Automotive Race car suspension Class

[Ranger Mike]

Look amigo, I am trying to help you but you are not taking any advice to heart. i told you back in June, rt ft needs a 1050# spring lft frt needs a 1000# spring lft WITH a sway bar (ARB) which you do not have.
Why in the hel* are your running a left front spring stiffer than the rt ft? Rt frt tire is always the hottest tire temp. Put a 1050# spring in the right front and 1000# spring in lft ft and run it AFTER you fix the RC location to 3 inch rt side offset. Still will not be right due to absence of the additional ARB with additional spring rate ( 220 #) but will get you a whole lot closer to winning.
https://www.google.com/search?clien...ate=ive&vld=cid:5a6efc51,vid:V2f-MZ2HRHQ,st:0

 

[Ranger Mike]

Happy Labor Day 2024.

How about a single piston costing you $ 65,000!
Thats $ 520,000 for 8 slugs..a little out of my racing budget!!

 

[Cape15]

This may not be the right thread for this, but does anyone have any advice on what is the best bearing setup for wide 5 hubs? I was ideally looking for ceramic ball bearings but not seeing much results and was curious if anyone on here could share or recommend something! Thank you in advance!

 

[Ranger Mike]

We ran ceramic bearings on all four corners of the Formula Car. May have been a slight advantage due to less friction but in my opinion not worth the big expense. Metal bearings are a lot more forgiving and last longer. Was a nice thought but no real lap time advantage.

Now if you are going for land speed record at Bonneville over 300 mph or racing a car over 175 mph for hours, then the ceramic bearing will make sense. Less thermal growth than steel (see table). This means the inner and outer bearing race and the ball bearing itself will GROW with temperature. So if the bearing components will grow 0.0001" in size for every 72° F increase, things will get real tight real quick. We have all seen the right front hub of round track cars getting red hot on a long green run. Nascar right front wheels are 1200° F! Brakes play a huge part of this so we have cooling hoses blowing on the brake rotors.
A number of things can alter the radial play during the fitting process. A tight shaft fit where the shaft is slightly larger than the bearing inner ring (often called an interference fit or a press fit) will stretch the inner ring so making it bigger. This reduces radial play by up to 80% of the interference fit. A similar thing occurs if the outer ring is a tight fit in the housing. A difference between the shaft and housing temperatures can also be a problem. If a bearing inner ring gets hotter than the outer ring, it will expand more and reduce radial play. This can be calculated as follows:
Chrome Steel: 0.0000125 x (inner ring temp - outer ring temp °C) x outer ring raceway diameter* in mm.
440 Stainless Steel: 0.0000103 x (inner ring temp - outer ring temp °C) x outer ring raceway diameter* in mm.
* The outer ring raceway diameter can be roughly calculated as: 0.2 x (d + 4D) where d is the bore in mm and D is the outer diameter in mm.


There can also be problems where, for example, the shaft is made of different material to the bearing and housing and expands more due to a different expansion coefficient. In such a case, a bearing with a looser radial play may be needed.


A standard radial play is usually suitable and these bearings are more readily available but, sometimes, a non-standard clearance is recommended. A tight radial play is better for low noise, greater rigidity and running accuracy if the load is purely radial. A loose radial play is preferable for high axial loads as it increases the bearing's axial load capacity. It will also better accommodate misalignment between the shaft and housing.

An 80 mm diameter "loose " bearing ( high load applications) has 0.0007" play built in. Now you can see effect of thermal growth of inner , outer races and the bearings themselves.

