Bob_98SR5

Guys,

For those of you contemplating upsizing your tires and the effects of in in terms of mph, lift, acceleration, etc., go to this page on the BF Goodrich website:

http://www.bfgoodrichtires.com/bfgap...ex.jsp?style=7

Once there, on the right hand side near the bottom under the section "Tire Tips", you should see a graphic w/ a yellow truck called "Off-Road Tire Size". Click on it and it will open up a javascript-enabled calculator.

Punch in your desired tire size and it will calculate the effects of upsizing. For the other tabs (Acceleration...Speedometer), you may need to input an additional data point.

Hope that helps.

Bob

Beowulf

Very cool!

Thanks Bob

Shane

I thought "up-sizing" was increasing the wheel diameter while not changing the tire diameter... or was that "plus-sizing".... can I get fries with that? :confused:

BTW, it appears that the "Highway Performance" and "Regain Performance" ones are backwards... installing larger tires without changing gear ratios does not increase RPMs at a given speed, it decreases them... nice looking calcualtors though...

UKMyers

Sweet glad someone found something like that. Any chance at saving that to the site somewhere to direct people to with the every so popular question of what going up in tire size will do to performance??

Shane

There are lots of other calculators around the web just like them, all you need is the equations and you can make your very own version on your own website. Mabye we should make a Yotatech calculator page...

cybrenergy

If somebody gives me the calculators, I would be happy to do the coding for it. After all, that's my day job

Corey

iTrader: (1)

That sounds cool Shane.
I can stick the saved HTML page on the Portal page.

I don't know how to make the calc though, but if someone can make the file and have it all in one directory along with any needed pics that is uses and zip it up and send it to me, I can upload it here.

Perhaps make the page with the same gray background color #373737 as the Portal page.

Shane

The equations are visible on the BFG page, for instance on the Ground Clearance one:

(new tire diameter - original tire diameter) / 2 = change in ground clearance

Shane

Just noticed the BFG one was done in shockwave... Cool...

cybrenergy

Actually, the version on their site is done in Flash. What I was able to do was download the flash file directly, so we could put the same identical calculator on this site if we wanted to do. Basically, we could have a link that invokes the same popup that they do.

Let me know if you want that on here and I will send it to whomever.

Corey

iTrader: (1)

So you have the Flash code embedded into a page?
If so, send it to my email in the sig file below, and I'll test it and see if it works after an upload.

Shane

shockwave....flash....animated gifs......it's all the same to me

I'm not really into that them there intarweb programmating thingamajigger stuff, really....I'm not

Corey

iTrader: (1)

Tire calculator has been added to the Portal page.

Thanks Bob for finding it, and thanks cybrenergy for getting the code, and then fixing it so it will be a popper window.

I had fun playing around with it to see what my RPMs would be at 55 if I moved up to a 32" tire.
It would be around 1800 I think it said instead of 2000 like it is now in OD.
Corey

rowan

the BFG site is pretty informational.

some of those calculations are off i think though.. shouldn't your RPM's go down with a bigger tire? mine went up.

and here's a question that i have had for a while, but its not really that important. with bigger tires, your speedo will read faster than your going.. is this easy to change, or have someone change? hmm.... thanks

Corey

iTrader: (1)

The calc worked for me.
My RPMs went down with the bigger tires, jsut as they did when I put the 31s on.

Also, the bigger the tire, the slower your speedo will read.
Whne my speedo says 55, my GPS which is accurate says about 59 to 60.

I am geared for the 235 size tire, and not 31s.
Corey

Shane

Yes, a couple of them are wrong or misworded.
With bigger tires and no gear change your speedo will read slower than you're actually going. You can regear the diffs and regain most of your previous performance, or get an adapter to regear the speedo. Thirdly, you can just get used to it like I do and calculate your true speed on your head.

rowan

yeah. i meant slower :pat:
either the site was wrong again on that one, or i thought it was. didnt even think about it. plus i am tired, im going to bed. goodnight guys

carpemanana

Yep- I saw this the other night just before I "Super-Sized" to 32x11.5x15 BFG TA/KO's. They are awesome!!! It's been raining here the past three days and they are very grippy plus quiet. FYI- BFG TA/KO are on sale at SEARS until Oct 10th. I got mine for $118 ea... not too bad eh?
One thing all the charts and calculators don't tell you though is real-world feedback. Going up one size did not affect my performance very much. My truck was actually pretty quick to begin with- I guess I am lucky because most people report problems with their acceleration. My original tires were stock Bridgestone HT's 31x10.5x15. They are sooooo lame compared to the BFG's. I kinda wish they had worn out sooner (55k) but I had to wait for my PP springs and AirLift to be installed before I upgraded the TA/KO's. Total lift right now (non-inflated) is + 2.5" with the mods. It rides nice and firm and is still very good at giving a smooth ride. I'll post before and after pix this weekend with a complete write-up. Stay-tuned!