Change at 4/32?
- Thread starter Doog
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You will get better MPG on the old tires, less tread squirm.
If the new tires have a mileage warranty, I would not mount them before those easy highway miles.
I drove through a horrific thunderstorm on 3/32 and did fine. Just kept it below 45, easy on 2 lane road, even do-able on interstate. The weight of the vehicle helps; you will be loaded for bear. 18 wheelers blast through rain b/c their weight helps push down to pavement.
If the new tires have a mileage warranty, I would not mount them before those easy highway miles.
I drove through a horrific thunderstorm on 3/32 and did fine. Just kept it below 45, easy on 2 lane road, even do-able on interstate. The weight of the vehicle helps; you will be loaded for bear. 18 wheelers blast through rain b/c their weight helps push down to pavement.
I'd run the new tires. I don't think I've ever ran a tire down to 4/32,much less any lower than that.
Squeezing the last $10 worth of tread out of a set of tires isn't worth it IMO.
Squeezing the last $10 worth of tread out of a set of tires isn't worth it IMO.
Originally Posted By: JHZR2
Has anyone done a study/test of braking performance at 4/32 versus the legal limit, which IIRC is 2/32?
Wonder what the practical difference is. Oherwise it is speculation and potentially waste in the name of safety where there is none gained...
Tire Rack did several tests. Video on their site. Edit: missed the post above, that's one of their videos.
Significant degradation in wet traction below 4/32".
Significant degradation in snow traction below 6/32".
Has anyone done a study/test of braking performance at 4/32 versus the legal limit, which IIRC is 2/32?
Wonder what the practical difference is. Oherwise it is speculation and potentially waste in the name of safety where there is none gained...
Tire Rack did several tests. Video on their site. Edit: missed the post above, that's one of their videos.
Significant degradation in wet traction below 4/32".
Significant degradation in snow traction below 6/32".
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Originally Posted By: eljefino
You will get better MPG on the old tires, less tread squirm.
If the new tires have a mileage warranty, I would not mount them before those easy highway miles.
I drove through a horrific thunderstorm on 3/32 and did fine. Just kept it below 45, easy on 2 lane road, even do-able on interstate. The weight of the vehicle helps; you will be loaded for bear. 18 wheelers blast through rain b/c their weight helps push down to pavement.
It's more complex than weight alone. It's a matter of footprint shape and inflation pressure.
Hydroplane resistance is a function of pressure (higher PSI = higher speed at which vehicle maintains road contact for a given water depth) and the width of the footprint; a wider tire "sweeps" a greater area clear of water at a given speed.
Trucks have both a high inflation pressure (80+) and a relatively narrow footprint.
You will get better MPG on the old tires, less tread squirm.
If the new tires have a mileage warranty, I would not mount them before those easy highway miles.
I drove through a horrific thunderstorm on 3/32 and did fine. Just kept it below 45, easy on 2 lane road, even do-able on interstate. The weight of the vehicle helps; you will be loaded for bear. 18 wheelers blast through rain b/c their weight helps push down to pavement.
It's more complex than weight alone. It's a matter of footprint shape and inflation pressure.
Hydroplane resistance is a function of pressure (higher PSI = higher speed at which vehicle maintains road contact for a given water depth) and the width of the footprint; a wider tire "sweeps" a greater area clear of water at a given speed.
Trucks have both a high inflation pressure (80+) and a relatively narrow footprint.
Originally Posted By: DuckRyder
Originally Posted By: JHZR2
Has anyone done a study/test of braking performance at 4/32 versus the legal limit, which IIRC is 2/32?
Wonder what the practical difference is. Oherwise it is speculation and potentially waste in the name of safety where there is none gained...
FWIW
IMO tirerack understates the problem
they are using tires they shaved down so they are all "new" rubber
A 5-6 year old tire with 4/32 or 2/32 is going to perform worse than the ones in their test.
