GM 10 bolt corp w/8.5 rings & 30 spline axles

[HookMeUp]

I don't want to open a can of worms but how strong is the 30 spline 10 bolt corp 8.5 axles?

I have them under my front and rear of the truck. currently run a set of 33's and don't forsee going up in sizes for many years most likly only mild wheeling...The price to swap out the 3:08 to 4:11 or 4:56 should be rather inexpensive and easier to locate all the parts, since these axles have been used in multiple applications for a wide range in years.

The reason I'm asking I have seen a lot of post or articles stating that 10 bolts are weak. my question is since there is 2 style 10 bolts do they all get lumped into 1 category?

Are the 8.5 10 bolts stronger and better choice to upgrade? If a 3/4 or 1 ton swap is not feasible at this time?

Thanks

 

[C1090blazer]

if i was you i would rock the 10 bolts specially if your goin to do "mild muddin" they are good up to 35in ....when they do break its because if you lock the front turn sharp and wedge the tire in a crack or something then floor it ....which it should break like that ....just my .02 cent

 

[Thunder]

The 30 spline rears are more common Than the front 30 spline. Fronts 30s were only produced for a few years. 1989-1991 aprox. So They are a little harder to find used parts for in the wrecking yards
IMO they are a upgrade over the 28 spline. 30s are marginally stronger.
I run 10 bolts locked front and rear on 33&35 tires. I have never broken a rear. But I have broke front axle shafts by being stupid and using way too much power than needed to get thru something. Loosing traction and suddinly finding that lost traction under full power will usually break them.
10 bolts on 33s will work good . Just be careful whith your right foot and you will be fine.

 

[GRINCH]

The 30 spline rears are more common Than the front 30 spline. Fronts 30s were only produced for a few years. 1989-1991 aprox. IMO they are a upgrade over the 28 spline. 30s are marginally stronger.
I run 10 bolts locked front and rear on 33s. I have never broken a rear. But I have broke front axle shafts by being stupid and using way too much power than needed to get thru something.
10 bolts on 33s will work good . Just be careful whith your right foot and you will be fine.

X2..

I ran my 30 spline ten bolts locked with 37"s
Just ease up on the stupid foot when it's binding up.

 

[cdoggwsu]

In my case I happened to find a good deal on a set of 3/4-ton axles that were already fully rebuilt and setup with the gears I was looking for (4.10) so I figured might as well as I'm getting fresh, stronger axles (well stronger in the rear anyway) and no need to pay for the gear swap.

Having to buy new wheels and tires for the 8-lug is a pain though, so the cost savings is debatable.

 

[chulisohombre]

you shouldnt have a problem with10 bolts up to 35s.if you are only runnin 33s they will be strong enough for a decent amount of wheeling.there is enough axles out there that you could swap in a different set of ten bolts with the gears you want for relitively cheap.its only 500 bucks for the gears if you know how to swap them yourself,or have a friend that has done it that can help you if you went that route.a lot of people say they are weak because they are running tires too big for the axles.thats the way i see it.you cant call something weak if you know you are maxing out the ability of the axles to withstand the abuse.driving ability and smart lines will save a lot of axles from breaking while wheeling.

 

[Cornfield creations]

In my case I happened to find a good deal on a set of 3/4-ton axles that were already fully rebuilt and setup with the gears I was looking for (4.10) so I figured might as well as I'm getting fresh, stronger axles (well stronger in the rear anyway) and no need to pay for the gear swap.

Having to buy new wheels and tires for the 8-lug is a pain though, so the cost savings is debatable.




I concur, that's what I am in the middle of right now.

 

[6.2Blazer]

There is really no difference in regards to the front axles between 28 or 30 spline versions because the factory shafts both have a neck-down on the inner shaft and will likely break under the same load. Some people will even say the OEM 30-spline carrier is slightly weaker, but otherwise the front diffs are identical. Most of the failures I have seen on front 10-bolts are either the inner or outer shaft, or the u-joint breaking. I did break 2 front shaft u-joints with 35's and an Eaton limited slip in the front, but it was always while the front tires were turned and down in a rut. I learned from my mistakes and ran it for several more years without an breakage on 35's.

The rear 30-spline shafts do offer a decent strength upgrade as compared to the 28-spline shafts. From my experience a rear 10-bolt either breaks a shaft, or grenades the factory Gov-lock diff. With the 30-spline shafts the Gov-lock usually goes first. The factory Gov-lock in my '90 grenaded with 33" tires and mainly daily driving, however this did happen shortly after the Blazer was stolen and thrashed pretty hard before being stripped. I did run a Detroit Truetrac with aftermarket shafts for several years with 35's and moderate trails with no issues.

For mild wheeling and DD status with 33's the axles would probably be okay just depending on how you treat the truck. However if you currently have 3.08's and want to go to 4.10's or 4.56's it would be much cheaper to buy a set of 3/4 ton axles with 4.10 gears already....4.10's are super common for 3/4 ton axles from the factory.

Granted 10-bolts have been around for awhile, but I wouldn't consider swapping out the gears to be cheap and easy. Granted, I did exactly this years ago before I knew any better but in my defense the entire rear axle needed rebuilt anyway AND insurance paid for it all since the blown rear end was caused by the theft (I gave them a quote to rebuild the rear axle using all OEM parts, which was as much as buying aftermarket gears and limited slips for both the front and rear axles).

Front 30-spline inner shafts are pretty hard to come by in regards to getting spares from the junkyard, but everything else on either the front or rears are pretty easy to find.

 

[chulisohombre]

3/4 ton also gives you a stronger braking system.but also usually need further modifications to work correctly with the bigger wheel cylinders on the rear.but some people have had to change nothing and it works fine,even with changing to rear disks.if you can find some 1/2 ton replacements and thats all you need for a good price,there will be a lot less work involved than 3/4 ton.and maybe less money considering needing new rims and tires.