225/60/16 Tires too big?

Originally posted by 96svxer
I've run 225/50/16 225/55/16 and 225/60/16. I dont understand why it would be unsafe. Your speedo is going to be off slightly, but as long as you have the same speed rating on the tire it should be fine. Save the 300 and go buy me some christmas presents!

Really? Wow! That's cool! I'm assuming the 225/60's rubbed a little bit, but it wasn't bad? I also assumed the speedo difference, but these are just going to be winter tires, so I'm not going to be using them a whole lot.

THANKS for the info!

[svxfiles]

A taller tire is harder on your transmission. If you save $200 on tires and have to spend $3000 on a transmission its not saving.

Originally posted by svxfiles
A taller tire is harder on your transmission. If you save $200 on tires and have to spend $3000 on a transmission its not saving.

Interesting... That I did NOT know. Do you have anymore info on this? We all know these svx trannies aren't exactly the creme de la crop

[svxfiles]

Inside your transmission there are friction materials simuler to clutch materials. They are used to slow and hold still rotating drums, to slip against steel plates, and with fluidic pressure keep the plates from slipping and to lock up the heavy rotating masses in the torque converter, all the while covered in 300 f 15 weight oil. Tire diameter increases or decreases the final drive ratio which can change acceleration, gas milage, engine speed and more. If the stock tire was 24 inches tall the distance traveled in one revolution is 24 x 3.14159 or 75.39816.if the 60 series tire is 26.63 it has to move the 3800# car 83.660541 inches with the same horse power. This causes additional heat. A while back i ran a 215 40 16 tire that was ( as I remember ) 9.253 something shorter, and the car ran VERY strong, but I'd have to creep into driveways or bash the bumper. It also looked ricey. Forgive me if I ramble, it's the cold medicine.

I appreciate the rambling. I think those tires would put a bit of extra strain on the tranny. I guess I will indeed have to hold out for some smaller tires.

Thanks,
Chris

A taller tire is harder on your transmission. If you save $200 on tires and have to spend $3000 on a transmission its not saving.

How is it "Harder on the transmission" at what RPM's at what speed? Just saying it's "harder" on the transmission isn't a reality. It's going to be harder on the transmission at certain RPM's and easier on the transmission at other RPM's and speed playes a big role on this. Without hundreds of hours analyizing it's impossible to tell. My dirt bike I have 5 different sprokets, to properly gear my bike do the track conditions. Everybody does it. Nobody ever has trannie problems.

Buy the used tires, use the 300 hundred you save and buy a tranny cooler.....I bet you know which tranny is going to last longer.

Inside your transmission there are friction materials simuler to clutch materials. They are used to slow and hold still rotating drums, to slip against steel plates, and with fluidic pressure keep the plates from slipping and to lock up the heavy rotating masses in the torque converter, all the while covered in 300 f 15 weight oil. Tire diameter increases or decreases the final drive ratio which can change acceleration, gas milage, engine speed and more. If the stock tire was 24 inches tall the distance traveled in one revolution is 24 x 3.14159 or 75.39816.if the 60 series tire is 26.63 it has to move the 3800# car 83.660541 inches with the same horse power. This causes additional heat.

I agree with the math, but I think we have to look at the whole picture here. Lets make an experiment:

Go out to your garage and hop on your 10 speed bike and ride around the neighborhood. All right now go steal your neighbors bike rims and throw them on your bike. Chances are they are slightly different sized. Notice any difference? Probably not. If you did it was slight and negligable. Ok now Go ride that same bike in two feet of snow. Not only are the neighbors laughing at you but it's much harder now isn't it. Much harder than the different sized rims. Ok. Now weld on two more tires to that bike. Man getting harder to pedel? Now weld on three more seats and grab your girlfriend and mom and throw them on the bike and ride around. Now throw some groceries in a back-pack, sit on your 4 wheeled bike with three passangers, ride up hill, into a head wind, in two feet of snow. Which was tougher, small difference in rim diameter, or riding up hill on your four wheel bike, in a head wind in two feet of snow? Everytime you do this in your SVX your transmision doesn't need to be replaced, and thats a much greater strain than changing the rim diameter.

