29.0's on LR

[tireman]

Anyone have any experience with the 29.0 on the LR ? My understanding is 1/2 to 1 inch of stagger. Im assuming from the stagger standpoint it is used on hard, slick, wheel-spin tracks. Very interested in conversing about the use of this tire: pros/cons, tracks, etc...Thanks in advance....

[MasterSbilt_Racer]

Anyone have any experience with the 29.0 on the LR ? My understanding is 1/2 to 1 inch of stagger. Im assuming from the stagger standpoint it is used on hard, slick, wheel-spin tracks. Very interested in conversing about the use of this tire: pros/cons, tracks, etc...Thanks in advance....

I have seen a new track record set on a hammer down bullring.

[Kromulous]

Its an interesting idea. I have always wanted to try 3 88's and one 90 on the RR, so i could get a lower profile side wall. i know in the Mods with the old mod tire it was worth, quite abit better feel in the car.

Although it wouldnt help with the crossmember digging in issues that some cars have.

If your aiming for that little stagger thou, you could just run 29's all around, and just stretch the RR to get that much stagger.

[billetbirdcage]

Keep in mind that tire construction comes into play here and not just stagger as many open tires the RR and LR construction is different on the carcass. I'll just say you probably need to look at which actual tire they are substituting on the LR

[MasterSbilt_Racer]

Keep in mind that tire construction comes into play here and not just stagger as many open tires the RR and LR construction is different on the carcass. I'll just say you probably need to look at which actual tire they are substituting on the LR

I know what you are saying. Pretty sure what you are implying wasn't the case on the one I looked at.

[7uptruckracer]

To that effect what kind of side wall construction are we looking at on each corner?

[billetbirdcage]

All I was pointing out is many may be changing the carcass of the tire when doing the big LR but clearly this depends on the tires your running so when your comparing what someone else is doing you need to know that stuff. If your on a economy tire, then it's very likely that all the tires have the same construction as many econo tires are that way. However if your running "open" tires then this will likely not be the case but could be.

Even on the econo tires, you may be changing the tire's spring rate thus you may still be getting a change other then just stagger. Changing the spring rate or carcass, can totally upset the balance on a car. Sometimes just changing a RR tire to another carcass can completely take a nuetral car and turn it tight or loose as hell on entry. It' all boils down to your knowledge, experience and how hard your willing to work at some of this stuff. If your not someone else is. There are so many tires and tire combo's out there it's staggering <- see what I did there, lol.

[Mr.Kennedy777]

A good question to ask is what you’re doing with the surface of the tire across the track when you’re running such low stagger. Let’s say we go from a paper clip style track to a larger radius turn track, both 3/8 oval. With a 91.5” tire on the outside of the paper clip you would need roughly 3.5” for true stagger matching of the wheel speeds in a corner. If you go to the outside groove on the wider radius track, you’re looking at a 1/2” change in stagger max. Dropping a lot lower would actually cause one tire to be losing a lot of traction through the turn with a rear end having both LR and RR axles connected the same to the rear end. Now I could see why one would do this, on a paper clip, especially if you’re utilizing a lot of rear steer, to avoid the car walking towards the flag stand on exit, I’m thinking the lower stagger would actually help the rear end move in such a way that it would counter-act that effect. I just don’t know which tire would spin more the left rear or right rear, I’m assuming whichever tire had more traction would stay connected better while the other tire would? I’m not 100% clear but that might be the reason it’s being done? If you could move the LR further ahead dynamically you’re going to gain loading, but maybe it makes the car too loose in and walk up the track on exit so the big stagger drop is being used to kind of trade off some gains in one spot for some losses at another? And maybe the trade off is actually more beneficial on certain tracks and/or conditions?

[MasterSbilt_Racer]

Tires either fight each other in the corner or on the straight. Pick your poison.

[MLR19]

Seems like people are running more LR drop, possibly to get the LR Deck/spoiler higher in a dynamic state. Could the bigger LR be used to reduce stagger to compensate for the added roll steer?

[Krooser]

A larger diameter tire will roll across the rough spots better...

[Mr.Kennedy777]

Tires either fight each other in the corner or on the straight. Pick your poison.Where do you gain the most going faster??

[Matt49]

We notice much more even tire wear across the surface and less RR heat entirely when running less stagger. With the rear steer in these cars, one could easily argue that we don't need any rear stagger at all. Until you get into what camber thrust advantages may contribute to side bite, I would tend to agree.

[MasterSbilt_Racer]

Where do you gain the most going faster??

Not the same every track, every time. I wouldn't think.

[Mr.Kennedy777]

i think that’s a great answer. The best answer I guess would be “everywhere” lol. Maybe they will invent a tire that could change shape like a drag tire. Lol roll out and shrink on the left rear in a turn and then stand up hard when you applied the throttle. 😂

[Mr.Kennedy777]

Or just allow a guy to run a limited slip and then you wouldn’t really even need stagger.

