83 vs. 85 spindles/bearings

[JeffW]

I am getting ready to transfer parts from my 83 Spec7 with sunroof to the 85 without sunroof. Is there any advantage/disadvantage to using the 83 or 85 spindles?

Thanks,

Jeff

PS What kind of weight savings should I see by switching?

[Marcus Miller]

Originally posted by JeffW@Nov 27 2005, 05:33 PM
I am getting ready to transfer parts from my 83 Spec7 with sunroof to the 85 without sunroof. Is there any advantage/disadvantage to using the 83 or 85 spindles?

Thanks,

Jeff

PS What kind of weight savings should I see by switching?

66777


The 83 are small bearing, correct?
If so, I'd toss them. We have seen spindle failures on the small bearing spindles on the west coast. Granted these were on an ITA car on Hoosiers, (not sure what RM Div runs for spec7?)

Have you pulled the sunroof operating mechanism and such out? (I assume so) I would guess the net difference is not much. but the weight will be distributed better.


Marcus

[Scott Nutter]

I'm not sure how much weight you would save on the front spindles, not that much of a difference. The rear axles are probably a pound or so lighter each? I've run the smaller spindles/axles for 4 years, I'm still improving so it might mean absolutly nothing but I've never had a failure at either end of the car. The bearings do seem to need repacked every other weekend but that's probably due to no brake ducts.

[lateapex911]

This is old info, but may be pertinant. I was on a team that raced 1st gen RX-7s in SS at the Longest Day 24 hour race at Nelson Ledges in the early 80's.

In our first year, both team cars had front bearing failures within 2 laps of each other at about 18 hours. Drivers had been complaining for awhile on both cars.

The next year we changed our strategy and changed the entire strut, pads, discs, damper and bearings..all of it, at 12 hours, and of course had no further issues. We discussed the matter with Mazda at the time (they were very involved and supportive) and the spindle and bearings were upsized subsequently. I'm sure it wasn't due to us, but it might have been a supporting data point.

[Marcus Miller]

Originally posted by lateapex911@Nov 28 2005, 10:49 PM
This is old info, but may be pertinant. I was on a team that raced 1st gen RX-7s in SS at the Longest Day 24 hour race at Nelson Ledges in the early 80's.

In our first year, both team cars had front bearing failures within 2 laps of each other at about 18 hours. Drivers had been complaining for awhile on both cars.

The next year we changed our strategy and changed the entire strut, pads, discs, damper and bearings..all of it, at 12 hours, and of course had no further issues. We discussed the matter with Mazda at the time (they were very involved and supportive) and the spindle and bearings were upsized subsequently. I'm sure it wasn't due to us, but it might have been a supporting data point.

66906

:023:
And I said, "let there be spares"
http://images.miller-motorsports.com/misc112705/PB270108.JPG
spare corners, fully asembled, ready to change out athe 13 hour mark.
Thanks to Mike at ISC, as always.

Marcus

[64oeg]

For what it's worth, Ive seen the larger spindles break as well. IMHO, it all boils down to maintainence. I ran a 1st gen with small spindles at WHRRI competivily for two seasons with no problems. I also repacked/inspected bearings after every race weekend. Plus, the spindles had at least a season+ on them when I got the car.

George