Harsh ride on 18" Alloys - 2015 GOLF TDI - SEL

New to this forum and already it looks like a winner of a site for ideas and information..
Just bought a 2015 Golf TDI . I wanted built-in navigation and with that came a lot of stuff I was neutral about, including 18 inch wheels with low profile Pirelli Cinturato P7's, in size 225/40 R18. At the recommended pressures of 38 lbs the ride is pretty harsh and clunky, as I had earlier test driven only the TDI in S trim with the smaller wheels and fatter tires, which had a much smoother ride.

How have y'all handled this issue, if it *is* an issue:

-Lower pressures? (not much scope for that with the narrow sidewall!)
-Wheel change? (would 17 inch wheels look too small on car?)

-Other approaches?

Thanks,
Roger

Here's a handy tire/wheel calculator: http://www.myturbodiesel.com/1000q/tire-wheel-gearing-calculator.htm Just plug in your stock size and you can compare different size and aspect ratio values. You want to keep the rolling radius as close to stock as possible. Also remember that narrower tires usually result in improved fuel mileage.

Check with local VW dealers as they sometimes have brand new "take-offs" on sale at good prices. The big VW dealer here most often has 3 or more sets on hand. You can also post the 18s here or over on VWVortex.

You're on the west coast. I am sure you can find a new set of take-offs over on the Vortex classifieds for not much money, probably with new tires on them as a bonus. The key is patience. You can use 205/55R16 which is the stock size on the S trim.
I am not a fan of 18" rims with such low profile tires either...

All good suggestions and you will improve the ride and mileage by switching to something like the 205/16 size.
When I bought the Jetta 1.8T gasser wagon it had the 225/17 on it and between the poor snow/ice properties, harsh ride and reduced mileage (even for the gasser) it didn't take long to swap on the set of 205/65/15s from the Jetta TDI sedan that had been totaled out. The roads in this part of the country are in horrible shape from the severe frost heaves and missing pavement. Picked up a couple mpg with the tire/wheel change.
You should have no problem finding a Vortex member to swap with.

Smaller wheels with larger tires will work to soften the ride. The mk6 TDI came with 17 inch wheels standard and a 225/45R17 tire, along with 25 Nm spring tensions. I don't know if the mk7 TDI spring tension is the same or not.

If you really want a softer ride, you could get 16 inch wheels. I don't think they'd look bad, just a little old fashioned.

I'm not sure where you are in California, but I just bought a 2015 Jetta SE with the Arlington alloy wheels and I'd like to switch to 18's. Maybe we could work a swap deal?

^^ Win/win!

I was unhappy with the ride on the stock 17s. in my '12 Golf, so I switched to 15s from a B5.5 Passat.

Handling and braking are unaffected. Ride is far better, and I picked up a couple MPG. Tires are far less expensive, too.

Re Bueller60's post, how does the rolling radius or effective wheel diameter compare with mine? I agree it would be best to keep that near the same. And what rim size are the Arlington alloy wheels you have? I live in San Carlos, CA.

If they are stock wheel/tire combination the rolling circumference will be the same. I measured that on the 17 and 15" ones before I swapped mine out just to make sure. The higher profile sidewall makes up the difference. You can go to the various tire manufactures websites and get the measurements to verify also. They also include revolutions/mile, which is probably the best indicator.

In the owner's manual for the 2015 GTI, there's a "Comfort" Pressure (33psi) and "Normal" Pressure (37psi) both at full load. Here's the pic I found from Edmunds' Insideline Blog. Check your owners manual. I would try this first before buying new wheels as this is the cheapest option.

Even at lower pressure levels those low profile/large diameter tire/wheel combinations make for a harsh ride if you live in areas of the world where road conditions are far less than ideal. Plus the mileage loss with them (especially at lower inflation levels) really make them a poor option.

Harsh Ride on 18 inch

rlt40 said:

Re Bueller60's post, how does the rolling radius or effective wheel diameter compare with mine? I agree it would be best to keep that near the same. And what rim size are the Arlington alloy wheels you have? I live in San Carlos, CA.

Click to expand...

Now I wonder if I should go to the 15 inch wheels. I presume yours on the Jetta are the 16 or 17 inch, right? One posting just above went to 15 inchers and likes the ride and mileage too.

Rlt40, I shot you an email with info.