mike or anyone else care to answer here's the ???? if i have 3.55 gears running 28.5" tires and decided to run 33" tires and a 4.10 gear do i have to change anything in my chip program considering these 2 setups arrive at the same final drive ratio?

 

Assuming that is the case, then no, you don't have to do anything to the program, it would end up working out. As long as it is the same final drive ratio, in effect, then you're fine, the speedo & odo will be accurate, and thus the shift points (in an automatic) would be correct.

 

Here's another one Mike, if you're here. Actually 2...

My stock setup was 30.5 tires and 3.73 gears. My current setup is 34.6 tires and 4.56 gears. My speedometer is off and my shift points seem to be off as well. If I'm coasting between 1000-2000rpm, I get a major loss of power if I step on the gas, and the truck stumbles along until the gas pedal is heavily depressed. It then kicks into gear and sends me back into the seat. The dealer had it hooked up to a scanning device and noted the improper speed reading between tires and gears and actual speed. Thus coming to the conclusion that this may be the problem. So my first question is, would the superchip be able to correct the speedo with the tires and gears I have? And secondly, I also have a set of 37's that I was thinking about running for mudding. Would it be possible, without having 2 separate chips, to get a flip chip of some kind to switch between tire sizes? I've also been thinking about the Superlift Truspeed calibrator because they say you can program 2 different tire sizes. I would love the performance advantage of the superchip (probably get one even if I go with the Truspeed), and it would be an added benefit if I could get my speedo corrected.

Thanks!

 

Sure, we can correct the speedo, odo & shift point problems due to tire size & gear ratio changes in the 1999 thru 2001 F-150's, it's a custom program of course.

And yes, we could do a dual tire size setup in the 2-program Flip Chip for you if you like, we have a nubmer of peole doing that for winter tires and summer tires, for example.

Just give us a shout when you get a chance & we'll be happy to go over this with you.

 

HEY, I HAVE A 99 150 AND I GOT 315/75 BFGs AND I AM GOING TO GET SOME GEARS FOR IT, I HAVE THE 3.73 NOW AND LOST A LITTLE POWER WITH THE BIGGER RUBBER. I AM TRYING TO DECIDE ON 4.10 OR 4.56 GEARS BUT I DONT KNOW IF THE 4.56 IS TOO LOW OR NOT I AM CURIOUS ABOUT WHAT THEY DID TO YOUR MILEAGE AND MOST IMPORTANTLY THE POWER DIFFERENCE FROM THE 3.73 GEARS. I APPRECIATE ANY FEEDBACK IT WILL HELP ME DECIDE WHITCH GEARS TO GO WITH.

THANKS ERIC

 

Hi Eric,

Welcome to F-150 Online!

I haven't checked so I could be wrong, but off the top of my head I seem to remember a lot of the various 315's that we correct for usually come in around 34.7" or so, and you'd want the 4.56 gears for that kind of tire height if you had 3.55's originally, but your don't, you have 3.73's, so you'd really need a set of 4.75's or so assuming a tire height of 34.5-35", to have the engine turning approximately the same number of rpms for a given speed that it did before with the factory tires & 3.73's. 4.10 is not near enough gear for a 34"+ tire in that vehicle with an original gear ratio of 3.55 or 3.73, like yours. Make sure to double check your exact tire height to confirm this, as depending on the aspect ratio, the actual tire height can vary quite a bit, so make sure you know exactly what the actual tire height will be. But in general, a tire in the 34-35" range needs a 4.56 gear in these vehicles with a 3.55 original gear, and about a 4.75 or so with 3.73 original gearing.

Realistically, you could just go with the 4.56's instead of trying to find a 4.75 or so, and the performance "hit" wouldn't be critical, you'd be close enough so that you could enjoy the vehicle properly with a 34.5-35" tire.

By the way, just so you'll know, when you type in all CAPITALS, it's considered SHOUTING in email or online environments, plus it's harder to read.

If you're going to do those tire size and gear ratio changes, you'll probably want to have the needed corrections done to restore accuracy to the speedometer, odometer & shift points if it's an automatic. We can take care of that for you in the Superchip, if you want to have that done.

Good luck!

 

Mike

Thanks for the info it was very helpful and I will probly op for the 4.56 gears and I do plan to get a chip to help with the changes. I will get with you when i need it. Oh yea the 315/75 BFGs i have are supposed to be 34.6" atleast that is what their web site says. Thanks again for the help.

Eric

 

Hi Eric,

You're very welcome, anytime!

Thanks for confirming that tire height, in that case the info I mentioned before is basically correct in your case.

We'll be happy to help you whenever it''s appropriate, just give us a shout when you feel it's time. Remember that you'll want to allow about 7-10 days for custom programming from the time you place that order to the time we usually get the custom programming done.

Good luck!