[svxfiles]

Getting an object to move is harder than keeping it moving (newtons laws of motion). A car is a heavy object, about 3800# with gas and a driver. to start it from a dead stop takes a lot of horsepower, just try pushing it by yourself. but after you get it started rolling, it becomes easier, and you can almost run with it on a level smooth surface. It takes more energy at start up, so it creates more heat at start up. Keeping it at 60 mph takes less power than getting it there so wear and heat are not as much of a problem or concern while cruising. I agree that tire height is not as important at speed, but that is not where the wear is as much of a factor. ps the tranny cooler is allways a good idea as long as the trans gets up to opperating temp.

Getting an object to move is harder than keeping it moving (newtons laws of motion)

I am very aware of this phenominom and complety agree. But we have to look deeper at this. The force required to start an object moving from rest is what we used to refer to as the Break Free Force or (BFF). This is just the force required to start the object in motion. This time is soo small it can not be measured, it's an instant, unmeasurable it's so small. The exact instant the object starts moving the BFF can not be applied. I did just did look this up in my advanced Physics Text book to make sure I was stating this correctly. So really we dont have to be concerned with this force because it only lasts for a nano-second.

But here are two experiments that will 100% prove to you that a larger sidewall will or will not make a difference. (can you tell that I like experiments?)

Experiment 1
Now this requires physical exercise again so make sure you stretch out properly...we dont want any pulled muscles. Now go upstair and put on your Richard simmons spandex and sweatshirt and go out to the garage. Put the car in neutral and push it. Now slap on the other tires and do the same thing. Do you notice any difference in force needed to move the car? I have slapped my Supra rims on my svx numerous times (225/50/16 vs 225/55/16) and push my car out of the garage early in the morning as to not wake the wife and have never noticed a difference. If you cant tell, neither will your tranny. check out my locker for pics.

Experiment 2
With the 300 dollars you are saving by getting used tires go out and by a tranny temp guage, stick it in and do some planned runs and record temperatures, now throw the larger sidewall tires on and do the exact same run, same driving habits, same outside temperature and record. Plot out a pretty graph on Excel and post it!

Thats diffentative proof. No opinion. Just facts. let us know what you find out. I would do it but I'm poor and cant afford a temp guage.

[svxfiles]

A more accurate experiment is turning the driveshaft to move the car, using a torque wrench. With a 7% taller tire it takes 7% more turning force to move the car, all other things being equal.

Ohhh that experiment is even better! But sounds like a darn lot of work though, but it would be great data.
I'm not sure if that 7% holds up with all the gear ratios though. I remember with gears driving gears, sometimes a logical thought like 7% wouldn't be true, but I could be wrong it's been a long time since I studied them. But either way you aren't going to trash your tranny by going a little bit larger in the sidewall. Just stay away from the 225/80/16 touring tires, that may be a bit much

[The Hunter]

Geeee lets see I have Pirelli 245/40/18s on my SVX and I dont seem to be in any danger. In fact the only danger is somone trying to steal them. (see Pic)

[svx_commuter]

I think you wil be fine with the larger tires provided:

You do not stomp on the gas from a standing still start.

I would take it easy from rest to about 40 mph and then nail it.

I think your top end will be higher.

Your gas mpg will be better.

If you keep the car for oh say 5 years you will be ahead of the "game".

[svxfiles]

Ok. the redline is 7000 rpm, but to keep it simple let's say you are driving in top gear at 6940 rpm. The overdrive is a .694 ratio, so at 6940 engine rpm, the driveshaft is turning 10,000 rpm.The rear end(s) ratio is 3.545. This spins the rear tires at 2820.8744 rpm. If the stock tires are 24.86 inches tall then the diameter is approximately 78.099927 inches or 6.5083272 feet, this times tire rotation gives you 18359.173 feet per minute, times 60, is 1101550.5 feet per hour, devided by 5280 feet per mile works out to 208.6295 theoretical miles per hour..IMHO, I think the top speed, and gearing are high enough.

[JENKIN]

Still no luck on snows? I'll trade you 4 new snows for the yamaha!!!!
jdh

[JENKIN]

oh, and i have a set of les schwabies 265x70x16 M&S (were on a 2201 F150 4x4) a renter left behind, I'd let you have them for nada.... just drive over to Yak and we can mount them (acetylene torch for clearance).
just foolin...... been at work for 24 hr now, and am getting silly.