Georgia Trail Riders Forum
CLASSIFIEDS => Wheels & Tires => Topic started by: slowbox on January 24, 2014, 09:06:15 PM
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Please note anything blue taco posts means my novice butt is threading here.....
I've been prowling tacoma forums and discovering some interesting but maybe counter-intuitive bits of info regarding tire width.
In a nutshell I've got a 3" lift planned, and wanting to keep my wheels but possible new tires:
Current stock tires: 265/70/16 BFG
Yet lots of recommendations for: 255/85/16
So less wide, but taller tire. Folks are proposing that the narrow tires actually provide a fair bit of function over the wide depending on conditions.
Here's the thread if curious: http://www.ttora.com/forum/showthread.php?t=180050
I found it curious, I dont expect to swap out my good stock tires yet, but didn't know GATR's take on it.
-tom
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I am no expert, but I figure for rock crawling the more contact area (wider) the better. I have seen narrow tires on mud rigs and snow rigs because it helps cut through the elements.
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For what we do, the more rubber on the ground, the more traction. The wider the better.
Sent off camber
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EDIT: I understand the concern with wide vs tall for specific vehicles.
Two dissimilar things are being compared: Width vs Height --- You can have a wide tire that is tall (relative to a short tire) and you can have a wide tire that is short (relative to a tall tire). Do the same thing for a skinny tire and you should get the point.
Wider tires (relative to skinnier tires) can cause/create some issues if you are not prepared for them:
1) Front tires rubbing against parts (control arms & anti-sway bar in my case) in the wheel well is a common issue if you aren't running spacers and/or wheels with enough backspacing. Some times you can have a problem with the rear tire rubbing also, but hopefully not due to turning.
2) Stress on steering components. The extra contact area with the terrain surface can add significant resistance to turning which impacts steering components.
3) Splashing of water and slinging of dirt, rocks, and mud. The extra overhang, especially if you go really wide due to the additional offset you need to avoid issue #1, will allow the tires to sling stuff around.
4) Stress on axle shafts. While not likely to be a concern, the extra width can add stress to the axle shafts in turning situations, especially in situations of really sticky tires with locked axles (not axles with lockers, but axles where the locker is locked up tight (a spool)).
5) MPG hit. More surface area equals more resistance which will theoretically impact your MPGs. Maybe not much, but theoretically there will be an impact.
When considering your tires, think about how you will use them and what you really to get out of them (long life, look tough, Load E rating, comfort on road, etc). Assign some sort of weighting to the various features that makes sense to you. I like to use Excel to focus my attention when comparing things, so I would create a matrix that captures the various tires I'm considering (Y axis) and matches that to features offered by the tire (X axis) (sticky-ness, gas mileage impact, longevity/life, max weight load for towing/hauling, on-road, cost, availability after the sale, etc, etc). Then find the tire that has the highest calculated value based on your weighting and tire feature matrix. Then, forget everything you did and see what you can find for cheap that looks good and that you think will work for your needs :)
This site will let you play with the various tire and wheel sizes and compare them visually and with measurements. http://www.rimsntires.com/specspro.jsp
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For what we do, the more rubber on the ground, the more traction. The wider the better.
Sent off camber
Doug, this guy's document doesn't agree with you: http://www.expeditionswest.com/research/white_papers/tire_selection_rev1.html
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A lot to wrap my head around here, I've written 2 paragraphs and erased them all because I simply don't know.
In some practical sense I can say I need tires for moderate commuting, not dedicated trail truck rubber.
Height is a plus for clearance. Width would seem to require more energy to pull in terms of friction, yet narrow points all torque into tighter band of space. On a grip friendly surface, narrow would carry, right?. In mud/snow surface I presume width is king.
***grain of salt pls... I'm just kind of tossing out some thots. I'm a spacial thinker (and i hate it) rather than a good numbers man.
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No Clark I don't agree with him lol. Physics don't lie. The larger the contact area of a like material, the more the friction, and therefore traction in the case of a tire. The wider the same height tire, the larger the contact patch.
Plus you can't wrap around a rock without width.
Plus anything that says expedition is all about gravel roads and camping...