[7uptruckracer]

The limited slip doesn't work on dirt very inconsistent its been tried off and on. If you trail brake you still have throttle applied and it won't unlock then you turn in on throttle and then say lift and all the sudden it unlocks. Or you have a hammer down track that slicks off and all the sudden its not locking and unlocking like it did earlier

[fastford]

we ran a DPI black gold unit with no stagger back in the late 90s when the 4 bar and rear steer was just coming in to play , won a lot of races on this set up , but we were on a big wide track , when we went to a smaller , tighter turn type track , it would not turn , now , Im wandering with all the dynamic roll steer these cars have today , it might work very good , I still have that unit and have been considering for a while now trying it again......

[CCHIEF]

Ran a Gleason in early 2000's and won quite a few races with it going away....with 5 " of step. BIG wide corner track.

[Mr.Kennedy777]

We are talking about a limited slip not a locker right? Can’t you adjust a limited slip to resist locking more and offer more variable speed between the tires? Because a limited slip never actually “locks” as far as I have known.

[Mr.Kennedy777]

I didn’t think if it was set up properly a limited slip would give you such inconsistency, might not give you the full locking effect a locker would, but do you ever actually want both wheels fully locked anyways? Maybe on a large track?

[7uptruckracer]

How often are late models fully off the gas I guess it the real question?

[7uptruckracer]

It all depends on what springs are inside it too. There are many different options and it can make a big difference. We run the lighter springs on asphalt now in the lockers so it unlocks quicker and softer so it frees the car up on entry and the softer engagement and disengagement is nice, If you go and run long tracks you can go to a stiffer spring where you don't need the turn in you would on a bullring. Its just not as straight forward as a spool and can be inconsistent ive run it with a detroit never tried a Limited Slip or Tru Trac

[fastford]

the black gold unit we ran was not a limited slip or locker type unit , it had something like gleeson gears in it that could transfer torque from on side to the other , if one tire slipped , it would apply more torque to the other , it did not like a lot of stagger , and did not like tight turns , but like i said earlier , we didnt have the dynamic roll steer that we do now , so I,m rethinking it again....

[7uptruckracer]

I think they use to refer to that around here anyways as a left side locker. I know some guys who ran it at VMS (Virginia Motor Speedway) which is a big somewhat flat dirt half mile that come feature time can get pretty black, they ran it in sportsman cars and it did well, but back in those days it was lift early drive straight and roll through the center. I just don't see it working for a car you don't get off the gas much very different from a spool but hey we can all learn something from a test. If you already have one then really you'll only have time invested!

[Mr.Kennedy777]

Fastford im pretty sure that’s the same as a limited slip, with helical gears, that’s how it prevents slip, is if the tire spins he torque is sent through the tire that’s “losing traction” and is allowed to spin to prevent tire slip. I’m pretty sure you would need to compare the ranges of the tires on the gears, if you went to a short track maybe you need like an inch or 3/4 of an inch to help assist the tire speeds on a tight turn radius, but enough it won’t hurt you in the straight?

[7uptruckracer]

On dirt around 10% slip is average so how do you account for that?

[fastford]

Mr K thats not how it worked , it took torque from the spinning tire and sent it to the other tire with the most traction , I never took it apart but you can see some spiral type gears , which i call gleeson and may be wrong , inside that could sence wheel spin , at least thats how it was pitched to me and thats how it felt on the track . 7UP , if your talking about the sprag set up that is in the left side drive plate , it was not any thing like that.

[Kromulous]

https://www.google.com/search?q=gleason+torsen+differential+animation&rlz=1C1NHXL_enUS684US684&oq=Trsion+Gleason+Diff&aqs=chrome.3.69i57j0l4.15423j0j8&sourceid=chrome&ie=UTF-8

There very interesting, always wanted to tinker with one.

[7uptruckracer]

I'm not sure, I am only familiar with Detroits they don't allowed True Tracs or limited slips in the asphalt division I run in. I know some offer Left Side Lockup, the track that I am speaking of made a rule against it, for whatever that means, I've tried a Detroit in dirt and its what we run in asphalt and we can change the spring stiffness (on both sides) to do different things. I just don't see it working on dirt where you trail brake and are never just rolling the corner like we do on asphalt, When I tried it on dirt i didn't like it thats as far as I can go.

[fastford]

https://www.google.com/search?q=gleason+torsen+differential+animation&rlz=1C1NHXL_enUS684US684&oq=Trsion+Gleason+Diff&aqs=chrome.3.69i57j0l4.15423j0j8&sourceid=chrome&ie=UTF-8

There very interesting, always wanted to tinker with one.

like i said , it didnt like stagger and back then on a tight turned track , i couldnt get the throttle push out of it , but things are different now with all this dynamic roll steer , one of the fastest laps I saw last year ar TST was with a spool and 1inch stagger , so it might help on over all forward bite over the spool , dont know.......

