The Liftmaster 8500 jackshaft sidemount opener is an engineering marvel – freeing up valuable overhead space while reducing clutter in your garage. Instead of the standard drawbar and motor ceiling installation, the 8500 mounts on either side of your garage door and directly turns the torsion shaft.

When building a garage work shop or garage man cave maximizing space is important. If you are like me, you probably have your garage cluttered with junk that rarely gets used. Then to top it off you look up and see an ugly garage door opener, punch angle iron, wiring and track hanging down from the garage ceiling.

Luckily, a new type of garage door opener exists to eliminate all of these issues. This opener will eliminate the eyesore in your garage and free up a ton of storage space. Lets take a look at the Liftmaster 8500 model opener and all that it has to offer.



1. Jackshaft Installation Requirements

Liftmaster 8500W Jackshaft Sidemount Opener
8500W Jackshaft Opener Purchase Link

First, lets get into who can actually utilize the low profile design of the opener. The 8500 comes with some manufacturer headroom requirements that can’t be ignored. Whether you will need an opener for new construction or retrofit, here are some of the basic requirements to install the operator.

Based on the size of the DC motor and drive mechanism in the 8500 it can support a garage door of up to 14ft tall, 18ft wide, 650 LBs or 180 square feet. Installing the operator on an overhead door that is over of these requirements will void your warranty and possibly damage your machine.

Since the 8500 is a shaft driven opener vs rail driven you must have a standard (not low clearance/headroom) torsion spring setup installed. This also has to do with the way the springs are wound. On a low clearance setup the torsion springs flip sides and are wound opposite.

Extension springs that stretch along the horizontal tracks are not compatible with Liftmaster’s 8500 operator either. Not only do they lack a main drive shaft, but they also are an unbalanced system. I have seen people make some crazy modifications involving sprockets with extension spring doors, but its best not to attempt these workarounds.

There are some Youtube heroes out there that will tell you to mount the 8500 upside down and don’t use the cable tension monitor. I wouldn’t advise this type of installation because of manufacturer specifications. You also cannot install this operator on Wayne Dalton Torquemaster doors. Again, this operator requires a standard torsion spring counterbalancing system.


2. Required Headroom

So now that we have established that you must have a torsion hardware based garage door lets look at the dimensions of the machine itself. Per manufacturer specifications the 8500W is 21.25″ in height, 7.5″ wide and has 7.9″ of depth. The older model 3800/3900 jackshaft opener is 16.25″ inches in height, 6.01″ inches wide and has 6.85″ inches of depth. Based on these dimensions we can conservatively make some key assumptions. The drive mechanism is based on the torsion shaft of your garage door entering the opener casing.

The top of the 8500 opener will sit 3″ above the top of your shaft. In other words you will need to have at least 4″ of space above the top of your torsion spring shaft.  Depth is rarely a problem with this machine unless you have installed temporary ceiling shelving or a storage rack. Make sure you also have 7″ inches of space projecting outward from the header area.


3. Required Sideroom

Most people have plenty of depth in their garage, however sideroom is sometimes a problem. From the inside of the door jamb on either side of your garage door you will need a minimum of 10 inches of space to the side wall. For the older model 3800 you will need 8″ of sideroom space.

The casing of the operator is 7.5″ inches wide with a small 2″ extrusion (shaft collar) where the torsion shaft runs through the casing. Keep in mind your torsion shaft must extend 2″ past the end bearing plate fixture, as this shaft will enter the casing of the 8500 operator via a special shaft collar.


4. Power Source Outlet Within 6ft

Be sure you have a 3 prong wall outlet near the upper right or left hand side of the garage door frame. A 6ft plugin line cord is included with the 8500 operator. The cord has a 3-prong connection head and requires 120V AC 60Hz.

