The ‘maximum weight’ stated on the sizing guide is the weight of the crash-test dog that was used during crash-testing. Each harness can withstand higher loads; however, the maximum loads have not been dynamically verified. The loads that are imposed during a collision are a combination of speed, stopping time and the weight of the dog.  If your dog fits the dimensions (A & B) for a of harness as per the sizing guide but your dog’s weight is higher than the recommended maximum. Options include: - Purchase the next size up harness size with a larger weight limit and request custom strap sizing during the purchase process. - Purchase the harness with the lower weight limit. Please send an email to contact@optimusgear.com so that we can ensure that you understand the caveats of the design and testing that come with this. If you exceed the ‘maximum weight’ by less than 10% please contact us. If you would like to discuss any of these options in more detail, please send an email to contact@optimusgear.com.