V8 rat trike....few questions.

Hey all.

Gettin a few things lined up for my rat trike and a few questions.
I have a rear end im gettin from a friend at work. its an 8.8 thats been drilled out to 6 lug. has 3.55 gears and a posi. Its gonna be about 70 inches wide with my rims n tires. does that sound good on width or to much?
if its to much i may have to see bout narrowing rear but that sounds pricey.

I was told by a fellow v8 triker that i really shouldnt want a posi due to the fact that the engine vs weight ratio makes the rear end not release in turns.
he also said that on hard launches it can get one tire to bite that it will cause you to swap ends. (im thinkin thats a term for spinning you around)[S

also...whats good to run as tubing to the rear to a rear mounted radiator?

and...can you have a decent extended front end and still have no trail??

im gettin my ducks lined up and will hopefully have my title straightened up for the ih and get her sold and then ill be buildin.

thanks all. RR

You will know more about the width when you start stacking parts together of course. I'm really not following what your friend was advising about the posi not releasing in a corner? Without posi that amount of power with low weight would make tire spin a constant nagging problem. I used large diameter copper tubing to a rear mounted radiator. Easy to work with and looks so Steampunkity.
Really looking forward to your build thread RR. Soon to have a total of four rats
on the road so i really need to be thinking about building something like this now.

Thanks for the response earthman.
If it works...heres the link to his reply on my hr.com thread. read it and see if it makes more sense. tnx, rr

http://www.hotrodders.com/forum/v8trike-rear-weight-ect-233227.html

RR, the posi argument makes sense to me for the reasons described in the link you posted. I can imagine it acting like a full-size Jimmy I once had with a limited slip rear. On snow and ice the thing was virtually useless and its short wheelbase would "swap ends" quicker than your mother-in-law's meatloaf.

.

would an open rear end make only one tire turn for launches n burnouts? heres a rough idea of the frame n front end stretch i want. just the first pic. rr

http://www.speeddemons.se/Trike/byggbilder2009/pickup0929.jpg

well that looks fun..... I would think that posi would make for some hard corners.... I look forward to your build, this is something I want to build sometime....

I don't think a limited slip differential could possibly cause turning problems. With a ratchet type locking differential maybe you would have turning problems with a light weight vehicle.

Hey RR, sounds like a cool project. With an open rear end, only one tire is going to spin. How well that works on a trike, I don't know. Never riden one myself, just bikes. Posi rear ends can be adjusted though by changing springs. You might want to talk to someone who builds rear gears for circle track racing. I know limited slip rears for stock cars are available as 1/2 tight, 1/4 tight etc. Maybe a little experimenting might be needed to find the best setup for the weight of your machine. A locker, or ratchet rear will unlock the outside wheel during deceleration in a turn, so it works great on a race car, but probably not a good idea on a trike.

Oh, one more thing. I think the guys explanation of trail is off a little. Zero trail wouldn't be the pivot at the neck being in line with the axle, but lining up with the contact patch of the tire. Normally, on a bike, if you draw a line down from the neck to the ground, it will lead the contact patch of the tire by say 5". That would be 5" of trail. Hope that helps.

To clarify, a ford 8.8 is not a locker like some muscle car guys think of them. Its an open diff with clutch packs that limit the amount of wheelspin by transfering some of the load to the wheel thats not slipping

But I can see how a limited slip could get you in trouble if you broke both rear tires loose and werent going perfectly straight. Open diff would be safer, but then you would get the 1 wheel burnouts.

Also how much limited-slip action you get is going to depend on how worn the clutch packs are in that diff

Thanks big irish.
Think the 8.8 would be ok then? I was told a posi or limited slip is a recipe for danger.
Cornering with the light weight leads to being pushed thru turns and if one wheel spins thens locks it can slam you around backwards due to the fast tire grabbing. RR

earthman said:

You will know more about the width when you start stacking parts together of course. I'm really not following what your friend was advising about the posi not releasing in a corner? Without posi that amount of power with low weight would make tire spin a constant nagging problem. I used large diameter copper tubing to a rear mounted radiator. Easy to work with and looks so Steampunkity.
Really looking forward to your build thread RR. Soon to have a total of four rats
on the road so i really need to be thinking about building something like this now.

Click to expand...

Steampunkity?

now THAT is a word to be reckoned with!
it's fun to type too!
Steampunkity [cl[[P

Steampunkity