But I'm no Einstein
But I did stay in a Hilton last night
Sent off camber
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If you are going 33 tall it seems that the 10" width would be a little unproportional for what we do, although this is not an uncommon size + you can run bfg's.
Have you thought about 285/75 R16 (33x11.5) you will have a few more options.
It is good to get opinions and ask questions like you are doing!
TAPATALK
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Another thing you need to look at is the side ply. It's easy to cut a tire off-road on the sidewall. You want a thick sidewall or one of the brands that uses Kevlar to keep things light.
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No Clark I don't agree with him lol.
Ah, that perspective thing! :)
The one thing in the article that caught my attention was about load distribution of 'vertical load' (i approached the article with skepticism). It made sense to me on paper, but I can't attest to real world application. My limitation with my 33x10.50x15s always appeared to be height versus width (ground clearance killed me). If I had to make a decision between width and height, such as being confined with a certain wheel well size and lift, then I would choose height based on my previous experience with those 10.50 tires I mentioned. Those skinny tires are BFG KM2s, so they grip like a mofo, but so did my shock mounts, control arm mounts, pumpkins, and skid plates. From an appearance perspective, my 35x13.50x15s look MUCH better/tougher than those pizza cutters I have.
I ran the 10.50s on the Bell FS trail ride and made it up the v-ditch with no issue (locked F&R), but I'll be running the 35s at Morris.
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He says he is writing to substantiate his belief
Sent off camber
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Once you get to 33" tires in BFG's I think they're all the same width up to 37" so there isn't much choice to begin with. To the original question, 265/70/16 or 255/85/16. The isn't much difference, so choose the one you think will suit you best based on your personal preferences (height, looks, etc.).
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But I did stay in a Hilton last night
Sent off camber
See Doug. That's where you went wrong. You're supposed to stay at a Holiday Inn Express. Your whole approach is flawed because you stayed in the wrong hotel.
Sheesh!!!
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Get out and wheel, see exactly what tires work well in the type of terrain we have here. Talk to real people out in the rocks, in the dirt, similar vehicle as yours, etc. then you'll have a real good idea on the next tire you want to buy.
The interweb is great but the real world stuff is going to be far better.
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But I did stay in a Hilton last night
Sent off camber
See Doug. That's where you went wrong. You're supposed to stay at a Holiday Inn Express. Your whole approach is flawed because you stayed in the wrong hotel.
Sheesh!!!
Exactly what I was thinking
//LMAO// //LMAO// //LMAO// //LMAO//
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Once you get to 33" tires in BFG's I think they're all the same width up to 37" so there isn't much choice to begin with. To the original question, 265/70/16 or 255/85/16. The isn't much difference, so choose the one you think will suit you best based on your personal preferences (height, looks, etc.).
Nah, they make a km2 33x10.50x15...I have a set of them.
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As Tony said, its alot of junk on the interwebs, I've been overdoing the research myself. Just get out there, watch closely, on difficult obstacles you can see whats up. Cutting a tire or having no traction when you are stuck between a few rocks is alot worse than all this analysis. You can buy some tires, then sell some tires, you will lose a bit of money as you figure out but its not that bad.
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BTW in the article posted, this guy uses a term "vertical load" that would be laughed at in engineering school. I personally have no idea what the formulas are for this, but I recognize some hand waving when I see it. He does not actually run the calculations an automotive engineer would be doing, they will be standardized. Narrow tires are for MPG, wide tires are for traction, all autosports. Cost efficiency of your build in the terrain you run is a whole other issue.
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Once you get to 33" tires in BFG's I think they're all the same width up to 37" so there isn't much choice to begin with. To the original question, 265/70/16 or 255/85/16. The isn't much difference, so choose the one you think will suit you best based on your personal preferences (height, looks, etc.).
Nah, they make a km2 33x10.50x15...I have a set of them.
They still make 15" wheels? //:o//
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Once you get to 33" tires in BFG's I think they're all the same width up to 37" so there isn't much choice to begin with. To the original question, 265/70/16 or 255/85/16. The isn't much difference, so choose the one you think will suit you best based on your personal preferences (height, looks, etc.).
Nah, they make a km2 33x10.50x15...I have a set of them.
They still make 15" wheels? //:o//
They may not for the taco. I am still running 15s since they are cheap for tires and wheels.
