Tire and Wheel Clearance Question

Good Evening,

I am new to the forum but the info I have seen out here is really great. I am hoping someone with a 31QBH or similar bunkhouse model can help answer a few questions. Here goes....

After reading a number of the posts (on this forum and others), I recently upgraded my tire/wheel combination. Since I didn't want to get involved with potential clearance issues, I stayed with a 15" rim as well as the 225/75R15 tire. I did however go with a load range E tire over the factory installed load range D (just a piece of mind thing).

I noticed however that the clearance between the cross shaft for the slide out and the tires is VERY close. Those that have the living room/dinette slide know that this cross shaft runs the entire length of the slide right behind the two wheels. When I say the clearance is close, I mean that on the rear tire I can't fit my hand between the tire and the cross shaft (so I'd say there is a 1/2 inch of clearance?). On the front tire, I can slide my hand through, but barely.

Can anyone else give me some comparison measurements/clearances to know if this is "normal?" I am now concerned that I'll be rubbing the inside of the tires, not necessarily rolling straight down the road, but cornering or go over rough surfaces.

I appreciate the help!

-Jon

Hello Jon, first off, welcome to the forum.
Our campers are close (other than the rear bunk room) and we have more clearace then you describe. Here is a photo, but it is a little hard to see: http://community.webshots.com/photo/fullsize/1180263399056654887QNLGxN
The clearance is the same for both tires. Send me a reminder if you need me to check more closely.
What year is your Cat?

Hi. Thanks for the response...I need to create a Signature for myself. My Wildcat is an 06 31QBH.

If you don't mind, let me know what your clearance is (I guess we can be somewhat non scientific about this and go based on whether or not you can slip your hand between the tire and shaft).

I'll post a picture as well showing my issue.

Jon,

I have an '04 29BHBP which is similar to your camper. Last summer I did exactly what you did, upgraded to LRE 225/75-15 tires. I didn't notice any difference in the clearance between the synchronizing bar and tires. Did you measure before the tire change or is this something you noticed after?

Thanks...

Welcome!

I have plenty of clearance with my '06 31QBH and my 16" tires (factory). I don't know if it is a west coast model thing, or what. My tires are 235/80r16D. The clearance between tires is 2" so my old wheel chocks don't fit. I need to get the vertical style.

Hi Mark - Thanks for the follow up. I had noticed the clearance before the new tires - which made me decide to stick with 15". I remember noticing that 'Wow, that cross shaft sure seems close to the tires, but I guess it's supposed to be that way, so I better not go with a bigger tire/wheel combination." I did notice that the tolerance was slightly greater with the front than with the rear. (I did the finger test to see if I could get my hand between the tire and the cross shaft - slightly tighter on the rear, but could get my fingers squeezed through).

After the new tires, the tolerance on the rear seems to be a little less - can't get my fingers between the tire and cross shaft any longer. The front seems to be the same as before the tire change.

I'm curious, if you don't mind - can you take a look and see how much room you have (and if you notice any rubbing on the insides of your tires). I spoke to Rod Batts at FR this morning and he is going to check one of the units that he has on site at his place which was supposedly built around my time in '05 and let me know what the clearance is on that one. Thanks - Jon

Jetskier - thanks as well for your follow up. Maybe the WC editions are different than the EC ones? Not too sure. My clearance between the tires is fine, nothing noticably different there. It's the clearance between the inside of the tires and the cross shaft for the slide behind the tires that has me concerned. Thanks - Jon

Here's a picture of what I'm trying to describe:

Looking from front toward rear - rear tire

I want to say they were using different frame fabricators in the earlier models. The west coast was more progressive on the tire issues. Since the frames are built with the tires installed before the factory gets them, they probably corrected the clearance issues for 16" combos. The 30'+ models weren't doing to well on the weight side of things. Now 16" tires w/ 6000# axles are standard where they were in option a few years back. I had conversations with the factory rep (Rachel Wolf) in Oregon about it. I told her my trailer weight about 12.5k on the scales when wet and loaded, but the sticker shows only 11430 with 15" wheels and tires. They don't upgrade the sticker even though they upgrade the tires/axles. Since 2008 models or so, I believe the east and west coast models are the same spec. They had two brochures in the past.

I see what you're talking about. I remember my bar is above the tire a bit. When leveled, what is your ground to door threshold height? Mine sits up 39". If you look at my avatar, you can see how high it sits and this is stock. They may have raised the trailer off the axles on mine to keep the clearance.

