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Author Topic:   Low Rear % Good?
TOTHEWALL_23
Dirt Roller

Total posts: 7
posted July 25, 2005 07:21 AM  
Just curious about this. I have been talking to a few guys that are real successfull hobby and stock car drivers that say one of there secrets to winning is they run a really light car with low rear percentage so that it takes less gear to get the rear spinning. In theory hitting the straightaway and taking off because they have say a 5.43 compared to everyones 6.00 gears. What do you guys think about this theory?

wetwolfone
Dirt Full Roller

Total posts: 51
posted July 25, 2005 08:32 AM  
quote:
Originally posted by TOTHEWALL_23:
Just curious about this. I have been talking to a few guys that are real successfull hobby and stock car drivers that say one of there secrets to winning is they run a really light car with low rear percentage so that it takes less gear to get the rear spinning. In theory hitting the straightaway and taking off because they have say a 5.43 compared to everyones 6.00 gears. What do you guys think about this theory?

I think they're pulling your leg.

Eljojo
Dirt Forum Champ
Total posts: 968
posted July 25, 2005 04:32 PM  
........oceanfront property in Arizona!

racer17j
Dirt Forum Champ
Total posts: 5390
posted July 25, 2005 04:42 PM  
The guys that say this threoy is out in left field dont know the half of it. Just to point out one thing and say your car will or wont run cause of it is senseless. Your whole operation has to be in check to run lower percentage but the whole idea is to run light period. If you build the car correct with fuel cell battery all your weight in the back that HAS to be there and take all the junk out that doesnt. You have your springs shocks and tires dialed in. You can run what ever percantage you want if you know what controls what but half the guys in here swear by a set of scales. Scales are a 2D answer to a 3D problem. reguardless of where the cross weight and BLAH BLAH is at you cant find the center of mass. I could go on all day but it is usless cause most dont open there minds and think out of the box.

sc1 racing
Dirt Freak

Total posts: 419
posted July 25, 2005 05:49 PM  
i ran a 6.00 final drive on a tight dry slick 1/4 mile track and was doing great. i like my rear weight lower. but i prefer a loss car. you can still be competitive lose tight will kill you.

TOTHEWALL_23
Dirt Roller

Total posts: 7
posted July 25, 2005 09:20 PM  
Like I said I was just curious. Racer17J you might know the people claiming this theory. Boeckman of Wall Lake and the Smith Boys of Lake City. They all fly around the track and are IMCA REGIONAL Contenders.

Steve Dupree
Dirt Freak

Total posts: 316
posted July 26, 2005 05:31 AM  
Hey there Wil "sidebite" Well we are going to think out of the box this weekend. We are going to take alot of weight out of the rear and go with a taller tire. Its time to find out your theory and i have won enough heats to be happy with the weight but now its time to see if i can beat those times without the weight. See ya in El Paso friday we are going to run a 91.25 tire with 6.50 final for the El paso 3/8 mile track. I have already led 12 laps in the feature at that track but a caution let them right back on my tail and took third because we couldnt go no faster because of gear so its time to see especially with our new motor. Goodluck to all this weekend.

Eljojo
Dirt Forum Champ
Total posts: 968
posted July 26, 2005 04:17 PM  
You are absolutly right Sidebite! I wasn't thinking outside of the box!!! There's a lot of ways to improve forward bite without adding weight. Preload the pullbar a little less, raise the J-bar on the frame side helps tighten it up too, a softer spring in the torque link, more angle on the lower bars of the four link, less angle on the upper bars of the Z link...what was I doing thinking within the box?
The vast majority of guys on the street stock forum are using stock or nearly stock suspensions. There are some basics that apply to stock cars which are not equipped with all-out racing suspensions. Most of those basics can be achieved with simple tools such as a measuring tape, a string line, a level and angle finder, and a caster/camber guage. However to fully tune ANY racing suspension, a set of accurate scales is a MUST! Percentages vary only slightly from car to car and track to track.
With that said, I'd like to have your input on "thinking outside the box" adjustments that will allow the avreage street stock to perform optimumally with a very low rear percentage.

