Subject: TRACY END PROP SHAFT BEARING
From: Rotary Engine
Date: 4/1/2010, 5:48 PM
To: AAA Put this in the To box


 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
 Hi Jean,
 Years ago when Tracy first started making PSRU's, I recall his website blog telling the
 story of
 several bearing failures. The bearings were of similar physical size but were from different
 manufacturers. This is a sealed bearing which means whatever lubricant the manufacturer
 put in is there for the life of the bearing. So maybe he stumbled on a lube difference.
 Bearings are
 manufactured to different tolerance classes. So maybe he stumbled on the wrong class of
 bearing
 a few times. The bottom line is why should you remake his mistakes? Just buy the bearing
 from him.
 If his axle supplier can get it and press it on, then he can get one for you. Sure he'll
 mark it up, but so will
 the auto parts dealer. At least with Tracy, you'll get the correct bearing and the markup
 profit will
 support someone who supports the rotary. Dave M


 I don't recall that was the prop bearing. As I recall it was the helical
 gear thrust bearing. Apples and oranges. I have the emails.

 I challenge anybody to show me two bearings of that EXACT size double
 sealed that have significant differences.

 Paul Lamar

    
I already contact a drive shaft manufacturer and i need a shaft of 24" long for my drive and they can make it for $600.00 for a ligt weight shaft with 1"dia gun drill shaft estimated at 8.5 lbs
with a 45mm bearings but if i can get to 1 3/8 shaft with tracy exact bearing it will be fine.

I already contact Tracy to have the shaft i need and he said it will be to expensive .

 I can reuse his housing to attach to the shock mount plate.

I do have all the parts on hand to built my angle drive at 3 to 1 ratio and i should assemble it as soon i solved my bearing and shaft problem
I do have an aluminum spool with 28 splines and i need to rebrouch to 31 or 35 splines.

I can buy a rought housing from Tracy and do some machining to suit my shaft but i can by pass his housing to have a lighter housing by using 2"I.D. x 3" O.D. and weld stiffner rib of alum 1/4 thickness to the gear end housing

and it will be on one pce instead 2 parts with Tracy Housing lighter.


Jean Prudhomme                   


You cannot put a prop on the end of a 24 inch shaft. It is against the
laws of physics. It is just not a bad idea it is the LAW. The penalty
for breaking this law is a crash and possibly death.

Paul Lamar

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