Talk to me about rear axle lengths...

[nikki]

I've the opportunity to learn some framebuilding skills over the coming year (hurrah!) and am poised to buy a basic jig. It comes with the option of either a 130mm or 135mm dummy axle, but I don't know which to go for: 130mm, 135mm ...or both?

What considerations might I want to be factoring into my decision?

I'm guessing I'm going to be starting off in road bike, gravel bike and hardtail mtb territory.

[Brucey]

availability of hubs/wheels and wheel dishing.  To  a lesser extent chainline.

Basically roadies are stuck on 130mm OLN even though the wheels have a ridiculous dish and the chainline is often a bit crap.

 To me it make sense (from a wheel strength , chainline and hub choice perspective) to choose 135mm OLN for touring bikes, bikes with triple chainsets, and bikes with disc brakes. I'd only choose 130mm OLN if I was (for some reason) desperate to use some OTP wheels that only come in 130mm OLN.

There are a gazillion other hub designs which are used in MTBs etc but practically none of these could be called 'proper standards' so building a frameset around them seems a bit daft to me. If you want more choice think about building a frame with unboltable dropouts so that you can change them later on as your whim takes you.

Needless to say if you build to 132.5mm you can keep your options open to some extent; both 130mm and 135mm wheels will go in.

cheers

[quixoticgeek]

While I' doubt 135mm and 130mm QR isn't going to disappear, 12x142mm thru axle is becoming very common on road frames with disc brakes, and 148 (aka boost), is popular on MTB. Fat bikers have 'standards' right upto 190mm.

If I was buying a frame jig and the choice was only 135 or 130, I'd get 135.

J

[T42]

Basically roadies are stuck on 130mm OLN even though the wheels have a ridiculous dish and the chainline is often a bit crap.

Hence probably the cracks on the drive side of my back rim.

[Cudzoziemiec]

Anything with disc brakes is going to need 135 at least.

[FifeingEejit]

Anything with disc brakes is going to need 135 at least.

142x12mm is effectively 135mm OLD in disguise.
The disc sits in the same place, the cassette sits in the same place, the dish is the same.

The extra 7mm is to allow the frame to be recessed on each side thus allowing it to assist you in positioning the wheel.

Which is also handy as it means a correctly designed 12mm wheel can be converted to an 8mm QR if youre wanting cross compatibility.

https://www.pinkbike.com/news/12x142-explained.html

But that's mostly wheel side, don't know what impact that then has on your frame jig.

[nikki]

Standards, eh! 

Thanks all. I think I'm tending towards 135mm to start off with, but assuming I'll have to develop a collection as time goes on!

[yorkie]

Standards, eh! 

Obligatory xkcd:

https://xkcd.com/927/

[mzjo]

I would have thought that the best length option was the one that allowed you to convert to the other by adding or changing spacers (which I would guess, not knowing a lot about frame jig design but assuming others would be designed like I imagine in my head, would be 130mm) unless you know that all you will build is based on mtb hubs (which might be the case given modern transmission and braking trends).

[Jakob W]

I've the opportunity to learn some framebuilding skills over the coming year (hurrah!)

Hurrah indeed! So, when do you start taking orders?

[hatler]

I would have thought that the best length option was the one that allowed you to convert to the other by adding or changing spacers (which I would guess, not knowing a lot about frame jig design but assuming others would be designed like I imagine in my head, would be 130mm) unless you know that all you will build is based on mtb hubs (which might be the case given modern transmission and braking trends).

Surely you mean "... would be 135mm"?

[nikki]

The deed is done: figured I'd go with just 135mm to start off with and then see if a 130mm one is DIY do-able with the lathes I might be able to access...

I've the opportunity to learn some framebuilding skills over the coming year (hurrah!)

Hurrah indeed! So, when do you start taking orders?

Heh! I can take orders any time, but I need to be on top of the liability and insurance situations before I hand anything over.

...unless of course we can justify a bike adapted for the Tame Valley Canal towpath as a conceptual art project and therefore already covered by my public liability... 

[Kim]

Is that one where regularly spaced muddy potholes are required in order for the cranks to rotate?

[mzjo]

I would have thought that the best length option was the one that allowed you to convert to the other by adding or changing spacers (which I would guess, not knowing a lot about frame jig design but assuming others would be designed like I imagine in my head, would be 130mm) unless you know that all you will build is based on mtb hubs (which might be the case given modern transmission and braking trends).

Surely you mean "... would be 135mm"?

Well no. I was thinking in terms of a dummy axle holding the fork-ends apart. In that case the logic would be that if your dummy axle was 135mm then you couldn't shorten it to allow 130mm spacing. However if it was 130mm then going out to 135mm simply requires a couple of 2.5mm spacers. I am sure that I have seen jigs worked like this. If you are building on a surface table then you wouldn't do it like that however.

[hatler]

I would have thought that the best length option was the one that allowed you to convert to the other by adding or changing spacers (which I would guess, not knowing a lot about frame jig design but assuming others would be designed like I imagine in my head, would be 130mm) unless you know that all you will build is based on mtb hubs (which might be the case given modern transmission and braking trends).

Surely you mean "... would be 135mm"?

Well no. I was thinking in terms of a dummy axle holding the fork-ends apart. In that case the logic would be that if your dummy axle was 135mm then you couldn't shorten it to allow 130mm spacing. However if it was 130mm then going out to 135mm simply requires a couple of 2.5mm spacers. I am sure that I have seen jigs worked like this. If you are building on a surface table then you wouldn't do it like that however.

Ah. Got it. I was being daft.

[Jakob W]

]
Heh! I can take orders any time, but I need to be on top of the liability and insurance situations before I hand anything over.

...unless of course we can justify a bike adapted for the Tame Valley Canal towpath as a conceptual art project and therefore already covered by my public liability... 

Hah! I wonder whether Dear Susan started out that way (wasn't he a fine artist or something before taking up framebuilding)?