Steve Dupree
Dirt Freak

Total posts: 316
posted July 26, 2005 04:41 PM  
I guess we will play in and out of the box but i need to know what made this car come alive. Was it the weight or what we have done. The car at 50% at this time and it feels great but i think i can beat a few times i have turned by loosing just a little a gaining more HP. We are only going to drop are rear % by 2% but we are also going to run a bigger tire at the same time so i think that will make up the difference in tracktion plus i dont have to worry as much about a push because both tires will be straight up in the main. I just cant find the right tire so i have 1" stagger or i would run the weight. I am going to check this out at both tracks i run because i have to know what is what. The last three heat races have been 1st,2nd,1st so i guess we will se after this weekend what the case is. You never know all i know is that 50% of 3500 is 1750 and 50% of 3000 is 1500 so if both cars have the same % and horse power that means the 3500 will out run it but that may not be the case because it takes more horse power to turn the 3500. I can weigh 3350 with 48% and have 1608 rear weight still more than a 50% 3000 lb car. I guess we will soon see.

sidebiteu259
Dirt Full Roller

Total posts: 56
posted July 26, 2005 05:18 PM  
Elojo What i have done to do increase foward bite and not pay attention to your myth of rear percentage off the scales is this. Before i start all your scales and this that and the other are static settings. I live my racing life in the dynamic. If you dont understand that please dont bother reading on. For years to increase forward bite in a "street stock" soft springs in the rear soft springs in the front and gentle (3)vavling shocks on the rear and easy ups from afco in the front(stock car line shocks), stiff anti roll bars on long arms(stock pieces)from the flag stand the car is taking all the bumps and what not it can take. When you stuff it in the corner the car will take a set and roll over how much i choose it to(anti roll bar diameter and arm length) with the proper roll couple dist. the car turns a nice radius that i need it to reguardless of size of track bank of track and stagger on the rear wheels. Now the exit with the soft springs and the o say 60% front end weight it has the springs compressed a decent amout for this lets say 3 inches. when the motor starts picking up in rpm coming out of the corner with the easy up shocks and three inches of travel stored in the springs and the soft springs in the rear it will transfer weight nicely and dynamicly will have a more balanced car then your staticlly set up car. Dont believe me walk out side and lift up the front of your wifes car and the front of your truck. The car has softer springs for easy ride while the truck has stiff springs so when you pull or tow weight it can take it. back to the car the car will raise up a good inch when you lift it. (is this cause you are really stong) Sorry but what you are doing is help relief the stored energy in the front springs. Now i can go on all day trust me i know my stuff think outside the box and im not talking the box of stuff that everyone from mods to sprints are using. Look at road course cars look at drag race cars there is plenty of knowledge in other forms of racing you just need to open your mind and look for it.

LUBEGUY07
Dirt Freak

Total posts: 302
posted July 26, 2005 08:09 PM  
tothewall 23 you are right about boekman and the smith boys i bet if imca weighed there cars and the rest of the hobbies there would be a weight rule in that class, i now the smiths real well and i know andy pertty well and they are very good drivers and at setting up their cars, everybody thinks its there big motors, and the people that have clamied them found out its not the motor

racer17j
Dirt Forum Champ
Total posts: 5390
posted July 26, 2005 09:55 PM  
Wouldn't it be a dull world if we all thought the same? I like my box! I think I'll stay in it and play...to win!
Steve--I'll be looking for a report on those results after the week end.

juliaferrell
Dirt Freak

Total posts: 370
posted July 27, 2005 06:23 AM  
I have a similar view as sidebiteu259. static weight is just that static weight. Just because your car scales out doesn't mean diddle. You can have things bound up ect and the static numbers are useless. The PROPER suspension has to be in place for those numbers to mean diddly. I see more cars out in left field that own scales and use them relentlessly than I do without. You have to have the big picture under control before you can start the details. Here is an example:

Had a car built by a professional dirt track car builder. It had this that ect ect. Went to the track the car wouldn't turn. I've seen runner sleds that would turn faster. This guys picked up the car and I looked at it and shoved on the corners ect and said, "Won't work" they said, "This guy has built more cars than you've ever seen" I said, "Doesn't matter this one won't work." It scaled fine had nice percentages ect ect. I couldn't convince anyone of anything so they went to the track for three or four weeks with a car that wouldn't turn any better than a runner sled.....this thing pushed like you took John force's drag car to a circle track. Why do I say like john force? Cause that's the way the car was setup like a drag car......Had coilovers behind housing mounted toward center of axle, mounted on bottom about 18" from the center of the contact patch....The suspension on a car has to work and be "FREE" ect before static weights mean a thing.

