Tire Profile

2015 GSW TDI 30K miles Lost a stock Brigstone & need tires BUT...
IN several 600 mile trips Milwaukee to Mpls, piggy gets better mileage in 5th gear even with downshifting on the grades, going by mileage, 6th is lugging. All driving is at 80 MPH & not trying for MPG.
I'm considering going from junkstone 205/55R1691H to Michelin Pilot Sport A/S +3 205/50R1691H & use 6th gear more often.
Advice?

Continental Pure Contact 205/55-16. 'Nuff said...

At 80 in 6th it's not lugging. Stick with the stock tire size so instruments remain accurate.

If you feel it needs more power in 6th get it tuned. Makes a big difference.

You won't gain anything by dropping your sidewall 10%.

Ditto

1854sailor said:

Continental Pure Contact 205/55-16. 'Nuff said...

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I've been running the Pure Contacts and have had excellent results throughout the tire life.

IndigoBlueWagon said:

At 80 in 6th it's not lugging. Stick with the stock tire size so instruments remain accurate.

If you feel it needs more power in 6th get it tuned. Makes a big difference.

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They may have some hills that are bigger than we see on our local interstates.

While it may not be lugging it may not be in optimum efficiency at those speeds, slightly higher RPMS will have the turbo working a little less and may save a bit of fuel.

That being said, I'd rather down shift on the hills to stay in the MPG than cut the sidewall down and miss out on the flat ground MPG of the taller gearing.

I've driven in Wisconsin a number of times ( including driving the length of it last year when I attended TDIFest) and in Minnesota a few times. I honestly don't remember any hills in either state.

Low revs and larger fuel request (and boost) is more efficient than higher revs and less boost. Pumping losses are lower at lower revs.

The Hudson / Knap hills near MN are roughly 1300'. I have not & will not attempt to climb these in 6th. Hills in the Dells area must by in the 900' range.
Downshifting to 5th on grades uses more fuel than just staying in 5th even at 80 MPH & about 2300 RPM.
At 60 MPH, 6th gear uses roughly 5 MPG than 5th gear. I do not believe this is due to driving habit & this is over 7 + trips from Milwaukee to Mpls. in all weather. Granted I drive using my human brain & avoid 'foot dancing' & get in the mid to upper 50's on the MPG meter. Not lugging the engine should yield better mileage which is why I question the overall gear reduction of this drive train's 6th gear ratio. Could this TDI be designed for higher speed driving like the autobahn?
If you look at the tire size / profile of S vs. the upgrade models, there is a bit of range in absolute tire dia.

The TDI is designed and geared for best MPG not higher speed driving of the autobahn. If you're pushing above triple digits you'd probably want to be in 5th for best MPG as you'll be in HP band. Will you be fine in triple digits in 6th sure, but you won't have as much HP as you would in 5th, as you need HP in those speeds not torque. I don't think you can hit max speed of 130MPH in 6th because its geared too tall, remember reading that here, could be wrong

VW tries to keep with in a small percentage of circumference of a 16" rim vs 18" rim.

A 195-65-15 tire is close but not exact to a 205-55-16, heck each brand of tire is slightly off in circumference of the same size tire.

Don't let anyone steer you against what you've experienced. I'd say enjoy the stock size and just down shift when you know you'll get better MPG, you won't be hurting anything.

Even if you downsize the tires, for from 205-55-16 to 205-50-16 you'll loose a little sidewall and ride comfort, and my not see the big enough change in overall gearing to recoup the benefit of staying in 6th vs stock tires and downshifting into 5th. if the 50 series tires were a bit cheaper, that also may weigh in my decision as well.

If I switched from 16 to 17" rims would these tires fit?.

205-55-17

Here's an excellent Tire, Wheel and Gearing Calculator that allows you to see the effects that changing tire sizes will have on your car.

Small Mountain = Big Molehill. Difference in not owning a DSG, is to shift and make your TDI happy at all times. Drive & enjoy, don't sweat the small stuff .

I drove my GSW to central MA today. Hills, not mountains, but probably about as much elevation change as in Wisconsin. It didn't have any trouble accelerating from 60 MPH in 6th, (1500 RPM or so). I didn't sense that it was lugging. It is tuned, which I think helps a lot. Also saw 47.9 on the MFI running at 75 MPH most of the time with the A/C on. Given the significant MFI error I've experienced thus far I'd suspect that's about 44 MPG. But the car only has 2600 miles on it.

IndigoBlueWagon said:

I drove my GSW to central MA today. Hills, not mountains, but probably about as much elevation change as in Wisconsin. It didn't have any trouble accelerating from 60 MPH in 6th, (1500 RPM or so). I didn't sense that it was lugging. It is tuned, which I think helps a lot. Also saw 47.9 on the MFI running at 75 MPH most of the time with the A/C on. Given the significant MFI error I've experienced thus far I'd suspect that's about 44 MPG. But the car only has 2600 miles on it.

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+1
Do it daily...
And up in Maine, and Vermont...
2200+ is NOT lugging a gen3 TDI on a hill...heck..never even get a downshift with a DSG and cruise on....

FiveLugNut said:

If I switched from 16 to 17" rims would these tires fit?.

205-55-17

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Yes. I run 215-55/17s on my 2015. They will not rub.

Your speedometer and odometer will be slow by about 4%.

FiveLugNut said:

If I switched from 16 to 17" rims would these tires fit?.
205-55-17

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Same size as stock alltrack tires, other than plastic beauty trim no difference in wheel wells, no issues

ZippyNH said:

+1
Do it daily...
And up in Maine, and Vermont...
2200+ is NOT lugging a gen3 TDI on a hill...heck..never even get a downshift with a DSG and cruise on....

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2200 in the Passat in 6th is 80-85MPH. 2,000 is right at 75MPH.

Hills in MA, hehehehe

740GLE said:

Hills in MA, hehehehe

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I agree. But I still have no recollection of any hills in Wisconsin or Minnesota. So I'm guessing they're comparable.

Thanks for the info. So the ride doesn't suffer when going from 16 to 17 because there is a nice side wall!!.

Ended up staying stock with Kellys. Got a deal & should save $ for house repairs. Bought one just to get off the donut. Did a bit of research & they aren't bad so bought the other three.
One thing I learned is a real tire fits in the donut well so the donut is gone.
I turned on the 'active' MPG thingy, drove a I94 grade several times, same speed, cruise on, same weather ... logged the lowest MPG ... the thingy changed so often low reading was far easier ... 6th was just slightly better at 60 MPG but at 80 was less. Go figure. The difference in roughly 650 miles is 1.2 gallons so my yearly saving would be spit. Just seams strange that this car likes 5th on these trips. 205/R50/16/91H.
BTW, some tire companies & dealer sites are not concerned with the load / speed rating. Go figure.

Lostyankee said:

Got a deal & should save $ for house repairs.

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Truly the wisest decision.