Slant Six Forum :: wheel hop during shifts *PIC*

: Hey guys hows it going?
:
: I have a wheel hop problem with my 69 dart. It
: only happens when I shift from 1st to 2nd. I
: have a 8 3/4 rear, 3.55 gears, posi,
: trailing lower link bars, dual stainless
: panhard bars. It only hops once but I still
: think it could break something. I do not get
: wheel hop any other time, just during the
: shift. I drag race and autox the car but I
: would like to keep the cornering part of the
: car as tight as possible. Any ideas?
:
: Thanks
: Andrew Wagner

: Maybe I'm missing something but it appears to
: me that you're trying to swing the axle in
: two different arcs at the same time . . .
: the result may be that you've effectively
: formed a rigid geometry between the lower
: links and the leaf springs. Its like you're
: running no suspension and so its tough to
: keep the wheels in contact with the road.

:
: That is the first thing that I thought of when
: I saw the picture.
:
: There used to be a product named "Traction
: Masters" that worked like what you are
: trying to do. The rear pivot point has
: centered under the axle and the front pivot
: was centered under the front spring mount.
: Thus perserving the suspension arc.
:
: Competion Engineering used to make a similar
: setup that had the front pivot bolted onto
: the spring right before the spring eye and
: the rear pivot just aft of the axle. They
: also had the bar running a bit longer, past
: the reat pivot point, so you could lock-out
: the spring action by running a bolt thru the
: rear bar.
:
: The current Cal-Tracs do something similar,
: with a more elaborate front mounting point,
: combining the spring and bar into one.
:
: The panhard bar may also be excessive. The rear
: suspension is fairly stable when you use
: poly bushings and good shackles.

: I had wheel hop durning accleration before I
: had the bottom link bars. I do not have any
: wheel hop now.

: I had wheel hop durning accleration before I
: had the bottom link bars. I do not have any
: wheel hop now. It only hops one time and
: that is during the 1st to 2nd shift. Its
: very quik but I still think it should not do
: that. The panhard bars are a something that
: I can not do with out. The rear supenion is
: too lose for autox, the car would just be
: all over the place without them. I only want
: to see if I can solve the one hop during
: shifts.
:
: Thank you for the info on the supenion!!!
:
: Andrew Wagner

: I too, was wondering if the problem was an over
: aggressive shift kit in the 904. Matt, the
: pivioting axle over the leaf spring with the
: control bar is called a "leaf
: link". How to make one is described in
: my old DC manuals. Just about everybody
: abandoned that approach for 4 links and
: ladder bars and of course the cal-tracs. I
: don't think it would be good for an
: autocross car. But maybe with the panhard
: bar... Hmmm, I will have to think on that
: one.

Author:	andrew [ Tue Sep 24, 2002 2:29 pm ]
Post subject:	wheel hop during shifts PIC
Hey guys hows it going? I have a wheel hop problem with my 69 dart. It only happens when I shift from 1st to 2nd. I have a 8 3/4 rear, 3.55 gears, posi, trailing lower link bars, dual stainless panhard bars. It only hops once but I still think it could break something. I do not get wheel hop any other time, just during the shift. I drag race and autox the car but I would like to keep the cornering part of the car as tight as possible. Any ideas? Thanks Andrew Wagner

Author:	cycledog [ Tue Sep 24, 2002 3:29 pm ]
Post subject:	Re: wheel hop during shifts
Quote: : Hey guys hows it going? : : I have a wheel hop problem with my 69 dart. It : only happens when I shift from 1st to 2nd. I : have a 8 3/4 rear, 3.55 gears, posi, : trailing lower link bars, dual stainless : panhard bars. It only hops once but I still : think it could break something. I do not get : wheel hop any other time, just during the : shift. I drag race and autox the car but I : would like to keep the cornering part of the : car as tight as possible. Any ideas? : : Thanks : Andrew Wagner Do you have a pinion snubber? cycledog@iglide.net

Author:	Doc. [ Tue Sep 24, 2002 5:18 pm ]
Post subject:	Re: wheel hop during shifts
Quote: : Hey guys hows it going? : : I have a wheel hop problem with my 69 dart. It : only happens when I shift from 1st to 2nd. I : have a 8 3/4 rear, 3.55 gears, posi, : trailing lower link bars, dual stainless : panhard bars. It only hops once but I still : think it could break something. I do not get : wheel hop any other time, just during the : shift. I drag race and autox the car but I : would like to keep the cornering part of the : car as tight as possible. Any ideas? : Thanks : Andrew Wagner Uhmmm...trailing lower link bars, dual stainless panhard bars... Do you still use leaf springs or is it now a coil spring? Anyway, the car look nice, the rear looks pretty low, is it soft or stiff on the rear spring rate? Need more info here, sounds like you have moved away from the standard A-Body leaf spring set-up. My guess is that you need more axle "wrap-up" control. DD

