Spare Tire (part 2)

[tazwing48]

I went an bought a used 225/50x17 tire. It mounted on my 5" spare rim ok.It also fits in the spare tie wheel well and the cover goes on top of with out hitting the tire. So this could be the answer to the spare tire problem.

Taz

[AZTB]

Re: Spare Tire (part 2)

I think you may onto something, Taz...thanks for the post...let's see how our panel of experts respond.

[PaulD]

Re: Spare Tire (part 2)

Typically, a 225/50x17 tire is rated for a slightly lower load than our stock tire but that should not be an issue for short term use as a spare. However, it may need to be inflated above normal air pressure to achieve that load capacity which brings us back to the issue of a high pressure spare. My main concern would be the rim width. That size tire is typically designed for a 6" or more rim. Mounting it on a 5" rim would cause abnormal wear ..... but who cares on a spare.
Another variation on this approach is a 205/55x17 tire. Has similar load capacity but is typically designed for a 5.5" or more rim. It is also slightly slimmer in width but that does not sound like an issue if the 225/50x17 fits OK.
After looking more closely at this myself, the main result here from my point of view is...
1) A 205/55x17 or 225/50x17 tire will fit on our spare tire rim and provide sufficient capability as a spare in the event our spare tire blows out. On a road trip, it should be easy to locate a used tire in these sizes and keep on going.
2) The stock spare tire has a 50 MPH speed restrictions. Using one of the above tires should allow you to at least drive the speed limit when it is mounted.
I do not plan to replace my spare tire anytime soon but it is good to know these options exist while I am traveling away from home.

Taz.....what is the load and air pressure info on the sidewall?

Update....as I searched more, I found a Yokohama 205/50x17 tire that was actually rated to fit on a 5.5" rim. Bottom line....not all tires have same rating even where they are a common size.

[merlot4]

Re: Spare Tire (part 2)

Paul, from an earlier thread my measurements were based on measured height from original spare to trunk liner to be 1 1/2 inches. Using the 185 spare tire, which is width in mm, that would be 7.28 inches wide; the standard tire is 235 50 17, or 235mm wide which is 9.25 inches wide;a 205 tire would be 8.07 inches (205) wide;a 215 tire would be 8.46 inches (215) wide, and a 225 would be 8.86 inches (225mm) wide.
If there is 1 1/2 inches of room to spare (sorry, I couldn't resist) that would add up to 8.78 inches, or 223mm for the compact spare width plus the space above it. So Paul, I agree that would work although it might be a bit tight. A rim that will fit, as I recall, is available and, as you say, would be preferable to the limited action spare. This thread goes back at least to last year, but I don't recall anyone trying this.

[5bird7]

Re: Spare Tire (part 2)

Probably no one tried it as a source for the spares that fit the spare rim was found. So far, the only problem tires seem to have been the Firestone tires on the 02 spare rims, not the MAXXIMs found on the 03 and newer tbirds spares.

[tazwing48]

Re: Spare Tire (part 2)

The 225/50x17 tire I have has load rating of 1433# at 44 psi,the tire on the car have a load rating of 1521 at 44 psi. The 205/55x17 tire is 1/2 shorter than the spare it will replace,the 215/55x17 is still shorter than the spare. The 225/50x17 is the only one that can the closest to the height of the spare. I have ran tire in the past on narrower rims than are called for,the only trouble I had was the centers wore out before the edges did.But there again it is just a spare tire to get you to the next town for repairs.

Taz

[AZTB]

Re: Spare Tire (part 2)

Just for clarification, Taz, you mounted the 225/50x17 tire on the stock spare tire rim that came with the Bird, correct?

[tazwing48]

Re: Spare Tire (part 2)

Yes the 225/50x17 is mounted on the stock spare tire rim.

