noob tire question?

[munky000527]

I have very limited car experience, and have never changed tires. I know nothing about the process.

I'm looking at getting the most affordable (least expensive) LRR tires recommended, but I have questions about the size that I should be looking for. My factory tires are 205/55/16" and I'm confused about how tires with a different size would still fit on my stock rims. I'm only looking at changing the width, not the diameter, as I'm a bit nervous about possible wear damage on the suspension.

Let's say I were to lower the tire width to 185 instead of 205 (not really sure if that's a good idea). Should I then search for a sidewall height percentage that would keep the original ratio in order to keep my stock wheels? In this case that would be 60, which would decrease the sidewall height from 112.5 to 111. Would that be close enough?

And if this is the proper method of sizing, what is the thinnest I can go with the stock wheels without putting myself in a dangerous situation?

[CapriRacer]

First, the biggest change you can make in tires is careful selection of make and model. That can have up to a 60% change in RR depending on what you are changing from.

But you should be aware that rolling resistance, treadwear, and traction are a technology triangle. In other words to get improvemtns in one, you have to sacrifice one (or more) of the others. So careful selection of a tire will pay benefits.

Second, going larger in tire size (meaning more width or more aspect ratio or more rim diameter or any combination) has small positive affects on RR.

You can read more about this here:

Barry's Tire Tech

But the tire size you mentioned: 205/55R16 is incredibly popular and you will probably find that you will find your best combination in that size.

[munky000527]

I'm much more interested in LRR and treadwear than I am in traction.

And I was actually thinking about decreasing the width, not increasing it. The article in that link says the opposite, but I thought that the least amount of tire surface touching the road would produce the least amount of friction. Tires with a smaller width also seem to be less expensive from what I've seen so far.

[euromodder]

Originally Posted by munky000527

I'm looking at getting the most affordable (least expensive) LRR tires recommended, but I have questions about the size that I should be looking for. My factory tires are 205/55/16" and I'm confused about how tires with a different size would still fit on my stock rims.

Only a few regular sizes will fit your rims and still keep the diameter within reason of the original diameter.
Adding LRR to the requirement will make the search even tougher.

You can get the Michelin Energy Saver in 195/60/16 , which is a close match, with a 1.4 % larger circumference - which is good for fuel efficiency, as it means 1.4% lower revs when cruising.
(It's one of the approved sizes for my car, along with 205/55/16.)

Over here the price for that tyre is a whopping 50% higher than the same tyre in 205/55/16 though - which isn't cheap to start with.

Though not the cheapest, the Energy Saver is among the best LRR tyres - especially when you look at fuel consumption and wear.

Goodyear's Efficientgrip and Optigrip also get good marks for RR and are available in 205/55/16.

Pirelli Cinturato P7 (not the old P7) also gets good marks for LRR and wear (somewhat unusual for a Pirelli).

[munky000527]

I was looking at size 195/60/16 and 205/60/16 to compare prices, and decided to measure the wheels. They're a little over 17", but all of the tires are 16".

[mcrews]

WTF!!!!!!
settle down.

1. do the tires fit? Duh. don't worry about what doesnt matter.
2. what you ganna order 17 and have a tire that doesnt fit!!
3. if you go to TIRERACK . Com the list the specs (measurements) of the tires. you can make comparisons there. don't try to go by the 55 or 60 or 195 etc. Those are "RATIOS" so they are not the same between tire sizes. At tirerack you can see the width in inches and the diamiter in inches. Don't go smaller on the diameter, you'll get less mpg. try to go 2-4% larger on stock diameter, it will lower you rpms when you are going down the road and that helps mpg.
4. In my personal opinion, going skinny is not all it is cracked up to be. reduces handling a great deal and you are stuck with the bad choice for a long time. Most eco mods can be undone the next weekend. Not tires.....you buy em....you own em.
Try to get a taller tire. inflate it to 45psi (for example) and try to find a tire with better RR. just my .02

[CapriRacer]

Originally Posted by munky000527

I'm much more interested in LRR and treadwear than I am in traction.

And I was actually thinking about decreasing the width, not increasing it. The article in that link says the opposite, but I thought that the least amount of tire surface touching the road would produce the least amount of friction. Tires with a smaller width also seem to be less expensive from what I've seen so far.

Friction with the road surface is not rolling resistance. Rolling resistance is mostly about internal friction - within the tire. This is controlled by the amount of deflection, the amount of material being deflected and the properties of the material. That's why tires of the same size have such different RR - the materials are different.

But lower mass also produces lower RR. So all season tires will be better than all terrain tires.

And as counter-intuitive as it may seem, a larger tire is better - it has more load carrying capacity so it deflects less under load and that is more than the affect the increased mass has.

But there is a safety aspect to this. Going smaller reduces the load carrying capacity of a tires, so under the same conditions it will run hotter and have more stress. That makes smaller tires more likely to fail - definitely not the wau to go!

[munky000527]

Thats interesting, so tires that deflect less and have the lowest mass are the tires with the best RR? I think this means I should be sticking with 205/55/16 like you suggested earlier. The problem im having now is that tirerack and any shops near me dont have any good LRR tires in that size for under like $80 or so.

Mccrews, I realized that the inner part if the wheel is probably what is 16 inches, it just didnt occur to me when i measured their diameter. Thanks for the info.

[CapriRacer]

Originally Posted by munky000527

Thats interesting, so tires that deflect less and have the lowest mass are the tires with the best RR?........

It's tread compound that makes the biggest difference. For practical purposes, deflection is pretty close to the same for all tires in a given size.

Also, the part of the mass that is important is the tread - and that doesn't vary a lot for new tires within a given size.

But the properties of the tread compound vary wildly.

And to put this in perspective, differences between sizes is small compared to the differences between makes and models of tires.

[munky000527]

Originally Posted by CapriRacer

It's tread compound that makes the biggest difference. For practical purposes, deflection is pretty close to the same for all tires in a given size.

Also, the part of the mass that is important is the tread - and that doesn't vary a lot for new tires within a given size.

But the properties of the tread compound vary wildly.

And to put this in perspective, differences between sizes is small compared to the differences between makes and models of tires.

Some of the larger size tires on tirerack are actually less expensive than my stock size. Would increasing the overall diameter of my tires by around an inch be dangerous? Would it likely touch any of the suspension components?

These are the sizes I'm looking at:

From:
205/55/16 (sidewall height of 113)

To:
205/60/16 (sidewall height of 123)
215/55/16 (sidewall height of 118)
215/60/16 (sidewall height of 129)
225/55/16 (sidewall height of 124)