RT5 front suspension

Need some RT5 folks with "expert" knowledge.

I have a '83 RT5, chassis 418. It had a pro life early on, so possibly had some damage/mods made. The tub is in good shape, with no evidence of major damage.

In looking at the front suspension we see 2 different upper arms, and 2 different lower ones. Not sure which is OEM/original, where the "other" came from or when. Would like to know more.

Hopefully, I can get the photos attached.

Big differences >>> left upper: has a round tube on leading edge, with back fabbed sheet, plated together; right upper: from outside appears to be all sheet fabrication. different attachment details outboard, and looks like the angle between ends is different, however different offset details on ends, so, might work out the same from pivots. left lower: had arrow tubing; right lower is all round tube.

Would appreciate any information. Also, if something is "wrong" would like to correct, so might be looking to match styles/parts to have same on both sides. I'd think the fully plated upper arm with areo lowers might be right... If so, perhaps someone out there has some spares to offer?

Thanks.

Bob L.

Bob, if you don't get what you need here, you might contact Steve at Wulff Motorsports.

He raced an RT-5 in the Pro series in 1989 and 1990, and is quite an engineer (and overall good guy).

I'm not an expert, but did own/race an '83 RT-5 for a couple of years...

You seem to have the same situation I had when I first got mine - Different angle upper rockers.

They *can* work fine (you'd just need to have the coil spring perches at different heights), but having said that you'll surely *want* matching rocker arms. And by matching, I mean the angle and lengths. The different styles of fabricating are probably not important, just cosmetic.

Regarding the lower wishbones, take them off and lay them on top of each other. The three ends should be the same.

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Originally Posted by RussMcB

I'm not an expert, but did own/race an '83 RT-5 for a couple of years...

You seem to have the same situation I had when I first got mine - Different angle upper rockers.

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Interesting.... wouldn't it be nice if they were opposite hand and could find/pair up to make 2 sets, one of each? Probably same sides, tho.

Which leads me to wonder it perhaps it was something done "in period" to setup cars on ovals? My car ran some Indy/PPG support races back then (Pocono, Milwaukee, IPR,....)

More to be learned...for sure. Hoping more chime in............

Thanks.

Bob L.

The right front suspension are original "OEM" to me. That left front rocker is something I've never seen, & I don't remember Ralt using streamline tubing back then for the lower a-arms, just round tube.
nick

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Originally Posted by last

The right front suspension are original "OEM" to me. That left front rocker is something I've never seen, & I don't remember Ralt using streamline tubing back then for the lower a-arms, just round tube.
nick

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Thanks. Believing you're right...Further looking: lower round tubes are repeated on rears. My front round one (RF) has camber adjustment built into outer rod end mounting, where the aero on left front doesn't...have to unbolt from upright to more rod end on left side.

Another difference I've found is to the outer attachement on upper arms/rockers. That RF "OEM" had a reinforcement strap over the outer "eye". Had same on LR upper/rocker, where the RR didn't have the doubler strip over eye... Other than the doubler over eyes, both rears appear OEM/same build/finish.

Found it "odd" too, that there are rear body mounting tabs on both arms inboard end, next to the toe link...so, bodywork moves with the suspension at back... not a lot, but is always going up and down....?

More I look, the more I find.... Impressed, the RT5 is a pretty efficient design when compared to my 80 March SV... much simpler and straight forward.

Bob L.

edit: NOW to find some OEM early stuff for the LF..... HELP?

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Originally Posted by Bob L.

<snip> ..., where the aero on left front doesn't...have to unbolt from upright to more rod end on left side.

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Ugh. That sounds like a major pain. I'd be looking to change that (if you expect to make camber changes often).

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Found it "odd" too, that there are rear body mounting tabs on both arms inboard end, next to the toe link...so, bodywork moves with the suspension at back... not a lot, but is always going up and down....?

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Can we see a picture of that? Sounds intriguing.

I was lucky when I got my RT-5 fifteen years ago and was able to pick up some spare suspension parts from someone to help me get matching rocker arms. Hopefully you can do the same. Sorry - I don't have any good leads for you.

I like the design of RT-5/4's, too, probably because I first started getting interested in SCCA races in the early 1980's. So, now I just think the Ralt supervees and atlantics are the way race cars are supposed to look. :-)

The RT-2's are cool, too.

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Originally Posted by RussMcB

Ugh. That sounds like a major pain. I'd be looking to change that (if you expect to make camber changes often).

Can we see a picture of that? Sounds intriguing.

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yup on camber...no easy fix, unless I get another arm.


let's see if I can get photo....not easy doing that on apex for me...


https://www.apexspeed.com/forums/att...id=89435&stc=1

Think I got it....(running out of room for pics. saved to apex....)

