Review
I will post here for both the FGMT and FireHammer just because it is easier.
FGMT
I love the adapters and what they allow us FG owners to finally have affordable and more tires to choose from. Gearing is slightly lowered when using the adapters and you may want to change to the Stadium truck gearing when using HPI tires. I did not find enough of a gearing difference at this time to justify the change.
Here is what I noticed with the adapters when I fitted them on the FGMT.
I would recommend that the adapters come with their own grub screws and not reuse the old ones.
Three of them fit well but the anodizing in the inside of one made it really tight. They also work with or without front cable disk brakes.
I also found that the stock axles are not all the same length and a bit of filing or Dremel work will need to be done to the end to shorten them enough so that the adapters will fit without any play.
FILING AXLE END:
The front square of the MT is slightly longer then the rear one and has a slot cut in it to hold the optional front disk from moving toward the rim. The square’s extra length is also to make sure the wider tires not make contact with the front arms.
REAR:

FRONT:
If you only want to use the stock HPI front tires that are thinner in width this set up works like a charm.
FRONT HPI’S:
If you would like to run HPI rears on the front another set with a longer square to push the rim farther to the outside will be needed to allow for the rim/tire to clear the front arms without hitting.
REARS ON FRONT:
YOU CAN SEE THE SPACE ON THE OPPOSITE TIRE STOP:
I tested these in the alloy front uprights and the stock plastic uprights with the same findings.
PLASTIC AND ALLOY UPRIGHT:
I’m not to sure the groove for the disk would be needed since the breaks would hold the disk in place and make it difficult for the disk to hit the rim.
ALLOY SET STOCK SETUP:
Here is the slight change that would need to be made to allow the rear HPI’s to fit the front. You will see in the following photos that the tire needs to be pushed out to clear the arms.
BRING THE TIRE OUT AND YOU WILL CLEAR THE ARMS:
Overall the adapters do exactly what they are marketed to do “Allows you to use the HPI set up on your MT”.