Taz

[divenmedic]

Re: Spare Tire (part 2)

Well what can I say other than the evil spare tire debacle raises its ugly head again. My 2002 T-Bird still has the Firestone spare, after reading some of the comments here I’m going to try the General G-Max AS-03 or the Fuzion Touring, 225 55R 17. There not the best on the market, but for a spare to get me home or to a shop I think they’ll do . . .any thoughts

[merlot4]

Re: Spare Tire (part 2)

The 225/50x17 tire I have has load rating of 1433# at 44 psi,the tire on the car have a load rating of 1521 at 44 psi. The 205/55x17 tire is 1/2 shorter than the spare it will replace,the 215/55x17 is still shorter than the spare. The 225/50x17 is the only one that can the closest to the height of the spare. I have ran tire in the past on narrower rims than are called for,the only trouble I had was the centers wore out before the edges did.But there again it is just a spare tire to get you to the next town for repairs.

Taz

I'm missing something here, Taz. The tires you have listed should be wider than the spare, could you clarify what you mean by "shorter"? I, for one, am happy that you tried this out and that it is workable on the spare rim, although I still would like a wider rim if I could find one inexpensively.

[tazwing48]

Re: Spare Tire (part 2)

The other tires I listed are shorter in Diameter compared to the factory tires.You need to be with in 1/4 inch or .250 of the diameter of the factory tire. The tire I chose is not correct for the spare rim. It should be on a 5 1/2 to 6 1/2 rim. The local tire shop, that was working with me to find a non Temporary Spare tire for me, felt that a 225/50x17 tire would work on a 5" rim if I did not run it at full air pressure or use it all the time. Yes the tire is wider than the spare tire,but it fits in the spare tire area just fine. If you could find a steel 6" rim to fit the T-Bird it would be better,I do not know if that rim would fit into the spare tire area. There has been a lot of talk on TBN about using
a 55 series tire instead of a 50 series tire on the T-Bird because it fills up the wheel opening. Remember if you do that the factory spare tire will not work with the 55 series tires,the spare tire will be to short in diameter and will cause damage to the differential if used on the rear of the car.

Taz

[merlot4]

Re: Spare Tire (part 2)

Thanks, Taz.

[cewhite3]

Re: Spare Tire (part 2)

....I do not know if that rim would fit into the spare tire area. There has been a lot of talk on TBN about using a 55 series tire instead of a 50 series tire on the T-Bird because it fills up the wheel opening. Remember if you do that the factory spare tire will not work with the 55 series tires,the spare tire will be to short in diameter and will cause damage to the differential if used on the rear of the car.

Taz

There should not be is a problem with using the T 186 60 Spare with 235 55 Tires.

The difference in the sizes are not that great.

The T 186 60 17 temp tire have an OD of 25.74"

The 235 50 17 tires have a nominal OD of 26.25" - 102% of the size of the temporary spare

The 235 55 17 tires have a nominal OD of 27.18" - 106% of the size of the temp spare.

I don't think that extra 4% is going to damage an open differential. It might casue the ABS system to set an ABS problem code, but that will clear up once the correct tire is reinstalled.

Differentials are designed to handle variation in the speed of the rear tires much greater than 6%.

The actaul rolling radius of tires supossedly of the same size can vary by 1% or 2%.

When you go around a turn with a 100 foot radius, the difference in speed between the inside and outside tires is around 6%.

When you go around a turn with a 40 foot radius, the difference in speed between the inside and outside tires can be greater than 15%.

When you drive in low traction conditions the difference in speed between rear tires can be really great (one can be stopped, the other moving at the equivalent of a 100 mph or more).

Ed

[divenmedic]

Re: Spare Tire (part 2)

Taz, have you had any problems with the 225/50x17 you put on the stock spare rim. My tire guy says it won't fit right or stay on right? Have you had any issues or problems

[tazwing48]

Re: Spare Tire (part 2)

I have not had to use the spare tire as of yet. I just looked at the tire it is mounted on the rim correctly. I keep the tire inflated at 28 psi. I do not know what your tire shop is worried about. No this tire should be mounted on a 6" to 8" rim to get correct wear, mileage and performance from. The tire warranty might not be good on this tire if mounted on a narrower rim. That is why I bought a good used tire. At he time I bought this tire no new temp spare tires where out there. I have no problem running this tire if I need to. This tire is a 225/50x17 mounted on my spare rim.


Taz