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I have been laying around nonstop for a day or so after working 3 14 hour days so I kept on digging on this topic, I definantly did sound like a jerk dismissing the articles points. There is little info on the interwebs about how tires are engineered. There is some good info on how drag racers calculate their suspensions, tire sizes etc but that is simpler than what we do as the normal force and friction can be calculated with much more simplification on a flat surface. I think this below forum thread (read posts in the middle) offers some insights into how complex this engineering is.
http://www.ls1gto.com/forums/archive/index.php/t-282956.html
Something that gets into the zone of the complexity is here:
"However wider tires ARE better for lateral traction (cornering) because
of the SHAPE of the contact patch. A thin tire has a long narrow contact
patch and a wide tire has a short, wide contact patch.
And a longer contact patch is bad, because under high cornering forces,
the tire is pointing in a different direction from the direction of travel,
due to the slip angle (up to 5ish degrees, depending on the tire compound).
And a long, thin contact patch being dragged across the asphalt at a five degree
angle will lose traction at the trailing edge, because the rubber gets
dragged sideways a greater distance.
This effect is THE reason why wider tires are better for cornering."
I think its important to note that offroad the loading of our vehicles varies alot on inclines and irregular surfaces as the tire forms to the ground, so the standard normal force calculations for friction are going to always be on angles, and there is going to be a heck of a lot of lateral movement as we traverse obstacles. Sidewalls are flexed, tires contact patches are being pushed laterally shearing, flexing laterally etc. For digging into ice and mud, I see alot of real world experience to get a narrow tire to go deeper into the surface and a wider tire would tend to have some flotation effect. For rock crawling, just getting your tires ONTO something is key, like a solid purchase on a rock. hence wider tires just to find purchase, a simple insight. Width also helps you not roll over.
Utlimately a huge amount of your tire traction comes from your compound, how much of the tire is applied to the ground/rock/obstacle, and the tread, and then the angle you are loading the tires at, and then the torque you are applying as the tire has some shearing, often in multiple directions. It is clear that the contact patch of a taller tire or a wider tire is not that different, but we drive both taller and wider tires offroad for crawling.
I feel like this article is so simplified, its like I should say, drive a heavier truck offroad for better traction...the normal force will be higher, clearly that is not the case as a heavier truck has a lot of trouble sliding on slippery surfaces, moving up inclines, and will throw itself around on its suspension as it articulates with far more force, momentum etc... requiring even more traction to stay put on an obstacle.
The engineering of what we do is very very complex, as the suspension keeps the tires on the ground, the tire compounds, the exact penetration into the dirt, rock etc of the facets of the tire lugs and tread, its probably almost impossible to model and rather has to be done just be measuring the forces under diverse experimental conditions.
The author of the article is basically saying its cheaper for him to put taller tires on his truck due to the issues with lifting it to fit wider tires, to get a similar contact patch.
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Given enough disposable cash, I'm sure the guy would buy his way out of a wide tire vs tall tire discussion. With limited disposal cash, it seems reasonable, to me, to consider options other than just doing without until he can lift the vehicle high enough to put a tall wide tire on it.
If the choice is to have a short wide tire vs a tall skinny tire, then I would land on tall skinny.
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Well ya, getting the height is key for offroad. But we drive tall and wide tires, dropping tons of money on the rubber!
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I guess it would depend on how much width your giving up and how much ground clearance your gaining. For a long wheelbase like yours the ground clearance will be more important. I would sacrifice an inch of tire contact for an inch or more of belly clearance. Your truck is gonna drag a lot. Get a good tire that will make up for the traction loss and lockers.
Sent from a 4g signal.
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Love the convo, thanks. 3" lift off stock taco is SOMETHING but not entirely accommodating to the tires you Jeeps seem to handle and discuss as norm. Maybe i should see if there's a coilover option for lifting a bit more. Dangit you guys. More, more more...
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Leave it as is... Nice truck
Get a beater XJ for the trail and a cheap trailer. Neither will depreciate much if at all, and then you'll know better what you want to do long term.
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^ solid advice
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I've been shopping for an XJ (cherokee) myself, I am sure you can get one already lifted, with tires, or an old YJ (early 90's wrangler), for the price of the stuff you are going to drop on the taco.
