Rear end camber...pros and cons?

[onevoice]

A long time ago, (30 yr?) Herb Adams had a book that said sure it can only help. The cheap and easy method he employed was to saw through the axle tube from the top, stopping before you go all the way through. Let the gap close, and weld back up. High tech is wasn't, but back then nothing was. He claimed the axles lived fine, and ran that way at the Daytone 24 hr race. The issue now is that with 335 / 30 rubber, do you really need to camber the rears? He was running 255/60's.

A lot of people discount nascar as old tech, but they are most like what we are mostly running, ie big HP, front heavy, live axle cars. They also know more about what happens throughout a turn than just about anyone because they spend large amounts of time in steady state cornering. When allowed, they run cambered axles. Is it worth the trouble for us? Not likely. As someone else mentioned, our cars already have rear tires that are proportionally oversized compared to the front. Camber is only going to make a difference when the tire is loaded maximally in a lateral direction. Unless you are running big tracks, with long sweeping turns, and you have used all the available lateral grip, you will probably never see the difference. You also might end giving up forward grip in a straight line.

[Matt@BOS]

I decided not to build camber into my floater. I wasn't building a race car, and and it isn't like I'm a race car driver. In my opinion there are so many variables to fine tune between the car and driver that the benefits of rear camber are going to be negligible to me in the long run. All hot rods are temperamental by nature and money pits, and I just wanted one less thing that would have to replace and spend money on more frequently. If you were making something that was purpose built to be fast, and you weren't constrained with our common respective tire sizes, etc, etc. then yeah I would say build a cambered rear axle...

Matt

[FETorino]

Originally Posted by Matt.A

I decided not to build camber into my floater. I wasn't building a race car, and and it isn't like I'm a race car driver. In my opinion there are so many variables to fine tune between the car and driver that the benefits of rear camber are going to be negligible to me in the long run. All hot rods are temperamental by nature and money pits, and I just wanted one less thing that would have to replace and spend money on more frequently. If you were making something that was purpose built to be fast, and you weren't constrained with our common respective tire sizes, etc, etc. then yeah I would say build a cambered rear axle...

Matt

Thanks for pulling me aside. What you are saying makes complete sense. It's hard enough to keep stuff from breaking as it is.

[Matt@BOS]

Originally Posted by FETorino

Thanks for pulling me aside. What you are saying makes complete sense. It's hard enough to keep stuff from breaking as it is.

Thanks! I'd like to think I learned something from building a huge money pit, haha. I just want to add that I'm no authority, I've just learned what works for me based on how much I want to spend, and how useful go fast parts really are to me versus $$$, and my driving skill. It seems everyone who can afford to spend big dollars on a car tends to go for the fanciest parts they can, myself included. At the end of the day we just have to acknowledge that money doesn't buy speed, or maintenance free parts. Just look at Blue Balz, that car is fast, but it probably has more money invested in tuning than some pro touring cars are worth. Any number of expensive parts have been replaced, and not all of them have been broken. Additionally some of them probably won't make a noticeable difference in the car's end performance, except in theory. While I have a different attitude, I definitely respect Cris and Karl for chasing after the tenths and hundredths of seconds.

Matt

[FETorino]

Originally Posted by Matt.A

Thanks! I'd like to think I learned something from building a huge money pit, haha. I just want to add that I'm no authority, I've just learned what works for me based on how much I want to spend, and how useful go fast parts really are to me versus $$$, and my driving skill.
Matt

Actually experiencing the benefit or lack of.. of parts through trial and error does make you somewhat of an authority.

Just like Todds comments about staggered tire widths and front vs rear grip if you are speaking from experience it's worth listening to.

I want to build a PT car. To me that means the car will be track oriented but able to drive it to the track. I want it to be usable (bearable or better) on the street. Right now the raunchy old school motor is the one compromise to this plan but it is a necessary compromise.

I used to be really good at drinking beer. I think I can still hold my own.

[Ron in SoCal]

Matt makes a number of very good points. Also the tire stagger issue lessens the urgency - thx Todd- but what may kill it for me is the axles as a wear item. I don't really want to have those as a near term service item. More research needed....

[DTM Racing]

I like to run my cars with the same size tire on all four corners, and I will say that the difference in rear end tracking with the cambered rear is fantastic.

That said, a full floater rear is not a street friendly piece. Recommended service intervals are 300 miles for drive plate greasing.

[TheJDMan]

Originally Posted by DTM Racing

That said, a full floater rear is not a street friendly piece. Recommended service intervals are 300 miles for drive plate greasing.

I would disagree. If you run a tube seal and grease your bearings then yes you will have periodic maintenance but certainly not every 300 miles. Frankly axle tube seals seem a bit pointless to me for street use. The only floater that needs an axle seal is a circle track application which spends a lot of time turning left. In that application the tube seals keep the gear oil in the center section. But in a street/track floater the tube seal is unnecessary. I'm not running tube seals in my floater and the gear oil lubes the hubs just fine. Granted I only have about 500 miles on the car to date but the floater has been a non-issue and I don't expect it to become one.

[Flash68]

Originally Posted by FETorino

I want it to be usable (bearable or better) on the street. Right now the raunchy old school motor is the one compromise to this plan but it is a necessary compromise.

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