Hardness of "race" v. "street" ring and pinon

Came across this in "Hot Rod" magazine and found it interesting.

"Richmond Gear offers "street gears" and "pro gears." The Richmond street-series gears are actually softer than OE-issue ring and pinions, while the pro series are softer still. Rockwell hardness tests of OE production line gears reveal a minimum Rockwell "C" specification of approximately 59 to 60 with a maximum figure of 65. The Richmond "street" gears register approximately 58 to 59 on the Rockwell scale with a maximum of 62. "Pro gears" (series 79) will register approximately 52 to 56 on the Rockwell "C" scale. Why incorporate a "soft" construction for high-performance gears? The reason is impact loading. When a relatively high amount of shock loading is introduced into a conventional "hard" ring and pinion, the gears can shatter. Softer construction allows for a certain amount of tooth "bending," but this certainly is preferred over shattered teeth. Because of the differences in Rockwell hardness, gears destined for drag race use only ("Pro" series) are not appropriate for street or street-strip use. The gears wear rapidly because of the softness. Due to this, all cars likely to see some amount of street use should make use of street gears."

Makes perfect sense, but if you'd asked I would have said that race gears would be "harder".

Rich Krause

Funny you post this Rich. I am putting in a set of Richmond "Pro Gears" in my 12 bolt this evening. I broke my 4.11's about a month ago and put in a set of Ricmond 4.56 "street gears". They broke after four passes. After speaking with Richmond I am going with the "Pro Gear". I only drive the car on the street about five miles at a time and I need the gears to survive 5800 RPM clutch dumps.

Richmond also recomends using a sleeve and shims on the pinion instead of a crush sleeve. This keeps the pinion stable during hard launches. Richmond says on hard launches the crush sleeve can be compressed and your pinion depth will change. This will result in ring & pinion failure.

Originally posted by red
Funny you post this Rich. I am putting in a set of Richmond "Pro Gears" in my 12 bolt this evening. I broke my 4.11's about a month ago and put in a set of Ricmond 4.56 "street gears". They broke after four passes. After speaking with Richmond I am going with the "Pro Gear". I only drive the car on the street about five miles at a time and I need the gears to survive 5800 RPM clutch dumps.

Richmond also recomends using a sleeve and shims on the pinion instead of a crush sleeve. This keeps the pinion stable during hard launches. Richmond says on hard launches the crush sleeve can be compressed and your pinion depth will change. This will result in ring & pinion failure.

That seems like good advice. I will do it when I next change gears.

What 60' times are you running, you seem to be going through ring and pinnions pretty quick!

In spite of the wear factor I would like to use the "Pro" gears, I have no problem with periodic replacement (I put ~4,000miles on in a typical year). But with the gears I am running (3.42) the R&P is only available as a "street" gear.

Rich Krause

My 60's are in the low 1.5's. The first set of 4.11's lasted for several seasons before they broke. I think the 4.56's may have been a little off and that's why they broke. They were making a lot of bearing noise and I think my brother did not have the torque correct when he set the crush sleeve. Tonight I will be doing it myself to make sure it is correct.

Aside from that, 5800 RPM launches in a 3500 lb car does not help either. That is why I am going with the Pro gears this time.

Danny Miller told me Pro gears were no good for a street car, he recommended them to me after I broke a pinion gear in my 9" last year but when I told him it was a street car and I was going on the power tour he backed up and said they wouldn't work. They need to be cooled every 5 miles or so or they'll flat wear out. So I guess I'll stick with replacing my ring/pinion every winter..

That's just what I was told.

Hmm, I'm using standard Moser gears in my 9". I've pulled MANY mid-low 1.5's last year "1.51 best" with 6K clutch drops in my 3715 lb tank. Never had a problem with the gears. They are now 4 years old and still holding. With the turbo setup that may change...hehe

Jose

Red,

I'm not convinced that the solid sleeve will keep anything more stable. All a sleeve does is generate enough friction on the pinion nut threads to keep the pinion nut from backing off without over preloading the pinion bearings. I've personally had problems with Ratec sleeves. I received 2 on a row where the faces were not parallel with each other. This makes for huge setup problems, Timkens don't seat squarely in the races, and it'll throw the pinion yoke **** eyed. If your going to use a sleeve, get a 2 piece machined one from Strange or chuck your Raytec up in a lathe and skim cut both faces in the same chucking before using it.

I've had gear sets run all season, and some that puke on the first launch also. I would like to hear of someone that has tried to run Pro gears with limited use on the street. Maybe they would least at least a year on the street and still be a bit more ductile at the track.

Rich,

Thanks for opening this forum! Us gear bangers need a place to vent our frustrations.


Steve

Originally posted by SABLT194
Red,

I'm not convinced that the solid sleeve will keep anything more stable. All a sleeve does is generate enough friction on the pinion nut threads to keep the pinion nut from backing off without over preloading the pinion bearings. I've personally had problems with Ratec sleeves. I received 2 on a row where the faces were not parallel with each other. This makes for huge setup problems, Timkens don't seat squarely in the races, and it'll throw the pinion yoke **** eyed. If your going to use a sleeve, get a 2 piece machined one from Strange or chuck your Raytec up in a lathe and skim cut both faces in the same chucking before using it.

I've had gear sets run all season, and some that puke on the first launch also. I would like to hear of someone that has tried to run Pro gears with limited use on the street. Maybe they would least at least a year on the street and still be a bit more ductile at the track.

Steve

I think the solid sleeve should work better than a crush sleeve. On launch the pinion wants to drive out the front of the rear end which forces it up against the rear bearing and race. The race may only allow the pinion to move forward a couple thousands before the bearing load overcomes the forward force but that could be enough to crush the sleeve a couple thousands over initial preload. It this happens then your preload could be shot to hell which could lead to gears breaking. This is all in theory but I don't think a solid sleeve can hurt.

As far as the Pro Gears on the street it is true that they will wear out quicker. They would never live through the Power Tour or anything even close to that. Since I rarely drive more than five miles at a time (local hangouts, track, etc.) I figured the extra strength at the track can't hurt. If I planned on hitting the road for a trip there would be no doubt that a set of street gears would go back in.

Who knows, If these Pro Gears don't stand up to the job I just may try a 9" ;)

hehehe the old debates are new again!

Do NOT use Pro gears on the street. They can not take the continuous heat generated. They were desighned to live about a season and be gone.

The Solid Crush sleeve keeps the Pinion from climbing the ring gear. This force the pinion back into the case crushing the sleeve. using the sloid spacer helps to stabilize the pinion in one place ;) Use it AND a girdle(cover) that supports the caps.

Good luck!

who needs a crush sleeve?

set the pinion nut preload and tac weld it in place

no worries :)