axel Posted May 30, 2009 Share Posted May 30, 2009 One of my Sube's tires went flat. If the tire can't be repaired, under what circumstances do all four tires need to be replaced? I've forgotten the drill. Quote Link to comment Share on other sites More sharing options...
edrach Posted May 30, 2009 Share Posted May 30, 2009 Check your local tire place, they'll know. But ask a few places to make sure they don't want to sell you a full set. If I remember correctly, on a 16" tire, tred depth on all four should be less than 3/32" different. Quote Link to comment Share on other sites More sharing options...
edrach Posted May 30, 2009 Share Posted May 30, 2009 I had a similar situation recently and couldn't find a slightly worn tire to match up with the other three. I bought two new ones of the same brand and size, put them on the front where they'll wear quicker and moved the fronts to the rear. Now I have a spare tiere that matches the two in the back. When the tires are evenly worn again, I'll start rotating front to rear to keep them all even. Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted May 30, 2009 Share Posted May 30, 2009 All tires ideally should match within 1/4" circumference at most. Get the same brand and model replacement tire. If the new tire doesn't meet the 1/4" requirement or is even close to it, look for someplace like a race shop that will shave the tire down for you. If it doesn't meet specs and it is an AT run the FWD fuse until that is done. Quote Link to comment Share on other sites More sharing options...
axel Posted May 30, 2009 Author Share Posted May 30, 2009 (edited) So then, would less than 3/32" tread depth difference between all the tires be equal to less than 1/4" tire circumference difference between them. Going by tread depth is less of a hassle than measuring tire circumferences. Edited May 30, 2009 by axel Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted May 30, 2009 Share Posted May 30, 2009 As long as the tread depth wear on the tire is even measuring the tread depth should work. Measuring the circumference gives a more accurate indication but is easiest if the wheel is off the ground. Quote Link to comment Share on other sites More sharing options...
OB99W Posted May 30, 2009 Share Posted May 30, 2009 So then, would less than 3/32'' tread depth difference between all the tires be equal to less than 1/4'' tire circumference difference between them. Unfortunately, a 1/4'' difference in circumference is equivalent to only a little over 1/32'' (actually, about 1.25 32nds) difference in radius (tread depth). Besides that, the tires would have to be otherwise identical in order for the tread depth measurement to be a valid means of comparison. Circumference may still be the better way to go, and is really the only way if the tires aren't an exact design match. The tires should, of course, be properly inflated when measured. Quote Link to comment Share on other sites More sharing options...
axel Posted May 30, 2009 Author Share Posted May 30, 2009 Well thankfully, my punctured tire was repairable. Had I been required to purchase 4 new tires because of one irrepairable tire, I would have had strong homicidal feelings:mad: toward the designers of AWD. For an AWD car owner to be forced to purchase three new tires because of one irregularly circumferenced replacement (in comparison to the other three) is obscene and outrageous. Even having to take a new tire to a speed shop to be shaved down to the circumference of the others is a bit much. I've got 4 Yokohama Avid v series tires on my Sube that cost me nearly $500, and have only 19k miles on them. There's still plenty of tread left. Having to replace them all at this point would have been totally unacceptable. Why can't Subaru( or anyone else) design an AWD system that compensates for tires that are not of near equal circumference? This issue makes AWD vehicles rather owner unfriendly, at least in this one regard. God, I'm really bummed out by this matter. Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted May 30, 2009 Share Posted May 30, 2009 Consumers probably don't want to pay for such an elaborate AWD setup. Many AWD auto makers have similar requirements to Subaru's 1/4" circumference rule. Tirerack has a pretty good list. I don't know, I figure you pay to play. How often do you really get an unrepairable flat tire. I've had maybe three in my lifetime. One a couple months ago and yes I did have to get four new tires but hey what are you going to do. Quote Link to comment Share on other sites More sharing options...
OB99W Posted May 30, 2009 Share Posted May 30, 2009 [...]God, I'm really bummed out by this matter. Although I can appreciate your concern, I'm not sure it merits getting so bummed. The question is whether the ''match within 1/4-inch of circumference'' requirement is totally Subaru being protective of your car, or partially something suggested by their lawyers. There's no doubt that a significant size mismatch can eventually damage the transfer clutch pack (auto trans) or viscous coupling (manual). However, probably very few of us always keep our tires evenly inflated, properly rotated, etc., so that it's likely the AWD is seeing some slight mismatches on a regular basis -- and yet the failure rate of the transfer system apparently isn't all that high. I'd also like to point out that for reasons other than the AWD, many of us try to keep a reasonably matched set of tires on our cars. I personally prefer tread design and depth to be close so that the car doesn't do anything ''unexpected''. Therefore, it wouldn't just be due to having AWD that I might replace more than a single tire if one were damaged. Quote Link to comment Share on other sites More sharing options...