Steve Dupree
Dirt Freak

Total posts: 316
posted July 27, 2005 07:57 AM  
LOL Yeppers i might be jumping right back into your box but will give full details. We have been turning mid 18s in our heat at our regular track and low 19s in the main that is when we get to race. lol Give a report on sunday. Goodluck to all and have a great weekend.

sidebiteu259
Dirt Full Roller

Total posts: 56
posted July 27, 2005 01:28 PM  
Well go right on ahead and stay in your box nothing wrong with running in the back all the time a track needs you back markers to make it intresting when the fast cars come up to lap you

Speedway65
Dirt Freak

Total posts: 344
posted July 27, 2005 01:42 PM  

 
We have won 6 features this year with 47% rear weight and 3021lbs overall,springs are lf-800 rf-900 lr-225 rr-200 and no front bar.Our car is built so light we have to add 400lbs of lead to make weight.Different strokes for different folks i guess!Check the picture out!

[This message has been edited by Speedway65 (edited July 27, 2005).]

[This message has been edited by Speedway65 (edited July 27, 2005).]

mansfief
Dirt Maniac

Total posts: 128
posted July 27, 2005 01:49 PM  
Wish I had a box. So, What would be a good spring and shock selection for a 3200+ lb metric. I am open to suggestions. I would like to try somthing new. have 47 percent rear weight with car I have now.

Eljojo
Dirt Forum Champ
Total posts: 968
posted July 27, 2005 04:23 PM  
You'd better ask someone other than me...LOL!

Steve Dupree
Dirt Freak

Total posts: 316
posted July 27, 2005 05:57 PM  
This has turned into a good conversation on rear % i think. Well if it wasnt for Sidebite we wouldnt have cut everything but are balls off in the car. If it wasnt for Racer17 we wouldnt have worked on getting our % up in the rear. So i think this is a good conversation and a good one for knew drivers. We really are going to try Will,s way SIDEBITE that is because we have to know and we have been getting really fast and if not for him we would be still way back there. We will let you know how we do this weekend. As far as weight goes i went fron 210 last year to 168 this year so that will tell you how much i care about racing. lol

DangerZoneRacing
Dirt Maniac

Total posts: 176
posted July 27, 2005 06:14 PM  
If a person really did think about it...sidebite does make sense too. but all the others make good points also. I would add my 0.02 but i dont want to be belittled by sidebite like he did to eljojo. No thank you. I'll keep my thoughts and info to myself then.

iowa_dirt_track_girl
Dirt Freak

Total posts: 461
posted July 27, 2005 06:33 PM  
well the side bite theory is all good but depends on what you run for tires you get really good bite with a 205/70/15 tire but with the g60 15 its hard to get a good side bite them tires are really good with forward bite as for them smith boys and boeckmans they are fast really fast on a tacky ruff track where it dont take no car to win but get them on a smooth glassy half mile track that is slick from top to bottom and they stink cause there cars dont work that good.I know with them its more motor then anything cause of the ones we have claimed from them and their camshaft is a killer anytime you can run a 620 verses a 683 and still turn the same rpm your going to be faster

sidebiteu259
Dirt Full Roller

Total posts: 56
posted July 27, 2005 09:45 PM  
I belittle those who are smart but dont use there brain to think. the answer is always in other forms of racing but the idea in a dirttrack racing is **** the other forms of motorsports are all wrong. Nothing they do works one bit for me. If you notice all of elojos answer to sidebite and forward where modified fixes. Not one was something out of his area all keyholed in to one class of racing. If he was looking for Forward bite maybe he should go to a drag shop and see what they do to get foward bite they dont use biscuit bars or pull bars and they run big block motors over the front wheels and pull the wheels off the ground (forwardbite)

Speedracer92
Dirt Full Roller

Total posts: 70
posted July 28, 2005 08:03 AM  
"I belittle those who are smart but dont use there brain to think"

Now that's funny! Telling people to use "there" brain instead of "their" brain! LOL

CLBaker25
Dirt Maniac

Total posts: 193
posted July 28, 2005 02:30 PM  
I don't think that you have to have alot of rear percentage. I think that you can use springs and shocks to get the car to hookup in the middle of the corner and off with not that much rear percentage.

Eljojo
Dirt Forum Champ
Total posts: 968
posted July 28, 2005 03:08 PM  
Man, I have brain cells I ain't even used yet!
I didn't mean to start a pizzfight. Just gave an opinion. I am glad to see that there are those among us who are willing to "think out of the box." I am dissapointed that I had to be attacked/belittled for sharing my experience.
I'm just one of them guys who don't use there brain to think with!
For an "Outside of the box" set up, spend an hour on the 4m modified tech section. Search word "Fastboys" Those guys have a leaf spring set up that utilizes a set of leaves clamped only at the front-with the arch in the front of the spring, a set of 10" long shackles, a floated RR perch and (excuse me for this) scale numbers such as 43% cross and 100+ lbs of RIGHT side bite. Yes it's a little more complicated than that, but you get the drift!

