Eliminating spare tires

[JDgreen227]

Was coming home from the local grocery store and stopped behind a late model Jeep that had a huge spare tire hanging on the back end...reminded me of the column a Detroit Free Press auto writer recently authored about automakers wanting to eliminate spare tires.

He wrote, quote: "Automakers are concerned with saving GRAMS OF WEIGHT...." (emphasis added) so they want to eliminate spare tires...."

So I contacted him: "I just put a 1995 vintage, full tread 1995 F-150 STEEL RIM with a mounted and fully inflated P235-75R 15 tire on a scale, and the weight was 66 pounds. According to my research, a new 2012 F-150 20-inch tire and ALUMINUM rim weigh over 85 pounds. So, if automakers are so concerned with saving "grams of weight" as you term it, why don't they use 15-16 inch rims and tires instead of 20 inch? Can you imagine the grams (actually POUNDS) of weight saved by using the smaller size, especially if mounted on an aluminum rim, rather than the steel one I used as a comparison? Additional benefits would be much less unsprung weight, and the cost of 20 inch replacement tires is obscene."

My wifes brother-in-law recently replaced the 20 inch OEM tires on a 4 year old Silverado---$350 each. That is more than DOUBLE what a 16 inch tire would have cost, and the quality OEM tires only lasted 52,000 miles in conservative driving.

The auto writer actually agreed with me !!!

 

[cmore]

I agree. The only reason I can think of for larger tires is looks. My car has a spare storage area but the std tire and rim won't fit the area. The car comes with smaller tires for the base model but the smaller tires and not available for my model. No spare may be somewhat ok while the 3 yr warranty is active not not good after it expires. They want to eliminate the spare to save some money in addition to weight.

 

[JDgreen227]

I agree. The only reason I can think of for larger tires is looks. My car has a spare storage area but the std tire and rim won't fit the area. The car comes with smaller tires for the base model but the smaller tires and not available for my model. No spare may be somewhat ok while the 3 yr warranty is active not not good after it expires. They want to eliminate the spare to save some money in addition to weight.

Just FYI, the compact spare and jack and lug wrench for my 2004 Lesabre weigh 36 pounds total with a steel rim, so using the compact spare saves at least 30-35 pounds over a full size spare with jack and lug wrench. IMO the REAL reason automakers want to eliminate the spares is just to make more profit.

 

[cmore]

I would be happy or at least happier, IF they offered a compact spare. The only way I can carry a spare is to take up a lot of trunk space with a 20" tire and rim.

 

[murphy1244]

The spare cost extra on my 08 focus.

 

[Diamondpilot]

Bigger wheels and tires give bettrr final drive ratios and help mpg ratings. They alsp add ground clrarance but do cost. You pay to play.

Smallest wheel I have in my fleet is 17"

Chris

 

[dkhntr04]

Bigger wheels also allow more room for bigger brakes.

 

[Bird]

Bigger wheels also allow more room for bigger brakes.

I can remember when that was the claimed reason for the wheels on some smaller motorhomes. Maybe I'm lucky I have old Fords.:laughing: The Crown Vic has 16" wheels and the Ranger has 15" wheels. But they do both have full size spares. Maybe I'm just old fashioned, but I much prefer the full sized spares even though I've used the Ranger spare only once and never used the Crown Vic spare.

 

[JDgreen227]

BIGGER BRAKES??? Who needs 'em, what with antilocks you cannot lock the wheels anyway so what is the reason for bigger brakes? My '04 Lesabre has 16-inch 4 wheel discs, weighs almost 3,900 pounds with two people aboard and will stop an unbraked 1800 pound utility trailer behind it easily. Bigger brakes mean more UNSPRUNG weight and the higher cost of bigger rotors and pads mean more $$$ at replacement time. 20 inch rims and tires are simply for looks, because of the short sidewalls they ride rougher and because of the wider tread they have poorer traction in ice and snow. They should NEVER have gone over 16 inches in rim size except for 3/4 and 1-ton trucks. $350 for a new tire? Simply obscene.

 

[WilliamBos]

BIGGER BRAKES??? Who needs 'em, what with antilocks you cannot lock the wheels anyway so what is the reason for bigger brakes? My '04 Lesabre has 16-inch 4 wheel discs, weighs almost 3,900 pounds with two people aboard and will stop an unbraked 1800 pound utility trailer behind it easily. Bigger brakes mean more UNSPRUNG weight and the higher cost of bigger rotors and pads mean more $$$ at replacement time. 20 inch rims and tires are simply for looks, because of the short sidewalls they ride rougher and because of the wider tread they have poorer traction in ice and snow. They should NEVER have gone over 16 inches in rim size except for 3/4 and 1-ton trucks. $350 for a new tire? Simply obscene.

What crook do you buy your tires from? A dealer? The bigger brakes give more surface area on the rotor, which runs cooler. Bigger brakes are not a waste!! I will not buy anything smaller than 17" again, but not bigger either. Don't need the unit bearings spinning any faster, and with smaller rims, they would.

 

[Bird]

Like WilliamBos said, there's a very good reason for bigger brakes sometimes. I didn't really like the 19.5" wheels on our motorhome, but when you're running 18k pounds, plus towing another 2500 pounds. maybe the bigger brakes were worth it. And when we had a fifth-wheel travel trailer with two 3500 pound axles and 10" brakes, the brakes weren't bad, but I don't think you could have adjusted them to a point of being able to lock them up. But when I replaced everything from the frame down with 5200 pound axles and 12" brakes (wider brake shoes, too), I could very easily lock up the brakes.

