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Author Topic:   RR hotter than left rear
A2KY2K88
Member
posted June 02, 2003 12:14 AM
Right Rear hot. Left Rear not. Whats the solution.???


jammin
Administrator
posted June 02, 2003 12:48 AM
more wedge.

jammin

A2KY2K88
Member
posted June 02, 2003 06:03 AM
???? Left rear is working and the RR is spinning, I would think less wedge, but maybe im wrong/?


jammin
Administrator
posted June 02, 2003 09:49 AM
Your heat is going to be in the tire with more friction. If a tire is cool, it is not contacting the track surface as hard as it should, thus less friction, less temperature. The target on the rear is to try to get your tire temps as close to even as possible, which means that your balance weight wise dynamically is close. If you place more wedge or cross in the car, you will increase the weight on the left rear and decrease the weight on the right rear, so it sort of compounds the adjustment. If your right rear is really hot, you are more than likely tight in and loose off depending on the dynamic characteristics of the car. I missed my crossweight in the mod a couple weekends ago and we had 196 degree right rear....I put about 1/2 of a percent of cross in the car and dropped the tire temp in the feature by about 40 degrees. From what I have seen with the IMCA McCreary tire, if you are operating over the 150 degree mark, you are burning it up...it will melt away. I would like to see my tire temps around 120 to 130 equally to get max traction and get good wear off of them. Of course, this has alot to do with track surface, but this seems to work for me.

jammin


dirtbuster
Member
posted June 02, 2003 12:11 PM
One way of looking at is to think about a truck tire. Unloaded the tire runs cooler than when it is heavily loaded. Meaning the tire doing more work is running hotter.
I dont know about the 150 degree mark being too much. After a feature our rear tires are almost always 170+ and close to 200 on the RR and they dont melt away or burn off. Those temps are pretty typical of most of the cars around our area anyway. We had a RR one night come in 300+ and the car was bad fast but it was a little hard on that tire.

[This message has been edited by dirtbuster (edited June 02, 2003).]

A2KY2K88
Member
posted June 02, 2003 12:39 PM
I had another very tenured and successful driver tell me the oposite. Less wedge because too much weight was on the left rear therefore the RR was spinning and that is why it was hotter. I took wedge out and it evened out the temperatures and the car was much more driveable, thats why im confused!


outlawstock17
Member
posted June 02, 2003 01:39 PM
a2ky, if the rear tires are locked together with a spool, they are always spinning at the same speed.


lucky13
Member
posted June 02, 2003 03:29 PM
I should have said started feathering at 150...not burning off.

jammin

dirtbuster
Member
posted June 02, 2003 05:22 PM
thats when i know the car is working good is when i can run my hands across the tires and they are feathered.. especially when the rear tires and the rf are all feathered. tells me they are all loaded and are working to turn the car.

How many nights do you run say a rear tire if you never get them warm or feather them?


xhubby
Member
posted June 02, 2003 05:51 PM
Last weekend, we ended our A-feature 6 degrees hotter on the RR. Tires gained the same amount of air pressure and the stagger did not change. Track was very dry slick. The car was great coming in & thru the apex, but we were getting whipped coming off. We were thinking about adding some more LR bite next time. Are we thinking wrong? From what I've been reading, that would increase the temp difference even more.


Wauge28
Member
posted June 02, 2003 07:00 PM
X-Hubby, 6 degrees!!!! Dang! Leave it alone.

A2KY2K88 OK, think about this...the wheels are locked together. If the RR is spinning, so is the LR. Unless you are running limited slip, they are locked together and both spin a the same RPM. I assume that is clear? Now, go to your bench ginder. Turn it on and very lightly, with your right finger touch the right wheel that is spinning. Now press your left finger to the left wheel very hard. Which one got hotter? Both wheels where spinning the same speed but one got hotter...right?

The wheel being pressed harder to the ground is getting hotter as it spins. The LR doesnt have enough spring pressing on it so it is not getting as hot as the RR with more bite.

