Help with Tire Sizing

ChasingOurTrunks

Well-known member
Hi folks,

My Canyon is due for a new set of tires, and our national tire warehouse (Canadian Tire) has a heck of a sale on right now for their Motomaster brand tires. Normally I'd stick to Coopers or BFGs, but it just so happens that Motomaster, the Can Tire store brand, are made by Cooper so I think I'm getting good quality for the price.

As for tire sizes, I know the biggest tire that can fit on my rig without a lift is 265/65/17. The tires I want are not available in that size; they have them, but the load rating is P (6 ply, I understand) but the roads out here are full of sharp rocks that make an E-rated tire a better idea (plus, I'm quite heavy all the time). However, I can go with 245/70/17 E-rated tires for the same price. These would be 10 ply, E-rated (or Light Truck) tires, and I think are a more robust option.

When I look at tiresize.com, it looks like the differences between these tire sizes are minimal:

The 245 is 30.5" as compared to the 30.6" in the 265
The sidewall is the same
The circumference is slightly smaller in the 245s - 0.2"
And the 245 has 1 more revolution per mile than then 265s.

The biggest difference is in the width -- the 265s are 10.4" wide, the 245s are 9.6", so less than an inch more narrow.

I've been thinking about it and I think it will work, but I wanted to check the wisdom of the masses -- Does anyone anticipate major problems, either in fitment or handling, if I were to go with the 245s?
 

bjp

Rez roamer
You’ll get plenty of strong opinions when it comes to tire width preferences. I’m in the 245-is-enough camp. I’ve always seen better snow/slush handling with 245s compared to 265s, and pretty much no difference in every other situation. Since I don’t change tires for winter, that means 245 has always been my preference.
 

ExpoMike

Well-known member
The diameter is so close, you won't see any difference with the computer/speedo. There are different opinions on narrow versus wide tires. That debate will never be solved but it seems that wider tires tend to be better for sand or very soft dirt where narrow ones seem to be better for mud/hard dirt/snow. It will have less rolling resistance so that might help .5 MPG Make sure you the tires are rated for the wheel width. Not sure what your wheels are but if the are in an approved range, you should be good.
 

rruff

Explorer
It will have less rolling resistance so that might help .5 MPG
I'm not sure which tire you were referring to, but in this situation the biggest hit to MPG would tend to be 10 ply vs 6.

All else being equal these will tend to improve rolling resistance (less of it): Lower load rating, greater width, greater diameter, lower profile. Some manufacturers use lower hysteresis compounds, and can have much lower rolling resistance than seemingly identical competing brands or models. Then there are aero, gearing, and inertia to consider.
 

Grassland

Well-known member
Went from P235/75R17 street tread to LT235/80R17 E load KO2s and gained handling and a marginal increase in fuel economy. I was loaded up weight wise all the time.
Fuel economy dropped going to LT34x10.5R17 D load KO2s

Let's see pics and thoughts once those new tires are on.
 

billiebob

Well-known member
Hi folks,
The biggest difference is in the width -- the 265s are 10.4" wide, the 245s are 9.6", so less than an inch more narrow.

I've been thinking about it and I think it will work, but I wanted to check the wisdom of the masses -- Does anyone anticipate major problems, either in fitment or handling, if I were to go with the 245s?
Should fit with room to spare.

I'm a fan of skinny rubber, especially in the winter. The last thing you need thru slush or standing water is floatation. My Rubicon came with 245/75R16s. I now run 185/100R16s. A bit taller a lot skinnier and much lighter. They ride better and they give an extra 5mpg .... 17mpg vs 22mpg .... which translates to an extra 95miles of range.

And that range is not theoretical. I have a regular 400km commute. I could never do it on one tank with the 245s. I now do it easy with gas to spare.

With winter tires pizza cutters are the best bet.

185/100R16s vs 245/75R16s and the pizza cutters last 20K kms longer than the stock 245s.
IMG_0453.jpeg

25 years ago I ran BFG KOs in the 33/9.50R15 size, I'd run them today if BFG still made them. Same thing incredible ride and great gas mileage.

