When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Iv'e got an extra ser of these never opened, paid like $35-40 .
For $15 plus shipping youn can have if you want, you got 1st. dibs. Anyone else after you also. I'm not sure if 8 or9 in.
Just a heads up regarding 10" bolts and 15" wheels. Back in the 90's I was autocrossing my '73 regularly and after rebuilding my suspension (including a fiberglass spring from VB&P), felt the rear was still a bit high with 8" bolts. I ordered a set of 10" bolts and installed them. This placed the end of the (stock length) spring about 1" from the tire sidewall of my 255/60-VR15's. I was convinced that 1" would be fine.
First couple of autocrosses after this I noticed a very slight rub mark on the inside sidewall of both rear tires from the spring. The next autocross I turned in a bit tighter on a turn and "BAM"- left rear tire lets go. My first though upon looking at the rear tire was I had rolled it off the bead of the rim. Then I looked under the car and saw that the entire sidewall was separated from the rubber bead of the tire. It had completely ripped the sidewall of the tire as if mounted on a lathe.
Check the clearance between the end of the spring and tire carefully. 1" might have worked fine on the street under normal driving conditions, but not for aggressive driving. I switched back to 8" bolts and lowered the rear 1" using another method.
Fastenal. They probably have a store somewhere in your area.
They had to order my Grade 8 10" long bolts, but it only took a day and they are inexpensive.
Originally Posted by keithinspace
I run 1/2" bolts. Grade 8 from Fastenal. Easy stuff.
I have used simple nylock bolts for years and they work perfectly.
Originally Posted by flyeri
Same here.. Got bolts at local hardware store or Lowes. I used nylock nuts and drilled the bolt for a cotter pin for added insurance.
They are suppose to be 9/16, but I'm sure 1/2" would probably be OK. I looked into Fastenal (online) a while back, and they do not have 9/16-18 (OE fine thread) in anything over like 7". Not sure if going in store and having them look in their computer would be any different.
...Fastenal...they do not have 9/16-18 (OE fine thread) in anything over like 7".
Honestly, we're talking about a bolt that sees almost exactly 1/4 the weight of the car. If you put the entire weight of the car on that one corner (the other three wheels in the air...stupid situation), that bolt would have to suspend the entire 3,000# weight of the car. And it, almost by definition, does not have a "shock load" applied to it.
A 1/2" Grade 8 bolt has a tensile strength of over 22,000#. That versus the weight of the entire car gives you a 700%+ factor of safety. That versus the highest possible normal load seen by the bolt and you have a well over 2,000% factor of safety. I think you're safe.
Seriously...a coarse thread 1/2" Grade 8 bolt is such ridiculous overkill it's not even worth discussing.
But if it makes you feel any better, those safety factors would increase to 950%+ and 2,800%+ if you used a 9/16" bolt.
My opinion: If you break a 1/2" Grade 8 (or even Grade 5) bolt in this particular application, your car has just been through a nuclear-grade event and this one bolt is probably all that remains of your vehicle.
Originally Posted by GUSTO14
Just a heads up regarding 10" bolts and 15" wheels. Check the clearance between the end of the spring and tire carefully. 1" might have worked fine on the street under normal driving conditions, but not for aggressive driving. I switched back to 8" bolts and lowered the rear 1" using another method.
I would completely agree with Mr. Gusto, but perhaps for different reasons. I had 10" bolts with my 15" rims and for whatever reason, the rear end 'set' differently than the small change in bolt length would indicate. It was odd.
Also, if the tire goes down on a 15" rim, the head of a 10" bolt will drag on the ground, creating all types of havoc. Probably never going to be an issue (hopefully...), but it is a fact. An 8" bolt is fully 'protected' by the rim in the event of tire failure.
I ran 8" bolts for a long time. I put 10" bolts in my car, played with them for a few months, and put the 8" bolts back.
That's my experience, and it seems to align with Mr. Gusto's experience, so I thought I'd share. I guess my point is: Don't spend a bundle on the bolts you use. I would put the odds at 50/50 that you'll go right back to 8" bolts.
Last edited by keithinspace; May 20, 2016 at 04:11 PM.
Just a heads up regarding 10" bolts and 15" wheels. Back in the 90's I was autocrossing my '73 regularly and after rebuilding my suspension (including a fiberglass spring from VB&P), felt the rear was still a bit high with 8" bolts. I ordered a set of 10" bolts and installed them. This placed the end of the (stock length) spring about 1" from the tire sidewall of my 255/60-VR15's. I was convinced that 1" would be fine.
First couple of autocrosses after this I noticed a very slight rub mark on the inside sidewall of both rear tires from the spring. The next autocross I turned in a bit tighter on a turn and "BAM"- left rear tire lets go. My first though upon looking at the rear tire was I had rolled it off the bead of the rim. Then I looked under the car and saw that the entire sidewall was separated from the rubber bead of the tire. It had completely ripped the sidewall of the tire as if mounted on a lathe.
Check the clearance between the end of the spring and tire carefully. 1" might have worked fine on the street under normal driving conditions, but not for aggressive driving. I switched back to 8" bolts and lowered the rear 1" using another method.
Good luck... GUSTO
This^^^^ is why you don't use 10" bolts. This has happened to folks on the street. There is also the issue if you just have a flat that side of the spring and adjustment bolt will drag the pavement! I have a VBP 330# spring and 8" bolts. I would like to get it a little lower, but taking the bolts to 0 threads exposed or installing 10"er's is not an option to me. Good luck!
This^^^^ is why you don't use 10" bolts. This has happened to folks on the street. There is also the issue if you just have a flat that side of the spring and adjustment bolt will drag the pavement! I have a VBP 330# spring and 8" bolts. I would like to get it a little lower, but taking the bolts to 0 threads exposed or installing 10"er's is not an option to me. Good luck!
I have a VBP 330# spring too, but the rear was too high, even with the nut almost to the end of the 8" bolt. I bought 10" bolts put a pair of grade 8 non-locking nuts on the bolts before cutting 3/4" off, grinding the cut end smooth, and backing the nuts off to restore the thread at the cut. I have 18" wheels, so the 9 1/4" bolt end is not near the tire.
DSCN4137 by Richard Hayes, on Flickr
I have a VBP 330# spring and 8" bolts. I would like to get it a little lower, but taking the bolts to 0 threads exposed or installing 10"er's is not an option to me. Good luck! 
