Long rear spring hanger bolts

I'm striking out finding some suitable length rear spring bolts for my hybrid application. With the combination of C3 batwing and C4 spring, I need an extra long set of bolts.



I need roughly 13 inch bolts, with 12 inches from the ends of each cushion washer. So far I haven't found any sources that sell bolts longer than 10 inches. Anybody know of any decent sources?
For the short term I could cut and extend the bolt lengths by welding in some lengths of tubing (I would have to do some tensile strength calculations of the tubing before I decided to use this long term), or use a couple of coupler nuts to form the correct length bolts, but I'm not totally sold on the thread strength of those things.
I've been kicking around a couple ideas using a long top bolt, and a heim joint lower section to allow a bit of flexibility and adjustment, but I haven't had time to work out the details yet. If I just found some long bolts it would save me a bit of time right now.

How about some grade 8 ready [all thread] rod?

Mike
I have not been able to find any longer than 10" either. I would like to drop my car another 1/2 inch in the rear however the bolts that I ordered from mid america will not allow me to go any lower.

I have considered tie rod adjusting sleeves as you mentioned and cutting the bolt in half. I wanted to look and make sure there was enough room and the spring would not hit the sleeve, looks like you have a ton of room.

here is the ones I was looking at using.

SCCA VETTE said:

Mike
I have not been able to find any longer than 10" either. I would like to drop my car another 1/2 inch in the rear however the bolts that I ordered from mid america will not allow me to go any lower.

I have considered tie rod adjusting sleeves as you mentioned and cutting the bolt in half. I wanted to look and make sure there was enough room and the spring would not hit the sleeve, looks like you have a ton of room.

here is the ones I was looking at using.

Click to expand...

I like those, Phil. They'd certainly be beefier than regular couplers. Question: Is one end LH threads?

00fxd said:

How about some grade 8 ready [all thread] rod?

Click to expand...

This is a good idea. You can buy 1/2-13 grade 8 from McMaster. I just bought some 36" pieces for like $10

You are probably not going to find 13" bolts, they seem to be 2" increments above 10". They also don't have much thread on them.

BBShark said:

00fxd said:

How about some grade 8 ready [all thread] rod?

Click to expand...

This is a good idea. You can buy 1/2-13 grade 8 from McMaster. I just bought some 36" pieces for like $10

You are probably not going to find 13" bolts, they seem to be 2" increments above 10". They also don't have much thread on them.

Click to expand...

Thirteen was just the minimum length needed to span the upper and lower donut/washer distance, and also provide some length for the nut to thread onto.

Here is a 14" bolt but it doesn't have much thread.
http://www.mcmaster.com/#91236a969/=1ghrwl

You should be able to easily find all thread or ready rod in 3" lenghts

I bought two of these:
http://www.mcmaster.com/#91257a199/=1go4rz

and cut to fit... the 5/8" diameter still fits and is available in 12" length. Note that the tensile strength is 150000psi

They offer numerous round bars in 5/8" or 16mm diameter so you can cut and thread it yourself - metric M14 is another option, stronger than the stock 1/2" but not as huge as 5/8"