BL/BP Legacy GT Meaty Tire Thread

it is 275s front and 245s rear; they are bfg track tires taken from a porsche 911 4s. The reason my 275s don't rub is large 18x9et42 offset only possible with the outback struts; from my measurement, even coilovers would require spacers. I will get in a picture one of these days...

 

It is the outer wheel on a turn that seems to drag; so if turning left then skids the passenger side wheel, which is then further away from the control arm, and yet there is space to fill. The front tires clear everything. So you're saying if it were a locking center diff, both front tires would be skidding? It's possible, but i doubht this what is happening; I will have to pay closer attention and see if there is anything else it is hitting. Actually my initilal thought had been that there is a maximum difference that he two front axles can turn without regards to the rear differential; is this a possibility?

 

 

Track tires that were used prior to you installing them?

If it were a locking center diff I'd expect the tires to scrub on the pavement at both ends of the car during turns. Nothing locks up, the fronts just scrub a little because they're not turning fast enough, and the rears scrub a little because they're trying to turn a little too fast.

 

I've experienced this in 3 different cars - one with a bad center diff, one with no center diff, one with (aftermarket) DCCD. In all cases, the effect was small in slight turns and got progressively worse as I turned tighter. The car with the bad center diff wouldn't actually skid much at all unless traction was low, it just lugged the engine down because it needed extra torque to get the center diff's output shafts to move at different rates.

 

If your car is fine until you turn the wheel past a certain point, and then that outer wheel locks up, that sounds to me like the center diff is fine and something is binding. And I'm guessing the binding comes from the inside shoulder of the tire colliding with the the wheel well, probably in front of the control arm and a little bit above it.

 

There probably is a maximum front/rear difference but if the tires are less than 1% different the that's probably not the issue. Code has a good question regarding tire models though, if they're different then the tire dimensions can't really be compared, you'd have to measure to really know the difference between them.

If I lock my center diff (dccd pro with 2011 sti driveline) it will only clunk my front wheels while I back up. I’ve done this on accident a few times after manually adjusting my center diff during a drive and forgetting to open it up when I was done.

I took pictures of my control arms ; the wheels are fully turned in those pictures and here's

from my youtube, so feel free to hit the thumbs up and subscribe. That video is from the interior when the thudding is most audible; when recording from the outside it is hard to hear the thudding over the road noise, but from what i can tell the wheel doesn't seem to noticeably bind. hmm now that i see my own pictures i wonder if my loose rod nuts might have something do with it; the alignment was not a professional job--it was done by me using my phone's orientation/gps sensors.

 

If I lock my center diff (dccd pro with 2011 sti driveline) it will only clunk my front wheels while I back up. I’ve done this on accident a few times after manually adjusting my center diff during a drive and forgetting to open it up when I was done.

 

could you let me know if the clunk sounds simliar

Edited October 11, 2019 by darthqwo

Very similar. Seriously, runs string around your tires and measure the actual circumference. You don’t even need to take your wheels off, just roll the car over the string.

Did you check for binding of the TIRE against the inside of the wheel well?

Specs? are you lifted?

 

Sorry it took so long to get back to you Lonely Driver!

 

It is lifted 1.25", I used the Primitive Racing lift kit (spacers).

 

Tires are 205/65R15, gravel tires. I only run them for rallycross. Never rubs, even going over jumps. Speaking of which, this car makes an amazing rally car. Just a bit on the heavy side.

awesome, I ordered primitive spacers as well. Hoping I can fit 225/50/R18 on my stock SpecB rims with 25mm spacers

Ah very cool, that's going to be legit. That's what I need, 225/50R18 or 235/45R18. I'm running 225/40R18 right now and there just isn't enough sidewall. And now with the lift, the tires don't fill the wheel-well enough.

 

Not sure about the spacers, I run 5mm spacers but that's just so I can clear the WRX 4 pot calipers.

Ah very cool, that's going to be legit. That's what I need, 225/50R18 or 235/45R18. I'm running 225/40R18 right now and there just isn't enough sidewall. And now with the lift, the tires don't fill the wheel-well enough.

 

Not sure about the spacers, I run 5mm spacers but that's just so I can clear the WRX 4 pot calipers.

 

 

What are your alignment specs now? Did you need new camber bolts?

What are your alignment specs now? Did you need new camber bolts?

 

Good question, I don't recall actually, sorry. My alignment shop did recommend near rear camber bolts I believe, we'll be taking care of that soon.

Did you check for binding of the TIRE against the inside of the wheel well?

 

Sorry for delay; i haven't been driving the car after my exhaust midpipe started clanking against the driveshaft at the flange after it hit a deer that i ran over; there was bloodshed to clean, but fortulately not too much, but definitely some hair and flesh on the flange bolts. Separately, i fell ill. But to answer you rquestion, wheels and tires are clear from rub on front.