You can see the twisted, sheet metal tab bolted to toe link. There's a Dzus fastener in upper part for body...

I started much earlier than 80, but thought the RT4 was just the best plunder I'd seen when my first at MAR....local Dr.who was always fast...

Bob L.

Yeah, that's interesting. I have not seen that on any of the (low number of) Ralts I've seen with bodywork off.

I don't know how easy it will be, but I'd try to find someone with spare parts they'd sell. May they are out there. You never know. Barring that, I'm sure someone here can suggest someone to make a matching spare (like Pat Prince).

Or, just use what you have. It wouldn't be the end of the world.

Thought of Pat, but since he packed up shop.......? Might have been one who made made my parts, too. Car was from Iowa, sure owner knew of Pat...

Rather like to get "right" bits.. with no connector links other than the blades, requires a slight pre-twist to reach different rocker heights, blade hole in bulkhead on left had been elongated....isn't ideal..(again, maybe for ovals?)

Keep outlook for parts going, thanks.

Bob L.

Yes, getting the front ARB to slip into the mismatched rockers without preload could be a problem. Maybe you could make a set of offset pillow blocks.

Depending on the track spec you have, I might be able to match these. Some rockers were made for ovals with a different angle. These IIRC did not have a need for sway bars up front as the springs were so stiff the bars didn't help. Therefore, the misalignment of the holes wasn't a factor. If you were using standard rockers then you would use extremely stiff sway bars on the ovals, up to and including solid bars.

There were several shops that would make their own rockers so don't be too concerned about the differences in appearance. The addition of reinforcing straps was often done to keep that weak area from breaking with slight impacts with either another car or a brush with the wall.

The rear body attachment is something I've never seen. Strange and shouldn't be needed. Possibly an attempt to keep the skirts firmly on the ground on the ovals.

I have narrow track and medium track rockers. If nothing else, I can let you have some cheap and you can use them as starters for proper fitments by a shop. I can recommend someone if needed. Let me have the track measurements - i.e. distance from upright mounting to pivot, and distance from shock attachment to pivot. Also, as best you can, the angle of the rocker. I also have a ton of sway bars, both front and rear.

Thanks, Charles. Will try to get some measurements in near future.

In info that came with car was a letter from Ralt to Truesports, 14Jan 83. In part it said: "Front anti-roll bar had been removed for shipping,......For Identification purposes the oval circuit bars have been painted red on one end..... Awaiting material for the softer bar, will ship with 2nd car...." Of course, this is early in the history. But does show different stuff for oval from "std".

A later page covered front anti-roll bars.... Said: "the car was supplied with alternative front anti-roll bars...bar fitted is for road racing, alternative bar is for ovals.... Oval bar itself is mfgr'd. with 3 deg of wind in it for setting up for the oval, which is equiv. to approximately 1 1/4 deg bank of the chassis. There is adjustment for this in mounting blocks... left hand have vertical slotted holes and right handed blocks have horizontally slotted holes... When you have set up required, check to make sure bolts are tight"

So, does appear some early stuff for oval vs. circuit racing from Ralt.

figured others might like to hear this.

Hope we can find a rocker for my left front and lower tubular a-arm....

Again, thanks. Will pm or email you (off line) when I have some numbers....

Bob L.

I'm glad Charles weighed in. He may know more about Ralt parts than anyone on this side of the ocean.

I'm also glad to learn about the slotted ARB mounts in front. I thought they were plain holes. I'll have to check mine out.

Marc Bahner probably has made more Ralt parts for FA or FSV than anyone in the country and in every variation used for ovals or road racing for nearly every team. He told me that he sold the jigs to someone but if you contact him he probably can fill you in. That's Marc Bahner Engineering.

Thanks for the thought....

Been learning a lot, since post. Charles W. has been very helpful. Seem 83 is sort of a 'tweener....different arms/uprights/track than most others. Believe, for now, will ride with stuff that is on my car... looks odd, but better dimensional checks match other side, and it's all here, now.... nothing else to buy. Will keep "odd/funny" look, as part of the car's history......real racers often have scars...

Heard great things about Marc. I've tried to contact him a few times (past&recent) about my 80MarchSV/history, has one of his tags.... never heard anything back.......so,,,,, guess he's not wanting to talk (with me?) about that...?

Again, thanks.

Bob L.

Marc probably doesn't have any info on the 80SV. He kept little tub-specific info, maybe the Bahner tub number.

You can reach him at 805.499.7301

Marc is moving for the next couple of weeks so may not be available until after that.