Volkswagen Passat Forum banner
1 - 10 of 10 Posts

· Registered
Joined
·
123 Posts
Discussion Starter · #1 ·
Now that I've been driving my 2005 Passat wagon Tdi (with 5sp manual conversion) for almost a year with no improvement in fuel economy, averaging about 32 mpg (US gal ), where a lot of you seem to be getting in the area of 40 mpg, I 've decided to go with larger diameter tires.
I need tires so now is the time to do it. I'm thinking of going with 205-60-16 as opposed to 205-55-16. If the charts that I'm using are correct the new tire dia. should be app. 0.8 in. larger in dia. 3% faster.
Or I could go with 215-60-16 which would increase dia. by 1.2 in. 5% faster., which I think I would prefer,

Have any of you done this and were you satisfied with results?
Thanks
 

· Registered
Joined
·
5,252 Posts
I don't think larger tires are going to have that much of an effect on real fuel economy. It will, however, have a direct effect on reported fuel economy since the car has no idea what diameter your tires are. (The reported fuel economy will go down, since each tire rotation will take more energy due to the greater distance covered.)
 

· Moderator/Administrator
Joined
·
26,187 Posts
I've used that site and seen it recommended before.
 

· Moderate Moderator
Joined
·
16,440 Posts
Are you doing mostly city driving or highway driving? For city driving you want to get the rotating mass (wheels) as light as possible. Look up the weights of specific tires on The Tire Rack website. For highway driving look for low rolling resistance tires. Keep tires inflated towards the higher side.

Yes, a larger diameter tire will change the overall drive ratio but it will also have a larger centripetal mass.

Do some internet searches on hypermiling techniques. Some of those guys take things to an extreme and then double it. :icon_eek:
 

· Registered
Joined
·
123 Posts
Discussion Starter · #7 ·
First of all want to thanks all of you that have offered an opinion I was not expecting the type of responses I received. I was more or less looking for a Yes or No.
So I bought the larger tires 215-60-16 Yokos mounted on 7.5 in rims.
It'll be interesting to see what the Passat looks like with it's new wheels.
 

· Registered
Joined
·
123 Posts
Discussion Starter · #10 ·
The transmission was supplied by Dutch Auto and I have no reason to believe it isn't the right one as it came from a European Tdi manual vehicle. At 2500 rpm the speedo indicates 120 kph, app. 70 mph.
I have a Malone 1.5 tune which I really don't want to change as I like it.
At some point we may mess around with the timing to see if any improvements can be had but I don't expect much of a change, if any, from that.
At this point I'll get the new tires installed and see what effect they have on mpg.
I should be able to provide some sort of updates after burning through a tank or two of fuel.
 
1 - 10 of 10 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top