#1
Okay so obviously I'm totally vehicle ignorant and I just have a quick question regarding tire size. I was looking at winter tires for my truck and I know their 17s hence the 70r17 but the site I get tires from is running a free shipping special for select tires.

What I have now are 265 70/r17. The tires I really like under free shipping conditions are 285 70r/17. Is this just a larger diameter tire? I have plenty of space for it if that's the case. So would I be safe getting these tires and how would it effect driving (power, lower gas mileage, etc)

Thanks in advance guys
#2
came in expecting a question about fatigue/exhaust but instead got a thread about tyres. misleading title. 0/10
#3
wow, reading this made me really tired


srs answer, I'd check your vehicle's handbook for which size tires to use. I know for cars using the wrong size tires can really fvck with things, but if its a bigger truck then I don't think it matters as much. But I'd do a lot of research online before buying/changing anything
Last edited by Bladez22 at Nov 2, 2014,
#5
The 265/285 refers to the WIDTH of the tire, not the diameter. Your rims should be able to handle the increased width, but be sure to check. Reference your vehicle handbook to see what size tires your stock rims can handle, or check online. If you're not sure, call a mechanic.
#10
The tires will be a little wider and taller. They could possibly work fine. The only problems is depending if the front tires will rub during tight turns or lock to lock. The other thing is they will throw your speedometer off a little. It's ideal that when you go to wider tires and want to keep the same overall diameter that every 20 points you raise in the section width (265) that you want to drop the series (70) by 5 points. Also having a taller sidewall will give you a tiny bit more tire roll in corners.

So to help keep things more kosher I would get 285-65R17's if they have those on special. They will be roughly the exact same diameter as what you have on there right now. Some quick googleing should tell you what people are running safely width wise on the stock rims (assuming they are stock). Hope this helps some.

It would also help to know if your truck has the factory stock size on it now, or if they are already bigger than factory. It should tell you the factory size on the door sticker inside the jam, or in your owners Manuel. A quick Google of your truck will also tell you.
Last edited by Way Cool JR. at Nov 3, 2014,
#15
OKAY since everyone in here is far from a mechanic..

e.g. 265/70/r17 = 265 width (as if viewed from the front or back of the vehicle) / 70 is the height of the tire from the rim to the edge of the tire vertically / 17 means it fits a 17" wheel

edit:
Quote by AeroRocker
The 265/285 refers to the WIDTH of the tire, not the diameter. Your rims should be able to handle the increased width, but be sure to check. Reference your vehicle handbook to see what size tires your stock rims can handle, or check online. If you're not sure, call a mechanic.

except this guy, he knows. depends on the rim how wide you can go
Last edited by JagerSlushy at Nov 3, 2014,
#18
Quote by JagerSlushy
OKAY since everyone in here is far from a mechanic..

e.g. 265/70/r17 = 265 width (as if viewed from the front or back of the vehicle) / 70 is the height of the tire from the rim to the edge of the tire vertically / 17 means it fits a 17" wheel

edit:
except this guy, he knows. depends on the rim how wide you can go
Well I'm an engineer and the 70 is the height as a ratio of the tyre width.
#19
Quote by JagerSlushy
OKAY since everyone in here is far from a mechanic..

e.g. 265/70/r17 = 265 width (as if viewed from the front or back of the vehicle) / 70 is the height of the tire from the rim to the edge of the tire vertically / 17 means it fits a 17" wheel

edit:
except this guy, he knows. depends on the rim how wide you can go

I hate to rain on your parade dude, but I know what I'm talking about, I'v been working on cars for a long time now. The height of the sidewall changes the wider the tire is within the same series. The sidewall on a 265 70r17 is 7.3 inches and the sidewall on a 285 70R17 is 7.85 inches. But the sidewall on a 285 65r17 is 7.28 inches. This way you keep almost the exact same diameter and only add width. If the tires he has now are the factory size and on the factory rims then he will more than likely be safe to go up to a 285 all around.

But like I mentioned in my earlier post he could possibly have issues with the front ones rubbing when making tight turns or lock to lock. It's not definite but it is something to try to avoid. He never mentioned if everything on the truck is OEM or aftermarket so it's kind of a shot in the dark. His truck may already have larger tires than the factory spec on the original rims. If this is the case then I would avoid going any wider to avoid any problems.

Quote by AeroRocker
The 265/285 refers to the WIDTH of the tire, not the diameter. Your rims should be able to handle the increased width, but be sure to check. Reference your vehicle handbook to see what size tires your stock rims can handle, or check online. If you're not sure, call a mechanic.

The 265/285 is the width, but since he is talking about both of them being 70 series the diameter also changes to. You have to divide the section width by the percentage of series. To get your section width you need to divide 265 (for example) by 25.4. Then your total from that you divide it by 70% (for example) and this gives you the sidewall height.
Last edited by Way Cool JR. at Nov 3, 2014,
#20
Quote by Way Cool JR.
walloftext

don't be so easily offended. I meant no ill will but ts doesn't need three paragraphs of tire sizing information, nor do I need numbers from a tire size calculator. I've been building cars a while too, eight if you count the one I'm on.



edit:
Quote by The Judist
Well I'm an engineer and the 70 is the height as a ratio of the tyre width.

i was inb4. but you're right. trying to keep it simple for those who have to ask what that number is
Last edited by JagerSlushy at Nov 3, 2014,
#21
Its really pissing me off that the width is measured in mm but the diameter is in inches...........

why
#26
wait, i had no idea that tire is tyre in the US I thought everyone was just misspelling it on purpose
#27
Quote by JagerSlushy
don't be so easily offended. I meant no ill will but ts doesn't need three paragraphs of tire sizing information, nor do I need numbers from a tire size calculator. I've been building cars a while too, eight if you count the one I'm on.



edit:
i was inb4. but you're right. trying to keep it simple for those who have to ask what that number is

Just to get this out of the way 1st. The guy you quoted first saying 'he knows' was not entirely right, especially in TS's question. I had to let TS know that his answer was not completely true at all.


Sorry if I seemed offended or took a stab at ya. But tire sizing does need to be explained in more than one sentence. Them numbers just don't tell someone all they need to know just by looking at them, especially to a novice like TS. The info I provided is good info and is very important to know.

The one thing some people don't realize, or just fail to mention, is that when you move up in width and stay in the same aspect ratio (series) you also go up in over all tire diameter (not rim size) by increasing the size of the side wall. This can make or break a tire choice for someone and also cause improper speedometer and odometer readings. It may not be huge in this case but it does change it. So, sorry if I provided possibly crucial info. And I seriously don't care what you may already know or need to know The info is all to help TS.
Last edited by Way Cool JR. at Nov 3, 2014,
#28
Quote by Bladez22
Its really pissing me off that the width is measured in mm but the diameter is in inches...........

why

Simply divide it by 25.4 and you will get the inches.
#29
Quote by Way Cool JR.
Simply divide it by 25.4 and you will get the inches.


why would i want it in the wrong units?
#30
Quote by Bladez22
why would i want it in the wrong units?

Sorry, I thought you were an American looking for the other way round. I was always irritated that they had the width in metric.