Ok I give, what do the letters mean?

Type AR, ARA, & ARSA? I know these don't have nose rings

Type ARI, RIA, ARISA & RISA I know these do have built in nose rings.

What are the abbreviations?

Some have two bolts?
Some have 4?
Some have alum beams and some don't?

Hyde A type mounts are normal or typical type engine mounts. These have beams for the engine to sit on....this is where the "A" comes from.

The B type mounts are "BackPlate" type mounts. They don't attache to the engine beams they moutn to a backplate...Think DA150 or even G62 or Tartan's like the TOC guys used to fly...


Ok now for the rules.
A = bigger disk stiffer no nose ring required

AR ="A" type "R" is for nose ring required

ARA= "AR" like above with the second "A" means it has aluminim beams

ARSA= same as the "AR" above but is a Shear axis limiting mount. This means it has a mount within a mount to keep the front and rear plates from shearing against each other. Basically the mount is built with another hockey puck in the middle to keep the front and back from moving sideways of shearing. And this one should have Aluminim Beams because of the last "A"

ARI mounts have the Nose ring incorperated. Hence the "I" So its an AR mount with a built in nose ring.

The you have the ARI with the "S" for Shear axis limiting mounts. Basically that is it.

I don't think there is a RIA or an RISA unless these are the latest mount for electrics. I know Merle has been making some Electric mounts. And its been a while couple of years since I needed a new mount. perhaps he is making a new style mount. Merle will amke anythign you want just talk to him and he'll kick it out ASAP. I have him amke my mounts pretty soft. This measn the Shear Axis limiter is important to me. If you run his normal mounts I would say its not needed.

There really is little difference in the 120-140-160-170 mounts. Its just stiffer as the engine gets bigger to reduce the movement. I run my 160's and 170 on mounts about as soft as the 140's or maybe a little softer.In some cases Merle makes the hockey puck bigger to help distribute the load to the rubebr and absorb the vibes. My opinion is the more the engine moves the more vibration is being absorbed by the mount and its rubber element.

Now he makes the "C" mounts these are composite type mounts that are stiffer. The Aluminum Beams on these catch all 4 mounting lugs....Merle will actually sell the beams to you and you can switch out the single bolt hole versions if you don't like them.

I personally have never had an issue with it. I use Blue locktite on the bolts and tighten up with a big "T" handle...I think in the past 6-7 years or running the mounts with type of beams I might had once maybe twice an engine come loose. And the bolt didn't fall it it just got loose and I notice it...stopped and tighten up.

Troy