running a 295 rear temporarily with a 285 a probl

[SPR]

I had a blowout recently where it caused me to replace the right rear. Since I need to replace the other tires as well and certainly must replace the right rear, I wanted to get a set of ps2's. As such I ordered a set of 235/295's. since I am in SD and I want other things done this thursday in LA and need to put a tire on the car, I had the one 295 sent to me.

Ok, so now that, that is over, Will it be bad if I were to drive the car with a 285 on the left and a 295 on the right? I have a limited slip diff and that is my main concern. Any issue? I am going to drive the car up to LA, but need I only limit the time driven to that or is it ok to drive around with the car in the meantime? Thanks Sean

Anyone??? btw the diameter difference is less than .2 so I wouldn't think it would be a big deal. Please let me know so I can either enjoy my car over the weekend or refrain. Mainly I am worried about my diff.

[Q-Ship986]

Hi.

I am having trouble determining what tires you have originally and for what car. It seems like you might have 225/40R18 front and 285/30R18 rear. Is this correct?

So, you bought what? 235/40R18 and 295/30R18?

Also, do you have an OE spare tire? Probably not, judging by your predicament.

--Brian

[SPR]

I have the spare but have already mounted the one 295 on the right rear and am curious about the dimater hurting the diff. As I am in SD and need to go to LA, the spare won't work because I believe that you cannot drive over 50 wtih it and I would be using the freeway the entire way. My other tires are waiting for me in la. I didn't initially think it was a big deal and wanted Lucent to do the mounting anyways as the local yokals here aren't very good with the balancing. ( I will have them check the mounting of the right rear when I get up there)

Hi. 

I am having trouble determining what tires you have originally and for what car.  It seems like you might have 225/40R18 front and 285/30R18 rear.  Is this correct?

So, you bought what?  235/40R18 and 295/30R18?

Also, do you have an OE spare tire?  Probably not, judging by your predicament.

--Brian

<{POST_SNAPBACK}>

[plima]

A 285/30-18 Michelin PS rolls 832 per mile; identical to the 295/30-18 PS2 according to Michelin's website data. Seems like its not a problem (for a while). In my opinion, if you like to drive "quickly" you will want the same type and size on the car at your earliest convenience.

[C4S Surgeon]

Shouldn't be a major prob. BTW what finally happened with your roll bar?

[SPR]

HI. thanks for the info. the 285 is a bfg kd and the 295 is a ps2. I finally took the car in and had the roll bar installed for free no less by Avio in LA ( my dad is friends with the owner and is having his turbo done by him). In any event it turned out fine. I had the front repainted, roll bar installed, and new windshield put in. However the windshield guy I think forgot to hook up the antanae as there is almost no fm reception! There are a couple of other things, but I am going to Lucent Thurs. after getting my corner balance from Hergesheimer resulted in them setting it so low I am hitting the bumpstops in normal Driving! They further refused to make it right. I am pretty appauled at their behaviour to say the least and will be remitting the cost of Lucent to them

Edited September 4, 2005 by SPR

[C4S Surgeon]

Glad it worked out for you, sounded like a nightmare install, my brother and I put his in a little while ago and it was a *****. Anybody that says it is easy hasn't done it, I'm actually doing mine this wknd.

Those guys should make the car right free of charge. Some of these 'tuners' are out of control. Good luck.

Edited September 4, 2005 by C4S Surgeon

[SPR]

serious! btw, Anyone know the actual diameter of the spare, and how fast and for how long it's use is actually limited to? Thanks Sean

[Q-Ship986]

The spare in my 986S is a T105/95R17, which has a diameter that happens to split the difference between your 285 and 295 sizes. (This, according to my calculations, because I am not at work and don't have ready access to the published specs.) If your spare is the same, the differences here are on the order of the difference between a new and a worn-out tire. Porsche can be picky, given PSM, ABS, etc., but I think these numbers are so close as to be a non-issue, particularly for temporary service.

Now, if you were going down in size, then you'd need to be concerned about load capacity...

Regarding the max speed when using a spare, this is what my owner's manual states: "The maximum permitted speed is 50 mph/80 km/h and must not be exceeded because of altered driving characteristics and for reasons of wear."

The spare has a reduced tread depth when new, which can be used until 2/32" remains, as with regular road tires. Keep it inflated to 60 psi.

--Brian

[SPR]

Thanks I actually found the same exact specs doing a google search! the diameter equates to within .05" of the 295. As such I don't think it will be that big of a deal running the 285/295 afterall, so long as I keep the traction control off- I read a post about a corvette having such a complaint, but otherwise I don't think it will hurt the lsd or anything. Thanks again!