Rod ends and jam nuts

We get our rod ends from (aptly named) Rod End Supply. Because we order in big batches (up to 500 at a time), we can give you a price break on small batches. RES offers three styles that are particularly appropriate to our cars:

To decode the part numbers, the suffix has an M or F for male/female thread, a number for diameter (as with aircraft hardware, diameter is referenced in 16ths of an inch, so 8 = 1/2”) and an L after the M/F for left-hand thread when appropriate (rights may have an R, but if there’s nothing, a right thread is assumed). Since rod ends for Locost suspension pickups (the connection between the control arm and the chassis) are generally male and half inch, and since traditionally the the rod end next to the chassis is left thread, the most common suffix is ..ML8, with a few ..M8 as needed for adjustment.

LX Series

My personal Locost fave. A self-lubricating, self sealing NylaFiber* race, and C1045 mild steel body for 6,660 pounds ultimate static radial load, which should be sufficient unless you hit a fire hydrant at speed. The Official Part Numbers are LXM8 and LXML8. Don't try to augment the self-lubricating feature by adding additional lubricants (WD-40, goose grease, motor oil, whatever) to the mix, as other lubricants may compromise the material of the race.


X Series

Exactly like the LX except with a heat treated 4130 chromoly steel body, good for16,238 pounds ultimate static radial load, which means if you hit a fire hydrant, you still won’t be driving home, but your rod ends should be in pretty good shape after they’ve been extracted from the wreckage.

And when I say, “exactly like,” I mean exactly; same shape, same finish, you literally can’t tell them apart without a hardness tester. We put a felt pen ‘X’ on the ones that come into our shop, but to avoid the possibility of screwup, when you order XM8 and XML8 rod ends from Kinetic, we have them drop shipped to you direct from Rod End Supply.


E Series

E for economy. These are two piece rod ends--a hardened/chromed ball and a mild steel body, with no race. Unlike the LX and X, the E requires lubrication and wears out anyway (metal-to-metal ball joints are one reason old cars were called “clunkers”). They’re plenty strong (12,224 pounds ultimate static radial load; since there’s no race there’s more material in the body) and if yours is only going to be driven short distances on warm weekends and you don’t mind walking around your car every morning with an oil can in your hand, they’ll save you dang near a hundred bucks.

I don’t recommend the E series for most folks because, in the long run, they aren’t as economical as the LX series, but we offer them, and offer them at a deep discount, because A) some Locosters have very little money to work with, and us offering cheap strong rod ends may save them from the temptation of cheap cast crap available elsewhere, and B) these are the rod ends you want if you’re entering the $202x Grassroots Motorsports Challenge**.


Jam nuts

Jam nuts are thinner than full nuts—the 1/2” size are 5/16” thick, versus 7/16” for full nuts (the big fat one on the right is a full nut, included for comparison), so naturally*** they cost more. The weight savings isn’t particularly significant, but the 40% increase in adjustment range sure is. Presuming the standard ..M8 threaded length of 1-1/2” and a minimum insert depth of 3/4” (diameter times 1.5), a jam nut allows 7/16” for adjustment and a full nut only leaves 5/16” I believe the “SJN..” prefix stands for Steel Jam Nut, and the rest of the number is self-explanatory (SJNR08 for right, SJNL08 for left).

What your Locost will need:

If you're building a “book” chassis…

Wait a minute. If you’re going straight by the book, you’re using rubber bushings scrounged from a Triumph Herald or the like, but most Locost builders nowadays use ball rod ends, for adjustability, precise fit, improved handling, and bling. So if you're building a book-but-with-rod-end-suspension-pivots chassis, you'll need:

(11) ..M8; 4 for trailing arms, 1 for Panard rod, 6 for front suspension pickups

(7) ..ML8; 2 for front suspension pickups, 4 for trailing arms, 1 for Panard rod,

(11) SJNR08 and (7) SJNL08 for the above rod ends,

and perhaps two ..M10 rod ends or studded rod ends for the upper control arms, depending on what spindles you're using, plus their accompanying SJNR10. Please contact us with your particular needs, for price and availability info—we generally have LXM10 and LXML10 in stock and quick access to other styles.

If you're building an IRS chassis, you'll need...well heck, you'll need to figure it out yourself 'cause there's a dozen ways of doing it, but we're confident you'll want lots of rod ends and we're ready when you are.

...or back to

*What’s NylaFiber? A proprietary composite material by Rod End Supply, which I presume contains nylon and fiber. They said the new fiber helps them move more freely than the fiber they used to use (which was Kevlar), so I figured, maybe it’s wheat bran. I asked the company’s president, Bob Douglas; he said no, NylaFiber is “…a Nylon Fiberglas matrix laced with a special lubricant. There are other things that make up the material but these are the base ingredients.”
**A drag, autocross and concourse competition for cars that cost no more that $20xx to build (your labor is free). It’s been going on for years, with annual budget increases of a dollar to compensate for inflation.
***Maybe they make jam nuts by grinding 1/8” off of full nuts.