Make sure in the case of new construction that you ask about an outlet being installed in the vicinity of the operator. Most builders will only include a wall outlet where a standard drawbar opener would plug in. If you don’t have an outlet near-bye its recommended that you contact a trusted electrician to wire an outlet for you. As a temporary solution you could run an extension cord to the closest wall outlet.


5. Cable Tensioner Pusher Springs

Garage Door Pusher Spring Bumper 15"
Pusher Spring Bumper 15″

An optional accessory you can use to help maintain cable tension is called garage door pusher springs. Jack shaft operators usually require a downward acting force to function properly. Wall mount openers from Liftmaster come with a built in cable tension monitor. This device helps to maintain cable tension during the start of open and close cycles, when cables are most likely to slack.

Maintaining tension helps prevent cables from slipping off the drums. I wrote an article describing how Pusher Spring Bumper Installation Helps Prevent Cables Coming Off Drums. It offers valuable advice on pusher spring sizes, compression and how to install them.

Cable tension should be similar to that of a stringed musical instrument. In the event of your wall mount opener repeatedly throwing cables, residential pusher springs can be installed at the end of the horizontal tracks to push against the top section of your garage door. This prevents the door from jumping during starts and stops.


6. Change Track to 15″ Radius

The radius of your garage door track is the the curved portion near the header. Most doors come with standard 12″ radius horizontal tracks. This track radius is definitely compatible with wall mount shaft drive openers, but not optimal. Consider switching to 15″ radius track (or more) –  the extra curve results in smoother operation.

The extra 3″ of track radius seems to help reduce the occurrence of cables being thrown off the drums and also prevents continuous force and limit adjustments. 21″ radius track is also compatible with the 8500W garage door opener. If you are just in the planning stages of your new garage door and opener ask your local door professional about a larger radius track option. If your door and opener is having problems throwing cables, you may consider retro-fitting it with a different radius track (15″ R or 21″ R).


7. Upgrade To 13-Ball Nylon Rollers

Garage Door Nylon Roller Sealed Cap
13-Ball Nylon Rollers

From my past experiences I would highly recommend using nylon 13-ball bearing rollers or precision bearing rollers with the 8500. If you are replacing an existing opener, we recommend replacing worn out rollers. It is crucial that the rollers operate smoothly around the radius curve of the track.

Worn out rollers will slide and grind instead of the smooth rolling operation needed for the 8500 to work properly. Some of the cheap builder grade black nylon rollers without ball bearings won’t get the job done. A small investment in new wheels will save you money down the road.

Important: Make sure your garage door is installed per manufacturer specifications. Also make sure that the door operates smoothly without jerking, popping or grinding. If the door doesn’t operate smoothly as is the 8500, 3800 or 3900 will not help the situation.

It is best used on doors that already run smoothly and have well balanced spring tension. Installing the 8500 on a sub standard installation will cause the operator to throw cables and lose limit & force settings. 


8. 8500W Installation Requirement Checklist

  • Maximum Garage Door Size: 14ft Tall , 18ft Wide or 180 Square Feet
  • Maximum Garage Door Weight: 850 LBs
  • Minimum Sideroom: 10″ Inches to sidewall
  • Minimum Headroom: 4″ inches above torsion shaft
  • Minimum Depth: 8″ depth space
  • Hardware Required: Standard Torsion System Only (Not Compatible With Low Headroom Kit)
  • Torsion Bar/Shaft Must Extend 2″ Past End Bearing Plate
  • Standard Wall Outlet : 120V AC 60Hz  – 6ft of Line Cord 3-prong


8.1 Optional Recommendations

  • Rollers: Nylon 13-Ball Bearing Rollers
  • Pusher Springs (Optional)
  • 15″ Radius Horizontal Track (Optional)


Does your garage door setup meet all of the requirements above? Great! Lets continue on…


9. Jackshaft Opener Lift Configurations

The 8500 operator can be installed on all standard torsion hardware door installations, but its best used on a few special applications that take space saving to a new level. Four main applications can be used with the Liftmaster side mount opener.