 

Follwoing my own pictures I tightned my nuts real good, but persists the problem. I still dont have a firm idea of the cause with the wheels still bolted; i have a new idea of what might be the cause however. My latest idea is that this results due to the difference in where the tie rods steer each wheel due to the extreme offsets during turns together with the fact that these are sticky tires. There is a difference in skid cadence depending on road friction, such as when it rains--the tires have less grip, and the skidding thuds are more frequent.

 

If it still happens with regular tires, then I suspect it is still due to the extreme offset and still possibly sufficient tire friction a well as the differential locking up is still a possibility. Unfortunately, if it doesn't i will not really know if offset is not an issue, as the tires are no longer sticky, but this would rule out the differential locking suspicion.

 

Here is a porsche thread that talks about this issue.

Edited October 23, 2019 by darthqwo
nevermind about ruling out differential lockgn since other set of wheels normal offset; it is unlikely to be case anyway

 

compared to my 235 tire

I've been really happy with the size and fit of my newest setup. It's comfy on bad roads, still have plenty of grab, tons of options, quiet.. Might be keeping a version of this wheel/tire combo for good.

 

-17x8, +48, 17lbs with a relatively meaty 235/45/17

-Lowered at least 1" all around - coilovers now, but going to JDM strut/lowering spring soon

-No rubbing and no fender modifications

 

Definitely not glamorous or hella, but practical, looks good and inexpensive.

275's mounted 18x9.5 on lowered wagon. no rubbing.

Whaaa? Those gotta be rubbing!

That's why you pay an expert to setup your c/o. No rubbing.

Well dang I need to rethink my set up when I go to a slick set up, would love to run a 18x9.5 on the track!

Well dang I need to rethink my set up when I go to a slick set up, would love to run a 18x9.5 on the track!

 

No you don't. Way too much tire for the car. Buy really good slicks. Bfg r1s works great in the less than warm conditions in the PNW.

 

Bfg r1 @ 235 with a great suspension setup was good for 1.5g. Which is enough to pop you out of the driver's seat with ease.

It's probably so stiff that there's only half an inch of suspension travel.

 

Still incredible to fit so much tire on there and race it. *Please don't try this at home with your LGT*

That's why you pay an expert to setup your c/o. No rubbing.

 

What coils are you on?

Edited October 29, 2019 by Gabo

What coils are you on?

 

Bc Racing. 8k spring rate?

 

Professionally setup based on actual test data. Duplicating this setup today would likely be expensive unless you got a good deal. It was 8 hours the first day and about 4 each the next 3 days. Went through a couple sets of wheel bearings and a set of tires before getting it right.

 

The shop owner called Phoenix Racing to get the race wagon setup to use as the basis for my car. Seems ironic to have purchased that wagon and looked at the suspension setup data to see the same trials listed. Small world...

 

I wish I had video from those days. After the last setup attempt, the shop owner said we've done all we can with those c/o. You need to start get something better: ast ohlins etc. after a couple wtf's, I asked what now? He asked if I'd tried throttle oversteer at the limit?

 

No cage, oem seats and belts. Keep adding throttle in a decreasing radius turn until the slicks are howling, then mash the throttle and hope it all works out. You get one good lap from the bearings doing this. I had to roll the seat belt several times to defeat the inertial reel so I could stay in the seat. I got The 5 fastest laps I've ever done. Then the brake fluid boiled. Best reason to keep the parking brake in the car...when you are motivated you can abs a parking brake.

 

I started shopping for a race car the next day...

 

Not saying any of this would happen to you, but the setup that made that tire combination viable isn't for everyone.

It's probably so stiff that there's only half an inch of suspension travel.

 

Still incredible to fit so much tire on there and race it. *Please don't try this at home with your LGT*

 

My vision blurs on rough roads...

I've been really happy with the size and fit of my newest setup. It's comfy on bad roads, still have plenty of grab, tons of options, quiet.. Might be keeping a version of this wheel/tire combo for good.

 

-17x8, +48, 17lbs with a relatively meaty 235/45/17

-Lowered at least 1" all around - coilovers now, but going to JDM strut/lowering spring soon

-No rubbing and no fender modifications

 

Definitely not glamorous or hella, but practical, looks good and inexpensive.

 

 

Nice, I'm surprised that tall of tire doesnt hit the bottom of the strut!

Related question - does anyone make aftermarket wheel bearings for 4th-gen LGTs?

 

SKF makes a nice upgrade for C5s, but I don't see anything with their "X-Tracker" branding for Subaru.