Where to start......the question about the hubs. Serpent does continual upgrades on parts as they see and get feed back on issues. In the case of the hubs, there was a change in those items part ways thru 21-22, and the weak point of the hub was beefed up quite a bit. Not completely unbreakable but a lot stronger than the first version. This has been carried over to the 25 car and since running the 24 with these parts I've only experienced minimal breakage. This particular item is a good tuning option that I have changed earlier cars over to, just to get that axle height adjustment as well being able change width of the car easily.

The upper bridges on the 23/24 car, although made stronger still had a tendency of twisting on really hard crashes as well as minor bends that would cause inconsistent caster, camber and toe issues. The new car has completely eliminated these bridges and have gone to very thick carbon fibre plates. With the plates they have changed the way that the caster pills install, now making it so you can change inner are height without fighting to keep every thing in place, so no its very nice to work on.

This brings us to the bulkhead/diff eccentric/eccentric holder setup. The bulkheads are completely different to be able to accept the new adjuster concept. The eccentrics are still being used to move the diffs up and down as well as adjusting belt tension but now the outer eccentric holder gives an additional up/down adjustment. This is nice to have as it now makes it so that the drive axle angle can be changed to almost parallel and eliminates some bind and help corner speed. As far as durability I cant really say if its stronger or weaker than previous versions, time will tell. I was questioning this whole setup as far as ease of adjustment goes, and once playing with it a bit it actually is easier to adjust diff height than the 24.

On another tangent I have worked on the 24 car a lot to get the durability out of it and get consistent performance. My second last version of the car is very similar to the 25 car. I used the bulkheads off the 20 car and had carbon plates made to be able to use the pills for caster adjustment. The 24 shock mount will bolt onto the 20 bulkhead with no issues. The only downfall is the 20 bulkheads are not pinned, but that is minor. The other option I ran was the 20 upper arm mount and used the 20 rear upper arms. The arm mount is the +4mm mount. Then I just used the normal height spacers under the arms for adjustment. Either of these are very strong setups and a nice alternative to the weaker 24 upper mount.

Getting back to the 25 car. The lower arms are changed again, they have different lower shock mounting holes which with the new upper shock mount, change the shock angle. This addresses a couple previous issues. Now you can get lock to lock steering without shock interference and the inner wheel rub issues has been eliminated. Both required a lot of work on the previous car to fix this. The arms are also recessed to allow for better lower shock retainer clearence. The lower shock retainers are also different and are now about half as tall as the previous low profile shock retainers. They are also made of aluminum now.

Since we are on shocks. The new shocks are now a linear configuration compared to the progressive shocks of the 24 car. The shocks are also shorter than the 24, so the springs are also shorter as well. The build the same as the previous shocks and when done they are nice and smooth. The clips to retain the pistons are little tough to get installed but once on the make a secure setting. I did notice that the tops of the shafts are machined cleanly and have to burrs that can damage to bladders.

The top decks are completely different on the 25 and utilize a different flex point. They move the pivot point deeper into the bulkhead. The top deck mount points still remain the same as the previous car as you could switch these between all the cars for different feel.

The roll bar mounts on the arms have been changed to metal holders like the S411 used, so now you wont strip out the setscrew on the retainer. Using this setup in the front also aids in preventing steering hub over rotation which stresses the DJC bearings and breaks them and/or breaks the steering hubs or other. I'm not sure how this is done but the stop for steering over rotation now feels very solid which should help durability of the car.

The spool out drives are now extended out slightly farther and no longer are on the tips of the blades. The old fix was to put spacers between the out drives and the spool, but no longer required.

The diff remains the same and come with seals that looks like some kind of x version. I still change the to the green seals as they just seem like a better seal. (SER401784)

The chassis, mine being the steel version is 1.2mm thick with a nice black finish. They did eliminate the arm sweep/arm toe insert adjustment. Not sure if that is good or bad, having used it a few times. I can't say if I will miss that option, although it did make lower roll centre adjustments confusing sometimes.

All in all, its a very nice solid car with many adjustments to take advantage of just about any track.