We all probably know about the standard lift torsion application with a shaft that is mounted just above the header level. Most people don’t know that three other applications called high lift, follow roof the pitch and full vertical lift. These special applications unlock the full potential of jack shaft operators.


9.1 High Lift Installation

Lets say for example that you measure 48 inches of space from the top of your door jamb to the nearest obstruction (ceiling). You have a few installation options in this scenario. Inexperienced garage door contractors will try to sell you a basic garage door opener installation with a rail and arm kit.

They will run 4ft worth of punch angle down from the ceiling along with all of the wiring and other equipment. Not only is that an eyesore, but its incredibly unprofessional.  In fact, I wouldn’t even install this type of setup without the customer signing off on the job or some special circumstance.

What if i told you it was possible to hug your garage door tight to the ceiling and mount your opener on the side of the door instead of the back end? This would free up the clutter above and maximize space in your garage. It is accomplished using a high lift kit, which extends the vertical track further up the header before curving.


9.2 Follow The Roof Pitch Installation

The third most common application is called follow the roof pitch (FRP) and is used in situations where garages have scissor trusses or vaulted ceilings. Instead of the horizontal track radius curving flat overhead it curves to follow the pitch or angle of the ceiling. Best of all, follow the roof pitch can be combined with a high lift kit. The result is a garage door that moves vertically up the wall above the header, then begins to curve with the roof line. Jack shaft openers like the 8500 are perfectly suited to handle these special installations.


9.3 Full Vertical Lift Installation

Its not very common to see a door with more headroom than the height of the door on residential homes – otherwise you would just install a taller door. Instead this track configuration is more popular in warehousing and industrial buildings. Jackshaft openers are best suited for Full Vertical Lift (FVL)

In order to install full vertical lift track you would need the height of your current garage door plus 18 inches. In other words, if you had a garage door opening that was 8ft tall, you would need 9 ft 6″ above the opening for a total of 17 ft 6″ of total floor to nearest obstruction space. This is done to prevent things like fork trucks from accidentally hitting low hanging garage doors.


10. Maximum Cycles Per Hour

The light duty wall mount operator is designed for residential and light commercial use. The opener carries a maximum cycles per hour rating of up to 10. This means you should only run the door up and down 10 times in a given 60 minute period. Using the operator more than the cycle rating could cause the machine to overheat, damaging internal components. It will also void your warranty with Liftmaster.

Keep the cycles per hour rating in mind for the installation application. If you are planning on opening an oil change center or car shop that requires the door to be opened and closed constantly throughout the day, this probably isn’t the machine for you. It may require a full commercial grade continuous duty opener.


11. Jackshaft Opener Model Variations

Chamberlain Liftmaster had three distinct side mount jack shaft driven opener models to choose from. The newest model is the 8900W, which features a built in WIFI This allows the user to control the door opener using a WIFI enabled device like a smart phone. The 8500W is considered third generation technology – improving upon the its predecessors models 3800 and 8500.

So if 8500W is the newest model, why are models 8500, 3800 and 3900 still available online? Chamberlain gave professional door dealers notice that the 3800 would be discontinued, but they still had remaining inventory to be sold and so did many dealers. A few large door companies purchased the closeout items for re-sale online and some still had inventory to sell through anyways.

  • Liftmaster 8500W (WIFI & MyQ Enabled)
  • Liftmaster 8500 (MyQ Only)
  • Liftmaster 3800 (Older Jackshaft, No MyQ/WIFI)
  • Liftmaster 3900 (Stripped Down 3800, No Remote/Lock/Accessories)

Nothing is inherently wrong with the older machines. In fact they are an outstanding value and many customers believe they work as well as the newer model. The main difference between the operators has to do with the MyQ technology being built in to the 8500 product line along with the WIFI on the newest operator.

With overall trends toward smart home technology Liftmaster felt it necessary to get ahead of the technology curve, but the drive mechanism, lock feature and photo eyes are all the same. The older models can also be retrofitted with special wall controls to function just the same as the newer versions.

