The distance from one side of the hub to the other side of the hub of the part that fits into your drops.

If there is no rear wheel in the frame, can you install the thru axle?

No, you have have hubs with 142mm axles, and they are held into the bike with thru-axles, which are threaded rods that go through the hub axle. And those thru-axles are long enough to go through the left dropout, the axle and the right dropout. So the thru-axle must be much longer than 142mm.

You need the right thru-axle for your bike:

https://robertaxleproject.com/produc...-x-1-0-thread/

When it comes to thru axles the correct axle to use will be dictated by the frame or fork, not the wheels. When replacing wheels keep using your existing axles.

Your original axles will probably have their specs silkscreened on them.

In some cases you need to remove tension from your derailleur. I know I have a bike where everything fits just fine and no issues with the axle or frame but because the clutch is adding extra tension it will not allow the thru-axle to thread in properly. Luckily that particular bike I am mentioning has the ability to lock the derailleur into a different position for situations like this. You might be having a similar issue but have different parts which are less likely to have that issues in the same way.

If the hub fits in the frame without stretching and the thru-axle fits properly without the wheel then try to loosen tension on the derailleur.

So are they both seated or not?

Some end caps are threaded on. For example, some Bitex axles use threaded caps, and some other brands' hubs are made by Bitex and so may share that design. Off the top of my head, (some, maybe all) Origin8 hubs are Bitex.

I'm sure. But those generally aren't the kind that fall off like I suspect the OP's did.

Very possibly this is the case (because brake disk rotor fits on the disk side and there is no "unallocated" space on the derailleur side) so only thing that can be wrong is hub width.

Dont have any tools because I am traveling through fricking Africa.

hub has these end caps which are not held by anything (they dont screw like I am used to on my other wheels), which I dont like btw, because hub body can just be separted accidentaly (maybe this is god this if you need service in the field?)

sorry guys for not having any pictures, when I come back home (sometimes this year) I will disassemble everything and show you.

I cant expalin to you how frustrating it is to wait for new wheel 3 weeks and when it finally arrived, its ******g wrong.

I can relate -- I just built a wheelset, but I cannot locate the necessary end caps for sale anywhere. I bought some that should've been right, but they were advertised incorrectly, so they were returned. I have resorted to manufacturing my own end caps, which was not supposed to be part of this project. Luckily, I seem to have more resources at-hand than you do, in your present location.

That said, if you can scare up 3 rulers -- or one 1 ruler and 2 flat objects with a straight edge -- and some tape, you might be able to fashion a suitable instrument to measure your hub with sufficient precision.

That seems an odd way to approach the problem, when you can just stick something through the hub then measure that.