Installed 215/55/18 = TOO BIG. need some help

So I wanted a little bit of a lift and a more aggressive look. I don't know a top about stance and wheels,tires,spacers etc. but I figured what the heck. From my google research I thought I knew enough to make a relatively well informed purchase decision. I picked up some used BBS (always wanted some) and from what I could find the true contact seemed like a good choice in tire for MPGS, went with 215/55/18 because I thought a 2" taller wheel/tire would give me 1" more clearance. I read an article on a VW site that made me think it would fit with out rubbing. They rub quite often, they look great, fill the wheel well perfectly but rub all the time. Wheels have 40et and I used 20mm spacers in the rear and 15mm in the front. I think they need 15mm in the rear and maybe 8mm in the front. I added a stage 2 Kerma tune at the same time as the tires. My MPG as dropped to around 30 from 47, I knew I'd take a hit but this is way to much. Has anyone went with taller than stock sidewalls? Is anyone running 205/45/18 or 205/50/18? Any other ideas besides changing tires? How will the different tire size effect my offset? Anyone in the market for 215/55/18 true contacts with 400 miles on them? Any help from the wheel/tire gurus on here is appreciated.

Another problem I'm having that I didn't anticipate is when towing (I like to tow) the effective higher gearing makes it difficult to start out on a hill with a decent load behind the car.

Ready, fire, aim...

1854sailor said:

Ready, fire, aim...

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helpful

hause said:

helpful

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Sorry, couldn't resist...

Did you use one of the on-line tire size calculators to size your new tire circumference to be the same as stock? If not then your odometer and speedo will be off. Was your MPG calcs done by hand or as per the car computer? Either way they will be off unless the tire circumferences match.

You made 2 major changes at once. Tires and tune. If you want to see the effect of the tune on your MPG then install your original tires and do a mileage run.

Then you need to sort out your tires. Seems like your new tires are way too tall.

What size are your original tires?

Beaker80 said:

Did you use one of the on-line tire size calculators to size your new tire circumference to be the same as stock? If not then your odometer and speedo will be off. Was your MPG calcs done by hand or as per the car computer? Either way they will be off unless the tire circumferences match.

You made 2 major changes at once. Tires and tune. If you want to see the effect of the tune on your MPG then install your original tires and do a mileage run.

Then you need to sort out your tires. Seems like your new tires are way too tall.

What size are your original tires?

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Correct, the tires are to tall. I think the stock tire size or 18" wheel is 225/40/18. I think my tires are about 2" taller, some of the online calculators give a little bit different figures. I'm basing mpg estimates off of hand calc miles per tank but I guess my odo could be off.

Your offset is based on your rims. What will change is the width of the tire on either side of the center line of the rim. Wider tires means more tire inside and outside of your stock ones.

I am running 19 inch tires with the closest size compared to stock diameter. Seems pretty close. My car is lowered and I like to tow as well so I get the occasional tire rub on the back going over big bumps with the trailer. My rims have a different offset (ET30) to stock so that could help with the rubbing.

Keep in mind that wider tires and larger diameter tires are heavier and they have more rubber contact area so increased rolling resistance. Both of these will negatively affect your fuel economy.

I took the fuel compromise for the larger tires cause I like other aspects of them.

Is anyone running 26-26.5" tires?

Here is a handy online tool I use to determine the sizes and the effects if I switch to a different size tire. You can go and adjust to the projected sizes until you like what you see.

http://www.1010tires.com/Tools/Tire-Size-Calculator

This calculator allows you to compare four tire sizes at once.

I think a 215/45/18 would work well.

To add to the plethora of calculators here is another one with what I believe to be more inclusive information. Such as to clearance information.
Also a little faster since you enter the original tire and then change to whatever next instantly.

http://www.rimsntires.com/specspro.jsp

Jetta_Pilot said:

To add to the plethora of calculators here is another one with what I believe to be more inclusive information. Such as to clearance information.
Also a little faster since you enter the original tire and then change to whatever next instantly.

http://www.rimsntires.com/specspro.jsp

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I'd never seen that one before. However, the one on myturbodiesel.com includes gearing information for a more complete picture. Just my 2¢...

1854sailor said:

I'd never seen that one before. However, the one on myturbodiesel.com includes gearing information for a more complete picture. Just my 2¢...

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While I agree with you, but the average driver/owner has no clue of gearing and final gears etc.

I think you underestimate the "average" TDI owner when it comes to Gear Ratios.

A 9% increase in a diameter is a little too greedy. I run 215/55-17s (6% increased circumference) and I have zero rubbing on my Golf. They did rub on my Mk6 when turning.

215/50-18 would probably fit.

Your odometer is 9% off right now, so congratulations, you're actually getting 33 MPG!

As an aside, I installed my new tires on only two wheels and did a trial run with them on the front before I bought an entire set. But finding a second set of 18" wheels might be a pain.

Important to remember that the tire size in inches is the size of the inside, not the outside.

So, gotta take profile into account when figuring lift, effect on gearing, odo etc, since it's the outside diameter that's important for all those things.

Hence the various tire calculator sites.

Wow I don't even think those would fit on the NMS Passat. Looks cool thou.

Do you have any rub without the spacers? or do you have issues with clearing struts?

As for towing, don't think its the tires that makes take off seem painful its just the straight up crazy low gearing. Try starting in manaual mode and shifting up from 1st, I've noticed the Passat wants to slip the clutch in second anywhere above 5mph instead of down shifting to first.

If you're looking to unload the spacers shoot me a PM i'm looking to pick some up and are keeping my eye out for some 42DD ones.

740GLE said:

If you're looking to unload the spacers shoot me a PM i'm looking to pick some up and are keeping my eye out for some 42DD ones.

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Just out of curiosity do you think that DD spacers are better than no name spacers? All they are is a disk with holes to fit your car!
They need to be "Hub centric" which is the more important spec.

I bought some made of anodized aluminum which don't add too much extra weight.

Here are a bunch on some come as a pair and some as a set of four on eBay USA, some even come with the longer bolts required.

Agreed that its just a piece of aluminum with holes in it.

How did the diameter of the spacer compare to the diameter of the hat of the rotors? At 20mm its a big spacer and don't want a "step".

Trying to keep it not look like spacers are there when looking through the wheel, so that strikes out ECS black spacers.

740GLE said:

Agreed that its just a piece of aluminum with holes in it.

How did the diameter of the spacer compare to the diameter of the hat of the rotors? At 20mm its a big spacer and don't want a "step".

Trying to keep it not look like spacers are there when looking through the wheel, so that strikes out ECS black spacers.

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Yes black will show up more until the start to rust a bit. The aluminum spacers are less conspicuous in my opinion having/had both.
Basically all spacers will take up the same space of about 5" diameter.