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9mm Axle upgrade to 12mm?

Jonathan's picture

By Jonathan - Posted on 01 July 2014

Hi everyone been thinking of doing this for a while but not sure if its actually possible. I want to upgrade my 9mm skewer rear axle to a 12mm thru axle. Obviously i would need to change hubs but is it possible with the 9mm dropouts? Apparently it can be done but im not sure with the dropouts?


Ian_A's picture

Unless your dropouts are replaceable, like the 2011ish onwards Trek's, then it's not possible. I converted (well the shop did it) my Remedy to 142x12mm maxle lite from 135x9 QR before I even got the bike. Luckily, my wheels could be changed with a conversion kit of just the inner axle and end caps.

You can go to 10mm bolt-up, which is probably just as stiff as 142x12, but I'm pretty sure you'll need to change the hub.

Jonathan's picture

So i can go to 10mm on 9mm dropouts? I dont think they are replaceable but ill double check when i have a chance


hawkeye's picture

The rear is already 10mm. Smiling

The front is 9.

I like the 142x12 on the rear of my Scalpel, but I reckon there's more to be gained from 15mm thru axles on the front if you don't already have it.

Jonathan's picture

Are u sure the rear is 10mm? Its the same dropouts of the old 9mm quick release skewer. I guess when i'm feeling better i will pull the wheel off and check with the vernier. Its probably not worth the expense to upgrade what with a new hub and all.

doc's picture

135mm QR Rear can take 10mm. I have used both 10mm bolt up and 10mm RWS Skewer, just depends on what config your hub will support

Antsonline's picture

Whether or not you can or cant is one question, but why you would want to is another!

Its a lot of work for almost no return.
I'm all for bike tinkering, but this is pretty out-there as 'something I have been thinking about for a while'

Empy's picture

Stffen up the rear end just go for a 10 x 135 thru-bolt axle like a Hadley.
There are other brands around but I have Hadley and it makes a huge difference.

Depending on your hub you may need a conversion kit or not or it may not be compatible at all.
Different brands have different kits so you may need to shop around.

A word of warning though; it is possible to do these things up too tight and crush or damage your rear hub.

Andy Bloot's picture

I have a similar DT swiss version on the front (not rear) of one of mine (came with the bike)
I noticed significant difference as well (as in less flex) over the BBQ skewer

delicious's picture

If your bike presently uses a rear qr, you simply cannot use a 12mm axle of any kind.
As mentioned by others, you can use a 10mm, either bolt through or bolt up, in any qr frame.
Happily, I've been using Hope products for many years and with the introduction of the Pro 2 in about 2008 came the cleverness and convenience of being able to swap axle configurations, front and rear, as required. There are other brands that do this too.
Why did I do it? Well, those that know me will know I'm a bike geek, so probably just because I could. Is there a noticeable stiffness advantage? Heck if I know. The feeling of stiffness in a bike is a subjective one, and can be argued at great length. A stiff frame + well built wheels + sturdy tyres + quick release = stiff bike. A crap frame + poorly built wheels + flimsy tyres + the biggest rear axle in the world = flexy bike.
What I do know is this. If you can feel flex in your bike, and you've convinced yourself that it is at the rear drop out, then getting a bolt up axle arrangement won't solve whatever the actual problem is...
When one invests in a modern bike that has modern features such as 15mm front and 142 x 12 rear then yes, one will feel that the bike tracks better, yet that feeling will be for a whole bunch of reasons. Add a 36mm stanchion fork, a 20mm through axle and bigger tyres and the whole shebang will plough through tough terrain and, provided it's set up correctly, will sit in turns completely unperturbed by anything, and will be a thing of beauty. And on it goes.
Whatever your bike is, leave it alone. The universe has already provided for you. Go forth to your favourite bike shop and grab your ankles...

Jonathan's picture

Yep, i think your on the money. I was really just curious to see if it could be done and how expensive it would be. It was just any idea if it was going to be cheap thing to do but to be honest i don't think the 1mm difference will be worth a new hub, axle and all the trouble. I was only really interested if i could go 12mm.

I might still call up the lbs tomorrow and have a chat with them to satisfy myself but other then that i'm good now.

Thanks for the help everyone!

fairy1's picture

On a 135mm spacing 12mm is pretty nuts, you also have a mounting flange that is a similar size to a regular 10mm hub and it's the tension on the flange that makes the rear end stiffer(unless the bolt expands like a Maxle).

I did buy a rear hub that was made for a 9mm DO and it was useless as it moved around in the frame so I had the axle bored to accept a Hadley 10mm axle, much better.
Also the only axles I ever snapped were 150X12mm but they were the early Hope Pro 2 ones which a lot of people broke.

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