edrach Posted May 31, 2009 Share Posted May 31, 2009 Well thankfully, my punctured tire was repairable.Had I been required to purchase 4 new tires because of one irrepairable tire, I would have had strong homicidal feelings:mad: toward the designers of AWD. For an AWD car owner to be forced to purchase three new tires because of one irregularly circumferenced replacement (in comparison to the other three) is obscene and outrageous. Even having to take a new tire to a speed shop to be shaved down to the circumference of the others is a bit much. I've got 4 Yokohama Avid v series tires on my Sube that cost me nearly $500, and have only 19k miles on them. There's still plenty of tread left. Having to replace them all at this point would have been totally unacceptable. Why can't Subaru( or anyone else) design an AWD system that compensates for tires that are not of near equal circumference? This issue makes AWD vehicles rather owner unfriendly, at least in this one regard. God, I'm really bummed out by this matter. Sorry you're so bummed out about this, but it's a fact of life with AWD. If you can design an AWD system that doesn't care about tire size, you'd make a fortune. I've only had this issue once and I've already posted my solution. You'd be even more bummed to know what a damaged viscous coupling costs on a 5MT transmission. Quote Link to comment Share on other sites More sharing options...
baccaruda Posted May 31, 2009 Share Posted May 31, 2009 Couldn't you max. inflate the old tires and slightly underinflate the new one until broken in? Quote Link to comment Share on other sites More sharing options...
StructEngineer Posted May 31, 2009 Share Posted May 31, 2009 God, I'm really bummed out by this matter. Yea, IMHO AWD just isn't worth it on these cars. Compared to my other FWD vehicles, I really dont see the gains. Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted May 31, 2009 Share Posted May 31, 2009 two things, a friend of mine bought a new 08 legacy last year, and was very surprised and concerned when i told him about having to replace all 4 tires instead of one. but he relaxed when i asked him how many times he had to replace just one tire on his old car that he traded in, he had never had to replace just one tire. replace a set, sure, but just one ...... only my wife drives over curbs that often. if you have an automatic and you put in the FWD fuse, you will feel the difference. if you are used to driving a FWD car it will feel ok with the fuse in, but if you are used to AWD, you will feel the difference. awd is much more stable in my opinion. Quote Link to comment Share on other sites More sharing options...
CNY_Dave Posted June 1, 2009 Share Posted June 1, 2009 Well thankfully, my punctured tire was repairable.Had I been required to purchase 4 new tires because of one irrepairable tire, I would have had strong homicidal feelings:mad: toward the designers of AWD. For an AWD car owner to be forced to purchase three new tires because of one irregularly circumferenced replacement (in comparison to the other three) is obscene and outrageous. Even having to take a new tire to a speed shop to be shaved down to the circumference of the others is a bit much. I've got 4 Yokohama Avid v series tires on my Sube that cost me nearly $500, and have only 19k miles on them. There's still plenty of tread left. Having to replace them all at this point would have been totally unacceptable. Why can't Subaru( or anyone else) design an AWD system that compensates for tires that are not of near equal circumference? This issue makes AWD vehicles rather owner unfriendly, at least in this one regard. God, I'm really bummed out by this matter. Tire rack will shave new tires ordered throudh them. Dave Quote Link to comment Share on other sites More sharing options...
CNY_Dave Posted June 1, 2009 Share Posted June 1, 2009 Yea, IMHO AWD just isn't worth it on these cars. Compared to my other FWD vehicles, I really dont see the gains. Depends where you drive, and what you normally do. No FWD car could do what I do in the snow, and where I am in CNY snow capability can be important when you have a 50 mile commute (well, if you want to get home at better than 15mph, anyway). The additional capabilities the AWD gives me are invaluable. Dave Quote Link to comment Share on other sites More sharing options...
zyewdall Posted June 1, 2009 Share Posted June 1, 2009 Depends where you drive, and what you normally do. No FWD car could do what I do in the snow, and where I am in CNY snow capability can be important when you have a 50 mile commute (well, if you want to get home at better than 15mph, anyway). The additional capabilities the AWD gives me are invaluable. Dave Yeah... depends on where you are. If you only need the AWD a few days a year... probably not worth the hassle and poor gas mileage the rest of the year. But, up in the mountains in Colorado, we deal with snow about 6 months out of the year. I have been known to follow my friend's FJ40 up his unplowed "driveway" in my subaru justy -- something no fwd car could do (and i've seen his driveway foil 4wd pickups when my subaru justy got through too -- tires...). Quote Link to comment Share on other sites More sharing options...
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