Author:	Dart270 [ Wed Sep 25, 2002 5:44 am ]
Post subject:	Re: wheel hop during shifts
Quote: : Hey guys hows it going? : : I have a wheel hop problem with my 69 dart. It : only happens when I shift from 1st to 2nd. I : have a 8 3/4 rear, 3.55 gears, posi, : trailing lower link bars, dual stainless : panhard bars. It only hops once but I still : think it could break something. I do not get : wheel hop any other time, just during the : shift. I drag race and autox the car but I : would like to keep the cornering part of the : car as tight as possible. Any ideas? : : Thanks : Andrew Wagner Hey Andrew, Sounds like you're having some fun. I thought you were running a 904? Are you sure it's wheelhop, because it seems like that would show up off the line first. If you are still running leaf springs, I recommend going with some new leafs. I've seen new springs (not necessarily even stiffer) cure wheelhop on several Mopars. Keep the rubber side down, Lou

Author:	andrew [ Wed Sep 25, 2002 12:15 pm ]
Post subject:	Re: wheel hop during shifts PIC
I still run the stock leafs. I know that they are old. Here's a pic. The shocks are new. Just reg ones.

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wheel hop during shifts PIC https://slantsix.org/forum/viewtopic.php?t=4219	Page 1 of 2

Author:	andrew [ Wed Sep 25, 2002 12:30 pm ]
Post subject:	Re: wheel hop during shifts PIC
Here's A pic of the back end at a corner!

Author:	Al T [ Wed Sep 25, 2002 12:40 pm ]
Post subject:	Re: wheel hop during shifts PIC
Maybe I'm missing something but it appears to me that you're trying to swing the axle in two different arcs at the same time . . . the result may be that you've effectively formed a rigid geometry between the lower links and the leaf springs. Its like you're running no suspension and so its tough to keep the wheels in contact with the road. ahtoews@shaw.ca

Author:	87Slant_sickness (Justin) [ Wed Sep 25, 2002 2:49 pm ]
Post subject:	Re: wheel hop during shifts
Hey andrew! so your sure this is wheel hop from 1-2 gear? my truck with an almost stock engine spins its tires after a clutch dump from 1-2 gear when i race, in the rain its difficult to drive, i can spin my tires up to 55mph sometimes, i have traction bars for an A-body with a 8 3/4 rear if your interested (been saving for when and if i get an A-body)and they'd stop wheelhop noproblem, i have a set for my truck that are custom made and i haven had a chance to put em on! Justin slantsickness@hotmail.com

Author:	kesteb [ Thu Sep 26, 2002 11:49 am ]
Post subject:	Re: wheel hop during shifts
Quote: : Maybe I'm missing something but it appears to : me that you're trying to swing the axle in : two different arcs at the same time . . . : the result may be that you've effectively : formed a rigid geometry between the lower : links and the leaf springs. Its like you're : running no suspension and so its tough to : keep the wheels in contact with the road. That is the first thing that I thought of when I saw the picture. There used to be a product named "Traction Masters" that worked like what you are trying to do. The rear pivot point has centered under the axle and the front pivot was centered under the front spring mount. Thus perserving the suspension arc. Competion Engineering used to make a similar setup that had the front pivot bolted onto the spring right before the spring eye and the rear pivot just aft of the axle. They also had the bar running a bit longer, past the reat pivot point, so you could lock-out the spring action by running a bolt thru the rear bar. The current Cal-Tracs do something similar, with a more elaborate front mounting point, combining the spring and bar into one. The panhard bar may also be excessive. The rear suspension is fairly stable when you use poly bushings and good shackles. klesteb@aol.com

Author:	Matt Cramer [ Thu Sep 26, 2002 3:47 pm ]
Post subject:	Your suspension is binding.
The locating links in that setup give you pretty questionable suspension geometry. The leaf springs force the suspension to follow one arc, while the links move in a different arc. The result is that the springs have to twist, or the links have to stretch, for the suspension to go anyplace. This not only causes wheel hop, but it places considerable stress on the parts. It's only a matter of time before something breaks. And trying to figure out what the suspension geometry of a setup that relies on its parts bending is a nightmare. While Chevy guys with their flexy monoleaf springs can get away with running those kinds of bars, Mopar drivers can't. You need a design that works with your leaf springs, not against them. The simplest way is to make a link that basically stiffens up the front leaf, like the Cal-Trac bars. You could, presumably, change your leaf spring perches so as to make the axle rotate around the leaf springs, but that seems like a lot of work.

