Downgrading from 19's to 17's on a 230TSI SEL

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carib230sel
Posts: 12
Joined: Fri Feb 28, 2020 10:44 am

Downgrading from 19's to 17's on a 230TSI SEL

Post by carib230sel » Tue Mar 24, 2020 4:07 pm

I am generally very happy with my Tiguan, but with every car I have ever bought I have always investigated what I can do to improve ride quality and reduce road noise.

The Tiguan starts off from a pretty good base here. Road noise is low for the class. As good, possibly, as my G30 5 series, which is itself praised as a very quiet car in its segment. Although SEL's come with 19" wheels and 50 profile tyres, there is not a huge amount of structure borne resonance coming from tyre to hub to suspension to body to interior. Good sub-frame isolation maybe ? And the ride quality, with DCC in the normal setting, is impressive considering the compromises involved: big heavy wheels, tall body with high CoG. It just breaks down a bit as the wheels thud into potholes.

I bought an as new set of 17" Montana alloys with Michelin Primacy 3 tyres off German ebay for 650 euros, as an experiment. Findings:
- first things first, they do fit over the brakes. Phew ! (I had checked VW's parts catalogue and brake calipers and discs seemed to be common between the relevant engine/trim specs);
- second, there is a huge difference in weight: a new 19" SEL wheel plus tyre weighs about 27.7kg. 17" Montana wheel plus tyre weighs 21.5kg. That's 25kg less across 4 wheels. Allow for the difference in rotational inertia as well, and the effect on acceleration and braking is like taking about 40kg out of the body;
- ride quality is slightly better especially over potholes;
- steering precision and feel are hardly any different, steering is maybe slightly lighter (I have the new wheels at about 35psi, the old ones as well)
- grip is still easily good enough for any sensible driver;
- road noise is maybe reduced but only slightly;
- fuel economy looks like it's better but too early to get reliable data.

Michelin Primacy 3 is of course a great tyre. What I deduce is that the Hankook is also a great tyre, if it was able to run the Michelin so close for ride comfort and road noise despite being stretched onto a massively heavy 19" rim in a 50 profile.
2019 230tsi SEL 4motion inc HUD, Keyless, Progressive Steering

carib230sel
Posts: 12
Joined: Fri Feb 28, 2020 10:44 am

Re: Downgrading from 19's to 17's on a 230TSI SEL

Post by carib230sel » Tue Mar 24, 2020 4:11 pm

Source for rotational inertia calculation:

http://hpwizard.com/rotational-inertia.html#answers
2019 230tsi SEL 4motion inc HUD, Keyless, Progressive Steering

carib230sel
Posts: 12
Joined: Fri Feb 28, 2020 10:44 am

Re: Downgrading from 19's to 17's on a 230TSI SEL

Post by carib230sel » Tue Mar 24, 2020 4:12 pm

Would love to hear from anyone on 20's, what is the weight of a rim plus (new-ish) tyre ?
2019 230tsi SEL 4motion inc HUD, Keyless, Progressive Steering

ExAudiSi
Posts: 161
Joined: Sat Mar 09, 2019 3:05 pm
Location: North Yorkshire

Re: Downgrading from 19's to 17's on a 230TSI SEL

Post by ExAudiSi » Tue Mar 24, 2020 8:07 pm

I've not weighed my 20s, but can confirm that they are very heavy!

Currently running on 17s with Goodyear Vector all-season tyres.
67 Plate, Pure White Tiguan 2.0TDI 4 Motion manual, electric tailgate, Miramar Grey 20" alloys and sports suspension.

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