Raising Bigfoot for more clearance?? - Page 2 - Fiberglass RV


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 06-14-2007, 08:23 PM   #15
Senior Member
 
Brian B-P's Avatar
 
Name: Brian
Trailer: Boler (B1700RGH) 1979
Alberta
Posts: 5,000
Here's Tom's Bigfoot:

Click image for larger version

Name:	<a title=Bigfoot.jpg Views: 63 Size: 59.1 KB ID: 8288" style="margin: 2px" />


To me, it looks like the official factory photo of a 1500-series trailer which starts off the FiberglassRV Bigfoot Album, as well as the 1989 and 1997 examples which follow (makes sense, for 1994). As of 2004 when I first downloaded specs from them, Bigfoot was listing the small 1500 as a 15B17CB or 15B17G, 16'-7" long. Since then, they have switched to the 2500 series, and the corresponding model is designated 17.5, and is specified to be 17'-5" long.

In a previous post, I babbled something about 1995, because I was a decade out in my thinking
... the change from 1500 series to 2500 series did not occur until 2005, as Steve said, so I assume Tom's trailer is a "17 foot", 15B17CB. I sometimes feel a decade behind in other ways...

So I guess we didn't really need the the photo.
__________________

__________________
1979 Boler B1700RGH, pulled by 2004 Toyota Sienna LE 2WD
Information is good. Lack of information is not so good, but misinformation is much worse. Check facts, and apply common sense liberally.
STATUS: No longer active in forum.
Brian B-P is offline   Reply With Quote
Old 06-15-2007, 12:28 AM   #16
Junior Member
 
Trailer: 2004 Casita 17 ft
Posts: 14
A friend replaced his whole axle assembly with the 15" wheel and axle when Bigfoot changed to 15 " wheels. He did this not to gain clearance but because he had a history of bearing problems on the heaviest side of the trailer. He had the Center Bath arrangement.The trailer exceeded the rating per wheel on the heavy sde. The new axle-wheel -tire combo is higher rated than the 14" assembly.He verified the uneven side to side weight by weighing each side of the trailer.
DickSmith
Dick Smith
__________________

__________________
Dick Smith is offline   Reply With Quote
Old 06-15-2007, 01:21 PM   #17
Senior Member
 
Pete Dumbleton's Avatar
 
Trailer: Scamp
Posts: 3,072
Send a message via Yahoo to Pete Dumbleton
Brian, indeed you are correct about air dam and relative vehicle heights; in the case where the trailer is already higher than the truck on the bottom, raising the trailer will likely have no air dam effect and there would be more wind resistance at the top of the trailer.

Tom, the concern about actually rotating the axle is that the axle beam normally has an arch for weight-bearing purposes and rotating it may affect its load capabilities. Also, the axle orientation will likely affect the alignment of the wheels/tires.

I would be more likely to consult with the makers of the axle than the makers of the box that sits on the axle in regard to application modifications...
__________________
Pete Dumbleton is offline   Reply With Quote
Old 06-15-2007, 09:54 PM   #18
Member
 
Trailer: 2000 Bigfoot 17 ft (15B17CB)
Posts: 75
When I purchased my new to me 17' Bigfoot a number of years ago, one of the first modifications I did was to raise the trailer. I bent the tongue jack in the first 5 minutes of ownership just going over a driveway crossing, and soon discovered it was very difficult to dump the tanks unless the sani-dump was at or below ground level (which around here many are not, being slightly raised with a curb surround).

At that time, I viewed several Bigfoot units with different axle configurations to see what to do. My original 14" tires and factory aluminum rims were in fine condition, so I did not want to discard them. The original 4" drop axle with the spring over conversion kit raised the trailer a little to much (around 5") for my taste. It just didn't look quite right to me with 14" tires - just a personal opinion. I do think, however, 15" tires would suit this option well.

I ended up ordering an identically dimensioned underslung 3500lb straight axle tube to which I installed my existing brakes and drums. I made custom 3/4" spacers which I inserted between the springs and axle to reduce the 4" lift to 3 1/4" to give me the look I wanted. If I remember correctly, the fabricated axle, U bolts, new bearings and seals cost around $200 and pretty much solved my clearance problems.

Last year, I finally got around to actually weighing the loaded trailer and discovered that I was at the limit of my tire capacity of 3500lbs when hooked up to my tug with the WD bars engaged. I was also somewhat over the GVW , even though visually there was no trace of any strain or overload. Since the tires were approaching 7 years old and would have to be replaced anyway I decided it was time for another upgrade.

