51 replies to this topic

[Brendan O]

Justin
Short answer... Run the rear a little lower than level.. This is base and tune from there. Don't be fooled by the body of the car.

On scale weights( static) if you raise rear perch you will put more weight on that corner..

On track if you raise the rear.. you will now transfer that weight faster to the front. Car will be looser raising the rear. To a point.. It may also help front grip..  TO A POINT!!!

What does not work is the Texas chopper.. Keep raising the rear bc you have no grip in the front. If the front is already too low and you raise the rear.. You transition instantly to solid suspension on the front and you get "death push". So raising the rear makes this condition worse. You would need to raise front before doing anything else.  If "EVER" you turn the front wheel and the car just grinds an refuses to turn, ALWAYS go to front ride height first. 95% of the time when you experience this condition, you are too low.

General speaking.. If not on the bump stop.. Lowering the end that has no grip will add grip.
Jim

 

This actually does clear things up a bit - at least for me.

[SaulSpeedwell]

I tried measuring shock travel last year with zip-ties around the shafts. All 4 zip-ties were jammed up inside the bumpstops. I figured it was a useless experiment, and that it was just the product of bouncing off the curbs. Was I wrong? Was the car too low? Where should the zip-ties be? Why do we have bumpstops if you shouldn't use them?

 

We may have a miscommuncation.  ANY good SM setup will have you hitting the bumpstops somewhere on the track, especially in the rear.  I'm talking about measuring the shock travel STATICALLY during your setup. 

 

The problems with using the pinch welds are numerous, although it is better than nothing, and there are plenty of fast guys and teams that at least claim to use the pinch weld measurement.  If all you care about is 1/8" precision, and you don't care about tire diameter (including in years when tires change from Toyos to Hoosiers), and you don't care about translating setups from one car to another one with a little body twist and smashed pinch welds, then the pinch welds are fine.

 

Admittedly, measuring shock travel is more difficult than measuring the pinch weld.

 

 

 

The problem with the pinch weld is

[DrDomm]

...I'm talking about measuring the shock travel STATICALLY during your setup. 

 

...Admittedly, measuring shock travel is more difficult than measuring the pinch weld.

 

Ok, how?

 

(I love threads like this...digging up month old posts...thanks.)

[Keith Novak]

Ok, how?

Measure the distance from the top of the shock body to the bottom of the bump stop.  It's more difficult because you have to get in there and there is a big coil spring in the way.

[Muda]

What does the tool you created to do that job look like?

[Keith Novak]

What does the tool you created to do that job look like?

Some people have calibrated their fingers well enough to stick them in the gap and know the distance.  These are the people who can also set diff lash by smell.  I'm not that good and my fingers are too fat so I made a set highly sophisticated tools that look a lot like bent pieces of wire coat hanger that have had a touch up on a bench grinder. 

[LarryKing]

A coat hanger bent something like this works  ________________/`````]

 

Since my finger   is exactly 17.4625 mm wide that's what I use.

[Bench Racer]

Since my finger   is exactly 17.4625 mm wide that's what I use.

It's a slow day at COTEX, so may as well play here.

 

Do you use KY jelly so that exact size finger fit dosen't get stuck.

 

Options are a good thing.

 

I don't want my finger stuck, therefore I measure from the bottom side of shock hat to the top outside diameter of the lower shock mounting bolt. Requires a standard measurement with the top of shock just meeting the FC bump stop before one starts schrunching the bump stops. Please do the above only for a 4 place metric dimension/tolerance. 

[Johnny D]

A coat hanger bent something like this works  ________________/`````]

 

Since my finger   is exactly 17.4625 mm wide that's what I use.

Like your drawing

J~

[DrDomm]

But if the car is on scale pads, there's hardly any room to get in there.

But let's say i can measure this. What's a good starting point?

[Bench Racer]

But if the car is on scale pads, there's hardly any room to get in there.

 

Are the scale pads on leveling platforms. IIRC my scale tops are 9 inches +/-  off the floor plus another 4 -5 inches to the bottom of the rocker panel for a total of 13-14 inches.

 

But let's say i can measure this. What's a good starting point?

Per this site 5/8-3/4 inch, read the set-up guide or pick a number, either way is a learning process.

[DrDomm]

Are the scale pads on leveling platforms. IIRC my scale tops are 9 inches +/-  off the floor plus another 4 -5 inches to the bottom of the rocker panel for a total of 13-14 inches.
 

Per this site 5/8-3/4 inch, read the set-up guide or pick a number, either way is a learning process.

Our leveling pads might be 4-5"...so like 9-10" of room. There might be some room for adjustment. Oh joy.

Yes, those measurements look familiar. Thanks.