Looking to make your car faster? Don’t underestimate the power of suspension upgrades. Most people take their suspension cues from fellow enthusiasts–buddies or message board gurus who own a similar car. Peer acceptance of a parts combination can be quite reassuring, but can these formu…

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Shaun
Shaun Dork
8/6/21 11:39 a.m.

This sort of relates to 'useless chassis bracing' by making a useless brace work:  I've noticed on three cars that had 100k plus on them that tightening the bejezzus out of the fastners that join the steel weldment that serves as the chassis for the dash sub assy to the cars frame firms up the steering feel, makes the car stiffness a few Hz lower, and wipes out some dash rattle & squeek for the price of a skint knuckle or two.    

jimgood
jimgood New Reader
1/13/22 4:17 p.m.

Don't be like some people (me). Check the preload on your springs. Lack of preload can cause some very weird handling issues, especially on diagonal corners.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
1/13/22 4:24 p.m.

In reply to jimgood :

No. The preload you're thinking of is a side effect of adjusting bump travel. You want bump travel. Preload may come as a result of that, but it's not the preload that's helping. There are a bunch of ways to prove this, the easiest of which is to change spring lengths and perch position without adjusting shock body length.

The only time preload comes into suspension tuning is on the initial movement of a fully extended wheel. That's a factor in motorcycles because they've got such insane acceleration and a high CG, but it's almost never a factor in a well set up car.

trigun7469
trigun7469 SuperDork
1/13/22 4:53 p.m.

Thanks for sharing this great

MrFancypants
MrFancypants HalfDork
1/14/22 9:38 a.m.

My most common suspension issue is bad/loose anti-roll bar links.  Usually a rattle and clunk.  If it's one of the front links I can usually feel it through the pedals.  Noise usually only comes when one side hits a bump and causes the bar to twist quickly over that bump.  Sustained cornering doesn't cause the noise, and for whatever reason it tends to be quiet at freeway speeds.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
1/14/22 10:06 a.m.

A loose sway bar link will make noise when a lightly loaded wheel changes direction and the link goes from tension to compression and back. You won't hear it mid-corner because it's always under load, and on the freeway you don't get many sharp movements of the wheels. You're most likely to hear it in a parking lot as a rattle. Luckily, it's mostly a warning of a potential future failure and doesn't really affect handling until the parts come apart. Then you have a big increase in oversteer or understeer which can be exciting.

Heim joints/rod ends are a poor choice for sway bar links because the ends have a short lifespan, but they're common in the aftermarket because they're cheap and they're "race spec". Better to use rubber bushings or a ball joint. 

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