Actually, the older 3800 model is compatible with built in Homelink in older model vehicles as a standard unlike the 8500. This eliminates the need to purchase a special product called a repeater to sync up the device to your vehicle. So if you have a car manufactured between 2000-2009 there is a higher chance that the 3800 will be compatible with your version of homelink than the newer 8500 model standalone.

So how does the Liftmaster model 3900 fit into all of this? Well, the 3900 is basically the same as the 3800 with a few differences. The 3900 is a stripped down version which only includes safety photo eyes and one remote control. The external lock, remote light and upgraded wall control are not included with this special online models. Its basically the same machine minus all the added accessories that many people don’t want. Older models are becoming increasingly hard to find as inventory from major distributors runs out.


12. 8500W Wifi Accessories

Do you want to be able to operate and monitor your garage door opener from anywhere in the world with just a WIFI connection? If you answered yes then you definitely want Liftmaster’s newest wall mount opener, model 8500W. With MyQ technolgy and built WIFI you can do just that and more.

You can make sure your garage door is closed and open and close it for guests, all from your computer or smart phone. The 8500W also includes accessories like the battery backup feature so you can operate the door during bad weather in case of a power outage. Here are some of the accesories that can be used with your 8500W opener.

Included Accessories

  • MyQ Remote LED Light (827LM) Operates automatically with the opener and works with the MyQ App.
  • Integrated Battery Backup (485LM) Operae your garage door opener during a power outage.
  • Automatic Garage Door Lock (841LM) Locks the door using a track latch mechanism.
  • 3-Button Remote Control (893MAX) Use on a maximum of three garage door openers or MyQ Light accessories. Compatible with any Chamberlain LiftMaster Garage Door Openers manufactured after January 1993.
  • Smart Control Panel® (880LMW) LCD wall display with various setting adjustments.

Optional Accessories

  • Mini Universal Remote Control (374UT) A universal remote control in a smaller size.
  • Wireless Keyless Entry (877MAX) Opener the door using a 4 digit passcode from the outside.
  • Remote Light Control (825LM) Control any light using a remote control or smart phone through the MyQ app.
  • Garage Door and Gate Monitor (829LM) Monitor and close up to four garage doors or gates within range.
  • Laser Parking Assist – (975LM) A laser marker vs a haning tennis ball for parking assistance.
  • Surge Protection – (990LM) Protect your opener or device from power surges during a storm.


Homelink Repeater Bridge 855LM
Homelink Repeater Bridge 855LM

Under certain circumstances your side mount jack shaft opener won’t be compatible out of the box with specific built in home link devices in some vehicles. Car manufacturers haven’t released a master list of vehicle models or years that require repeater accessories. They consider that information proprietary for unknown reasons.

For that information you will have to look through your owners manual. Homelink systems have an icon that looks like the outline of a house. If you have tried programming your vehicles homelink system to your garage door opener without success its likely you will need a repeater.

You might be wondering why the 855LM accessory wasn’t included with the standard accessory opener package. Chamberlain had no way of determining what car purchases would match up with their openers.  They didn’t know if that vehicle owner would want to use homelink vs the traditional visor clip on remote. Chamberlain also didn’t know if everyone who bought a homelink enabled vehicle would use their garage door opener. Too many variables existed so they elected to exclude repeaters from the standard accessory package, saving millions in the process. Auto manufacturers didn’t help out much either leaving a battle as to who was responsible. I’m actually surprised a major lawsuit hasn’t come about as a result of this fiasco.


  • Homelink Repeater – (855LM) – Sync your homelink enabled vehicle to your garage door opener.
  • Car 2U Repeater (CAR2U RPTR) – Sync your Car2U enabled vehicle to your garage door opener.


