The ANURA Differential Assembly Guide --15-JAN-09--
The first few batches of the Anura (2007-08) had a differential with a screw-on freewheel, with an 8 speed cogset. This had a few problems in that it was difficult to remove the freewheel to change the cogs, and there was a very limited number of cog sizes available. Thus extensive work was done to modify the differential to accept, 8, 9 or 10 speed cassette clusters for the 2009 Anuras. To accept this modification, the frame and the axles had to be changed, so unfortunately, this new differential is NOT retro fittable to the 2007-08 Anuras. At this point we also took the opportunity to change the axles from the locknut location to using collars to locate the rear axles. This makes it much easier remove the diff. to change the cassette clusters (rear cogs). To accommodate any variation in frame tolerances, a spring was used to locate the cassette and the differential. Unfortunately this spring has been found to be in-adequate to locate the cassette well enough to allow a good gear change. Furthermore, the axle collars were made without the shoulder to give running clearance from the outer ring of inner axle bearings, so there is a slight amount of drag on the rear wheels. Thus we are now supplying our Distributors and Dealers with a "Diff. Upgrade Kit" which will eliminate this problem. It consists of a 12.5 mm long "Cassette Spacer" to replace the cassette spring and seat, a clamp or 17mm "Diff Collar" to locate the diff. on the LHS, and two new 15mm "Axle Collars". These instructions show how to fit these components to the 2009 Anura.
Latest Diff. Upgrade Kit 
Note all components of latest kit are anodized black, whereas earlier kits had silver axle collars, and bronze cassette spacers. Some photos show early kits and some show latest kits. Click on pictures for larger pictures.

1) First thing to do if modifying from an assembled state is to remove the wheels. Use a 6mm hex key to remove the capscrew (bolt) and washer holding the wheel onto the axle.

2) Once the capscrew has been removed, grab the wheel via the hub and slip the wheel off the axle.
Having trouble removing the wheel? Sometimes due to manufacturing tolerances, the wheel can be stubborn to remove, try using a punch and hammer and hit the drive pins from the inside to get it to break free.
3) Next step is to remove the brake calipers, be sure to remove the capscrews holding the caliper adaptor to the frame so you don't loose your fine-tune adjustement. Use a 5mm Allen key for this.
4) Undo the left hand axle collar with a 2.5mm hex key.
5) Remove the left hand axle, due to tolerances it will either slip out without too much effort or it may require some assistance from leverage. I use a couple of flat blade screwdrivers to lever against to bearing and the head of the capscrews holding on the disc brake rotor. As you remove the axle the axle collar will slip down, either let it drop or hold onto it with your right hand and pull out the axle with your left.
6) Repeat steps 4 and 5 for the right hand side...but this time you need to support the weight of the diff center as you remove the axle. What to expect to be in there when you remove it will be the other axle collar, a spring, the cassette assembly and the diff center. Don't be alarmed if the cassette separates from the diff center, it is not meant to be captive like a rear hub - the axle holds it all in place once assembled.
7) First part on our list to be replaced is the spring and the spring seat. The spring should be easy to remove, it may be caught under the seal, if so a pair of pliers may be of assistance here.
8) The spring seat can be removed with either a pair of circlip pliers or a pair of needle-nose pliers. If you have neither of these you may need to find something hook-like to pry it out with. You will now no longer need either the spring or the spacer.
9) The spring and spacer get replaced with one single "Cassette Spacer", it measures approx 12.5mm in length and will fit inside the seal on the cassette body.
Latest "Cassette Spacer"
10) The next replacement part is the diff play adjustment clamp, slip it over the left hand side axle driver on the diff. We mount it up now to make assembly easier and adjust it last to take up the side-play. A 4mm hex key is used for this. Latter kits have a neater "Diff. Collar" which does the same job, and requires the same 2.5 mm key as the "Axle Collars"
Latest "Diff. Collar"
11) The final replacement parts are both of the "Axle Collars". The original collars are completely flat on both bearing faces, the new ones have a rebate or shoulder so that the outer edge does not rub upon the outer surface of the axle bearing. Take care to mount the new collars with the rebate facing outward / toward the axle bearings mounted in the frame.
12) Slip the right axle part way in as shown above and place the collar on the end of the axle. Assemble the cassette and diff center together. Fit the chain over the cassette as you slip the assembly into position and slide the axle in. You may need to jiggle the whole assembly round a bit so that it lines up with all the bearings and shuffles the spacers around etc.
13) Make sure the axle is fitted all the way into the bearings, the first picture shows correct fitment and the second shows the gap left when not fitted all the way home.
14) Once the axle has been confirmed that it all the way home, press the cassette against the axle collar and tighten the grub-screw in the collar. These screws do not need to be over-tight, 2Nm should be more than adequate.
Tightening right hand axle collar.
15) Same procedure for the left hand axle, fit the collar the right way around, slip the axle all the way into the diff center until there is no gap as shown above and tighten the collar. Both axles should now be correctly fitted with no play, if side-play is detected in the axles, make sure the axles have no gap on the outside and re-do the appropriate collar.
Tightening new left hand "Axle Collar".
16) The last adjustment is the diff side-play, it should now have approx 1-2mm of movement left to right on the axles, we need to minimise this so that that the gear selection can be adjusted to index properly. Whilst pushing the whole diff assembly to the right, slide the diff side-play adjustment clamp or "Diff. Collar" leftward against the axle collar and tighten with a 4mm or 2.5 mm hex key, no more than 4Nm should be needed to secure this clamp, and 2Nm with the "Diff.Collar".
Tightening "Diff. Collar".
17) Re-attach the brake calipers and double check their adjustment. Check all the bolts securing them and the cable clasp.
18) Some of the axles have a machining fault with the position of the holes on the drive flange that the hub drive pins engage into, I like to try every six combinations by slipping the wheel on and engaging the drive pins into the flange, removing slightly and trying the next series of holes by rotating the wheel 60 degrees. I find one combination will work really well and like to mark both the flange and hub for future reference. For very stubborn cases, ask us about alternative measures. Fit up the axle bolt and washer and tighten to 10Nm. Job complete!