Ok I’ve broke 2 gears this year. First weekend out I broke a 5.83 pro gear that I’d run all year last year. Changed to a 5.67 pro gear and broke it this week. Car is 3300lbs 421 700 hp PG, 1.80 low 33/16/15 tires 9” rearend. I always ran a street gear in my dragster because the pro gear wouldn’t hold up so thinking about going to a street gear in the Nova. Anyone had issues with pro gear and changed to street gear with any luck

Pro gear.... Kidding

This is a 66 Chevy II 3000lbs 23 427 sbc powerglide 4.51 Motive *performance* street gear, 275 dot radial tire 400hp plate system.

With the 28X10.5 tires and 5.13 gear never had an issue with the street gear. Guy that does my trans and rears said I needed the pro gear because the pinion gears were so small going to the 5.67 or 5.83 but there not lasting. No more power than I have it shouldn’t be breaking them so I’ll try the street gear. Not really wanting to put a 10” in it yet.

quote:

Originally posted by C Hodge:
With the 28X10.5 tires and 5.13 gear never had an issue with the street gear. Guy that does my trans and rears said I needed the pro gear because the pinion gears were so small going to the 5.67 or 5.83 but there not lasting. No more power than I have it shouldn’t be breaking them so I’ll try the street gear. Not really wanting to put a 10” in it yet.

The pinion hasn't been the problem, the ring gear has correct? 5.14 36 ring gear tooth quantity 5.67 34 tooth Q Motive Performance gear.

I think you'll be alright Motive performance street gear C Hodge.

Give it try. Nothing too loose pro not working out.

First was the pinion teeth all broke. I haven’t pulled it apart to see if it the pinion or ring gear this time

quote:

Originally posted by C Hodge:
First was the pinion teeth all broke. I haven’t pulled it apart to see if it the pinion or ring gear this time

If you have beadlocks you could put a shorter narrow tread slick on it. That looks cool and it works good M/T stiff sidewall.

Take a different approach on the gear, maybe a 5.29 gear if you can get a short enough slick on it. Maybe a radial PBR?

quote:

Originally posted by C Hodge:
I always ran a street gear in my dragster because the pro gear wouldn’t hold up so thinking about going to a street gear in the Nova. Anyone had issues with pro gear and changed to street gear with any luck

you've got the wrong guy setting up your 3rd member. I've always run Pro gears in my Mark Williams 3rd members in both my dragster and my door car without issue.

Not sure what brand you are running. But heard a rumor the Richmond pro gear was having some problems. Not sure if it's true or not but heard of a lot of people breaking them lately.

quote:

Originally posted by ts393c:
Not sure what brand you are running. But heard a rumor the Richmond pro gear was having some problems. Not sure if it's true or not but heard of a lot of people breaking them lately.

Last Motive we ordered came in a Richmond box. It had a Motive part #.

It might not be a bad idea for C. Hodge to post an image of the broken ring on a portion of the ring we can have a look at the pattern. Not saying it wasn't setup correctly but it couldn't hurt to have a look.

This a a 5.00 gear I set up to run in conjunction with a 1.69 low Powerglide transmission, for 370 pro tree index racing.

Pattern look at all like this C Hodge?

This message has been edited. Last edited by: Mike Rietow, September 28, 2020 12:15 PM

Both I have broke were Richmond gears.

I would not. My experience is that when pro gears give up the ship, they usually make noise and vibrate before they go away all together but street gears just shatter. Pro gears are softer to absorb impact while street gears are harder so they wear better. Years ago building a dragster with street gears was popular since they were light, but I had a set of street gears blow up in spectacular fashion and take out the driveshaft, center, & a 4-link bar while denting the framerail. I believe your problem is due to the size of the pinion like you mentioned, but my $.02 I'd be afraid to go to street gears.

Aren't there certain gear ratios that are weaker than others?

I don't know, just putting it out there.

quote:

Originally posted by M120:
Aren't there certain gear ratios that are weaker than others?

I don't know, just putting it out there.

Yes! I've had several PM conversations with the OP, I originally suggested the 5.67,he just did a huge tire backhalf.

Time for a shorter tire or try a street gear, or lets look at the pattern. I'd do a shorter tire and 5.29 street gear if it were mine.

What carrier case are you using? And spool? Id bet the case flexes and breaks the gear

quote:

Originally posted by Will Harrison:
What carrier case are you using? And spool? Id bet the case flexes and breaks the gear

Could be! Need a image!!

Bought a moser 9 inch 4.86 gear set up about 15 years ago. and it knock a tooth off last year... Street gear to boot. Should not be breaking that much

The pinion head gets drastically smaller from 4.86 to 5.67.

Maybe it has a hard hit active stator converter. I have a PTC pro tree active stator sprag converter, that'll knock the taste out of your mouth at TB release.

I think the converter builder has more leeway active stator, as far as stator selection (mods), in comparison to spragless for range of torque multiplication below stall.

For this reason if it's a spragless converter, you can rule this out OP.

Huge tires, small pinion head, I could see the hard hit PTC Opel core 8" converter I have, doing ring and pinion carnage repetitively.

numerically the higher the number the weaker the pinon. It gets smaller. May need to go to the 9 1/2 gear set

so you are breaking gears that are made for high horsepower hard hitting drag cars and doing so with very mild combo, Sounds like something else is issue.

while a 9.5 gear set would be strong.It cost and may not fit with your case w/o grinding. Plus seems like extreme for your combo. Just thoughts.