I mostly compared it on a weight basis, and weight of those suspension types didn't change much over time. And spamming dampeners like on the Leo 2 is not hard even in the 60s, but again this was just a worst-case comparison for the torsion bar. Torsion bar suspensions contemporary to Chieftain still offered better ride quality and were lighter than the extreme Leo 2 type (though for some reason US TBs on the Pattons had really poor late life handling, at least in the specific case of Israel, which is a rocky country).
Besides, if Hortsmann (and other spring-based suspensions) really was competitive in ride quality, the Americans wouldn't have adopted it just after getting HVSS and reported that TB offered better ride quality and the Soviets and Germans wouldn't have been so hell-bent on it (moreso for the Germans considering that Horstmann equivalents would also have been doable with the poor materials they had in WW2).
More curious is the British case itself. The postwar service tanks used Horstmann and later Hydrogas, but the FV 300 series, Vickers export tanks (even the MBT Mk 1 which used other Chieftain components!), CVR(T) series, FV 432 series (1960s!) and the Warrior (stuck in development hell in the 70s before Hydrogas became available), all of those vehicles used torsion bar. And out of all the suspensions that Vickers would design during the war (wishbones for Vanguard/Valiants, air struts on Tetrarch), a revived A6's Horstmann was not one of them. If anything the Chieftain having Horstmann is the anomaly.
Did the REME guys ever complain about CVR(T) and FV 432 torsion bar maintenance?
Hydrogas offers better ride quality, somewhat improved wheel travel, can reduce weight by 100kg minimum per wheel and doesn't take space in the hull, it just was still a bit too expensive in the 80s to see really massive use but choosing it over torsion bar if it works is absolutely legitimate. But it wasn't the case in the 60s (though that's partially because the units that went on the MBT-70 were very complicated). Of course we all know about the ability to increase gun depression/elevation but you can also use those units to block the suspension when firing, which drastically reduces the rocking effect. Hydropneumatic is excellent, just usually for the 80s and beyond. It's one of those times when the British actually chose the expensive but high quality option. Too bad this wasn't the case for the rest of the Challenger.
This is what you must do to replace a bogie:
View attachment 621530
Chieftain was just as bad because the track is supported by a return roller on the bogie itself and center guides run through it. At least HVSS fixed this problem since the return roller was not on the bogie. And you need a crane to remove that bogie. The idea that removing a bogie is somehow easy is a misconception.
Meanwhile for removing TBs, you just need to release the stress on the torsion bar, undo the cap that protects the torsion bar, undo some bolts in the hull itself on the torsion bar mount and pull it out (something you can do with just humans since TBs are light enough). Releasing the stress is done with a jack that gets put under the tank
Or you can drive onto something that does that for you. Granted if you are a Patton tank driver it will be a bit harder to reach the bar because there is no coating on it, but it's not that hard.
And remember, a torsion bar requires no maintenance as long as it doesn't snap, and since most of the work is done on the surface of the bar/spring, an external spring element can be taken out over time by enemy fire, thrown rocks and what have you. A TB doesn't.
Now, it's true that removing TBs bent by a mine is a PITA that requires a factory job BUT: if a mine bent your TBs then the hull itself requires factory work or will be written off anyway, it's not dependent on the suspension type. By the way a 9.5kg mine with 50/50 RDX and TNT that explodes under a T-54's track will lose a wheel and swingarm.
A Chieftain that runs over a 8.9kg TNT mine: hull breached (pictures are too large sadly).
So much for easy maintenance.
