The problem

The Surly Karate Monkey is a very good frame. In order to offer quick handling, it has got short chainstays (430mm). This is possible thanks to a specific bent seat tube. But the problem is that it is not easy to find a front derailleur which offers correct mud clearance.

deraileur clearance troubles

Bontrager ACX 2.2, no monkey nuts.

tire touching the derailleur

Bonty ACX 2.2, old XT front deraileur, no monkey nuts

We can see on The surly blog, a detailled article about this problem : front derailleur and big tire fit. They give advice as to which deraileur to chose, but none of them really offers a lot of clearance.

A better solution

My solution is to use a specific collar for road bikes called "Braze on collar system". It allows 2cm of clearance with a Bontrager 2.2 ACX tire, and without the monkey nuts !

KM derailleur clearance

Bonty 2.2, NO monkey nuts

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KM derailleur clearance, other side

Bontrager Jones ACX 2.2, NO monkey nuts

All the pics were taken WITHOUT Monkey nuts with Bontrager jones acx 2.2.

There is more clearance than every other front derailer type can offer ! One can choose the front deraileur of your choice, it just have to be compatible with the collar mount. Mine is a shimano tiagra.

Braze on collar

Road derailleur on braze on collar

Shimano

The Tiagra has a good price and is very eazy to find.

You can also go with a lighter choice like the Dura ace

Dura Ace

For the collar, I used a Massy, like this one :

Massy collar

Conclusion

The use of a cyclocross triple front derailleur in assocation with a collar is is the best solution for huge clearance, better than choosing to ride without a front derailleur !