If someone know which bearing Tracy use on prop shaft if yes
 what brand,ball or roller and
 bearing number



 Jean Prudhomme

 I don't have it here but I think it is a 1.3875" ID and
 the OD is 3.350". It is .75 inches wide. Double sealed.
 Inch series. Probably a Chevy Pick up truck rear wheel bearing.

 Search the internet for ball bearing makers and give
 them the dimensions.

 Paul Lamar


 Do you know if is a roller trust bearing or ball trust bearing??

 When you have a chance could you send me the bearing number and brand

 Jean Prudhomme


 It is a ball bearing Jean. The Chevy Truck has a lot of
 side load on the rear wheel while cornering so it must be
 a combination of axial and radial load.

 I am getting ready to go to Germany
 so I may not get out to the hanger for a couple of weeks.
 Try to find it on your own. Start with an auto parts store.
 Just measure the bearing they bring out and if the dimensions
 are correct that is the right one.

 Ball bearings are ball bearings.

 Paul Lamar


 Paul
 Your statement that ball bearings are ball bearings.
 "It aint necessarily so".
 It's over 40 years since as a design engineer I designed bearing systems but
 if my memory serves me well there are deep groove ball bearings that have
 greater axial load carrying capabilities than the standard type. If this
 particular bearings is required to take high axial loads then I would be
 surprised if it wasn't a deep groove type. Care needs to be taken in
 selecting the correct bearing for this application
 Bob Izett -Perth, WA

 Well yes that is true and I totally agree but any rear axle bearing
 THAT size will work. Tracy's prop shaft is an actual section of a GM rear
 axle. The side loads on the rear axle are similar to the thrust loads on
 a prop shaft. In fact the retainer for the ball bearing is the same
 way GM retains the rear axle ball bearing. Namely it is pressed on.

 Tracy has sold well over 100 gear boxes with many of
 them flying for the past 10 years so it must be OK.

 There is nothing seriously wrong with it but it could be designed
 to be as strong yet lighter in weight. The bearing itself is very
 heavy being over 3 pounds as I recall.

 I should have said a rear axle ball bearing is a rear axle ball bearing.


 Paul Lamar

Jean Prudhomme wrote:
 I am using an axle shaft of 1.771" dia for the inside dia  bearing and i intend to use a TIMKEN TAPER ROLLER BEARING # U497  O DIA 3.148" this bearing as been use on high torque axle with 35 splines

made of aircraft 300M material also gun drill 1" bore true.

 If someone have the information on Tracy bearing to find the spec,s before i finalized my housing,the prop will be almost on pushing load.



 Jean Prudhomme

That shaft and bearing size is way overkill Jean. About 18,000 pounds.
You are not launching the space shuttle :) Way over weight.

If you are going to copy something copy the Ross. It has been flying for nearly
40 years and is ten pounds lighter than Tracy's box.

It uses light weight needle bearings and has a 2 inch hollow shaft.

Paul Lamar