WOW!! That is tight I'll take a look at mine tonight after work and let you know how much room I have.

I found a picture of my setup.

Even with the tire covers on, you appear to have plenty of clearance! This is really puzzling to me. It's almost as if both axles on mine are offset to one side more than the other? It would stand to reason that if I had them moved over an inch I'd be OK....certainly not something I'm about to do myself (if that's even an option?).

Lippert is suggesting an offset cross shaft - something they've used when people change tire sizes. That's a several hundred dollar option that I purposefully didn't choose, which led me to keeping the same size tires.

I think you need to lift it an inch or two to create vertical separation.

Do you think I can achieve vertical separation by adding heavier duty springs? I don't have any options with adjusting the current springs - everything is bolted as is, with no "extra" holes to adjust up or down on the frame.

You could add a spacer or have the springs re arched. The spacer would be cheaper and quicker.

There's a difference in the WC to EC models. I can lift mine another 3-4 inches if I wanted to use an elevator to get inside the coach. I'll try to dig up another photo of the spring hangers for comparison....

How close is the bottom horizontal member of the I frame to the tire? Is that the same distance as the other side? If your axle is off center, the other side frame member would be A LOT further from the tire, and the tire could possibly be too close to the outside fender - if that's the case, the axles may need to be recentered.

The bottom horizontal frame member is not visible in your photo, but in jetskier's, it appears to be about the same distance as his slide cross-shaft.

Here is another option.

http://www.ezaccessory.com/Wheel_Spacers_s/27.htm

Thanks All - this forum is great. Lot's of good ideas.

I'll need to look at the shaft relative to the bottom of the I frame (my suspicion is that the shaft is wider if you will, than the bottom of the I Frame, but I'll check). And I'll check side to side to for comparison sake to check axle centering.

With regard to spacer - do you mean wheel spacer? Does anyone have any experience with these? I am asking for "other" trouble with this - it certainly seems to be a cheap fix.

The only reason I brought it up is I've used some on the front of my '85 chevy. I had some wheels that would not fit with the brake calipers and needed the spacers. Never had a problem. Even have a snow plow on the front of it which adds around 1000 extra lbs.

Here's the spring setup I have....



I'm curious to see yours.

Here's a shot of mine that I had taken last night. As you can see, I have no opportunities to raise this thing without replacing springs or adding new brackets.

Wow! I have at least 2-3 in more height just from the spring hangers alone.

I think raising it is the best option. You might see if a frame shop could torch off the hangers and add some similar to the ones in the photo I posted.

JonC,

I just took a look at my cat and mine looks just like yours, except I've got a 1/2" of clearence between the rubber of the tire and the square tubing. Just enough to get my fingers through. My leaf springs and shackles look the same as yours no height adjustment, the gap to the "I" beam is the same on both sides.

Personally I don't think you will ever have a problem. Take it to a parking lot and do some tight turns both ways and when the tires are flexed as much as possible stop and get out and take a look if the gap is any different or even if the tire is touching. I know rolling down the road it will never get close just slow speed maneuvering.

I have an '05 29BHBP - same frame as the 31QBH and have very little clearance between the slideout drive mechanism and the tires. I replaced my tires/wheels with 16" 215 85R16 LRE and have had no clearance issues - the new tires are actually skinnier than my old 15" tires by a little bit.

I recently returned from a trip to Southern Florida (from Maryland) and had no problem. Furthermore, I have put somewhere between 25-30K miles on my Wildcat since new and have not had a clearance problem (except for when I added EZ-Flex suspension last summer that lowered my 'Cat by 1"- I have since changed to Equaflex for more vertical clearance and am fine now.)

If your camper does not have wet bolts and brass bushings, I would look into replacing the stock plastic ones with brass bushings/greasable bolts.

grover wrote:JonC,

I just took a look at my cat and mine looks just like yours, except I've got a 1/2" of clearence between the rubber of the tire and the square tubing. Just enough to get my fingers through. My leaf springs and shackles look the same as yours no height adjustment, the gap to the "I" beam is the same on both sides.

Make this x2 - ours is identical.

Shooter and Grover - sounds like 1/2 inch of clearance is "normal" then. And I assume you've not experience any rubbing on the insides of the tires, whether rolling down the road or in tight maneuvers? I can't remember if it was Lippert or FR who alluded to the fact that with the tight clearance, the only time it "might" rub is in tight turns.....huh??? I can't believe that this is engineered to such minimal specifications.

I've not had any rub marks at all on the tires and I've backed it in some pretty crazy places. So I would say it's all good.