Put more cross/LR bite in the car then take your temp gun to your friend and have him measure the temps for ya. you can then say, I told ya so.

FYI, don't try the bench grinder thingy...I was only using that as an example. Jammin might have to edit my post in fear of fingerless drivers walking around the pits.


jammin
Administrator
posted June 02, 2003 07:45 PM
xhubby...if your tire temps are that close and you still dont have enough forward bite, just add lead to get more rear percentage...hang on!

jammin


dirtracer14
Member
posted June 02, 2003 09:09 PM
Funny this topic is up....i came in from the main sat with a rr that was so hot i couldnt hold my hand on it....i was braking alot so i went to the lr to see if the brake heat was helping heat the tire....only to find out the lr was cold....i mean about as warm as the air outside. I have no idea how hot it was but when i got home and cleaned the tires the rr was ripping the tread off the car was pretty good early but the last 5 laps it started getting away from me.i guess i learned somthing this weekend


xhubby
Member
posted June 02, 2003 09:20 PM
jammin, would we want to keep the lead centered or add it to the left side. I'm not sure we have any more room anywhere for more lead. We have to weigh 2500# & my son (the driver)only goes for about $1.20 if you wet him down.lol Thanks.


old racer
Member
posted June 02, 2003 09:31 PM
Old racer, you sound very educated in racecar set up. I am not here to argue...well not too much anyway. You say that the sliding is what creates heat not the spinning? Common senses tells me that the tires doesnt know the difference. It also tells me that the area of ground those treads slide accross are much great when spinning foward at 80 MPH than sliding sideways at a few feet per second. Also, needing RR bite when loose getting in because the RR is hotter? Again, a little arguement...When you get off the gas to enter the turn, the wheel with the most bite will "drag" the car. If the LR has bite, it will loosen the car going in becausse the car will rotate around that "draging" left rear. Vise Vers, whent he RR has more bite it tightens the car going in because the car wants to rotate around the RR pulling the car to the right. That very short instant that tire drags can not creat nearly as much heat as a guy matting it comming off and breaking the tires loose.

My theory is based on two factors. 1. We are racing on dirt. 2. The driver is lifting for an split second to enter the turn. If he is flat footing it, it is a$$ backwards. I can say with pretty good confidence that the "flat footer" is usually really fast in one and two and in the parking lot by turns 3 and 4.

jammin
Administrator
posted June 02, 2003 10:55 PM
I have seen situations where on a very slick track, with a person running alot of right rear where the tires get hot and give away and make a person think that they are loose on entry because of the heated tire....and it was simply a matter of wedge to keep it from heating up like it did.

jammin


old racer
Member
posted June 03, 2003 08:11 AM
I do too. I think that is how we all learn.. I know I have learned very much from this forum!!!


lucky13
Member
posted June 03, 2003 10:09 PM
I also have a rr wishbone and lr z link.....the car was good in low and fast but if i got up in the dry it would drift...


old racer
Member
posted June 04, 2003 11:22 PM
So did we decide on more wedge or less wedge. I vote less cross.????????????


lucky13
Member
posted June 05, 2003 07:30 AM
We had this problem of LR warm and the RR hot a couple of races ago. We raised the top link on the LR 4-link, we didn't fool with the z-link RR. It loosened the car up and it also made the temp. between the rear tires close. Good luck.


washeduptoo
Member
posted June 05, 2003 08:44 AM
We had this problem of LR warm and the RR hot a couple of races ago. We raised the top link on the LR 4-link, we didn't fool with the z-link RR. It loosened the car up and it also made the temp. between the rear tires close. Good luck. Also when talk about backing a car into a turn, you are talking about using the gas to make the car turn?


washeduptoo
Member
posted June 05, 2003 08:46 PM
Sorry, but I missed typed or my mind went blank when I typed in it loosened the car up, it tightened the car up when we raised the top link. Again, I'm sorry for the misinformation.


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