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Hindsight being 20/20 I think I would have gone Jeep route. But its paid for, so that's that. However with that said, this tacoma is an absolute pleasure to drive... its smaller than my last truck, but maneuvers and has comforts (batmobile-like from my perspective) that I never imagined. Previous was '96 ram, which I still thot was luxury by simply having automatic windows. I'd gotten so used to driving that older truck which was breaking down and averaging a tow every few months. I went through 2 rebuilt transmissions in 4 months. I was nervous driving it any further than 50 miles any direction...and it sucked having that feeling all the time. It was just a source of stress. This toyota, complete opposite. Feels dang good.
Simply no room for 3rd vehicle at my little place. So I'm gambling on using the $1500 sale money from that old truck to lift this taco, and toss a few more beans at tires and some armor. I wont for a second question Jeep fans---prefer Jeep fans over toyota fans (I cringe at fellow toyota owners claiming offroad superiority type stuff). Still! There appears to be great/easy ways to outfit a tacoma for casual OR.
In a few years maybe a Jeep... If a promotion comes along, and private school for kids turns out to be cheap, and all that noise works...also maybe a new house with a decent garage would be swell too... but for now, this is what I'm working with. :)
edit: jgerhard --- You sound like you know your stuff so thats why i left my friggin life story in a post here. I've read and re-read all your posts. So by no means am trying to argue anything whatsoever. Just making the best out of situation.
-tom
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... and private school for kids turns out to be cheap,
Nope.
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... and private school for kids turns out to be cheap,
Nope.
^i know, i'm not sure if im being sarcasticy sometimes or just pointlessly hopefull :)
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Hey, no worries, enjoying seeing you catch the bug. I am monitoring QA fixes for a software release tonight so I have time to chat online.
I think those of us that have commented just want you to know whats up before you get in too deep, especially since you have family to think of. Perhaps you have seen the J.E.E.P thing, Just Empty Every Pocket. Not sure of the Toyota line of thinking lol. For me it started when I had RC cars in middle school, I would just pour through the Tower hobbies catalog and RC Car action mags. Then it was guitars, then it was girls. I had big dreams on my Tacoma when I got it. Had kids, derail that. I had the good fortune to have a job I can achieve well at, and be able to get a JKU as my wife likes it too, we didn't want a minivan or another big SUV. Took 2 years to even upgrade the Jeep. Then I found GATR - this club is like moving from toys to TOYS. One day you are looking at pictures in a magazine and then one day you are on a moutainside surrounded by awesome equipment going sideways around boulders.
It is a bit expensive to get into this sport/hobby and we are throwing tens of thousands of dollars of vehicles around in rock parks. The scenery, beautiful views, crazy trails, and awesome rigs everywhere is so cool.
So I would hate for you to have the total dismay of a major body damage issue on an early foray out. I have seen it at least once this year. I would say sliders, tires + lift, armor, lockers, tow points in some order. Don't wheel with thin walled tires or without sliders. The club staff and members can get you in and out of the rest. The first +serious+ advice I got when I asked for it after a ride with GATR was to build the axles. Went to Allsouth, joined CORE, broke out the wallet, am hooked on the upgrade process now cuz I can see how much my vehicle can do with the improvements.
I am actually not very experienced, I have an affordable build ontop of a great platform that can do some good stuff and I've started doing big obstacles at the end of the year at Jeepfest (obstacle course) and GATR fest (much bigger). But the top builds on here can probably double my shock travel and obstacles. I just moved through the new-to-the-sport stages recently so I am closer to your end of the build process in financial decisions, core build steps, than some of the advanced guys. Matt, Doug, Tony, Bobby, Jason and Clark are really experienced in wheeling and mechanic'ing. Its your build, enjoy the sport your way, be safe with your vehicle.
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I typed 2 stupid paragraphs and just erased it all. I'm mid 30's and actually just learned how differentials work through RC car rebuilding this past year. Actually love my RCs.
I'm advertising/graphic/pc/network/webdesign... i'm a pile of stuff. Chateau Elan has kept me managing their marketing for 11 yrs now, but truth is I dont know crap about too much.
-Tom