Author:	andrew [ Thu Sep 26, 2002 5:40 pm ]
Post subject:	Re: wheel hop during shifts
I had wheel hop durning accleration before I had the bottom link bars. I do not have any wheel hop now. It only hops one time and that is during the 1st to 2nd shift. Its very quik but I still think it should not do that. The panhard bars are a something that I can not do with out. The rear supenion is too lose for autox, the car would just be all over the place without them. I only want to see if I can solve the one hop during shifts. Thank you for the info on the supenion!!! Andrew Wagner Quote: : : That is the first thing that I thought of when : I saw the picture. : : There used to be a product named "Traction : Masters" that worked like what you are : trying to do. The rear pivot point has : centered under the axle and the front pivot : was centered under the front spring mount. : Thus perserving the suspension arc. : : Competion Engineering used to make a similar : setup that had the front pivot bolted onto : the spring right before the spring eye and : the rear pivot just aft of the axle. They : also had the bar running a bit longer, past : the reat pivot point, so you could lock-out : the spring action by running a bolt thru the : rear bar. : : The current Cal-Tracs do something similar, : with a more elaborate front mounting point, : combining the spring and bar into one. : : The panhard bar may also be excessive. The rear : suspension is fairly stable when you use : poly bushings and good shackles.

Author:	Matt Cramer [ Thu Sep 26, 2002 7:18 pm ]
Post subject:	Re: wheel hop during shifts
Quote: : I had wheel hop durning accleration before I : had the bottom link bars. I do not have any : wheel hop now. They may cure wheel hop, but those link bars are not a good match for the suspension. They turn it into a wierd, bound-up hybrid between leaf springs and a four link. I still say you should either get something that stiffens the front leaves, or go to a true four link. : : The panhard bars are a something that : I can not do with out. The rear supenion is : too lose for autox, the car would just be : all over the place without them. I only want : to see if I can solve the one hop during : shifts. I can't see the Panhard bars from the picture you posted, and I'm having trouble imagining how you could use two of them. Can you post a picture showing them, or a sketch of how they're arranged?

Author:	Dart270 [ Fri Sep 27, 2002 6:49 am ]
Post subject:	Re: wheel hop during shifts
Quote: : I had wheel hop durning accleration before I : had the bottom link bars. I do not have any : wheel hop now. It only hops one time and : that is during the 1st to 2nd shift. Its : very quik but I still think it should not do : that. The panhard bars are a something that : I can not do with out. The rear supenion is : too lose for autox, the car would just be : all over the place without them. I only want : to see if I can solve the one hop during : shifts. : : Thank you for the info on the supenion!!! : : Andrew Wagner Andrew, Are you sure your "wheel hop" is not just a second gear tire scratch? Just thought I'd ask. Also, Matt is right, I can't see any Panhard bars in your pic. A Panhard bar mounts parallel to the axle housing and it would be tough to use two Panhard bars without causing the same stretching/bending problem of arcs. A Watts linkage might help, though. Check out <A HREF="http://www.tsmmfg.com">www.tsmmfg.com</A>. If you have old leafs and have never tried new, I recommend you get some HD leafs with PolyU bushings. I only run leafs on my '64 rear suspension (no sway bar even), and it is not all over the place on the track. You may have to have the leafs de-arched or custom made so they are stiff but don't ride too high, but some strong 5 or 6 leaf packs ought to make a huge difference. Food for thought... Lou

Author:	kesteb [ Fri Sep 27, 2002 2:56 pm ]
Post subject:	Re: wheel hop during shifts
Quote: : I had wheel hop durning accleration before I : had the bottom link bars. I do not have any : wheel hop now. It only hops one time and : that is during the 1st to 2nd shift. Its : very quik but I still think it should not do I too, was wondering if the problem was an over aggressive shift kit in the 904. Matt, the pivioting axle over the leaf spring with the control bar is called a "leaf link". How to make one is described in my old DC manuals. Just about everybody abandoned that approach for 4 links and ladder bars and of course the cal-tracs. I don't think it would be good for an autocross car. But maybe with the panhard bar... Hmmm, I will have to think on that one. klesteb@aol.com

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Author:	Matt Cramer [ Fri Sep 27, 2002 4:40 pm ]
Post subject:	Leaf link?
Quote: : I too, was wondering if the problem was an over : aggressive shift kit in the 904. Matt, the : pivioting axle over the leaf spring with the : control bar is called a "leaf : link". How to make one is described in : my old DC manuals. Just about everybody : abandoned that approach for 4 links and : ladder bars and of course the cal-tracs. I : don't think it would be good for an : autocross car. But maybe with the panhard : bar... Hmmm, I will have to think on that : one. It won't behave like a four link at all unless the axle is free to rotate about the springs. If that were the case, that suspension geometry would give you some pretty severe wheel hop, so I'm assuming the axle is attached to the leaf springs in the conventional way. It looks to me like he's running a set of Chevy-style traction bars.