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Model 3’s traditional multi-part steel
rear sub-assembly construction, while
full replacements saved £519. Similar
patterns emerged when comparing
against other manufacturers’ vehicles,
with the Model Y demonstrating
lower repair costs than other models,
including the Mercedes EQE, Hyundai
IONIQ 5, and several internal
combustion engine vehicles.
“The key insight from our testing is that
vehicle manufacturers must integrate
repairability into the design of a mega
cast component,” explained Darren
Bright, Principal Engineer, Automotive
Repair at Thatcham Research.
“In Tesla’s case, the inclusion of
replaceable cast rear rail assemblies at
just £31 each provides a cost-effective
solution for minor impacts, while the
relatively low cost of full replacement
mitigates concerns about more severe
damage scenarios.
Tesla’s repair guidelines establish
industry benchmark for mega
cast repairability, though some
technical gaps identi昀椀ed.
implementation will replace 177
components across front and rear
castings, while Volvo’s single-昀氀oor pan
cast will consolidate 100 components.
INDUSTRY IMPLICATIONS
“Tesla has established important
precedents for mega cast repairability,
but our research highlights
areas requiring industry-wide
standardisation,” notes Billyeald.
“As this technology proliferates,
establishing comprehensive repair
protocols, non-destructive test
procedures, and technician training
programmes will be essential for
maintaining vehicle safety, insurance
and lifecycle sustainability.”
The mega cast chassis has important
implications for sustainability. In
practical terms, lower repair costs
mean that damage which might have
resulted in a total loss on a traditionally
constructed vehicle is now more likely
to be economically repairable. Fewer
write-offs translate to more vehicles
remaining in service after collisions,
preserving the energy and materials
already invested in their manufacture
and delaying the environmental cost of
early replacement.
Thatcham Research’s 昀椀ndings will
inform the development of repair
guidelines, training programmes,
and industry standards as the UK
automotive sector prepares for this
technological shift. The organisation
is developing comprehensive
documentation to enhance the
industry’s existing understanding
of mega cast implications and will
continue to monitor and evaluate new
mega cast implementations as they
emerge in the UK market.
Without this provision of reasonably
priced partial and full replacement
parts and the associated repair
procedures, our 昀椀ndings would have
been very different.”
With manufacturers including Toyota,
Volkswagen, Volvo, and Hyundai
announcing mega cast implementation
plans, the research provides essential
benchmarking data. Toyota’s planned
TESLA MODEL Y TESTING DEEP
DIVE
In low severity testing at 15km/h, the
mega cast exceeded expectations
Research conducted with real-world claims
data from UK insurers and Allianz Centre for
Technology (AZT) Germany.
by sustaining no structural damage,
allowing complete vehicle repair
without any work required on the mega
cast component itself. These 昀椀ndings
challenge initial industry concerns
about the vulnerability of large
single-piece castings to minor impacts.
Medium severity testing at 25km/h
necessitated full mega cast
replacement due to crack propagation
and structural misalignment.
However, at £716 for the replacement
component, the total repair cost
remained competitive with, and often
below, traditional repair methods for
equivalent damage.
The research highlighted key
considerations, including the fact
that repairs requiring welding of the
aluminium mega cast structure must be
conducted at Tesla-approved facilities,
raising questions about repair network
capability as the technology becomes
widespread. This requirement could
necessitate vehicle transportation
between repair centres if the initial
facility lacks appropriate certi昀椀cation,
potentially adding time and expense
to the repair process. Additionally,
the scale and irregular shape of these
mega cast components present
handling challenges for smaller body
shops.
The study underscored the importance
of implementing clearer
non-destructive testing (NDT)
procedures to effectively identify
potential damage in the mega cast
structure that may not be visible to the
naked eye. This enhancement would
ensure a more thorough assessment
and safeguard the integrity of the
structure.
The full research report is available
to Thatcham Research members
and includes detailed technical
speci昀椀cations, repair cost comparisons,
and recommendations for insurers
and repairers preparing for the mega
cast era.
JOURNAL
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