4 Post over or under racetrack

[bornbadbob]

Possibly one of the dumbest questions out there but I see pics that show a 4 post under racedeck and some that look like it is on top. What is the correct method, I have always assumed a lift should be in direct contact with the concrete, am I wrong?

 

[finn]

Lots of lifts out there on top of some sort of pad. There’s a current thread on controlling rust on the post baseplate that gets into it.

 

[Skooterj]

I would think that if your flooring was designed to be driven on, you could put the lift on top of the flooring also. The flooring will only see the weight of the car and the weight of the lift spread out over the 4 legs bottom plates. I bet that works out to be less PSI that the PSI of just the car via the contact patches of the tires.

Lets run the math...tire contact patch is usually between 25 and 50 square inches. Average car weight is 4000 lbs. So 4 tires, 1000 lbs each divided by 50 square inches = 20 PSI

4 post car lift weight is about 1000 lbs. Contact patch size is 144 square inches(12x12). So, with car, 1250 lbs per foot divided by 144 square inches = 8.7 PSI

 

[kbuhagiar]

Possibly one of the dumbest questions out there but I see pics that show a 4 post under racedeck and some that look like it is on top. What is the correct method, I have always assumed a lift should be in direct contact with the concrete, am I wrong?

Six of one, half a dozen of the other...

My preference is to have some sort of rubber isolation pad between the post and concrete.

Although it is an excellent product and could support the weight, I would be concerned with the 'slip' factor inherent to the Racedeck tiles.

 

[kngelv]

Six of one, half a dozen of the other...

My preference is to have some sort of rubber isolation pad between the post and concrete.

Although it is an excellent product and could support the weight, I would be concerned with the 'slip' factor inherent to the Racedeck tiles.

I have been driving vehicles on my 4-post lift for over a year and have not had any slippage issues on my RaceDeck floor.

James