How is driveshaft length measured?

blykins · #1 (**permalink**) 12-04-2003, 07:22 PM

From tip to tip...or just the part not including the U-Joints?

If someone told me they had a 10.5" driveshaft...is that the whole stinkin thing...or just the "shaft" part?

Also....how many people have had troubles on street cars with short driveshafts?

scottj · #2 (**permalink**) 12-04-2003, 07:29 PM

Center of the U-joint to center of the U-joint

SuperHart · #3 (**permalink**) 12-04-2003, 07:32 PM

I am under the impression that driveshaft length is measured from the centerpoints of each U-joint. At least that is how I measured mine when I took it to be shortened. The machinist instructed me to insert the yoke into the transmission as far as it would go, then measure the distance from the centerpoint of the tranny yoke to the centerpoint of the differential yoke. Then he said to subtract 1 1/4-1 1/2" from the measurement to allow the driveshaft to move without binding on the tranny output shaft. The final number is your driveshaft length. Check with the person who is going to size your driveshaft and don't forget to spend a little to have it balanced.

PNJSNAK · #4 (**permalink**) 12-04-2003, 07:43 PM

Go to Denny's Driveshaft web site. You can down load necessary drawings that show you what to measure and where, depending on what type you need. Totally satisfied with the product and very fast delivery. Note sure of the exact web address but Phone # for questions is 716-875-6640.
Jim

TonyMadrid · #5 (**permalink**) 12-05-2003, 06:08 AM

The site for Dennys is:

www.dennysdriveshaft.com

Use the measurement charts provided at the site for your particular application. Once you have the measurements, just call Dennys and provide him with the info and he'll build you a nice balanced driveshaft.

Tony

CowtownCobra · #6 (**permalink**) 12-05-2003, 07:11 AM

I had a problem with a "too short" drive shaft. Like 1.5 inches. Luckily it was discovered before the tail shaft bearing in the tranny gave out.

blykins · #7 (**permalink**) 12-05-2003, 07:13 AM

You mean it was an inch and a half too short? How long was it?

GOCATS · #8 (**permalink**) 12-05-2003, 07:16 AM

I would check with the company that is going to make your driveshaft. I asked that question 3 different times to 3 different companies and got three different answers.

. So when it was time to have one made I called Republic and asked them what they wanted in the way of measurements. I gave the measurement from outside of yoke to outside of yoke. Fits just fine and not too short.

CowtownCobra · #9 (**permalink**) 12-05-2003, 07:23 AM

Blykins,

It was like 19.5 inches when it should have been 21. Could feel it vibrating in 5th gear.

Seperately, I've seen some FFR drive shafts that were only 8, maybe 9 inches long. Large u-joint angles.

blykins · #10 (**permalink**) 12-05-2003, 07:24 AM

How long are your driveshafts guys? Especially you with Toploaders....I'm showing 40" between bellhousing and pinion yoke...and my yoke accepts a universal joint directly...doesn't have a bolt flange like an 8.8". If I get the tranny I have my sights on, it will be 27" long...that will leave me 13".

BB427 · #11 (**permalink**) 12-05-2003, 10:56 AM

My driveshaft is 3" from weld to weld on the tube itself.
Unique 427 SC
Long tailhousing toploader (27")
Jag IRS

Brent

misfit41 · #12 (**permalink**) 12-05-2003, 12:25 PM

I am sure lots of you guys know,,but unless you want alloy,,a drive shaft is a cinch to make and requires no special tools,,I have had good success with the few I have done,,best yet,get a used one with the proper yokes on both ends,grind off the weld,knock out the end,make a STRAIGHT cut with a band saw,tap it back in flush,then weld it up,balance is almost never a problem since both ends are balanced .
if you run into a yoke matching problem,ford old part number C3AZ E u joint has both standard ford yoke sizes on either side,so you can fit wide to narrow,,or vice versa..Tk

blykins · #13 (**permalink**) 12-05-2003, 12:36 PM

Thanks everyone....lots of help as always.

I'm using a Strange pinion yoke, so I'll probably just go with one of their U-joint kits to go with it...comes with the straps and everything. I'll just need to find a good tranny yoke now. Actually my dad has a full driveshaft left over from his 97 Cobra...so I may see if it's the right spline or not...With my luck, I'm sure it's not.