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Discussion Starter #1
Want to use a P225/65/R17 as a spare tire
I know it's a little smaller than the 235 someone recommended,
but I just wanted to know if the smaller size will be an issue.

Thanks
Phil
 

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That's the size I have. Do a search for " spare tire" you will find numerous articles on this. Mike in AZ. has a the sizes and measurements listed.
 

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The size of your spare really depends upon the size of the tires you are currently running. In my case, I am running Nexen tires, 255/50 front and 295/40 on the back. That's a front diameter of 29.1" and 30.5 in the rear. The sweet spot between the two would be 29.8".

My spare is a General Grabber STX 245/R65-17 with a diameter of 29.45". Not exactly 29.8" but pretty close. With this tire size I am confident that I can use it at either end. Some have said that you don't need to worry about the spare size when using on the front.

Tim
 

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Our differential notices wheel slip and locks the rear end. If the tires are different sizes it [could] see the same thing and lock up? Close should be o.k.???????? But as you said, we don't all run the factory wheels. On some all wheel drive vehicles the system even notices worn tread and new tread.

bird
 

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The fronts don't care about Left to Right "stagger in diameter. The Auto Trans can Cancel out the Traction Control and the stagger won't be noticeable. The Manual Trans cannot be cancelled, so the stagger may cause concern. Someone with experience please chime in here, as I have Auto trans only.
 

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Our differential notices wheel slip and locks the rear end. If the tires are different sizes it [could] see the same thing and lock up? Close should be o.k.???????? But as you said, we don't all run the factory wheels. On some all wheel drive vehicles the system even notices worn tread and new tread.

bird
I'm sure that there are technical experts that will straighten me out, but here is my take on the Torsen....

The Torsen rear axle actually tries to increase the lock-up as the amount of torque into the pinion is increased. This allows low-torque inputs (like coasting around a corner or parking) to provide full differential action. As the torque is increased into the pinion, the differential action becomes significantly less available and the two rear tires tend to act like they are connected with a high pressure clutch. When doing a full throttle takeoff, applying 500-1000 ft/lb of torque (remember engine torque times first gear ratio equals drive shaft torque) will yield a fully tightened up Torsen helical gearset. The differential will act more like a live axle at this point. This is why you will ALWAYS leave two, equal length, black marks....

Note to self - - - applying high torque when taking off in a turn could be dangerous if you find wet pavement or sand in the turn......

The fronts don't care about Left to Right "stagger in diameter. The Auto Trans can Cancel out the Traction Control and the stagger won't be noticeable. The Manual Trans cannot be cancelled, so the stagger may cause concern. Someone with experience please chime in here, as I have Auto trans only.
You're right about the fronts, Fuji...

The rear wheels do not have independent speed sensors on the SSR. The rear wheel speed sensor is located in the transmission output section and sees the aggregate wheel speed.... this goes for both automatics and manual.

The anti-lock brake (and traction control) computer looks at the aggregate rear wheel speed and compares it to the fronts....

Regards,

Mike
 

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Want to use a P225/65/R17 as a spare tire
I know it's a little smaller than the 235 someone recommended,
but I just wanted to know if the smaller size will be an issue.

Thanks
Phil
Out of all these comments and feedback, I'd be interested in each one assessing the last time they actually had a flat tire on the road.:|

Maybe I have just been lucky in that regard, but my streetrod which I owned for 39 years had 14" smaller tires on the front and 15" much larger ones on the rear. I as a result and lack of room anyway...........carried no spare.

From trips to Florida on up to New York state and in between and many, many trips to Pigeon Forge, Tenn. for (Shades of the Past) rod runs...........coming from Raleigh and or last several years, Sunset Beach, N.C........................NEVER HAD A FLAT.

My last Vette had "run flat" tires (I think they "suck") the side walls are so stiff, they do not ride/handle (in my opinion) nearly as well as normal tires on prior Vettes and others.

I can only recall one flat on my '93 Chevy pickup some 20 plus years ago..........

Bottom line, as has been stated here before..............Go with triple A (AAA) or similar and know you're covered just in case.

Since I traveled back across the country after buying my SSR, one of many "extras" I got was a complete wheel/tire for the front.......(never been on the ground), cause prior owner had some gouges in one of the front rims. I can tell ya a spare tire takes up quite a bit of room in that cargo space..............better used for something you really might need.:|
 

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Out of all these comments and feedback, I'd be interested in each one assessing the last time they actually had a flat tire on the road.:|

Maybe I have just been lucky in that regard, but my streetrod which I owned for 39 years had 14" smaller tires on the front and 15" much larger ones on the rear. I as a result and lack of room anyway...........carried no spare.

From trips to Florida on up to New York state and in between and many, many trips to Pigeon Forge, Tenn. for (Shades of the Past) rod runs...........coming from Raleigh and or last several years, Sunset Beach, N.C........................NEVER HAD A FLAT.

My last Vette had "run flat" tires (I think they "suck") the side walls are so stiff, they do not ride/handle (in my opinion) nearly as well as normal tires on prior Vettes and others.

I can only recall one flat on my '93 Chevy pickup some 20 plus years ago..........

Bottom line, as has been stated here before..............Go with triple A (AAA) or similar and know you're covered just in case.

Since I traveled back across the country after buying my SSR, one of many "extras" I got was a complete wheel/tire for the front.......(never been on the ground), cause prior owner had some gouges in one of the front rims. I can tell ya a spare tire takes up quite a bit of room in that cargo space..............better used for something you really might need.:|
I must disagree. I had a flat tire in the Seattle area, from hitting a curb while avoiding an emergency vehicle. I was unable to get the tire locally in a timely manner so I had the new one ordered by my mechanic in SoCal and drove home on the spare I had mounted under the bed with the simple-engineering spare tire kit. It was less than spending the three days waiting for the tire, and I still have the spare for the next time. Relatively inexpensive security. I have used it since then as well so I consider it a good investment and it takes up no room in the bed except for the tools.
 
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