Rear D-Ring bolts question

[sclui56]

Just want to get a definitive answer on the length of these bolts. The standard bolts holding the D-rings are M12x1.75x55, while the ones used to mount the D-rings for a tire carrier equipped H2 are M12x1.75x65 (same as SMA as well as the SUT).

Question is - I used the original M12x1.75x55 and mounted the D-rings assembly for a tire carrier b/c I didn't have access to the longer 65's. After everythig was secured & torqued to approx. 85 ft/pound, the exposed thread inside the bumper is at least 1/2 " in length, and the rule-of-thumb I was taught long time ago is that the minimum required left-over thread should be sufficient for at least 5 complete turns, so 1/2" is certainly more than that.

According to the above, I fail to see the benefit of using the 65's b/c the extra length is not holding onto anything more than the 55's did, yet SMA basically said it's unsafe to use the original 55's.

Am I missing something?

[sclui56]

Just want to get a definitive answer on the length of these bolts. The standard bolts holding the D-rings are M12x1.75x55, while the ones used to mount the D-rings for a tire carrier equipped H2 are M12x1.75x65 (same as SMA as well as the SUT).

Question is - I used the original M12x1.75x55 and mounted the D-rings assembly for a tire carrier b/c I didn't have access to the longer 65's. After everythig was secured & torqued to approx. 85 ft/pound, the exposed thread inside the bumper is at least 1/2 " in length, and the rule-of-thumb I was taught long time ago is that the minimum required left-over thread should be sufficient for at least 5 complete turns, so 1/2" is certainly more than that.

According to the above, I fail to see the benefit of using the 65's b/c the extra length is not holding onto anything more than the 55's did, yet SMA basically said it's unsafe to use the original 55's.

Am I missing something?

[sclui56]

Just want to get a definitive answer on the length of these bolts. The standard bolts holding the D-rings are M12x1.75x55, while the ones used to mount the D-rings for a tire carrier equipped H2 are M12x1.75x65 (same as SMA as well as the SUT).

Question is - I used the original M12x1.75x55 and mounted the D-rings assembly for a tire carrier b/c I didn't have access to the longer 65's. After everythig was secured & torqued to approx. 85 ft/pound, the exposed thread inside the bumper is at least 1/2 " in length, and the rule-of-thumb I was taught long time ago is that the minimum required left-over thread should be sufficient for at least 5 complete turns, so 1/2" is certainly more than that.

According to the above, I fail to see the benefit of using the 65's b/c the extra length is not holding onto anything more than the 55's did, yet SMA basically said it's unsafe to use the original 55's.

Am I missing something?

[sclui56]

Phil, the specs are identical, except for length, so there's really not a question about the correct specs or not, besides, if these (original) are the bolts GM chose to secure the D-rings, which in turn can be used to carry the vehicle's weight, why wouldn;t they carry the additional weight of the carrier?

Thanks a lot for the reply.

[HUMMERcustoms.com/TAZ]

sclui56
Take it from an old farmer who has bought things and used it for what it was not entended for, as well as alot of experience with using what I had on hand to make something work. You do not have to worry, the important thing is the the measurement You gave. It is plenty but more important is bolt grade. If You fill hole threads then what is actually going to do the job is the stress the bolt itself takes so that makes grade more important. You should be alright.
Rick

[sclui56]

RLTAZH2,

Thanks for the confirm on this one, I was confident that the original bolts are fine, except I started reading the instructions from SMA, and also got a confirmation that the bolts on the SUT are 65's, hence my question to the experienced here on the forum. In the end, it simply didn't make any sense for the extra length to grab nothing.

Thanks!!