tire size increase

[kimfish1]

I recently posted a question about this subject. However, since the increase involves only a 9% greater circumference, why can't I just make mental adjustments for the speedo variation and not make any other modification? Any suggestion will be highly appreciated.

 

[armadillon]

errr....what exactly are you asking? Are you asking: "Do I have to adjust my speedometer or just remember that I'm 9% off?"

I'm sure you saw this: http://www.miata.net/garage/tirecalc.html in the Tech Library. It also lists an RPM change as well. But I still don't know what you're asking.

 

[Rose2300]

why cant you? i dont know hahaha

 

[armadillon]

You have to be sure that your mental capacities are up to spec. Capacities are adjustable and usually change with regard to alcohol.

Do not post and drink!

 

[kimfish1]

Thanks for the wise answers. From a technical point, I can calculate tire diameter, circumfrence, RPM for any tire without a conversion chart. I only want to be assured that a 9% tire increase is not enough to mess with the tranny or computer. I can deal with the speedo reading change.

 

[armadillon]

Gotcha You can see that we thrive off of humor here. A 9% increase will not effect anything to my knowledge.

 

[kimfish1]

Thanks very much. I do have a sense of humor but was getting frustrated with all the conflicting answers I've received here locally- from spending $300 to adjust the computor to modifying the tranny to "you can't do that or you'll tear somthing up." I feel your opinion has merit.

 

[armadillon]

If it's an increase that small the added stress isn't much at all. It depends on what you do with your truck. If you want slightly larger tires to look cool and you do minor wheeling, I wouldn't worry too much. If you put larger tires and do far more wheeling, you're probably going to want to do a beefier rear axle swap.

You may want to update your profile so we can see what setup you have. If I recall correctly you should be able to run up to 31s on your stock 4wd setup and shouldnt have to do any modifications. There may be slight rubbing. If you want larger I'd recommend doing a slight lift in the front whether it be 2" leveling coils or a body lift.

And just so you know, make sure you use the search feature a little more. Tire increase threads are WAY common and slightly frustrating since they pop up. I'll give you a break since I'm still pretty new myself, but look:

http://www.google.com/cse?cx=partner-pub-5354086480683247%3A6isglneri0k&ie=ISO-8859-1&q=max+tire+size#gsc.tab=0&gsc.q=max%20tire%20size&gsc.page=1

Every thread is pretty much dedicated to "How big of tires can I go?" followed by other posters saying "you can fit up to these and then you have to do [whatever the modification is]"

You can imagine for those that post every day that re-answering the questions get super annoying.

 

[kimfish1]

Thanks, Armadillon. My truck is a 98 Ranger ext cab, 3.0, 4 spd auto. It has only 65000 mi. and I'm planning to keep it indefinitely. Having time on my hands, semi retired, I'm trying to fix it up without major body alterations or being tacky. The only fault I find now is that the tires seem too small- too much wheel well showing. New wheels &235/75R15 tires should help that a lot, as well as setting the tires out 1" further. Just wanted to explain my reason for questions I probably should have known the answer to. Thank you again.

 

[armadillon]

No worries! I completely understand, it's always great to have confirmation of your theories. I can do almost anything on a vehicle, but it's a hell of a lot easier when you have someone you can look at and they give you the "yes, you're doing it right" nod