DSC_0044.JPG
 
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ChasingOurTrunks

Well-known member
@Grassland - I will for sure share some impressions once I get them installed. Waiting on Canadian Tire to call me and let me know they have arrived.

@billiebob that's pretty incredible - I didn't really think about the fuel economy on a thinner tire but that would be a huge boon for my little rig as range is always a bit touch and go. Thanks for sharing that as it further confirms this choice!
 

rruff

Explorer
@billiebob that's pretty incredible - I didn't really think about the fuel economy on a thinner tire but that would be a huge boon for my little rig as range is always a bit touch and go. Thanks for sharing that as it further confirms this choice!
Wide tires have less rolling resistance than narrow ones, all else being equal. Aero drag will be a little higher though. The most important aspect is the specific tire. My E 35x13" ATs with 3 ply sidewalls (Hankook ATMs) have less rolling resistance than the OEM street tires. This is not normal or expected, but it is very welcome!
 

ChasingOurTrunks

Well-known member
Figured I'd post a 1-week update. Since getting the tires installed, we've been in a good mix of weather - warm dry pavement, heavy rain, and in the mountains we tackled some deep snow and some icy roads. These tires are fantastic. I'll keep posting updates as I use them more.

One Week Update:

Cons:

1) Slightly - and I do mean slightly - louder than the stock Wrangler Duratracs. I would rate the tread as being 50% more aggressive, but I would say the noise is only 5% louder, so hardly worth worrying about.

2) The E-rated tires aren't available in all sizes so if you are wanting a 10-ply, you need to do a bit of homework on the tire sizes (which I did, with this thread, and am very grateful to the collective wisdom of Expo for the help - as you folks said the tires fit no problem).

That's it. That's all the cons so far.

Pros:
1) Steering feels a bit more "nimble" - that's subjective, and hard to notice in what I affectionately refer to as my "Sports Truck", but it does feel like it needs slightly less effort to steer. This is much more pronounced at slow speeds, but at highway speeds it's not at all twitchy or anything and tracks the line really nicely.

2) Excellent performance in the wet. With traction control off, I used to be able to fairly easily break free my Duratracs in the wet if I wanted to, even when the truck was new-ish with only 6,000 kilometers on it. I am so far unable to break these loose in the wet.
- On ice roads, they were fantastic in two situations:

2a)) Going up the mountain near where I live, there are a lot of stretches of dry road where the sun hits, but then where the road is in shade, it was actually very icy (as in, cars skidding off the road icy - more in a moment). These tires felt grippy and I can tell they earned their M+S rating.

2b) On the way up, we noticed an F-350 in the ditch on it's side but it looked like it had been there a while, and we didn't see anyone in it on our way by. We spent a bit of time messing around in deep snow and on the way back down we decided we would stop to make sure the Ford was empty. It was heading up hill, but it was off the road in the downhill lane in a 3-4 foot deep ditch, pitched over on it's side; the drivers side doors and front quarter were in rough shape. But we didn't know that when we stopped and we're glad we did, because there was a gentleman in the truck who apparently had been there since he decided to go up the mountain for coffee that morning (it was now 1:00). We were the only ones to stop in several hours but that's a reflection on humanity that I will save for another thread. Anyway, we had a set of maxtrax and a kinetic recovery rope, and my little 6,000 lbs Canyon was "The Little Engine that Could" this day as we had him out and on the road in short order. Candidly, I didn't expect to be able to do this but wanted to give it the good ol' College Try for the sake of the Ford driver before giving him a ride to civilization as he had a several hour long wait for the tow truck still ahead of him, but the siping on these tires meant that I was able to grip really, really well on the icy surface and put a lot of energy into the kinetic strap. Within about 20 minutes, he was back on the road. The tires did spin a bit, but for the most part they bit hard and fast. For additional context, in order to ensure everything was as safe as it could me, my wife was standing further up on the road and flagging people down to warn them of the situation ahead while we extricated the Ford; one person tried to slow to speak to her, and instead she skidded right past her and nearly ended in the ditch herself -- in a Land Rover, so not exactly the wrong tool for the weather -- and she ultimately decided to turn around and head back till the road was cleared. The others were having to go extremely slowly to avoid the same fate as the Ford as they went by. It was skating-rink icy (as a Canadian that's a metric I know a thing or two about!); In fact it was so icy that despite my genetic pre-disposition to walking on ice, when I first got out of my truck, my feet went out from under me completely, and I have a nice bruise on my backside to prove it.

