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Post by nitromania on Feb 11, 2023 16:42:57 GMT -6
How is it retained in the cup on the speedo drive end?
I was able to just pry the cup off, the external rubber seal seems to sit in a groove in the cup.
With the cup off and wiped out with a scotchbrite pad to clean the crud out, it now seems like the bearing is not really "retained" in there. Are they press fit to the shaft? What keeps the outer bearing shell from spinning in the cup, or does this not happen?
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Post by midniterupper on Feb 13, 2023 6:41:00 GMT -6
Hey, very good question. I have wondered about that set up as well for retaining the drive axle bearing. As far as I know the bearing "floats" in the cup while installing the drive axle into position. (The bearing is tight on the drive axle of course.) When the opposite end of the shaft is secured in position with the chain and gear torqued down, the bearing finds it's best position in the cup. Then when you tighten the track, the bearing's outer race is locked into the cup by the pressure/force created by the track tension and no spin occurs (unless the bearing becomes seized).
I have had my '76 Nitro track removed several times and inspected the cup with no apparent wear or damage so the design must work. Maybe someone with more experience will chime in on this topic to shed more light and explain why Rupp chose this method. Sure is convenient when installing your track though!
Good luck!
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Post by nitromania on Feb 13, 2023 20:16:30 GMT -6
Makes sense I guess. Still haven't decided which way I'm going to go when I get the replacement driveshaft and drivers for the Indy track.
I can either use the original bearing size and sleeve the shaft end, or
Use the bearing and lock collar that fits the shaft and get a spacer made to mount inside the cup.
Original Rupp bearing: OD- 55mm, ID- 30mm
Bearing to fit Cat or Polaris driveshaft: OD-52mm ID 25.4mm or 1" shaft dia.
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mutt
Senior Member
Posts: 36
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Post by mutt on Feb 13, 2023 21:41:19 GMT -6
Makes sense I guess. Still haven't decided which way I'm going to go when I get the replacement driveshaft and drivers for the Indy track. I can either use the original bearing size and sleeve the shaft end, or Use the bearing and lock collar that fits the shaft and get a spacer made to mount inside the cup. Original Rupp bearing: OD- 55mm, ID- 30mm Bearing to fit Cat or Polaris driveshaft: OD-52mm ID 25.4mm or 1" shaft dia. Thats one way to do it. Even If you lock the bearing on the shaft. You need the proper length spacer also on the chaincase side or it will push through and tear the chain and gears up. As Polairs and Cats bearings are floaters Another way 86-87 Arctic Cat el Tigre driveshaft is very close to Nitro within 1/8 inch, Make new bearing cups to fit the Nitros mounting holes, out of Cat or Polairs ones and lock it to the tunnel like they do. The Nitro bearing holder no longer needed as a holder mill off the holder leave the slightest amount, can bolt it back up for working speedo |
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Post by nitromania on Feb 14, 2023 18:33:51 GMT -6
The idea of making a new bearing cup to retain the bearing would be the way to go if I new how to accomplish it....
I would probably have to weld extensions to the bearing retainer flanges as the Rupp tunnel hole and bolt pattern are significantly larger than a Cat or "standard" bearing retainer. I have not found any source for them, yet...
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Post by Ruppsforever on Feb 18, 2023 18:36:30 GMT -6
I would think the track tension would prevent it from spinning in the cup.
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Post by bobsapp on Feb 19, 2023 14:11:17 GMT -6
The outer race of the bearing turned in the hub. Wearing the hub. Get another good used hub.
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Post by nitromania on Feb 19, 2023 19:21:54 GMT -6
The outer race of the bearing turned in the hub. Wearing the hub. Get another good used hub. So, does that mean originally they were a press fit? There are no witness or wear marks in the aluminum hub. I was able to pry it off once I got the separate rubber seal out of the groove it was retained in. Digging around my pile of leftovers I did find that a Scorpion driveshaft uses a larger bearing (like the Rupp does) but is retained with the three bolt flangette like most other sleds. The kicker here is the Rupp is on the 3.5" bolt circle and Cat, Polaris etc bearings and retainers are smaller. The Scorp bearing retainer matches the Rupp pattern to bolt into the tunnel. Also, the Scorpion bearing is a spherical outer race to use the flangettes while the Rupp bearing is not. It is flat as is the cup it sits in. Unfortunately though the Scorp bearing ID is larger than the Cat shaft I was planning on using so I'd still have to sleeve it to match unless I could find a spherical roller bearing with lock collar with a 28.5mm ID and 62mm OD. That would make it a bolt together deal.... Then I would turn the cup off the Rupp retainer and bolt it on and retain the speedo drive too. |
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mutt
Senior Member
Posts: 36
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Post by mutt on Feb 27, 2023 15:45:55 GMT -6
The idea of making a new bearing cup to retain the bearing would be the way to go if I new how to accomplish it.... I would probably have to weld extensions to the bearing retainer flanges as the Rupp tunnel hole and bolt pattern are significantly larger than a Cat or "standard" bearing retainer. I have not found any source for them, yet... The easiest cups to modify are 1987 and earlier Cat as the are round not triangle-ish. Simple ring to fit bigger Rupp pattern. Or bolt a plate on the Rupp tunnel to fit the Cat cups |
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Post by nitromania on Feb 27, 2023 17:53:40 GMT -6
I found an old Scorpion driveshaft in my spares pile from when I had Scorpions. One shaft has three drivers (round shaft) and uses a Peer FH 206-18 spherical bearing. The retainer for it is on the 3.5" bolt pattern which matches the Rupp bolt holes in the tunnel.
The OD of the bearing is 62mm. I have a new bearing and my buddy at work is going to make a sleeve for the Cat shaft (w/new 2.52 pitch drivers) and I'll use the 206 bearing with Scorpion retainers.
At least thats my plan if I can find another Scorp bearing retainer.
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