tires effecting transfer case?

[but]

Ok so I am getting a set of used tires that came off of a fwd. My friend was telling me that I would mess up my transfer case,but I thought that was only if i had a size difference on one. He says the wear from the front vs the back will break my transfer case?? if this is true please explain.

 

[pj91gsx]

Ok so I am getting a set of used tires that came off of a fwd. My friend was telling me that I would mess up my transfer case,but I thought that was only if i had a size difference on one. He says the wear from the front vs the back will break my transfer case?? if this is true please explain.

not true at all. If you have different size tires, your tires may wear differently. The rear tires are likely to bark if you have different size tires. Breaking your transfer case is not right either. I had different gear ratios from front to rear and never broke my transfer case, it broke the driveshaft. If it didnt break the driveshaft it would have broke the rear end.

 

[ramsack]

General rule on awd is to run the same size tires all around. I have all the same size tires, but my front and rear and 2 different manufacturers, so they are off by a little bit. People tell me i'm nuts for running it like that, that it will fry my center diff. or viscous coupling. Well, the center diff. is made to absorb differences between front and back speed differences. My question is, do you drive the car in a perfectly straight line its whole life? No. That is the point of diffs, to absorb speed differences, and they are constantly doing it as you drive. And the viscous coupling needs a large torque difference to actually lock up, so i don't see it hurting that either. An 1/8" - 1/4" difference in diameter isn't enough of a speed difference to mess with the center diff. or viscous coupling IMO. Just don't go crazy with circumference differences from front to back and you will be fine. You can even get wider wheels in the back than the front, or staggered diameter, as long as you keep both tire circumferences within a reasonable similarity.

 

[1995gsx20g]

im not saying its perfectly fine but when you put a spare tire on the car it is smaller than the rest of the tires so in reality there is more room to play with than you think but its playing with the safe zone.

-the same size tire on the same width rim is ok. as long as the tires aren't bald and brand new.

-assuming you have factory ratios the weakest link is the center diff imo.

 

[but]

Ok thanks guys. They are all the same size,just more wear in the front (obviously) from being fwd. I just dont quite understand the "breaking the differential" aspect of it. I am just going to run them for a couple months.

 

[ramsack]

1995gsx20g, about the center diff...would the 4-spyder center diff. be a better contender to handle minor tire size differences? I'm not ever looking to make crazy power, and if some day i get aftermarket rims, I would like to go with a staggered setup and wider in the back that the front. In theory if the tires do come out to be a bit off, I could always get different rear diff or transfer case ratios to compensate best I can, right?

 

[pj91gsx]

Ok thanks guys. They are all the same size,just more wear in the front (obviously) from being fwd. I just dont quite understand the "breaking the differential" aspect of it. I am just going to run them for a couple months.

i had a jdm trans gear ratio 3.909 usdm 3.545. <ratio for the transmission final drive and the rearends. I put a jdm in mine, and broke my driveshaft. I had 3.909 in the front and 3.545 in the rear. It usually breaks something in the driveterrain.

In theory if the tires do come out to be a bit off, I could always get different rear diff or transfer case ratios to compensate best I can, right?

no, that would be custom made stuff. and you dont want to go threw that.

 

[ramsack]

I wasn't asking if I wanted to do it, I was asking if it could be done...which I'm sure it could. I know it's a totally different league and driveline, but for instance supercars that are AWD like lambos and such don't run even widths front to back.

 

[1995gsx20g]

the problem doesn't lie in the fact that the 2 spider diff is weak(even though it is) its the fact that while driving down the highway in a straight line, your rear diff output would constantly be rotating more than the front diff output within the center diff and to be honest the design just can't handle those constant loads. a 4 spider diff may help but i would definitely not call it a solution.. for a daily driven vehicle.


as with getting new ratios yes that would work but i personally don't know where you could find one that wouldn't be custom made just for your setup. just like pj91 said above. its all about how much your willing to pay for it to be done. is it worth it? to eaches own.

 

[eclipsegsx1736]

This thread is getting a little off topic.

Any difference in overall diameter from front to back is going to put stress on the viscous coupling. The center diff spiders will be turning more than usual, but yes this won't wear it out. The viscous coupling, however, is only designed to slip for short periods of time, enough to go around a turn, or for it to lock up and stop slipping (in the event of excess wheelspin). Having it constantly slip a small amount will generate excess heat and cause it to burn out faster. It's just not meant to work that way.