TOTHEWALL_23
Dirt Roller

Total posts: 7
posted July 28, 2005 05:36 PM  
wow. I really opened a can of worms here didn't I? Racer17J you say that smith and boeckman are just average drivers or whatever because they don't race against anybody that good. Which might be true but I was just curious about their theory on things since I will be one of those "NOT SO GOOD" just starting out drivers that has to race with them. I do know Boeckman is consistently fast over here at these tracks. He also got into some trouble at alta for a aluminum insert hood!

Steve Dupree
Dirt Freak

Total posts: 316
posted July 28, 2005 05:59 PM  
Hey sidebite Eljojo seems like a nice guy and dont know why you are attacting him. Everyone has opinions thats what make the world go around. Lets keep this nice because this is a good discusion and one everyone will learn from. Race day coming soon and we are excited car is loaded and ready to go. Yeppers going to take this ford with 91.25 rear rollout to a 3/8 fairly flat track a give it all i got. Have fun abe safe The " TOO BAD " team I do have a ? before i leave though to the dirt track girl. What do you see in those 205,70,15 there are alot of tires out there and gears from you to choose from. I will tell you this and this is simple math and from drag racing too...... The more around the tire the more tire patch you have on the track with that you have more traction. So a lower gear with a bigger tire will always work out better. I would still love to run with you running 35lbs. preasure with those tires and me running 20 lbs. with a 235,70,15 i think it would be a neat race. You are the only one ever i heard of running that kind of preasure or for that fact that size of tire unless it was a emergency because of gear. Oh well to each his own. Heres a excample... Here is a 205/70/15 tire patch at 35 lbs. {....} heres a 235/70/15 with 20 lbs. tire patch. {.........}. A 205/70/15 is like 80 inches around a 235/70/15 is about 88" around alot more tire and alot more traction all you need is gear and motor to turn it.

Blackgold
Dirt Full Roller

Total posts: 71
posted July 28, 2005 09:54 PM  
I agree that the surface patch is bigger with the 235 versus the 205. We ran a bomber class that required us to run 7 inch rims and usually ran 225's but were geared a little low so we went up to a 255 to try to gain a little on the gear. Driver hated the way the car handled. We blew that motor and went back with a higher rpm motor and changed back to the 225's and the drivers first comment was "I've got my car back again. I think probably the 255's were too wide for 7 inch rims. Also, If I remember high school physics class right, we were taught that friction of surfaces was some kind of ratio where a smaller patch with more weight per square inch would hold as much as a larger patch with less weight per sq. inch. If this holds true with tires, the 205's would havemore weight per sq. inch than the 235's on the same car. Would this weighting possibly allow more air pressure and add sidebite by the tire cutting in more? We ran against one driver that was consistantly fast, and he ran 215's. Part of his reasoning was that the smaller tires weighed less and cut his rotating weight.

iowa_dirt_track_girl
Dirt Freak

Total posts: 461
posted July 29, 2005 08:55 PM  
You are exactally right BUT the only reason we run the 205 is because we have to the rules mandate that size actually what they say is 205/70 or 75 15 or 14 inch tires

one tire that we found that is really good is the bfgoodrich touring T/A pro series really good tires

our tires do get really good forward bite but the tire patch isnt as big as your 235 tires but also it takes more motor and less gear. Where you can run a 620 gear i would have to run a 683 to turn the same rpoms with the same motor you guys know what iam saying.

OK lets get into this 35lbs thing!
what are you guys with a 205 70 or 75 series tires w/o tubes running for pressures?


bobaluuu
Dirt Freak

Total posts: 474
posted July 29, 2005 10:12 PM  
sidebite, I think your a fantacy racer. why dont you post your tracks link so we can see your racing record. Then if your a real deal, please accept my appologies. But regardless there is no need for the arrogant attitude you seem to be lording over us.

------------------
Light it up, Baby!

JohnG
Dirt Maniac

Total posts: 137
posted July 30, 2005 07:48 AM  
sidebites theory wont work.

tried it..

with soft rear springs the car squated to the ground almost and has no forward bite, it just pushed of the corner.. 49 rear wt percentage.

