Opinion - Tires, Speedometers, Odometers, and MPGs Options

[dcecc1968]

So I purchased a 914 last year that has 7-yr old Yokohama AS430's 205-50-15's, with lots of tread, but one of the tires is bad (sidewall is splitting). I'm debating whether to purchase one replacement tire or to replace all 4 (since they are all have an old manufacturer's date). I'm debating whether or not to stick with the wider tire or to go back to stock size.

Everyone here seems to like the wider tire than the stock tire, but doesn't this produce inaccurate speedometer readings (9.1% according to the tire calculator tool) and I believe produces a falsely high mileage reading as well? Also, I guess this would really make by MPGs look a lot better as well.

I want to use mine as a daily driver, not for autocross (well maybe.. who knows). So my question is do the wider tires help the 914 perform much better than the stock size tire under these driving conditions?

Before I drop lots of $$ of new tires, I'd like some feedback from the experts.
Thanks,
Don

[r_towle]

stock diameter tires are what you would shoot for.
I think a 195/60/15 is about as close as you can get to the stock diameter.

205 tires are much smaller than stock, so yes, everything will be off.

With the taller tires you will experience lower temps on the highway because of lower rpms overall.
It will also be slightly slower from 0-40 due to the taller tires...the short ones basically re-gear the whole setup.

After you choose your tires, you can send your speedo to Palo Alto Speedometer/North Hollywood speedometer (same company) to have them recalibrate it for the diameter of the tires you purchase.

Rich

[r_towle]

165/80/15 is the stock tire, 25.39 inches in overall diameter

195/65/15 is about 25 inches in diameter, depending upon the tire/brand etc

205/50/15 is about 23 inches in diameter

rich

[toolguy]

A 205 should NOT go on anything smaller than a 6 inch wide rim. .

[MLedesma]

Please for your safety do not drive on 7 year old tires (even if they have good tread).

[r_towle]

A 205 should NOT go on anything smaller than a 6 inch wide rim. .

Myth

[messix]

I tried 205 65 to get near stock height and there is some fender pulling and on my car the le spoiler needed some tweaking to avoid contact when turning.

195 55 or 60 should be a good ride, fit and look.

you cant really trust the speedo on these old cars and the odometer should be +- 3% too be in very good condition.

many of the other guys that have had old Porsches have commented that the speedo's are not all that accurate from new.

[solex]

I just put 195/65's on mine to get it back to stock-ish ride.

I had 205/50's originally and they were not recommended on a 5.5" rim.

I really like the ride with the new tires, much more comfortable and braking has actually gotten better.

[dcecc1968]

Thanks for all your input/advice. I didn't think about the re-gearing effect of the smaller diameter tires, but certainly makes sense. The "old" rubber concerns me too, which makes it less fun to drive (even if its only a figment of my imagination). I have 8-spoke Empis, which appear to be a wider wheel.

I think I'll go with 195-60's or 65's and replace all 4.

[Chris Pincetich]

I think I'll go with 195-60's or 65's and replace all 4.

Good call (IMG:style_emoticons/default/beerchug.gif)
I've had 195/50s - first years of ownership 2004-2006
Then 205/50s - 2006-2011
Winter tires at 205/65 - 2011/2012 required raising front to avoid rub at lock, which tweaked alignment
Then 195/65 Winter tires - perfect!!
Now 205/50s - high performance Dunlop Star Specs summer tires 2011-present

I really liked how the 195/65s raised the car up a bit compared to 205/50s

My daily and weekend drives force me through 10-20 miles of single-lane windy country roads, and I like to go to the occasional AX race. My tires wear quickly on the 914 (IMG:style_emoticons/default/beerchug.gif)

[solex]

Here is what my car looks like now http://www.914world.com/bbs2/index.php?sho...=215739&hl=

[dcecc1968]

Solex, Nice looking wheel/tire set up .

[solex]

Solex, Nice looking wheel/tire set up .

Thank you

[dcecc1968]

Got some new boots, went with Falken ZE 612's 195-60-15. Drove it home, parked it for a week, went out to drive it and blew a tire. (IMG:style_emoticons/default/mad.gif)

Thankfully I purchased road hazard and Discount Tire replaced it free of charge.