[billetbirdcage]

On dirt around 10% slip is average so how do you account for that?

Typical wheel spin % is much much higher then that, in my testing back 25 years ago (before it was illegal) with real censored traction control 10% was too low to produce the fastest lap times. Dropping the wheel spin typically tightened the car, so if you started limiting the wheel spin you ended up adjusting the car. However once you got down to around 13% no matter if you adjusted the car and tried lowering spin % you weren't going to lower the lap times. It took a lot of work to get faster times under 15 to 18% and you had to really work at it. I assumed years ago when I was doing the testing that 13% or so (for our tires at the time) was the minimum slip angle the tire needed to produce maximum traction. You would be shocked if you saw the actual % of un-managed wheel spin on a Late model.

[billetbirdcage]

https://www.google.com/search?q=gleason+torsen+differential+animation&rlz=1C1NHXL_enUS684US684&oq=Trsion+Gleason+Diff&aqs=chrome.3.69i57j0l4.15423j0j8&sourceid=chrome&ie=UTF-8



I can't say if the one afco had years ago was exactly the same but it was a gear type design, but one of the Hav-a-Tampa regulars did a fair amount of testing with one until:

I think it was Dixie back around 96 to 97, when he was running the low line and letting the car drift out to the wall on the straights. It had a ledged cushion against the wall some even on the straights, when he drifted out to the wall coming off the corner and banged the cushion with the RR, it unlocked and tried to drive heavily with the LR and nosed the car into the wall and took him out while leading the race. He took it out after that and said F' that.

Not sure how prevalent that is now a days with the newer stuff but I can see how you might end up with some issues.

[7uptruckracer]

I’ve never done that kind of testing sounds cool, just basing that number on what I was told by a higher up that at least 10% but maybe the a least is much higher. Or it could have been referring to asphalt not sure I do know I have seen someone install a Davis Traction Control system and it did a lot of what you said it tightened the car up and made it slower by about .2 but sounds like interesting info


Typical wheel spin % is much much higher then that, in my testing back 25 years ago (before it was illegal) with real censored traction control 10% was too low to produce the fastest lap times. Dropping the wheel spin typically tightened the car, so if you started limiting the wheel spin you ended up adjusting the car. However once you got down to around 13% no matter if you adjusted the car and tried lowering spin % you weren't going to lower the lap times. It took a lot of work to get faster times under 15 to 18% and you had to really work at it. I assumed years ago when I was doing the testing that 13% or so (for our tires at the time) was the minimum slip angle the tire needed to produce maximum traction. You would be shocked if you saw the actual % of un-managed wheel spin on a Late model.

[Kromulous]

I think it was Smokey Yunick that said the best you could hope for on dirt was 30% slippage, not sure but i remember reading that number somewhere. Seems plausible i guess.

[fastford]

Typical wheel spin % is much much higher then that, in my testing back 25 years ago (before it was illegal) with real censored traction control 10% was too low to produce the fastest lap times. Dropping the wheel spin typically tightened the car, so if you started limiting the wheel spin you ended up adjusting the car. However once you got down to around 13% no matter if you adjusted the car and tried lowering spin % you weren't going to lower the lap times. It took a lot of work to get faster times under 15 to 18% and you had to really work at it. I assumed years ago when I was doing the testing that 13% or so (for our tires at the time) was the minimum slip angle the tire needed to produce maximum traction. You would be shocked if you saw the actual % of un-managed wheel spin on a Late model.

I remember reading a article on bloomer testing traction control back several years ago and he was like 3/10ths faster with out it , I may be wrong , but I think some wheel spin is faster than none...

[let-r-eat]

Yes. You definitely need wheelspin IME. RPM X Final ratio you are running and then compare that to your actual speed on the racetrack. You'll see most cars running around 100MPH actual speed on the track has a gearing that puts them somewhere between 120 to 150mph. Depending on rollout you could calculate the slippage. There is an enormous amount of information that can be used in knowing those numbers. Not all track surfaces are the same.

[a25rjr]

I can't say if the one afco had years ago was exactly the same but it was a gear type design, but one of the Hav-a-Tampa regulars did a fair amount of testing with one until:

I think it was Dixie back around 96 to 97, when he was running the low line and letting the car drift out to the wall on the straights. It had a ledged cushion against the wall some even on the straights, when he drifted out to the wall coming off the corner and banged the cushion with the RR, it unlocked and tried to drive heavily with the LR and nosed the car into the wall and took him out while leading the race. He took it out after that and said F' that.

Not sure how prevalent that is now a days with the newer stuff but I can see how you might end up with some issues.

I know one HAT car owner that ran them quite often.

At one particular track, his driver had a 1st and 2nd. Funny thing is, all the other cars were 4bar, and his was mono-leaf with coilovers!