Iโm not a tire expert but IMHO running a single โ80-Eโ tire with three โ85-Gโ tires, for long term use, would cause a serious alignment issue. The โ80โ tires are not as tall as the โ85โ tires and the โEโ tire will be softer (and lower) then the โGโ tire when loaded. Both of which will cause the axle height of the โ80-Eโ tire to run lower thereby causing the alignment issue. You might get by if you had a pair of โ80-Eโ tires on one axle and a pair of โ85-Gโ tires on the other axle.
To be safe, I recommend you replace all five tires with the same size. However, if you want to keep the โ80-Eโ tire for a spare โ remember that the โspace saverโ spare tire in most cars is smaller than the mounted standard tire and the auto engineers determined that you should be able to get by with it safely for a very short distance in good weather and good driving conditions. But, can you be sure that you will need and use that spare โ80-Eโ tire in good conditions only?
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