 

[Ken45101]

Bigger wheels and tires give bettrr final drive ratios and help mpg ratings. They alsp add ground clrarance but do cost. You pay to play.

Smallest wheel I have in my fleet is 17"

Chris

If they want to change the final drive ratio, that's what the differential gearing is for.

Tires are relatively reliable today but problems still do happen. Try getting a replacement tire on a Sunday evening in the middle of a long distance trip! Don't forget, the space saver spares are usually rated for 50 miles distance and 50 mph max.

Car tires shouldn't be as bad but I've had to wait 6 weeks for the factory to produce new tires for the motorhome and it took a couple of days to get a replacement spare for the horse camper.

 

[JDgreen227]

As Ken 45101 says, differential gearing is a more practical way to change overall ratios than is by changing to a larger tire. The problem is, if you go to far in tire upsizing the engine may end up running at an rpm too low for the power curve. While people who maintain their tires properly rarely have a flat tire today, there are going to be situations where the "flat-fix kits" automakers provide as an alternative to a real spare are going to be useless as far as a repair goes. And good luck at getting the replacement tire you need when you need it. Two weeks ago I purchased a set of new Michelins for my wife's car, they were a common size and model, yet even Discount Tire had only 3 in stock and we had to wait for them to obtain a fourth tire. The odds of being able to get a replacement on a Sunday evening 500 miles from home are d*** poor.

 

[cmore]

As Ken 45101 says, differential gearing is a more practical way to change overall ratios than is by changing to a larger tire. The problem is, if you go to far in tire upsizing the engine may end up running at an rpm too low for the power curve. While people who maintain their tires properly rarely have a flat tire today, there are going to be situations where the "flat-fix kits" automakers provide as an alternative to a real spare are going to be useless as far as a repair goes. And good luck at getting the replacement tire you need when you need it. Two weeks ago I purchased a set of new Michelins for my wife's car, they were a common size and model, yet even Discount Tire had only 3 in stock and we had to wait for them to obtain a fourth tire. The odds of being able to get a replacement on a Sunday evening 500 miles from home are d*** poor.

I had a 98 Camaro and ran over a peace of metal that slit the tire. Luckily it had a compact spare and was able to get to a station. An fix a flat would have been useless.

I live in a rural area and don't even have cell service in some places.

Chev could have made the spare tire storage area large enough to put in a spare. The base model has a 17" and u can get up to a 22".

 

[Diamondpilot]

You can blame the current administration for high tire prices. Look into it. There is something like a 40% tax on import tires.

Chris

 

[Bird]

As Ken 45101 says, differential gearing is a more practical way to change overall ratios than is by changing to a larger tire. The problem is, if you go to far in tire upsizing the engine may end up running at an rpm too low for the power curve. While people who maintain their tires properly rarely have a flat tire today, there are going to be situations where the "flat-fix kits" automakers provide as an alternative to a real spare are going to be useless as far as a repair goes. And good luck at getting the replacement tire you need when you need it. Two weeks ago I purchased a set of new Michelins for my wife's car, they were a common size and model, yet even Discount Tire had only 3 in stock and we had to wait for them to obtain a fourth tire. The odds of being able to get a replacement on a Sunday evening 500 miles from home are d*** poor.

Yep, you're right, of course. Isn't part of the problem too many choices? If you were buying tires for a car 50 years ago, how many sizes were there, and how many manufacturers were there? There's so many now that I don't think any dealer could stock all of them. And 5 years ago when I bought the new set of of B. F. Goodrich Long Trail T/A tires for my Ford Ranger, neither Discount Tire, NTB, Sears, nor the local Ford Dealer had any in stock for 15" wheels, as the Ranger has, although they did have them for the 16" wheels. Of course Discount Tire ordered them for me, but if I'd been in a big hurry, I'd have sure been out of luck.

 

[JDgreen227]

You can blame the current administration for high tire prices. Look into it. There is something like a 40% tax on import tires.

Chris

The Michelins I recently purchased were made in Canada...not sure if that qualifies as an import or not. Discount Tire had something like 30+ different models in the size I needed, the prices ranged from about $114 to $155....not sure how many, if any, were made in the USA.

 

[dodge man]

Picture a large pick up truck running on tires and rims that are designed for a Prius. How would it handle and how would it stop? Not very good would it. There is a reason they have gone to bigger tires and rims, they help a vehicle stop better and handle better. Yes, there is a cost, mainly in weight.

 

[JDgreen227]

Picture a large pick up truck running on tires and rims that are designed for a Prius. How would it handle and how would it stop? Not very good would it. There is a reason they have gone to bigger tires and rims, they help a vehicle stop better and handle better. Yes, there is a cost, mainly in weight.

I own a Y2K GMC Yukon XL that came with 16 inch Load Range E tires standard...even when towing 6500 pounds with a hitch weight of nearly 900 pounds, I never felt it needed larger tires nor brakes.

OP said removing the spare tires for weight savings is really stupid when they add so much extra weight with huge tires and wheels. That is what I was trying to say. As for handling being better, I would say the extra mass of unsprung weight cancels out the advantage of the larger tire. And what about the additional rolling resistance and it's effect on fuel usage?

 

[Diamondpilot]

Picture a large pick up truck running on tires and rims that are designed for a Prius. How would it handle and how would it stop? Not very good would it. There is a reason they have gone to bigger tires and rims, they help a vehicle stop better and handle better. Yes, there is a cost, mainly in weight.

You are right. My F350 SRW diesel 4x4 has the high 11,500# gvwr package. No way a small tire and wheel combo is going to do that. There is a reason it has 18" wheels.

Chris