The Legendary Modolo Kronos Caliper
Back in the early 80s, a few of us were lucky enough to own Modolo Kronos brakes. Personally, I don’t think I appreciated just what an iconic piece of kit they were to become. Lord Nobby of the desert still has his. He kindly sent me this piece ‘wot he wrote’ …
The Modolo Kronos brake caliper simply oozes class! It was manufactured in the early 80’s and its beautiful design and ergonomically advanced features were light years ahead of its contemporary’s. Even today it holds its own against all the modern carbon paraphernalia. These are rare beasts and are extremely hard to find these days with only 2000 sets ever being made. They adorned many an 80’s time trial machine - especially Low Profile bikes of the era. Ian Cammish owned a set and used them on his Brian Rourke in 1983. Stuart Dangerfield also used them on his machines. This incredible little caliper was fitted to some of the best riders’ bikes of the era and even adorned bikes used to break competition records. They may not have stopped you all that well, but in a time trial the idea is to go as fast as you can without braking so most riders were happy to make some sort of compromise.
A lot has been said of these works of art but you’d be hard pressed to find any advice on servicing them anywhere. As a result of my own inquisitive mind, for the first time (as far as I am aware), here is a guide as to how to dismantle and reassemble your Kronos Caliper.
For such an ingenious piece of kit I was amazed at how easy it was to do and how simple the device is. Modolo were certainly ahead of their time when they designed this little rarity.
You will need to undo the two countersunk style cap-screws using an allen key - see first pic below.
Next, the castellated nut needs to be screwed off. This can be done by using a wide headed screw driver or any steel edge that fits nicely into the grooves. I used a pair of small scissors and it worked a treat. Again counter clockwise to undo. Second pic above.
With the castellated nuts removed you can now gently tap out the dowel pins that hold the arm in place on the main body. See third pic above … with dowel pins nicely exposed.
When removed, you can ease the arms out like this by removing the cable adjusting barrel which holds the spring as above.
Once the dowel pins are removed, with the arms closed, you will see two screws (as above). These hold the arms to the inner mechanism that slides up and down.
Below … the two screws have been removed (counter clockwise) … note the washers are brass which aids in a smooth operation of the arms when attached fully to the main body.
The Inner mechanism, with both arms fully removed, will just slide out of the main body housing along with the removal of piston pin. Again, brass is used to aid a frictionless motion of the caliper.
Third pic above show the back of the inner mechanism have a slot that slide nicely up and down on the specially designed caliper bolt that is also located inside the main body housing. Very effective and simple design.
Reassembly is basically just the reverse of disassembly.
First pic above - the inner mechanism slides easy into the housing then the piston pin screwed in through the top to hold the mechanism in place. Just ensure it sits on the sliding groove.
Middle pic above … inner mechanism located inside main body and located in sliding groove.
Install each arm then screw in the screw until flush with each arm.
First pic above - both arms nicely installed.
Now that both arms are attached to the inner mechanism you can line up the holes where the dowel pins go and just slide in the dowel pins nice and easily by hand.
Above - both dowel pins fitted and flush with main body.
Thrird pic above - Screw in clockwise the main adjusting barrel arm with the spring and do it up hand tight. Then check the spring tension by pressing inwards on both arms. This just confirms the spring is working soundly.
Barrel fully installed and tension on spring fully restored.
Reinstall the castellated nuts just a tad more than hand tight as the countersunk screws will hold them in place.
Castellated Nuts fitted in place.
With castellated Nuts fitted, screw in the counter sunk type capscrews and tighten up.
All that needs to be done now is to fit the brake pads which simply slide in. If needed, the rubber protection can then be fitted and you’re done.
Third pic above - fitted on a low Pro machine ready for action.