As for 17j bagging on smiths and boekman, hes just jealous, they go anyplace and top 4, period, any place. The stock car shootout was a good example in marshalltown, boeckman started last,lol, and was between the smiths the last half of the race.

seidle also goes anyplace and top 4s. i guess if all the hobby cars in iowa except the two smiths, boeckman and seidle stink, 17j is right!!!!!


sidebiteu259
Dirt Full Roller

Total posts: 56
posted July 30, 2005 11:47 AM  
stiffing up the rr 25 lbs in spring rate and it will turn but hey any chassis guy could have told you that.

iowa_dirt_track_girl
Dirt Freak

Total posts: 461
posted July 30, 2005 01:34 PM  
Hey john you forgot to mention bonnett also in that deal

JohnG
Dirt Maniac

Total posts: 137
posted July 30, 2005 06:14 PM  
Sorry I dont know Bonnett or even his car number for that matter, I am not sure if he ran DSM the night I did or was at the stock car shootout.

Smith told me Bonnet had over 200 hobby wins when I was asking them then they were moving to stock car and if they thought it was about time or what??

I personally dont see what those 5 guys are proving when they are fast enough to top 4 any place any time.

Smiths are going by what Dave spends thinking stocks are too expensive, he buys at least a rr tire every race if not two. Nobody else I know of, like Blessington buy half or even quarter that many tires!!!

racer17j
Dirt Forum Champ
Total posts: 5390
posted July 30, 2005 06:56 PM  
didnt donavon smith with the season opener this year in webster and didnt they get second and third place last year in the fall jambore

Steve Dupree
Dirt Freak

Total posts: 316
posted July 31, 2005 09:47 AM  
Well Eljojo here is my report and we are not playing racecar dummy no more. We will let all you other guys run without rear %. El Paso track really it was ok but we would have done better with more weight but we got hit in turn 4 and off to the wall we went so the rest of the race we ran with about 2" off toe out that is after the put the fire out. So we fixed car and off to the next track in Las cruces NM. Our track usually goes dryslick but it didnt this night. We ran the heat with no weight and 16lbs in the rear.Lap times:22.62/21.81/21.35/20.86/21.42/23.79/20.97. The B-main that we had to run the track was about the same but we put all are weight back in the car but only a little gas and we wernt running that hard just so we had something for them in the A-main Lap times with weight:19.96/20.68/19.88/19.59/19.60/19.70/20.23/19.67/20.14/19.66/19.57/19.56 and we tokk 2nd and was lapping the field at the end of twelve laps. Now the A-main It was a tuff start three restarts to try to get this thing started and on the third restart a car spun us in turn 3and4 and noone seen anything........lol so to the back we go with all are little weight and a little hot under the collar. 25cars single file 24 laps left for fun. Here we go:Oh please note this is in traffic and yes we did set are own personal best during this race. 18.94/19.02/19.02/18.56/18.95/18.82/19.06/19.40/19.14/19.16/18.97/18.80/18.66/18.77/19.03/19.06/19.29/18.86/18.30/18.32/18.63/18.49/18.66 We were on fire at the end as far as speed goes and the car was just feeling better and better. That was are first 18.30s ever in this car 3490 Ford Torino on a 5/16 with 15% of banking. Well there you have it we will never run without running as much rear % as we can with in reason. More Rear % is better DONE DEAL. Oh forgot to say we made it up to 10th. Sure wish we wouldnt have been put to the back Might have been our nite. Goodluck to all and talk at you soon.

Eljojo
Dirt Forum Champ
Total posts: 968
posted July 31, 2005 10:15 AM  
Thanks Steve! Sorry to hear about your bad luck, but I had some of that last night too. I blew out the throw out bearing and lost the clutch right before q-fying.(DNQ) Started on the tail (18 cars) 14 laps to go I am in 8th and one of the leaders smacks into lapped car and they both go for the outside wall. I turn low and my buddy knocks the RR down on my car----the race is red flagged and I go to the pits and change tire--back to the rear I go! Fast car----handles at about 90%--- finished 7th! I have to say I was happy with that.
Check my facts: www.volunteerspeedway.com
I'm going to add a little more weight to the Camaro and open the stagger to 2". 150-165# LR bite Prolly get to about 56% rear.
Low rear percentages may work for some guys on some very tacky tracks with lots of gear and low horsepower mills----especially on big tires. But I don't have any of those factors to enter into my racing equation!
Seeya! JoJo

racer17j
Dirt Forum Champ
Total posts: 5390
posted July 31, 2005 12:29 PM  
Just posting here so the new guys that want too see what is said about weight %. Is it better and my answer would be yes.Did i try it and my answer is yes i was a test dummy. lol Dont worry about the rude post you read just read what is important and that is a set up car that is atleast 50% rear weight no matter what you compitition is running. You will handle better and be faster in the long run.

    

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