Originally Posted by Track Junky (Post 493723)

No kidding....maybe we should transfer it over to the Bad Funny Finger thread :lol:

Originally Posted by Track Junky (Post 493723)

No kidding....maybe we should transfer it over to the Bad Invisible Finger thread :lol:

Originally Posted by FETorino (Post 493727)

Now that gentlemen is how you HiJack a thread.:trophy-1302:

Originally Posted by FETorino (Post 493727)

Now that gentlemen is how you HiJack a thread.:trophy-1302:

Originally Posted by compos mentis (Post 493736)

If any mod moves this thread it should be Flash.

And it should be done in :secret:...



:lol:

Originally Posted by Track Junky (Post 493741)

Not sure that would be appropriate....Rob might end up calling Daves thread Bad up yours Finger :catfight:

Originally Posted by Track Junky (Post 493717)

Hey mods....How about moving this great suspension technology stuff over to where it might be more appropriate for others to ask questions about their own cars? :idea:

Originally Posted by Ron Sutton (Post 493299)

Originally Posted by FETorino (Post 493712)

Ron

What would you consider Large-ish scrub radius in the case of these 275-315 range of tires?

I have heard that an inch or under can be thought of as zero.

Maybe a little more detail on scrub would be good. :idea:
I never created a descriptive verbal scale ... until now.

In my experience & by my personal scale ...
0-1/4" = Zero
1/4"-1" = Very Low
1-2" = Low
2-3" = Moderate
3-5" = High
5-7" = Very High
7" + = Extreme

* But this relative to the situation. When we designed a new Modified chassis that dropped the Scrub Radius from over 7" to under 5" ... we thought of that as "low scrub radius ... for the NASCAR Modified class we raced in on the West Coast. :excited:

So, with this new "descriptive verbal scale" ... I need to restate my advice with a slight wording change.

If your PT car has a scrub radius "Moderate or higher" … you need to be careful with how much caster you can put in the car … because caster combined with a high scrub radius creates a “jacking effect” when you turn the wheels. Dynamically, this jacking effect “de-wedges” the car … loading the inside front & outside rear tires more … while also unloading the inside rear tire & increasing the degree the car diagonally rocks & loads the outside front tire.

All of this helps the car to turn better. But go too far … and the car will get loose on entry. This is where track tuning comes into play. If you have a large-ish scrub radius … sneek up on the caster you put in the car … until you get the car “free” on entry … then reduce the caster a tick … or tune something else to allow you to keep that amount of caster, so the car turns well in the middle. But don’t keep a set-up that makes the rear step out on corner entry.


I was having a conversation stating there is a nominal effect on scrub due to height differences in tires. That difference in scrub between a 30 and 35 series tire of the same section width on the same wheel would be pretty minimal and in real world probably insignificant. But with all things it is best not to assume and really dig into what amount of scrub becomes noticeable or detrimental.:headscratch:

:cheers:

Originally Posted by Ron Sutton (Post 493788)

[B]Hey Rob,

... I've seen drivers that couldn't tell you if they hit a pothole or not. So I think "noticeable" is also relative. :confused18:

.

Originally Posted by Matt.A (Post 493789)

Rob is probably going to have to worry more about swells than pot holes. Although if he does take his boat out on the road, I'd hate to be in it when he hits a pot hole with his hellaflush rims.