14. 8500W Opener Cost

The new Liftmaster premium series opener carries a well above average price tag. Back when we first wrote this article in 2009 the cost was closer to $400 for the 3800 model. Prices have since gone up significantly with the release of the 8500W WIFI enabled smart opener. Most garage door professional dealers will retail this operator around $600 per unit plus tax.

To give you some perspective, a basic builder grade chain drive opener costs $150. On a relative basis I would consider this operator on the high end of residential range. However. the fact that it can handle light duty commercial doors and specialty track applications justifies the added cost. Although Lifmaster bases its warranty on years instead of cycles, you can be certain the 8500 premium series will last much long than a builder grade opener – the kind you have probably seen at big box stores.


15. Side Mount Opener Building Applications

I already covered how important jackshaft operators are for 3 specific garage door track applications, so now I feel its important to cover special building applications. The main advantage of the side mount operator is that it eliminates the need for an operator rail and motor hanging from center of the ceiling. This makes the the 8500W perfect for installation on full vision glass doors. Doors with glass in every section are obviously easier to see through, so using a jackshaft operator is a must.

Another advantage of the opener is how quiet it operates, being equal to Liftmaster’s belt drive series. This also makes it perfect in residential applications where a bedroom may exist above the garage or share a side wall. Lastly, rare occasions exist where obstructions are present in the middle of the garage where a traditional bar operator simply wouldn’t work.

It is also capable of mounting to either side of your garage door in the event of an obstruction or personal preference. Side mount openers are extremely popular on high end homes, man caves and pole barns. They successfully bridge the gap between the 10ft and 14ft door heights – a range where standard residential openers aren’t quite strong enough & commercial duty openers are overkill.


16. Voiding Your Warranty

This operator comes with a generous warranty to protect your purchase. It comes with a lifetime motor warranty which sounds great, but is actually pretty useless. In over 10 years as a garage door professional I ran across maybe one instance of a defective motor.

Next you get a 5 year parts warranty, which is definitely important considering in past years there have been some issues with the absolute encoder and travel modules. Those issues look to be resolved as Liftmaster issues future product upgrades and releases.

Finally, the operator comes with a 1-year standard accessory and battery backup warranty. You can count on the battery lasting a year, but not much more than a few years. Be sure to look at the dates on your battery pack to make sure you weren’t given old battery inventory in the first place. Sometimes components can sit on warehouse shelving for years before being sold.

Although Chamberlain offers an attractive warranty program there are ways you can void your warranty. The most obvious is ignoring the door dimension and weight guidelines of,18ft max door width, 14ft max door height and 650 LB max door weight.

Since the opener is considered a light duty commercial machine it can only operate 10 cycles per hour. As mentioned earlier, installing the machine in any fashion other than what is specified in your owners manual is grounds for a voided warranty. This includes installing the machine upside down or using extra sprockets and gears. It also includes using one opener to operate two doors simultaneously.

Lightning strikes during storms that create power surges can fry electrical components like the logic board, which also voids your warranty. A faulty power source can also damage internal parts. Finally and most importantly, improper door installation – which includes a wide range of possibilities such as installing the wrong springs on your door.

If you suspect you have a faulty part or defect you can claim your warranty by calling Liftmasters hotline or consulting your local Liftmaster Dealer. Do not file a fake warranty claim. Not only is it morally wrong, but often times parts and openers must be sent back to Liftmaster for examination and testing.


17. Cost vs Performance

You get what you pay for is a phrase I have heard my whole life and it certainly applies to the Liftmaster 8500W wall mount opener. The operator can be installed on most residential garages, but is versatile enough to be used for special applications.

The power, quietness and versatility of this opener is what makes it so popular among do-it-yourselfers and door pros alike. If quality is what you are looking for that is what you will get with this machine.

I have read hundreds of reviews from happy customers online and have personally sold several thousands of these operators over my 10-year career as a garage door sales professional.  The 8500W is the best shaft driven operator out there putting Wayne Daltons idrive competitor out of production.