Originally Posted By: JHZR2
Has anyone done a study/test of braking performance at 4/32 versus the legal limit, which IIRC is 2/32?
Wonder what the practical difference is. Oherwise it is speculation and potentially waste in the name of safety where there is none gained...
FWIW
IMO tirerack understates the problem
they are using tires they shaved down so they are all "new" rubber
A 5-6 year old tire with 4/32 or 2/32 is going to perform worse than the ones in their test.
Originally Posted By: Astro14
Significant degradation in wet traction below 4/32".
To be honest, looking at the video, there was a significant degradation in wet braking distance at 4/32" already. The distance increased by nearly 50% compared to new tires. That's huge. So what's one to do? Replace tires when they get down to 6/32"? 8/32"? I guess it's a personal decision, trying to balance cost vs safety.
Significant degradation in wet traction below 4/32".
To be honest, looking at the video, there was a significant degradation in wet braking distance at 4/32" already. The distance increased by nearly 50% compared to new tires. That's huge. So what's one to do? Replace tires when they get down to 6/32"? 8/32"? I guess it's a personal decision, trying to balance cost vs safety.
Originally Posted By: Rand
IMO tirerack understates the problem
they are using tires they shaved down so they are all "new" rubber
A 5-6 year old tire with 4/32 or 2/32 is going to perform worse than the ones in their test.
Agreed.
IMO tirerack understates the problem
they are using tires they shaved down so they are all "new" rubber
A 5-6 year old tire with 4/32 or 2/32 is going to perform worse than the ones in their test.
Agreed.
Originally Posted By: Rand
IMO tirerack understates the problem
they are using tires they shaved down so they are all "new" rubber
A 5-6 year old tire with 4/32 or 2/32 is going to perform worse than the ones in their test.
I agree, probably impossible (or at least difficult) to account for in a test.
Another interesting point, on the sedan the 2/32 tires were still going something like 44mph at the point that the 4/32 tires had stopped (which was already ~100ft past new tires).
IMO tirerack understates the problem
they are using tires they shaved down so they are all "new" rubber
A 5-6 year old tire with 4/32 or 2/32 is going to perform worse than the ones in their test.
I agree, probably impossible (or at least difficult) to account for in a test.
Another interesting point, on the sedan the 2/32 tires were still going something like 44mph at the point that the 4/32 tires had stopped (which was already ~100ft past new tires).
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I would run them until they become horrid in heavy rain conditions. 3000 miles 5-10% of the life of an average tire for a RAV4
My previous Nokian WR G2 and Bridgestone RE960 tires ($$$$) all did really well in heavy rain down to 3/32 before shed off or damaged. My current Conti ExtremeContact DWS($$) are done for heavy rain at 5/32" left. You definitely get what you pay for.
My previous Nokian WR G2 and Bridgestone RE960 tires ($$$$) all did really well in heavy rain down to 3/32 before shed off or damaged. My current Conti ExtremeContact DWS($$) are done for heavy rain at 5/32" left. You definitely get what you pay for.
Originally Posted By: Astro14
Originally Posted By: JHZR2
Has anyone done a study/test of braking performance at 4/32 versus the legal limit, which IIRC is 2/32?
Wonder what the practical difference is. Oherwise it is speculation and potentially waste in the name of safety where there is none gained...
Tire Rack did several tests. Video on their site. Edit: missed the post above, that's one of their videos.
Significant degradation in wet traction below 4/32".
Significant degradation in snow traction below 6/32".
It is tire design dependent. Some are meant to wear well and work with water/noise at end of life while other companies for drop that from compromise equation.
Originally Posted By: JHZR2
Has anyone done a study/test of braking performance at 4/32 versus the legal limit, which IIRC is 2/32?
Wonder what the practical difference is. Oherwise it is speculation and potentially waste in the name of safety where there is none gained...
Tire Rack did several tests. Video on their site. Edit: missed the post above, that's one of their videos.
