Spridgets and Road Grooves / Ruts

[Jim_Gruber]

Folks is your Spridget extremely suceptible to changes in road surface i.e. uneven asphalt, road grooves, mound of asphalt displaced by heavy trucks, etc. You know wht I mean, crappy uneven road surfaces. Bugsy my 68 Sprite seems extremely sensitive to several roads in the area and I need to be very vigilant in driving particularly at speed. One road in particular I drive on every day the difference in level between center hump and tire tracks is a good 6". Now my Acura or Subarban can straddle those humps but not a Spridget. Bugsy really moves around as he tries to follow the undulations and irregularities of the road surface but its a two hands on the wheel time.

Front end has been rebuilt, sway bar installed along with lowering kit, new Peter C Shocks all around, steering rack has been rebuilt, tires correct pressures, and camber set to 1/8" or so. I love the responsiveness this setup brings but driving down some roads that see heavy truck use is just plain scary. Any suggestions to keep responsiveness but at the same time reduce tendency to follow every change in road surface.

 

[Sarastro]

I haven't noticed anything like this, but we don't have many roads like that either. Remember your sprite is much narrower than virtually all modern cars, so it won't fit the ruts as well. I'd expect to feel them a lot, especially ones as large as those you describe.

 

[Pythias]

The tires CAN make a difference, but since your ruts are THAT bad, it really wouldn't improve to change them. .. I drive ON the hump instead of trying to straddle it. most often towards the left of the lane, but if there are oncoming cars then towards the shoulder. It DOES take attention to keep one side of the car on that hump, but at least the car doesn't dart around.

 

[Jim_Gruber]

Bill,

You've been to Dayton I know and know just how bad our roads can be around here. What I really need to do is drive another Spridget on those same roads and see if it's the roads or Bugsy. 8 years of owning Bugsy and I've never driven another Spridget. Now if your brother would get his act together and get his BE running...

 

[RickB]

I drive down I-90 every day and there are a couple spots just east of Issaquah westbound that scare me pretty good. In fact a few years ago there was a huge crash there between two trucks and one passenger car. Fire & death kind of thing.
Anyway, there are cracks and uneven pavement right there and Frank really darts around. There is also some kind of spring or something that spreads water out over the roadway through some of the cracks.
I notice that if I underinflate the tires to about 20 lbs it doesn't have near the trouble - but then I spend more on gas.

 

[WALTER]

Hi Jim,
My Sprite isn't on the road yet. But my experience from other vehicles tells me it could be slop in the suspension (i.e. tie rod end) or an alignment issue. Jack up one side of the front end and see if you have any play in the steering direction.

Good luck,
Walter

 

[zimmy]

drop ur tire pressure 5 lbs and see
how it goes....z

 

[texas_bugeye]

Mine really jumped around till I readjust the plunger on the steering rack.
I removed 1 washer and it made a heck of a differance.It really wasnt noticeable as far as wheel - road feel but it did make it less jumpy.
All the front bushing and rod ends and everything else are new.

 

[Pythias]

Bill,

You've been to Dayton I know and know just how bad our roads can be around here. What I really need to do is drive another Spridget on those same roads and see if it's the roads or Bugsy. 8 years of owning Bugsy and I've never driven another Spridget. Now if your brother would get his act together and get his BE running...

Nope, Never been to Dayton Ohio in my life. And my brother doesn't have a British Car, AT ALL.. must have me confused with someone else?

 

[asoupley]

Hey Jim,

I live just a few minutes away from you. You'll have to take a spin in my 70' and compare the difference. I'll warn you ahead of time, she is roadworthy, but I still have a LOT to do to her.

Just let me know when.
Tony

 

[RickB]

The other Bill from Washington does have a brother with a spridget, maybe you meant him? (BillM)

 

[Jim_Gruber]

Yep the other Bill M not Bill L. Confused I am.

Tony,

One of htese days we need to hook up and we'll trade for a short while. Just curious if Bugsy feels the same as other Spridgets in the handling category. And yes, Bugsy is always a continuous improvement project. BE Bonnet is ugly now and doesn't fit right yet, but I like it.

 

[JerryB]

""""""Any suggestions to keep responsiveness but at the same time reduce tendency to follow every change in road surface.""""""""""""


Usually more castor will make the car more stable if the roadway has been grooved or scraped for rain drainage for example. Now if the road is really really bad then there is not much you can do.

You want at least 3* negative camber and your camber """""""and camber set to 1/8" or so.""""" set to 1/8 negative and not "or so" but exactly. Toe should be 1/16" in. The castor is adjustable to add a few degrees BUT you must be very creative with the suspension.

Now another problem arises if you are using a 60 or 70 series tire that is quite a bit more wider than the original bycycle tires. The car will want to wander and tend to follow grooves in the road. The original suspension was "designed"? for bias ply narrow tires. Also try higher tire pressures.

All this implies that the front suspension (and the rear) is in good condition.

 

[Glen_B]

I didn't care for the bump-steer response of my bugeye, so I put ONE grade 5 washer under each front shock mount hole, raising the shock by about 2mm. This slight change in camber made a noticeable and appreciated difference in the steering and handling, particularly the response to bumps...
I'd thought about it for some time and decided to try it after seeing that on the yellow race bugeye that was on e-bay and craiglist in Reno a few months back. It was worth the effort.


Glen Byrns

 

[jlaird]

Did it make any difference in the centering of the wheels when comming out of a corner?

 

[Glen_B]

Jack,

I didn't feel any real difference with the re-centering of the steering after a corner. It still feels pretty neutral without any tendency to seek. That's the way I like it! The car and I get along best when only one of us steers.

Glen

 

[jlaird]

Hmmm, when you come out of a corner it does not try to center like a modern car?

 

[Guest]

A front end seeking center is a function of a combination of SAI (Steering axis inclination) and either positive or negative caster. Since SAI is a fixed value that can only be manipulated by offset wheels or taller or shorter tires, that leaves caster. Yours is likely dead zero or very close to it. Problem is, lack of self centering tends to cause wandering and/or unexpected pitching left or right at higher speeds. :shocked:

 

[Guest]

Several things come to mind..... First off, do you have radial or bias-ply tires? Bias ply tend to follow irregularities in the road surface way more than more compliant radials. Second, what about toe change under load? This is where the tie-rods are NOT parallel to the same plane as the lower control arm through out suspension travel, which I've seen toe change of up to an inch in a few cases where this wasn't adjusted out of the front suspension. (talk about recalcitrant steering tenencies!)
The next thought goes to caster... is there any caster or is it at or very near zero? Then I think about SAI... steering axis inclination. This is where the line through the ball (trunion) joints intersects the line through the center of the tire's tread at the ground. This can be off simply by having incorrect wheel offset or incorrect tire diameter.

A competent front end man should be able to get you set up properly! Good luck!

 

[Trevor Jessie]

Unfortunately there are no easy ways to adjust the caster on a Spridget.