Question on tires and regearing.

[RttH]

I really would like to gain a little more clearance to my Montero (lots of rocks here in Colorado). I am running 32 x 11.5 x15 (this =31.5") and am considering going to 33 x 10.5 x 15. (32.5") My question is this...Would I be better off going to a 16 in wheel and getting 255/85/16 (=33.5")? would the extra 1"-2" really make that much of a difference?

Next question...when people speak of regearing are they regearing the transmission or is it front/rear axels?? I fear that if I were to go to 255/85/16 that I may need to regear, especially offroading here in the mountains.

Thanks in advance!

Roger

 

[WFTW]

They're refering to regearing the axles. I don't see why you'd have to regear for a 33.5" tire, but I'm not the one driving around in the mountains. I'd suggest getting the larger tires then driving it for a bit to see if it's necessary.

I had 37" tires on my old H2 and didn't regear. Though, I'm putting 40" tires on my Jeep and am regearing.

As for the tire size issue, you only gain a 1/2" for every 1" you go up in tire size. For example, if you have 32" tires and you put on 33" tires, then your gain is 1/2". Personally I've always been of the thought that every little bit helps. But, if you really want a gain, throw on 35" rubber.

 

[Redline]

I agree, put on the taller tires first, drive it and see. Everyone's tolerance for power/gearing is different. Your conditions (mountains/altitude) make a big difference too.

I'm currently in the middle of re-gearing my 4Runner, but this is after lots of mods 16,000-miles of use in this car and a few years of 4x4 experience (which you may also have).

Cheers

 

[RttH]

So are there advantages to changing my wheels or am I ok with staying with the 15". I am agreeing with trying taller, but now looking at the cost of having to go and buy 16" wheels. Thanks again!

 

[Redline]

It's all money, lots of it.

Do you have the clearance for the taller 33-inch tires? 16" wheels offer a few more choices in the 255/85R16 size over the 33x10.50 I believe.

I like a taller sidewall, so I prefer 15" or 16" wheels over 17,18 or 20, etc. on light-trucks.

So are there advantages to changing my wheels or am I ok with staying with the 15". I am agreeing with trying taller, but now looking at the cost of having to go and buy 16" wheels. Thanks again!

 

[RttH]

Thanks for your help.

Here is another question...Given that both are about 33" which would have less rotational weight? I am ok with going to a 16" rim, and since the suspension upgrade I have much more clearance in the wheel wells. I know 33" would fit fine, probably not wider than 12.5. I would like to have about 10.5" width.

I have seen 35's on Montero's but I believe they had to modify much more and change gearing. This is a daily driver and also used for extended trips. Locally, my brother and I head up into the mountains on jeep trails.

Thanks again!

 

[WFTW]

I had 17" wheels when I was running 37" tires, and I'm staying with 17" wheels when I get the 40" tires.

Let's say you have a 20" wheel (like you see on big vehicles that are "pimped" yet never see a dirt road) and 35" tires. You are going to have less sidewall, which means when you go off-road and air down your tires, you're not going to have that extra tread grip that you would get if you had 15" wheels and 35" tires. You'd also risk the tire coming off the wheel (if you don't have bead locked wheels).

Hope that explains the advantage of choosing the proper wheel/tire combination.

If I were you, I'd keep the wheels that you have on there and just find tires that fit them.

Keep in mind that when you put on larger tires, you put more stress on your axles and drive components. I don't know anything about your type of vehicle, so I don't know what size axles you have, but you might want to look into that. For instance, a D30 axle probably wouldn't last even 1 off-road trip with 40" tires. I had D44 axles in my Jeep and went up to 60's because of the large tire size I'll have.

 

[Redline]

To agree with WFTW,

In general, more sidewall is better in my opinion for regular cars and light trucks (not sports cars or hot rods).

This is what I like to say about a tall side wall: It's the sidewall that does the work.

On-highway the vehicle will ride much nicer (softer) with a properly inflated, taller sidewall. Off-highway you have more sidewall to let down and drive on/with than a stubby sidewall and lots of wheel (if you compare two 33-inch tall tires, one with 15" wheel, the other with 18").

There is not as much difference between 15 - 16" than the more drastic examples we are giving you. Either will be fine. If the tires you want are available in 15", buy them. If you don't like the tire/tread options go with 16".

Regardless off 15 or 16" you are talking about nice sizes that are not overly wide (just my preference). 33x10.50 or 255/85R16 are terrific sizes!

I had 17" wheels when I was running 37" tires, and I'm staying with 17" wheels when I get the 40" tires.

Let's say you have a 20" wheel (like you see on big vehicles that are "pimped" yet never see a dirt road) and 35" tires. You are going to have less sidewall, which means when you go off-road and air down your tires, you're not going to have that extra tread grip that you would get if you had 15" wheels and 35" tires. You'd also risk the tire coming off the wheel (if you don't have bead locked wheels).

Hope that explains the advantage of choosing the proper wheel/tire combination.

If I were you, I'd keep the wheels that you have on there and just find tires that fit them.

Keep in mind that when you put on larger tires, you put more stress on your axles and drive components. I don't know anything about your type of vehicle, so I don't know what size axles you have, but you might want to look into that. For instance, a D30 axle probably wouldn't last even 1 off-road trip with 40" tires. I had D44 axles in my Jeep and went up to 60's because of the large tire size I'll have.

 

[RttH]

Many thanks!! I appreciate the help. This site and magazine are great!!

Roger

 

[Redline]

You are welcome.

Welcome to the site as well

Many thanks!! I appreciate the help. This site and magazine are great!!

Roger

 

[madizell]

Here is another question...Given that both are about 33" which would have less rotational weight?

I don't think there is enough information to answer the question, and there are too many variables involved to make a general statement. You will probably find that two comparable tire/wheel combinations in terms of overall diameter are quite similar in weight. But, choice of tire has much to do with weight of the combination. Even staying with a same brand and style, different diameter comparison, there are very few 15 inch tires that are the same as 16's except for the diameter. Seems like all the 33 inch 15's are also fatter than the 16's, so the difference in weight is probably negligible. Try scanning the tire spec sheets to see if weight is posted, and assume that a 15 and 16 inch wheel of similar construction will weigh about the same.