Significant degradation in wet traction below 4/32".
Significant degradation in snow traction below 6/32".
It is tire design dependent. Some are meant to wear well and work with water/noise at end of life while other companies for drop that from compromise equation.
Originally Posted By: rjundi
It is tire design dependent. Some are meant to wear well and work with water/noise at end of life while other companies for drop that from compromise equation.
this is true but there is also basic physics
if you only have 2/32 of an inch of tread its not going to be effective at evacuating water at anything approaching highway speeds (55+)
I watched the video its fairly surprising you can also infer
it took something like 350+ft to slow from 70 to 44 but
video is good if you take it for what it is and apply common sense.
The narrator even says its a personal choice when to replace tires etc.
It is tire design dependent. Some are meant to wear well and work with water/noise at end of life while other companies for drop that from compromise equation.
this is true but there is also basic physics
if you only have 2/32 of an inch of tread its not going to be effective at evacuating water at anything approaching highway speeds (55+)
I watched the video its fairly surprising you can also infer
it took something like 350+ft to slow from 70 to 44 but
video is good if you take it for what it is and apply common sense.
The narrator even says its a personal choice when to replace tires etc.
Originally Posted By: Quattro Pete
Originally Posted By: Rand
IMO tirerack understates the problem
they are using tires they shaved down so they are all "new" rubber
A 5-6 year old tire with 4/32 or 2/32 is going to perform worse than the ones in their test.
Agreed.
I agree.
My Michelin Exalto A/S are at least 5 years old/58,000 miles. They are down to 5/32 and I am begining to see slippage. The ride is getting harder and the rubber feels hard. They will come off in December and my winter tires will go on and the A/S tires will be replaced next spring UNLESS I see significant issues when the rains start. I shudder that I used to drive tires untill they were almost bald when I was a kid.
Originally Posted By: Rand
IMO tirerack understates the problem
they are using tires they shaved down so they are all "new" rubber
A 5-6 year old tire with 4/32 or 2/32 is going to perform worse than the ones in their test.
Agreed.
I agree.
My Michelin Exalto A/S are at least 5 years old/58,000 miles. They are down to 5/32 and I am begining to see slippage. The ride is getting harder and the rubber feels hard. They will come off in December and my winter tires will go on and the A/S tires will be replaced next spring UNLESS I see significant issues when the rains start. I shudder that I used to drive tires untill they were almost bald when I was a kid.
The current tires are Dunlop Signature CS as are the new ones. They are about 2.5 years old.
I would absolutely run the old tires for the trip, save the new ones for winter. If the lesson from the videos is that tread depth is so important, well, save that tread depth on the new tires for winter when it's most important.
Really the video is misleading. If they put the dry stopping distance (I'd guess 110~120 ft) it would be obvious that even with a new tire you have to slow down considerably in the rain. And because you don't know the tread depth of the people around you it would make sense to really slow down no matter what your situation.
Really the video is misleading. If they put the dry stopping distance (I'd guess 110~120 ft) it would be obvious that even with a new tire you have to slow down considerably in the rain. And because you don't know the tread depth of the people around you it would make sense to really slow down no matter what your situation.
I'd replace, but its also because I don't use all season tires in winter (I have dedicated winter tires) so now would be as good of a time as any. I refuse to roll on bald tires. Terrible and rain and more puncture prone.
Well, my decision has been made to replace them on Saturday when I got a "$25 off any service" coupon good until September 3rd in the mail from my tire shop. I'm going in tomorrow. So that will cut my install costs by 25%. Plus I will be traveling to Florida and with all of the rain lately I don't want to have to slow down to avoid hydroplaning. I spoke with my brother and he said: "You will feel pretty stupid if you get a flat or hydroplane into an accident and think about the 4 brand new tires sitting in your garage 1200 miles away at home." Good point.
Thanks to everyone who commented.
Thanks to everyone who commented.
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