<!-- / icon and ***le --> <!-- message -->I am working with a couple different steering boxes I have to determine which to use and a buddy comes by (he has been building hotrods since Moses parted the seas) and is pushing hard for me to set it up with cross steer. I have been figuring that I would put the steering box just inside the frame rail near the firewall, pitman arm up on the outside of the frame and run a drag link. What are the issues between the two styles? One issue is bump steer, but from what I know (almost nothing) if its done right bump steer is not too much of a problem. The car is short and has a lot of power Any opinions, suggestions, advice, pictures, lunch, money etc would be appreciated. <!-- / message --> <!-- sig --> __________________
OK I am learning too so what I say / ask may be totally wrong... Aren't hairpins and wishbones the same regarding configuration and angularity? Secondly if the box is near the firewall, that seems to rule out cross steer (as maddog said, he was gonna run side steer with this set up). Thirdly, I have seen rods in magazines with the drag link parallel to the wishbone, no where near the angle that would supposedly eliminate bump steer, what's up with that?
Just to clearify- With the box near the firewall I meant it would be side steer. Yes, Guy with the coupe, split wishbones and hair pins would be the same geometry (with respect to caster change), 4 bar would keep the axle in the same position (as in caster wouldn't change) but not exactly sure how this relates to bump steer. Also I, like you, have seen all kinds of stuff that has been done, but I am concerned with all this horsepower and such a short wheel base, bump steer could be a real problem under power, not that I would ever do such a thing.
Hi maddog, interesting question...i was talking to Rich the other day about which to use on my topolino..i figured vega cross steer to be easiest and maybe the safest with such a short wheelbase car as our's are,,,,as opposed to side steer..Rich said he thought it was a good line of reasoning...myself, i am just getting into the steering geometry on mine , hell i still have to get the front end i want here,,,but i been thinking alot about it ....at this point i am leaning towards hairpins, don't have a techincal reason for it, but i like the clean look they have over 4 bar...thought about split'n the whishbone i have laying here, but have rear too much about heating and bending them to get em dialed in...BUT REMEMBER I DON'T KNOW A THING ABOUT EM, SO.........i could be misleading about them..but it seems to me that hairpins only have 3 adjustment points, so caster should be reasonably easier to set then with 4 bar....maybe...right here would be a great spot for some of the EXPERTS to join in and set the record straight.... on another note, would be cool to see some updated pics of your topo.... .
The thing about wishbones is, short of bending them, you are stuck with the caster that you set them up with. I plan to set it up without bending anything and it that is not quite right, I will change the mounting of them at the frame. Just for you, Kid, some pics.
looks great maddog!!!!!!!!!!like that big block chevy ya got under there!!!!wonder what it weighs and what these lil things drive like in general???? so you aren't going to use the frame that was for sale with it and didn't you buy it with the car???man i been meaning to tell ya thanks for telling me to jump over to this forum....found my topo thru a lead that kinda came from here.............but that is another tail....metal is looking alot cleaner, tells me ya been busy..........gonna shoot you a im on a few things.....check it out when ya get a chance.........here's one pic back at ya....gotta lov the bare toes...the wife said i look like Fred Flintstone...also glad i'm almost 5'6" tall...not much room in here for tall people...yeah i'm a picture ***** tonite...hahahhahaha...
The caster is so easy to change a small pie cut up by the axle . Moses was a Great guy,and your buddy is a great person to suggest cross steer. It cuts bump steer why down. and makes the sreering very smooth
think i'm gonna go with a narrow super bell dropped axel...i am modifing a 28 ish ford model A frame to set my topo on....once i get the rear end then i can start to build the rea z section...
Two more Topolinos well on the way. I just love this place. Some day we will take over the hot rod world. O god, I just embarr***ed myself ! ! ! ! !
planing that TOPOLINO WORLD ********** thing again, Rich??????????? .........................hopefully we can plan a topo cruise in at YOUR place next summer....we just need to start a fuel fund to get maddog there from the far coast...i'm in for a gallon or 2..............,,,mayne i'll mail him my flathead plymouth 6 banger to make it easier (insert cheaper here ) to get here...he can trailer the bb chevy and we'll swap it out when he gets to my part of the world and then he can finish the trip belch 'in fire...........
A gallon or two? That'll help. Now I just need 800 gallons more. Good to hear the world ********** thing puts Fiats on top.
When my Anglia was originally built at Blair's, it had a Corvair box at the base of the firewall. A drag link went forward to a bell crank at the front of the frame that used a cross steer style drag link and then a conventional tie rod to connect the front wheels. It is a four bar/coil over set up. It was changer to a Vega later, I may go back to the Corvair/Bell Crank set up when we restore it later this year. Chuck Finders used this on many g***ers of the day. It allowed a four bar to be run with out any bump steer. There were no Vegas Boxes yet Remember if that little Fiat comes off the ground and smacks back down there is going to be a lot of wheel travel rather quickly and any bump steer will probably scare the bejesus out of you. I would either duplicate this set up simplify it with a Vega
here's the deal on bumpsteer with a draglink, the draglink must be the same length as and parallel to your wishbone/hairpin/parallel 4 link.
Xenia, even in a perfect arrangement, the axle travels in a different arc than the drag link, so some bump steer is unavoidable. anyone else, do I have this right? Hotroddon, I like that idea of a bell crank at the front of the frame. Brilliant, lets you put the box where you can and eliminates any bump steer, I like that idea. Front tires are gonna come off the ground? Gulp. Got any pictures of that arrangement?
maddog what I was explaining is to have the axle and draglink traveling in the same arc. picture a parallel 4 link, the reason caster doesn't change is because the upper and lower links travel in the same arc.
Here is the true scoop--With a cross steer set-up, bump steer is virtually eliminated, but there is one major caveat. With cross steering, 99% of the time the drag link which runs from the steering box across to the p***enger side spindle is going to be in exactly the same position as the wishbone. This is not a problem if you are running hairpin radius rods or parallel 4 bars, because the tie rod and the drag link can run between the upper and lower tubes. If you are running early Ford split wishbones, then you have to either heat and bend the spindle arms so that the tie rod and drag link run above or below the wishbones, or else buy aftermarket bolt on dropped spindle arms. This problem gets even worse if you are running a dropped axle. If you are running a small block Chev V8, there is also a real tight spot where the steering box, drivers side motor mount, and drivers side exhaust manifold outlet all end up in almost exactly the same spot. There are "work arounds" for the clearance problem, but it is damn tight. If you use the other style of steering, where the drag link runs from the steering box to the drivers side front spindle, you avoid a lot of problems, but the penalty you pay is bump steer.---from mild, to "Holy ****!!!", depending on how you set up the drag link position-wise in relationship to the drivers side front spindle and radius rod pivot points.
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