nominal bore	C2 (tight)	CN (normal)	C3 (loose)	C4 (looser)
Over	Incl.	Metric .001mm	Inch .0001”	Metric .001mm	Inch .0001”	Metric .001mm	Inch .0001”	Metric .001mm	Inch .0001”
_	10	0-7	0-3	2-13	1-5	8-23	3-9	14-29	6-11
10	18	0-9	0-3.5	3-18	1-7	11-25	4-10	18-33	7-13
18	24	0-10	0-4	5-20	2-8	13-28	5--11	20-36	8-14
24	30	1-11	0-4.5	5-20	2-8	13-28	5-11	23-41	9-16
30	40	1-11	0-4.5	6-20	2-8	15-33	6-13	28-46	11-18
40	50	1-11	0-4.5	6-23	2-9	18-36	7-14	30-51	12-20
50	65	1-15	0-6	8-28	3-11	23-43	9-17	38-61	15-24
65	80	1-15	0-6	10-30	4-12	25-51	10-20	46-71	18-28
80	100	1-18	0-7	12-36	5-14	30-58	12-23	53-84	21-34

Less temperature disfussion ( runs cooler ) , lighter weight per bearing.
Make sense?

 

[Ranger Mike]

Pretty good weekend for Indy racing and Nascar

 

[UFO]

Track Tuning Tips
See post 1419 on page 41 for driver tips
Track tuning

Two things any crew chief better have in the tool box , next to the Rolaids, are Stagger tape and a Tire Pyrometer. Preferably one with a memory that will permit you to take readings and will display three readings per tire.

Tire temperatures are the only real way to tell what is going on and it is empirical. Learn how to use the tire pyrometer and make a habit of doing it correctly. I have a nice techy one that tell you to stab the right front tire inside, middle and outside then move to the right rear tire. The cursor ques you where to take the readings. Insert the sensor needle 1/8 inch into the tire at a 45 degree angle and be consistent. You will be stabbing three places on the tire face. Inside edge ( not on the edge but an inch from the inside edge) the middle and the outside ( not the very outside..,an inch from the outside edge). When taking readings try to do it as soon as the driver comes off the track as these tires cool very quickly. Tune and test day is ideal as you can do it on the track if you are solo ones in that session. Then jack up the car and take tire stagger readings right front first. Record the tire growth and this will tell you about stagger.


The optimal tire temperatures should be in a range of 190 to 240 degrees. On a short track it is normal for the outside edge of the RF tire & the inside edge of the LF to be 5 to 10 degrees cooler. This is because of the way the tires travel down the straightaway. On a larger track with longer straights, this spread will be even further. On an oval, the RF tire will have more negative camber, thus resulting in the inside edge of the tire contacting the track more than the outside edge giving you the higher temperature. On the LF you will run with more positive camber, so just the opposite holds true. While cornering these temperatures should even out if you have the correct amounts of camber & or weight transfer. The more camber you run, the higher these spreads will be. On a small track were you spend a lot of time cornering, you'll find the spread not as high. This is because your spending more time cornering than on the straights, thus distributing the temperatures across the face of the tire more evenly. If you try to achieve even temps across the tire you may develop a push. This is telling you that you have too much positive camber. Although the tire may be flat on the track, on a straightaway, the tire will not be flat on the track while cornering.
The best way to read tire temperatures is to run 10 laps on a particular setup. Read the temps and don't expect to learn everything reading the temps only once. It will take a number of these sessions to sort everything out that is going on with the tires. Make sure you are not locking up the brakes or making any sudden changes in your steering outputs. These will all create erroneous tire temperatures readings.

A tire with too much NEGATIVE camber will show an excessively higher temperature at the INSIDE edges. Lean the top of the tire out to the outside.

A tire with too much POSITIVE camber will show an excessively higher temperature at the OUTSIDE edges so lean the top of the tire in.

A tire that is OVER inflated will have a higher middle temperature than the inside & outside edges.

A tire that is UNDER inflated will have a lower middle temperature than the inside & outside edges.

A car with too much toe OUT will show higher temperatures on both INSIDE edges of the front tires.

A car with too much toe IN will show higher temperatures on both OUTSIDE edges of the front tires.

A RF tire that is HOTTER by more than 10 degrees over the RR indicates a tight PUSH (understeer) condition.

A RF tire that is COLDER by more than 10 degrees over the RR indicates a loose ( oversteer) condition.

