Different diameters front and rear

[LeakySeals]

Purchased a FWD car with 195/65R-15 studded snows in front. They need to go. In addition to being loud on the highway, I found sidewall cracks. The sticker on the door says 205/65R-15 is supposed to be on the car. Confirmed by multiple tire sites. I want to buy just 2 for the front ASAP, then another 2 in a few months, Can i run both diameters, 205 in front, 195 in the rear till I can complete the set?

 

[Whipcitywrencher]

No Problem.

 

[eljefino]

You didn't mention if you had ABS or traction control /VSC. Those are deal-breakers.

You should also check to see if your load range is adequate on those smaller tires. I've found that size to be XL, often, though.

 

[Hall]

It will be fine. The new tires (right size) will be a 1/2" taller but no one will notice except for you. The difference in speedo readings isn't even worth worrying about but if you want, put the 205s on the front like you mention.

My old Accord spec'd 195/65-15 but the speedo was off by quite a few MPH. I put 205/60-15 tires on it and it corrected the speedo accuracy to almost perfect. I have a spreadsheet somewhere with the data based off of the speedo reading compared to GPS speed (I drove while our son took notes!).

 

[AZjeff]

Originally Posted by hallstevenson
It will be fine.


Not if it has ABS.

 

[Whipcitywrencher]

I Doubt it, but it could effect your abs if its real sensitive.
Here's some tire specs you can go by.
https://www.tacomaworld.com/tirecalc?tires=195-55r16-205-55r16

 

[tcp71]

Generally abs sensors have 20-60 inductive pick up points per wheel rotation. On most modern cars, the front to back differential will cause the ABS/Traction control system to throw an error. The effect of that may just be an abs light, shutting down the ABS/Trac system along with the light or even putting the car into limp mode (awd vehicle).

 

[CapriRacer]

Bad idea.

The best tires should be on the rear to prevent spin outs. You've not only proposed putting the newer tires on the front, but they are bigger, too!. Those 2 items really increase the risk.

 

[krzyss]

The real answer is: maybe.

The newer the car the more likely it has systems that depend on assumption that wheels are turning at the same rate.
The systems that may be affected:

ABS
indirect TPMS

Not sure what car you have.

KrzyÅ›

 

[KalapanaBlack]

195 and 205 are not the diameters, but the width of the tires.

65 is the aspect ratio, which is the sidewall size in relation to the width.

So a 205/65 is taller than a 195/65 because the 65 is basically the same percentage of a larger number.

As others have said, most likely the difference in size will play havoc with any electronic systems the car may have. If it doesn't have any reason to monitor wheel speed, you'd be fine to mix sizes. If the car is monitoring wheel speed for any of its systems, those systems will probably not work as intended. So this depends on the car.

If your state doesn't care about size or load index, mixing a 205/60R15 with your 195/65R15s will give you 4 effectively same-diameter tires and will mean the car won't care about the extra width, because you're adjusting out the difference in aspect ratio (i.e. diameter or height).

In PA, the car wouldn't pass state inspection with under size or under load tires. A standard load 205/65R15 will have a load index of 91 or 92 (extra load is 94).

Standard load 195/65R15 would probably be either 89 or 91 load index, but the smaller overall diameter/height would mean even if it's a 91, it would fail inspection for the underSIZE tires. If it's a 89 load rating, they would fail for underLOAD as well.

Best thing is, of course, 4 new correct-size tires, but if NH doesn't inspect tire size and/or load, the 205/60R15s will mix fine even with electronic systems on the car.

 

[LeakySeals]

Originally Posted by CapriRacer
Bad idea.

The best tires should be on the rear to prevent spin outs. You've not only proposed putting the newer tires on the front, but they are bigger, too!. Those 2 items really increase the risk.

The plan was wait till spring and buy all 4 in the correct size. But after looking at the side wall of the front studded snows think I need to do something now and I don't want to buy this size again. I want to get the right size on the car. Which risk is higher driving on these tires with the cracks or bigger front tires for a couple of months?

 

[LeakySeals]

Originally Posted by KalapanaBlack
195 and 205 are not the diameters, but the width of the tires.

65 is the aspect ratio, which is the sidewall size in relation to the width.

So a 205/65 is taller than a 195/65 because the 65 is basically the same percentage of a larger number.

As others have said, most likely the difference in size will play havoc with any electronic systems the car may have. If it doesn't have any reason to monitor wheel speed, you'd be fine to mix sizes. If the car is monitoring wheel speed for any of its systems, those systems will probably not work as intended. So this depends on the car.

If your state doesn't care about size or load index, mixing a 205/60R15 with your 195/65R15s will give you 4 effectively same-diameter tires and will mean the car won't care about the extra width, because you're adjusting out the difference in aspect ratio (i.e. diameter or height).

In PA, the car wouldn't pass state inspection with under size or under load tires. A standard load 205/65R15 will have a load index of 91 or 92 (extra load is 94).

Standard load 195/65R15 would probably be either 89 or 91 load index, but the smaller overall diameter/height would mean even if it's a 91, it would fail inspection for the underSIZE tires. If it's a 89 load rating, they would fail for underLOAD as well.

Best thing is, of course, 4 new correct-size tires, but if NH doesn't inspect tire size and/or load, the 205/60R15s will mix fine even with electronic systems on the car.

Thanks. The fresh bought Malibu classic has a current inspection sticker in New Hampshire so I guess they don't look at tire sizes. It's a 2005 so it has abs. It will only be for a month or two before I can get the back ones or what do you think about the condition of the tires I just posted? Can I get by with them for a couple of months till I can get all four? I will be out on the highway

 

[KalapanaBlack]

Originally Posted by LeakySeals
Originally Posted by KalapanaBlack
195 and 205 are not the diameters, but the width of the tires.

