(Answered) Frankenmechs and speed

[CloaknDagger]

pg 289

Maximum Tonnage: The FrankenMech’s weight limit is determined
by the tonnage of the donor ’Mech from which the
center torso was taken. Physical attack damage is based on
the FrankenMech’s tonnage—not the tonnage of the donor
’Mech from which it got a specifi c limb.

Engine: While almost any engine can be used, the FrankenMech’s
maximum tonnage dictates its performance.
Divide the engine rating by the maximum tonnage and
round down to fi nd the Walking MP. Calculate the Running
MP as normal.

So to clarify, if I have a 60 ton mech Center Torso as the basis of the mech, the speed calculations are based off that of a 60 ton mech even if at the end the mech comes to less that 60 tons in total?

So using using a rifleman's CT, and legs, but everything else from a commando, and a total weight of 35 tons, I calculate the speed as if it's a 60 ton mech, not a 35 ton mech?

[Xotl]

Correct.  The base chassis of an Omni doesn't move any faster than the fully loaded versions, either.

Think of it as not just the engine that has to be able to deliver the output, but also the myomers and actuators must be able to perform the faster movement, which they simply can't, and all other moving parts must be able to withstand the increased stress coming with faster movement, which they don't.

The actual out-of-universe reason is purely balancing, though.  Otherwise people could create underweight 'Mechs and just claiming that they now move faster.  To prevent things like that, the rules are as strict as they are.

[CloaknDagger]

Correct.  The base chassis of an Omni doesn't move any faster than the fully loaded versions, either.

Think of it as not just the engine that has to be able to deliver the output, but also the myomers and actuators must be able to perform the faster movement, which they simply can't, and all other moving parts must be able to withstand the increased stress coming with faster movement, which they don't.

But you can still use a smaller CT and larger legs. So the myomer explanation doesn't really make sense. And really, the reinforcement doesn't either. It's just an engine swap to speed up a mech, so regular structure can handle a lot of speed.

The actual out-of-universe reason is purely balancing, though.  Otherwise people could create underweight 'Mechs and just claiming that they now move faster.  To prevent things like that, the rules are as strict as they are.

I always thought that the explanation for the reason mechs don't speed up as they take damage is because the gyro is set for fully loaded regular. But in this case, since it's in the repair bay, you would be able to set the gyro to compensate.

But here, I don't really see what the problem is, since a 35 ton mech is a 35 ton, even if the CT is heavier than usual.

How is that different from a 35 ton mech with a regular 35 ton CT and 60 ton legs?

[Xotl]

Honestly, it's a pure balancing mechanic.  All in-universe explanations were invented after the fact, simply to give you something to work with.  In-universe fluff and physics do not factor into rules, because rules are there to make the game work and keep it fair, not to mirror what could actually be done in the real world.

These forums are to ask questions about how the rules work.  If you want an explanation as to why, you would have to ask in the "Ask the Writers" forum, but as this isn't really a vital element, you're likely to get a handwavium answer.

I hope this is still of some help.