A tire with the HIGHEST average temperature is the corner of the car that you should work on first.

A tire with the LOWEST average temperature is the corner of the car that you should work on second.

A RF & LR diagonal average that is the same or higher than the front & right side average indicates too much wedge.

A RF & LR diagonal average that is more than 10 degrees lower than the front average and right side average indicates not enough wedge.

Let’s look at a few examples.

RF
I----M----O
208--202--194
Indicates too much negative camber.

RF
I----M----O
194--202--208
Indicates too much positive camber.

RF
I----M----O
204--188--197
Indicates an under inflated tire.

RF
I----M----O
204--210--197
Indicates an over inflated tire.

RF
I----M----O
204--198--194
Indicates correct camber. Overall average temp is 198.6.

RR
I----M----O
227--225--223
Overall average temp. is 225.

If the RR & RF temp above came off the same car we have a very loose racecar. The RR is 26 degrees hotter than the RF. If this RR is also the hottest tire on the car, it indicates the RR is spinning and or sliding in the corners. We need to go to a weaker RR spring to keep more weight on this tire and prevent the wheel spin. This should cool this tire & tighten up the chassis.

Caution -Temperature Averaging works when you have a fast car and need to fine tune it. If your car is a log wagon and wallowing around like a whale cure the handling first.





Panhard bar
Do not forget- The mid point between the right and left side anchor points on both panhard bar and J bar is the Roll Center. This Rear RC can be offset many inches from the vehicle centerline.

When Panhard bar has chassis mount on frame right side the Rear roll center will DROP under body roll. Opposite if chassis mount on left side.

If you raise both mount points on the Panhard bar, you are raising the Rear RC. The rear roll center will still move downward in body roll as above stated.

Hi RM

Ranger Mike said
If the RR & RF temp above came off the same car we have a very loose racecar. The RR is 26 degrees hotter than the RF. If this RR is also the hottest tire on the car, it indicates the RR is spinning and or sliding in the corners. We need to go to a weaker RR spring to keep more weight on this tire and prevent the wheel spin. This should cool this tire & tighten up the chassis.

Doesn't a weaker spring on any side of the rear make less role couple in the rear, causing less load transfer on the rear and more on the front axle? This would make the right rear lighter not heaver.

 

[UFO]

Tie down shock keeps weight on rt ft forever .

I don't think a tie down shock on the right front keeps weight on, infact I think it does the opposite, When brakes and latteral force combine with max load on the rt front the spring compresses as far as it's going to. When it's tied down and some of the load goes away with no braking and some throttle the spring is pushing the axle and the frame apart with near the same force, but the shock is holding the axle and the frame together. The shock is unloading the the force on the axle corner weight equal the spring force minus the frame corner weight, so the resulting useable down force on the axle is the corner weight. Since the corner is compressed, it lowers dynamic cross weight, and should have less load. Do you agree with this theory?

 

[Ranger Mike]

see post # 1664

 

[Ranger Mike]

850,000 views...WOW, Thank you
rm

 

[Ranger Mike]

Good video on tire side wall flex, contact patch etc

 

[Ranger Mike]

I thought you would like some good news in 2026
So you think we don't make things in the USA any more???
Subject: US Manufacturing total GDP compared to the worlds GDP , a look at 2014 and today, end of 2025 estimate. ..the 2025 stats are not in yet!
Often when we talk about manufacturing and industry in this country, we talk about loss, decline and shrinking markets. Contrary to much of this type of news, many indicators show that our industrial economy is doing quite well and overall we are still the largest economy in the world.

Recent reports about the USA slipping to number two are based on projections and statistics using weighted methodology and are not accurate. These forecasters of doom and gloom make for comedic reading when you need a laugh.

China And India Will Overtake U.S. Economically By 2075, Goldman Sachs Economists Say


https://www.forbes.com/sites/dereks...goldman-sachs-economists-say/?sh=7642e65a8ea9 Totally WRONG!

