No VIN yet. I am also curious about the large span of time until the build complete date. Perhaps they anticipate tuning and adjustments? I am just happy that it's progressing. Also the length of time between build complete and delivery. So it would seem that mine gets built, and then waits for a pile of them to be built, and loaded in the boat.

So if work sends me to the UK, maybe I can find a way to sneak a peek.

Bruce

 

My build completion date is also scheduled for June 5, but as of last Thursday, there was no other news. I've been bugging my GM enough over the past several weeks, so I'm going to (not so) patiently wait until the 5th to ask for an update and hopefully get the VIN. I need the VIN to order the TPM sensors for the wheelset I'm having built. However, the car may well get here before the rear Michelin PSSs that are currently out of production.

 

So what kind of wheel set are you getting built?

Orkney

 

The 20" black diamond cut gyrodynes were my first wheel choice, but unavailable on the V6 models, so I took the 19" propellers that came standard. With the help of a couple forum members I was able to find a set of low mileage gyrodynes. Will be shoeing those with PSSs. I'll be sticking with the 255s in front, but going up to 305s on the rear. Will probably sell the 19" set, but not until Michelin starts making those rear tires again.

 

I just checked for availability today on Tire Rack and the PSS 295/30-20s are available right now, it is the 255/35-20's that are back ordered until June.

I might consider putting 305's on as well when I have to replace these tires. I assume others have done this? They don't have any clearance issues or fitment issues on the stock rims? I wouldn't think so going from 295 to 305 but always best to ask.

Though going this way may be more troublesome, as the PSS 305/30-20's are also back ordered, and with no specific ETA.

 

My local tire dealer has set aside a pair of the 255s for me, and we're still waiting for the 305s. They may be available shortly, since the 295s were recently backordered as well.
Fitting the 305s should not be an issue since a number of folks on this forum have installed them with no reports of interference except when mated with wheel spacers.

 

Don't go too crazy. Staggered tires are okay on a RWD car, but on an AWD you don't want to have the rear tire diameter significantly different from the front diameter.

 

Hmm, I get what you're saying, though my car still came with 255's up front and 295's in the rear like the RWD cars. I assume that is factored into normal handling... this is primarily a RWD car either way. The Porsche Turbo S also has staggered tires (20x9 @ 245/35 up front and 20x11 @ 305/30 in the rear) so it seems pretty normal (and Porsche has a wider of a gap in size too.)

I'm not married to the idea of getting the 305's, I just like the look of wider tires. Though the difference in width between 295 and 305 is barely noticeable.

 

I'm talking height, not width. The 255/35 and 295/30 are only 0.06" in diameter different. If you change the back tires to a 305/30, that difference in height expands to 0.18". Since the vehicle is AWD the electronic center differential must compensate for this difference because the rear tires are making slightly fewer revolutions than the front tires. While 0.18" is not a tremendous amount (you could have this variation from tire wear) the further apart you travel from equal sizes, the more stress you are putting on the center differential unit when it is activated. This is the same reason they tell you to only use a flat bed when towing an AWD car.

I'm trying to figure out a way to stick more rubber under my AWD, but the lack of good tire sizes is making it challenging. The rear might allow for 325s, but squeezing a 275 up front will be hard, and nobody makes a matching tire setup in this profile anyways.

 

The first batch of 6 speeds for the US is finally in production. My GM texted me that mine is currently in production and scheduled for completion next week.

 

Congrats! Very good news indeed!

Orkney

 

So I did a little investigating.The stock 255 fronts and 295 rears have a 2mm difference in tire diameter (687mm front vs 685mm rear.) Moving to 305's in the rear ups them to 691mm (or 4mm difference - still pretty negligible.) If we also move the fronts to 265's then we have 694mm front and 691mm rear, which is back down to 3mm. Of course, you could also use the 265's up front and move the rears to 315's and also have 3mm difference (694mm vs 697mm.)

Will the 265's fit up front and 315's fit in back on the stock rims, without rubbing? Probably doesn't matter since I don't see any 315's available. However, 265's up front and 305's in the rear still allows for several tire options.

275's up front and 325's in rear is back to 2mm difference, but those might rub. But you will have a hard time finding matching tires in those sizes.

Btw, sorry for the derail... this should probably be in another thread since this isn't specifically about the 6 speed.

 

Unfortunately, 255 and 305 tires are already at the upper capacity limit of the 9 and 10.5" wheels respectively. Go wider than that and you start to distort the contact patch and it becomes difficult to mount the tires.The tire might fit in the wheel well, but you'll need wider rims.

P.S. OP not offended by the derail.

 

Keep in mind that 4mm difference in diameter doesn't seem like much, but its equates to the front tires spinning 4 additional revolutions more per mile than the rear tires. The center differential has to make up for this, and over the long term this can accelerate wear or cause damage. Electronic differentials certainly aren't the most robust units.

 

In full-time AWD, it'd be bad., but isn't this system essentially RWD unless the rear tires lose traction? I'm not sure how the power engages to the front wheels, but it seems it'd be a non-issue unless the difference in diameter was enough to confuse the computer deciding when to apply that power and how much to apply.


I've done zero research on this though. <shrug>

 

Yeah, that was the point I made earlier... most of the time you'll be 100% RWD, it should only redirect torque to the front wheels if it detects the rear wheels losing traction, which should only happen in adverse weather or when pushing the car to its limits on corners, etc. For me anyway, that wouldn't be a problem.

I'm only now starting to investigate this, but it does seem reasonable based on what we're told of how the car performs.

 

Hmm, I'm looking at the specs of the 265/35-20 PSS tires and they show a rim width range of 9-10.5", so its at the edge of acceptable but looks like it should fit without stretching. Likewise with the 305's look like they fit the 10.5" rims at the edge of acceptability.

Honestly, given the stock tires are 255's up front and 295's out rear on the 20's I'm surprised they didn't go 1/2" wider on the rims. A 9.5" rim up front and 11" rim in the rear would put them closer to center on fitment for the stock tires rather than being close to max.

Cool. Though this may still be better off in its own thread.

 

I wasn't too concerned about the 265s up front and 305 on the rear (I'm going with 305), however, when you were considering 315s or 325s on the rear, I thought you might be pushing the envelope too much.

 

On the surface, this logic would make sense. However, the AWD system in the F Type is much more active than you realize. It activates almost every time you make a turn, to some degree, and any time you get on the gas hard. On top of this, the center differential is an electronically controlled clutch pack differential. Traditional mechanical differentials (especially viscous couplings) can handle some difference in speed from front to rear. They get hot when adjusting for this speed difference, but typically don't fail or wear prematurely unless they are significantly overheated. The clutch pack design is essentially a clutch like you would find for a transmission (only with more plates and electronically controlled). When you change tire diameter from front vs. rear the center differential will have to slip its clutch plates against one another. This will wear out the clutch pack more quickly. Just keep that in mind when going to sizes with a greater difference in diameter.

Here's a video on our transfer case:

 

Awesome news.

Is it safe to assume that they're using this same production run for Canadian bound cars? I was given a July 31st pick up date -- but if production is starting now, maybe I'll get mine even sooner.