Hello Guys and Gals, I have been working on putting back together an old front engine dragster for a couple of years now, as money allowed, SOS . Had to completely replace sheetmetal for body and replace almost all tubing for frame , while still trying to keep her as she was in her Glory Days. My question concerns the amount of caster to have on the front axle? She is one of the old swb chassis rails @ 130 inches wheel base. Have built mild sb chevy for power, as she is mostly for fun now. But still need her to track straight though. Would love to hear from some of you who have run or are running one these ladies from the past. The new rear engine jobs just don't trip my trigger. Thanks
18*-22* max! Trust me ya don't want any more than that especially if you are running a front tire taller than 21". If you get it going and it feels twitchy to ya,slow the steering down.Do not add more caster.
Caster is where the wheel relates forward or back from center. If your axle is centered and measures the same back to a given point it will be zero . So everything would be fine. Camber is how far the top of the wheel leans in or out. Old photos show them straight up to a heavy negative camber probably due to wheelies and hard landings rolling them in at the top. I hope this helps.
""Caster is where the wheel relates forward or back from center. If your axle is centered and measures the same back to a given point it will be zero . So everything would be fine."" Huh????? I'm in no uncertain terms confused.
Always ignore the first couple of posts on HAMB. It's usually crap. Caster is the rotation angle of the king-pin from vertical. 15-20 degrees sounds good to me. The short wheelbase cars can be driven more than the long and fast cars. I wouldn't worry too much about tracking straight like say a 5 second car. A 10 second car you can drive like a malibu to the grocery store.
I asked 20 different people and got 18 different answers when I built mine. I went with 13 degrees. Anything over about 18 and it will be hard to back up if the wheels get cocked sideways. You will have to muscle them back straight. Under 10 and it will not be as smooth to steer. Hopefully ROOMAN will see your post as he seems to be the most knowledgable FED guy here, and has built some very nice diggers.
I ran 35* caster and negitive camber,1/8" toe-in, on my 127"w.b. FED.. 283SBC,pg 5:10 rear. It ran straight as a string.
We went thru this about a year ago when i was getting ready to put mine together. Got from stock to 30 from everyone and figured 15 was in the middle and went with that.
Correct a mundo on the hard to back up without flopping . Also the more that you put in the harder it is to bring the wheels back straight,as you are lifting the front weight of the car. Just my opinion-I could be wrong
I have run an FED for a number of years recently. I went from a standard 17" wire wheel with Goodyear front runners to a set of 18" 12 spoke Americans with speed rated Bridgestone M/C tires on 'em.The car originally had 28* caster. I used to back up real fast after a burnout and stage quick to rush the other lane. The first time I backed up fast after the wheel&tire change that car whipped my ass,or more to the point my right hand.LOL By the time I got my hand out of the butterfly and got the damn thing stopped I was damaged.I used to run a vertigate shifter in my 32 and couldn't drive the damn thing without severe pain for over 2 months after. Neil&Parks chassis who have one of if not the fastest Jr. Fueler in the country does not build a car with over 20* caster. I backed the caster down and never had a problem again. I test drove a car with 38* deg. of caster when I was looking for an FED and if you let or turned the car to full lock either way(when I say let I, mean if you turned the car any where near lock and let the wheel go it would turn to lock on it's own and you couldn't turn it back without outside help,and that sucks). Recardo,,,,The question was meant be facetious not serious.LOL Although I gotta admit I wonder what he meant.
I've got about 30 degrees in mine (going from memory) but I'm a FED novice. I would defer to the more knowledgebale guys like Rooman or Don Ross and the like. FWIW - I am way more concerned with going straight than I am backing it up. OTOH I figured if I have problems I can always make up a spare axle. I've looked at alot of the short wb old cars - they usually had a TON of caster. I wonder what cars like the Winged Express had/has. BTW - I could care less about your intro, however posting a digger question without posting pictures!! For shame!!!
my rail used 3.25 x 19" front spoke wheels also I didn't do burnouts so I didn't back up either, cause it has no reverse! but it would need assistance in the pits if the wheel was to the locks left ot right but with the big tire it didn't "flop" ove like a 17" spoke does on an anglia or p&s spindle.
As good as I remember the short '60s rails had something like 40 degrees - small tires with not much weight on them. Altereds with more tire and more front end weight ran 15 to 20 degrees.
My Dad's cars always ran alot (like 30*) and yes if he turned too far they would flop over I donno about nowadays cars with reverse that could definately be a problem He still has a Woody Gilmore car I could measure it if you need But it flops over too so its also got alot in it
15 to 25 is comon. The idea is it helps the car track straight. Set the toe in to .125 - .190 - depending on how ( sloppy ) the front end is - this will allow the wheel / tire to align under load to ( zero ) The ( wheel flop ) problem can be solved by adding a set of stops to your front axle - set them in a position to conact the spindle ( before ) the wheel / tire assb starts to lay over.
Well I was hoping to get a little helpful info on this board. But you guys came though with alot of helpful info, never happened on the other boards. She has 22 degrees caster now, had a hellava lot more when I got her so I didn't know if she needed more or not. The front tires are 3.25-19 or 110/90-19 as they are nowadays on bonranti wheels. Will set the toe at 1/8 inch, has very little "slop" in front axle. Will run her slowly for a pass or two to see if this seems OK. Will let ya'll know how she goes. Will try to post some pics soon. My wife calls her The Other Woman and says she wishes I would rub on her as much as I do the rail. Ain't she just too cool? Again thanks alot for the info. This Board Rocks
Oh yeah! First time I did a really hard cross-the-line-burnout in my little 120" FED "Short Circuit", and was backing up ,I thought I ran over the starter cause' I was fighting the wheel so much. Worse on a sticky track. Wish I still had that car. Last I heard it was in Oregon, I think around Coos Bay, and was called Oregon Outlaw II; and that's been several owners since I owned it. BUTCH.
do it your way, and know your car, 20* caster is enought to make a normal front engine car go straight , "back when" most cars with over 20* was there because the owner had the steering to fast. So they used more caster to help drive the car . And most of those guys did put stops on the front end so as not to let the tires flop in a turn. Have you seen old film were guys had to pick up the front of a car in order to get it turned around well those cars had stops on the front end . Here's mine
My AA Fuel Coupe car had 30 degree castor. It went straight as a string. HOWEVER,,,we never did burn outs and never backed up and if you turned too sharp while in the pits someone would have to aassist in putting the wheels back staright again. If you are going to do burn outs etc and back up, stop at about 15 to 18 dgrees.
Thats a wild front axle set up, kinda raises a hazey memory about it? Cant remember right now, who built it?
My 1969 Don Long car has about 35 degrees castor but as noted in other posts it was built in the days before backing up from a burnout was part of the pre run proceedure. On all of the new cars that we build we normally dial in about 18 degrees and that seems to work well with a 22" od tire on both front engine and back motor cars. If you have any shimmy problems on a run a little more castor may help although we generally cure that with a steering damper. Make sure that the wheels are balanced correctly too as that can make for an exciting ride when they start hopping up and down at speed. Good luck, Roo
The car is a 1958 Scotty Fenn Chassis Research Te 440 car. It was one of the first cars Scotty put in production, around 1960 NHRA required srping on front ends, this is one of a few unmolested chassis left
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