I didn't take any pics of the recovery. I do have pics of the bruise on my bottom, but this is family site. The point is the tires worked great - far better than I expected in those conditions.

3) In deep snow, they cut through very easily and had solid traction all around. No complaints at all in deep snow - I would be high centered before I ran out of traction with them for sure; my Goodyears used to get pretty plugged up (even when new-ish) in the snow with ice, and would just spin.

4) In mud, they self-cleared very well; I suppose it could be considered a "con" but they sure do fling the mud out of the treads effectively, as evidences by the sides of my truck (The canyon box's fenders stick out a bit and tend to catch the mud flung from the front wheels). The previous owner sprung for the 3M film though, so it has no impact on my vehicle.

5) Price was exceptionally good. These are E-rated tires with a tread pattern that I would compare to the BFG KO2s. For KO2s at Costco - the cheapest place to get 'em - I was quoted at $1700 Canadian for a set of 4 tires. I got these 4 at Canadian Tire for $1406.00, and that included a front-end alignment (which I reckon costs about $150 at least). At this price, they also include a 6 year warranty that includes road damage, so basically I'm set for tires for the next 6 years even if I wreck them on a gravel road like I did my last ones. I think (but am not 100% sure) this also includes rotations.

In freedom dollars, this means my set of tires cost me only $1,042 USD. That's $100 USD less than a set of KO2s from TireRack before installation costs, which I think is a screaming good deal when you consider the warranty.

And, as mentioned in my first post, these Motomaster-brand tires are made by Cooper Tires, right here in Canada apparently, so I've got no qualms like I'd normally have with basically every store brand except Kirkland.

I'll post again in a few months once I get a few thousand more kilometers on them and have a sense of how they wear, keep balance, etc. over time.
 

ChasingOurTrunks

Well-known member
Thanks klahanie!

The gent in the Ford had called a tow truck but when I came upon him, he said the truck was still 3-4 hours away from being able to respond; by then it would be dark and his situation would have degraded considerably as mountain weather is unforgiving. I agree with you on the unwritten rule too. I find the "close to home" folks defintiely have an easier time getting to help, but they are also often the least prepared for the winter conditions (the number of folks who ended up off the road on Highway 2 in AB in sneakers and windbreakers is shocking) so we try to make it a rule to stop and check. In recent years, police have taken to using yellow caution tape for any ditched vehicles that don't have people in them to demonstrate there's no life-safety issue, which is handy and makes me want to carry some of that tape myself.

I'm not 100% sure they are Canadian made, to be honest - I do know for sure that the Motomaster tires are made by Cooper, BFG, and Goodyear for Canadian Tire as they hold a huge portion of the Canadian market (15% or some such thing). However, which tire is made by whom I am less clear on -- I was told mine were made by Cooper, and I was also told that the Coopers for Canadian Tire were made out East here in Canada. But this was from the folks at the store, who may have been mistaken. This site says "Canada or USA", but not sure how reliable it is. If Goodyear bought Cooper, it could be the Motomaster tires by Cooper are made in Goodyear's Canadian plant?

I dunno - Wherever they are from, they are round and work great, so that's something anyway!
 

wicked1

Member
I've got skinny 235/85r16's on my tacoma. They're great. No problems. Even in soft sand, I drive right through where I see others getting stuck. Not sure how, but I'm not complaining. (My guess is my super heavy truck and relatively small contact patch is perhaps compressing the sand enough to hold it together to give me traction.. I don't know.....)
 

ramblinChet

Well-known member
Always keep in mind that with a wider tire on stock rims with stock suspension you may encounter a bit of tire rub when turning, or when the suspension is compressed, etc. For most applications, this is not a big deal though.
 

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