Chamberlain RJO20 and EZ-Set springs

[herbiethemisfit]

One of the torsion springs broke on my 16x7 garage door last weekend. Decided to replace with the EZ-Set torsion springs from Menards based on past (good) experience. Bought the conversion kit which includes the drums, winding unit, brackets, etc. Decided to use 2 springs so I purchased the additional winding unit. I was able to reuse the existing torsion tube/shaft. Everything installed fine.

Also decided to replace the old Genie screw drive GDO with a jackshaft opener. Menards carries the Chamberlain RJO20, which I believe is identical to the Liftmaster 8500. Picked one up (11% rebate!) and installation of that all went fine.

Opener works great. Is nice and quiet. The only issue I have is that it is slow. Way slower than the old opener. I haven't timed it yet but it is probably pushing 20 seconds. So my first question - is that normal? Did a fair amount of searching the forums but couldn't find anything specific.

My second question is regarding drum size. The EZ-set kit came with new drums that are about 3" in diameter. The original drums are 4". Any issue with swapping back to the 4"? That would give me about a 25% increase in speed. I would obviously unwind the springs, do the swap and then wind them back up. I believe I would have to wind them a bit tighter to compensate for the larger pulley.

 

[herbiethemisfit]

FYI - I attempted to swap the drums this weekend but they did not fit. There is not enough clearance with the EZ-set winder/bearing bracket. Switched back to the smaller drum (which is closer to 2.5" than 3").

Only option I see to speed it up is to go to a sprocket/chain setup with 2 different sprocket sizes.

 

[xavier296]

I just installed an 8500 on my high-lift garage door, and I agree that it is much slower than the original setup with a normal height door and liftmaster chain-pull motor. I just figured it is the price I pay for a high-lift.