Tire Size Dilemma

[JMS]

Ok, So I purchased a 2004 Jetta GL a few months back. Right now I'm in need to replace the front set of tires. I realized today that the previous owner at some point went from the stock 195/65R15 to 195/60R15. I'd like to have the stock tire size on there but I don't want to have the 65R up front and the 60R in the back (and the other way around when I rotate them at some point). Does it really make a difference if I have the 65R/60Rs on the car at the same time? I'd rather do this than replace all 4 with the 65Rs because the tires on the back of the car are pretty much new.

I guess my other option is just to put the new 60Rs on the front, but - I do a lot of highway driving and I'd rather have the larger tires and have the better fuel efficiency.


Thanks

[MagicRat]

Originally Posted by JMS

. I'd like to have the stock tire size on there but I don't want to have the 65R up front and the 60R in the back (and the other way around when I rotate them at some point).

In theory, with a mix of 60 and 65 series tires, during high speed cornering or lanechanging, the 60-series tire would start to build cornering forces slightly faster than the 65 series tire.
Again, in theory, this would lead to a feeling of slight instability when cornering. The car may require some minor steering corrections in high speed cornering (like freeway on-ramps) which may not otherwise be required.

So I would agree, in theory all tires should be the same size.

To play it safe (and cheap) just buy 2 new 60-series tires.

If you go for four 65 series tires, any fuel savings probably are not large enough to pay for the added cost of 2 extra 65-series tires because the change in tire height would give you approx a 2% decrease in highway engine revs; probably too small a change to have a measurable effect on fuel economy.

If you feel like gambling, go for two 65 tires and see how they handle. You may find the handling change may be negligible.

[JMS]

Thanks for the advice.

If it's a minor issue with stability I'm not too concerned. No one so far that I've talked to outside of AF has told me not to do it yet.

If anyone else has opinions on mixing the two series of tires, let me know!

[MagicRat]

Originally Posted by JMS

Thanks for the advice.

If it's a minor issue with stability I'm not too concerned. No one so far that I've talked to outside of AF has told me not to do it yet.

If anyone else has opinions on mixing the two series of tires, let me know!

FWIW I have mixed tire sizes quite a lot over the years.
Frankly, with your typical older floppy-handling American car, minor tire size variations produce no noticeable problems.

Imo it takes a precision-handling car (like yours) and an experienced, picky driver to notice a change.

[Moppie]

Originally Posted by MagicRat

Imo it takes a precision-handling car (like yours)

One of the funniest things I've read here in a long time



JMS I would stick with the current 60 series tires, there is little to no benifit in changing.
I believe the 65 series are not very common, and were used by manufactors to try and tie you into using only one brand of tire.
The 60 series is much more common, and will give you more options to choose from in terms of tire choice.


As a general rule, for any car, regardless of how well it handles, it pays to keep the amount of grip front and rear balanced.
The best way to do that is to use the same brand and model of tire on all 4 wheels. A difference in aspect ratio of only 5% would then be almost insignificant.

I have different brands of tyres on the front and back of my car, and there is diffidently more oversteer than Honda ever intended.
I would even go so far as to say it is a little bit dangerous.

[MagicRat]

Originally Posted by Moppie

One of the funniest things I've read here in a long time .

Oh dear, let's not have JMS get too mad at me

I was being serious, but then my standards for precision-handling are pretty low, I guess......... just look at my sig.........