65 is the aspect ratio, which is the sidewall size in relation to the width.

So a 205/65 is taller than a 195/65 because the 65 is basically the same percentage of a larger number.

As others have said, most likely the difference in size will play havoc with any electronic systems the car may have. If it doesn't have any reason to monitor wheel speed, you'd be fine to mix sizes. If the car is monitoring wheel speed for any of its systems, those systems will probably not work as intended. So this depends on the car.

If your state doesn't care about size or load index, mixing a 205/60R15 with your 195/65R15s will give you 4 effectively same-diameter tires and will mean the car won't care about the extra width, because you're adjusting out the difference in aspect ratio (i.e. diameter or height).

In PA, the car wouldn't pass state inspection with under size or under load tires. A standard load 205/65R15 will have a load index of 91 or 92 (extra load is 94).

Standard load 195/65R15 would probably be either 89 or 91 load index, but the smaller overall diameter/height would mean even if it's a 91, it would fail inspection for the underSIZE tires. If it's a 89 load rating, they would fail for underLOAD as well.

Best thing is, of course, 4 new correct-size tires, but if NH doesn't inspect tire size and/or load, the 205/60R15s will mix fine even with electronic systems on the car.

Thanks. The fresh bought Malibu classic has a current inspection sticker in New Hampshire so I guess they don't look at tire sizes. It's a 2005 so it has abs. It will only be for a month or two before I can get the back ones or what do you think about the condition of the tires I just posted? Can I get by with them for a couple of months till I can get all four? I will be out on the highway


They aren't great, but I would rate the possibility of driving on bad roads with malfunctioning/non-working ABS and/or traction control less operationally safe than living with some sidewall cracking for a few months. I would pay more attention to the shoulder of the tread and the grooves and sipes - are there radial cracks around the edge of the tread where it meets the sidewall? Are there any large cracks in the rain grooves and larger sipes? Those are the most problematic areas. The cracks in your picture just look to me like average 3-5 year old tires.

 

[krzyss]

Try to find DOT date of manufacture.
That may be more telling than a little cracked sidewall.

KrzyÅ›

 

[LeakySeals]

Some more pics. Front and rear. Are they good to go for a couple of months until I buy new correct 205 size all season radials?

 

[KalapanaBlack]

I don't see any age issues at all around the shoulder or in the tread. If I were rendering an opinion on if they should be replaced, I'd say absolutely not. Shame that they're the wrong size.

 

[Dadillac]

Those sidewall cracks aren't that bad. Me I would run them until I planned on replacing all four at the same time. As others have stated the ABS traction control and other electronics will not like the two different sizes.

Don

 

[Smokescreen]

Originally Posted by Dadillac
Those sidewall cracks aren't that bad. Me I would run them until I planned on replacing all four at the same time. As others have stated the ABS traction control and other electronics will not like the two different sizes.

Don


yep.

 

[y_p_w]

Originally Posted by CapriRacer
Bad idea.

The best tires should be on the rear to prevent spin outs. You've not only proposed putting the newer tires on the front, but they are bigger, too!. Those 2 items really increase the risk.

I've certainly heard that. I've had mismatched tires on a FWD car where I just put the new tires on the rear and rotated the old tires to the front. I figured I would just do that indefinitely.

However, I got lazy and didn't get my tires rotated and just a got a new pair today. The installer refused to install the new tires anywhere but on the rear. And I've got a Subaru. I'm just trying to even out the wear before I start rotating again. I'll probably just rotate those to the front myself. I know the diameter difference is just going to get worse.

I totally get the issue with rear ends being lighter, but we still rotate for wear.

 

[faramir9]

Originally Posted by LeakySeals
[/quote]
Thanks. The fresh bought Malibu classic has a current inspection sticker in New Hampshire so I guess they don't look at tire sizes. It's a 2005 so it has abs. It will only be for a month or two before I can get the back ones or what do you think about the condition of the tires I just posted? Can I get by with them for a couple of months till I can get all four? I will be out on the highway

First, studded snows on the front and all-seasons on the rear is bad. That's a case where the argument about "best tires on rear at all times" makes sense. (Sometimes it's overblown, but not here.)

I owned an '04 Chevy Classic for 6.5 years and know this car well. Your car likely does *not* have ABS. Mine did not, nor did any I read about in forums. (The one option some had was power seats.) Check if the ABS light comes on when you start the car. If not, you do not have ABS, so be careful to pump the brake rather than stomp and steer.

Also, the car is specced for 205/65R15, but with that tire size the speedo and odometer are off by 2.2. to 2.3%, I found. (Drive 307 miles and it reads 300.) Chevy kept things as cheap as possible when adapting the '97-'03 Malibu for the rental Classic. The Malibu had 215/60R15 tires and standard ABS. For the Classic, they bagged ABS and went to a slightly cheaper tire size, but without recalibrating the odometer. It still should not be off by as much as it is, but so it goes.

I ran 195/65R15 Pirelli P4 the last three years I owned the car. The speedo and odo were within 0.4% and it passed PA inspection, even though the tires were 91 load index and the OE tires were 92. (No clue why tires that size are 89 or 91, but never 90.)

Can you buy four tires now, and sell the four that are now on the car on CL, maybe? The Altimax Rt43 has a $50 rebate going. If not: How much tread is left on the rear tires?

Sorry to ramble on. I learned a lot about the '04-'05 Chevy Classic, good and bad. Good luck.