[hogwild87]

Anybody running a taller tire in the rear?

[parish8]

I have th 305/35/20 which is speced at 28.4” tall. There is only about a pinkey width of space in front of the tire.

If you kept it to a 275 and you pulled the liner maybe

[hogwild87]

Originally Posted by parish8

I have th 305/35/20 which is speced at 28.4” tall. There is only about a pinkey width of space in front of the tire.

If you kept it to a 275 and you pulled the liner maybe

I’m running a 275/60/15 now but I was thinking more like a 29.5/10.5 if possible

[Cdflyer]

COPO’s run a 30” tire. I would assume removing the liners would allow you to do it without issue.

[hogwild87]

Originally Posted by Cdflyer

COPO’s run a 30” tire. I would assume removing the liners would allow you to do it without issue.

I’ve never looked behind the liners but I was thinking more the physical restrictions of either the fender itself during the squat

[laynlo15]

On the drivers side there is a wiring harness that runs right in the middle of the wheel tub, easy to remove the inner liner of the fender well. It takes about 10 minutes to take the liner out and get it moved. I just had mine out because my roll cage bolted thru the wheel tub. Easy stuff. 29" will be close, may not be able to lower it with a 29", don't know it the 29.5 will clear and it may depend on the offset of the wheel as to how much it moves it inboard. You could do it without the liner for sure

[cwebster]

Originally Posted by laynlo15

On the drivers side there is a wiring harness that runs right in the middle of the wheel tub, easy to remove the inner liner of the fender well. It takes about 10 minutes to take the liner out and get it moved. I just had mine out because my roll cage bolted thru the wheel tub. Easy stuff. 29" will be close, may not be able to lower it with a 29", don't know it the 29.5 will clear and it may depend on the offset of the wheel as to how much it moves it inboard. You could do it without the liner for sure

I remember the harness warning above when I was considering my options (thanks laynlo15). I checked and found that the wiring harness is routed differently on the ZL1 so I didn't have to worry about that. I'm sure the wheel well (tub) is the same but our liners may be different so my clearances may or may not be relevant.

I'm running MT ET S/S P345/35R18 on my ZL1. They're cited as having 27.8" O.D., 12.4" tread width, and 13.5" cross-section (at the bulge). On my car there's still about 1/2-3/4" clearance from the center of the tread to the liner at its closest point but only 1/4" on the forward inboard corner of the tread. With 11" tread width I could go taller but I wouldn't want to go more than another 1/4-1/2" considering how much the tire will "grow" at speed. You probably can't return a tire if you find it doesn't fit so your caution is appropriate.

If you wanted to go taller I guess nixing the liner is an option. I don't understand why you'd want to go taller though... A larger diameter will offer less of a mechanical advantage and increase rotational mass. Even if the tires are the same weight, moving the weight of the tread farther from the center will require more power to overcome the inertia. The larger tire will rotate at a lower engine RPM too. It seems to me that both of these effects will slow your 60' times, although you may end up with a faster trap speed. Isn't it all about the 60' when you're trying to get faster?

If I've got this wrong please explain. My DRs are almost done and I'm actually trying to find a shorter tire to give me a mechanical advantage and _reduce_ my rotational mass. Because of the surprise torque management giving us the infamous "nose dive" launch, I'm looking for anything that'll improve my 60' without voiding the warranty. If my logic is flawed I'd like to know before I pull the trigger on this tire purchase too.

--Cal

[KingLT1]

Guys with 6th gens have been going to shorter tires because there are no aftermarket gears yet. Ideally you add more tire and gear as you increase power. It's a simple formula that has been proven over and over in the drag racing world for 50+ years if you want more traction. I am guessing at Hogwild's power level, a 29" tire would probably help him being he is running 8's. Generally speaking, a Taller tire actually will reduce trap speed slightly and increase 60ft for a better ET. That being said, it all comes down to your power level and setup.

[Snowblind]

Originally Posted by hogwild87

Anybody running a taller tire in the rear?

I think I run the same tire as Parish (MT 305/20) but I believe that they are 28.7 tall. I would say that the 29" will work but 29.5 may not imo...it's pretty tight on the inner well side.

Even if you could shoehorn a 29.5 in there, does your tire need room for expansion ? I have removed the liner on my car, their is minimal gain in space behind it. It may require some grinding for that monster tire if you go that route...good luck with it.

[hogwild87]

Originally Posted by Snowblind

I think I run the same tire as Parish (MT 305/20) but I believe that they are 28.7 tall. I would say that the 29" will work but 29.5 may not imo...it's pretty tight on the inner well side.

Even if you could shoehorn a 29.5 in there, does your tire need room for expansion ? I have removed the liner on my car, their is minimal gain in space behind it. It may require some grinding for that monster tire if you go that route...good luck with it.

Thanks for the heads up, I’ll lyk what i find once I get to that point

[parish8]

Originally Posted by Snowblind

I think I run the same tire as Parish (MT 305/20) but I believe that they are 28.7 tall. I would say that the 29" will work but 29.5 may not imo...it's pretty tight on the inner well side.

Even if you could shoehorn a 29.5 in there, does your tire need room for expansion ? I have removed the liner on my car, their is minimal gain in space behind it. It may require some grinding for that monster tire if you go that route...good luck with it.

I thought they were 28.7 but they screwed up the mickythompson site so you can’t see the specs and summit has it listed at the sorter height.

I would go with a 275 if I could get a taller one but I think they jump from 28 to 30 and that is probably too tall.

My understanding with more height and more sidewall is it gives you a longer contact patch. Think about a 305/35/20 and it may be pretty wide but likely only has let’s guess a 6” long contact patch. Go down to a 15” rim and now the tire can squat and get a much longer patch, maybe a 12” long patch. A taller tire would increase that effect.

[Snowblind]

Originally Posted by parish8

I thought they were 28.7 but they screwed up the mickythompson site so you can’t see the specs and summit has it listed at the sorter height.

I would go with a 275 if I could get a taller one but I think they jump from 28 to 30 and that is probably too tall.

My understanding with more height and more sidewall is it gives you a longer contact patch. Think about a 305/35/20 and it may be pretty wide but likely only has let’s guess a 6” long contact patch. Go down to a 15” rim and now the tire can squat and get a much longer patch, maybe a 12” long patch. A taller tire would increase that effect.

Ha, I hate the new Mickey website too.

I did walk out to the garage with a level and measured 28.7 .... but the wheel was off the car and not on it. I agree with you, the more power you make the taller you need to go. The 15" inch conversion is also a no brainer with the powah you guys are cranking out.

[hogwild87]

I’m also going with a 3.73 diff

[laynlo15]

Kevin, I don't think that 3.73 will be best for your F1 setup. Your gonna start blowing the tires off if you leave that A8 in there Remember the A8 has a 4.50 something first gear. Your gonna multiply the Torque so quickly I think you'll have traction problems for the first 60ft or more. Now if your going turbo 400 that's different. Na car might benefit from that but I don't think its going to help your car with the power you have. Mike from magnuson had to pull power because they were blowing the tires off with the 26" tall tire and now they are going back to a 28" DR.