Look at the telling data point of how well we’re doing - In 2014 Taken alone, the U.S. Manufacturing GDP would be the 11th largest economy in the world. Today THE UNITED STATES MANUFACTURING GDP $ 2.9 trillion , 8th biggest GDP

Nominal GDP Rankings by Country 2014​

1. United States $17.6 trillion
2. China $10 trillion
3. Japan $4.8 trillion
4. Germany $3.9 trillion
5. France $2.9 trillion
6. United Kingdom $2.8 trillion
7. Brazil $2.2 trillion
8. Italy $2.2 trillion
9. Russia $ 2.1 trillion
10. India $2.0 trillion
11. THE UNITED STATES MANUFACTURING GDP $ 2.04 trillion

That’s something to think about the next time you see a doom and gloom article about U.S. manufacturing. Here’s the full world economy visual from CNN Money.

We still make some of the best products in the world. This article from a few years ago gives a top 10 list of things made in USA. https://worldpopulationreview.com/countries/countries-by-gdp

Nominal GDP Rankings by Country 2023​

1. United States: $28.7 trillion
2. China: $18.27 trillion
3. Germany: $4.4 trillion
4. Japan: $4.1 trillion
5. India: $3.9 trillion
6. United Kingdom: $3.5 trillion
7. France: $3.1 trillion
8. THE UNITED STATES MANUFACTURING GDP $ 2.8 trillion
9. Brazil $2.3 trillion

   10. Italy $2.33 trillion
   11. Canada $2.24 trillion
USA MANUFACTURING last year was $ 2.8 Trillion and is still 8th in the world. In 2014 the total annual GDP USA was $7.5 trillion ahead of number two.

Nominal GDP Rankings by Country 2024​

Source - https://www.imf.org/external/datamapper/NGDPD@WEO/OEMDC/ADVEC/WEOWORLD

1. United States: $30.51 trillion
2. China: $19.23 trillion
3. Germany: $4.74 trillion
4. Japan: $4.19 trillion
5. India: $4.19 trillion
6. United Kingdom: $3.84 trillion
7. France: $3.21 trillion
8. THE UNITED STATES MANUFACTURING GDP $ 2.94 trillion https://nam.org/mfgdata/facts-about-manufacturing-expanded/

   9. Italy $2.42 trillion
10. Canada $2.23 trillion
11. Brazil $2.13 trillion
USA MANUFACTURING is $ 2.94 Trillion and is still 8th in the world. In 2014 the total annual GDP USA was $7.5 trillion ahead of number two. In 2024 USA is 10.98 $ trillion ahead of number two.

2024 US GDP % growth was for the year - 2.37 percent. USA MANUFACTURING is $ 2.9 Trillion and is still 8th in the world. In 2014 GDP USA was $7.5 trillion ahead of number two. In 2024 USA is 11.5 $ trillion ahead of number two.

Nominal GDP Rankings by Country 2025 End of Year est.​

Source - https://www.imf.org/external/datamapper/NGDPD@WEO/OEMDC/ADVEC/WEOWORLD

1. United States: $30.8 trillion 2025 year to date (Q3) $ 30,331 trillion
2. China: $19.4 trillion
3. Germany: $ 5.0 trillion
4. Japan: $ 4.28 trillion
5. India: $4.13 trillion
6. United Kingdom: $3.96 trillion
7. France: $ 3.36 Trillion
8. THE UNITED STATES MANUFACTURING GDP $ 3.08 trillion

   9. Italy $2.54 trillion
10. Russia $2.53 trillion
11. Canada $2.23 trillion
USA MANUFACTURING is $ 3.08 Trillion, 8th in the world. In 2014 the total annual GDP USA was $7.5 trillion ahead of number two. In 2025 USA is 11.4 $ trillion ahead of number two.

2025 US GDP % growth was for the year - 3.0 percent 12/28/2024 https://www.atlantafed.org/cqer/research/gdpnow