This year, I ordered a slightly narrower 3" diameter underslung 5200lb axle with six bolt hubs and 12" brakes, to which I installed HiSpec 15" aluminum trailer wheels with ST 225/15 load range D tires. I purchased new springs which were listed at 2050 lb capacity each and installed them with Dexter's HD greasable shackle kit along with all new bronze bushings replacing the prematurely worn out original plastic bushings. I also installed Dexter's shock absorber kit at the same time to finish up the suspension.

So far I am very happy with the new set-up. It looks good to me with the larger tires compensating for the loss of the 3/4" lowering blocks, and overall height only a around an 1 1/4" taller due to the combination of taller tires and the slight lowering effect of the thicker axle. Most importantly, even though the "official" GVW is unchanged, I have peace of mind knowing the effective load capacity of this axle configuration now comfortably exceeds the actual load.

Please note that I am not a mechanical engineer and cannot certify that my modifications are safe or correct. Anyone who choses to try this combination does so at their own risk.



Steve.
__________________
Steve C. is offline   Reply With Quote
Old 06-16-2007, 06:56 PM   #19
Junior Member
 
Trailer: 29 ft Arctic Fox and 17 ft Bigfoot
Posts: 20
The previous owner/s already modified this rig by installing a 3" Dexter 5200# axle with 6 bolt drums. The rims are 15" aluminum with ST 225-75R-15 load range "D" on them. It has been fitted with a shackle and a 4 leaf spring stack. This was all done by a previous owner. BTW, the fender skirts are dangerously close to the wheels now. A good bump and I'm sure they might touch or worse as is. I have purchased a Dexter K71-383-00 spring over kit. Yes, it will give me 5" of add'l. trailer height. But, that is what I am looking for. I hunt some areas that the roads are rough. I mean rough! The add'l. height will be a plus. My plan is to weld the spring perches on for additional strength. I am less concerned about air dam effect as I am about hitting the bottom of this rig with a rock, tree stump or anything else that might cause damage to the underside. This Bigfoot is going to get a lot of back country use. I have an adjustable tow hitch that will allow trailer to be towed level. If the swing down stabilizers are not adequate, I will grind 'em off and weld on the scissor type. My tow vehicle is not really a mileage miser anyway. But, it will tow this Bigfoot very well.
__________________
Tom Myers is offline   Reply With Quote
Old 06-17-2007, 12:24 PM   #20
Member
 
Trailer: 2000 Bigfoot 17 ft (15B17CB)
Posts: 75
Quote:
The previous owner/s already modified this rig by installing a 3" Dexter 5200# axle with 6 bolt drums. The rims are 15" aluminum with ST 225-75R-15 load range "D" on them. It has been fitted with a shackle and a 4 leaf spring stack. This was all done by a previous owner. BTW, the fender skirts are dangerously close to the wheels now. A good bump and I'm sure they might touch or worse as is. I have purchased a Dexter K71-383-00 spring over kit. Yes, it will give me 5" of add'l. trailer height.


Tom,

I'm surprised the 15" tires fit inside the fender skirts at all. I wonder if the axle is narrower than original, or if positive offset rims were used as there isn't a whole lot of clearance even with the original 14" tires.

Dexter's conversion kit K71-383-00 works for 2 3/8" diameter axles which I believe were factory installed on all earlier (pre 2005) 17' Bigfoots. I think you will need PN# K71-385-00 for your replacement 3" axle. Since you have access to a welder, it may be cheaper to just buy 3" spring seats and weld them on, as the kit is made to bolt on with a recommendation to tack weld to prevent movement. Of course, beefing up the kit installation with full welds is a good plan.

As Pete has said earlier, Dexter recommends the installation of bump stops to limit the suspension travel to what it was before the installation of the conversion kit. I think this will be especially important for rough road travel. Also, if you do not already have it, you may want to consider Dexter's heavy duty greasable shackle kit PN#K71-358-00. The standard shackles are flimsy and the thin plastic bushings don't last very long at the best of times. If you go this route, don't forget to order two extra bronze bushings for the frame mounts, as they are strangely not supplied in the kit.

Another option that you might want to consider is the addition of shock absorbers. Both Dexter and Monroe make kits or you could fabricate your own mounts and just buy the required length shocks.

Good luck with your project,

Steve.
__________________
Steve C. is offline   Reply With Quote
Old 06-17-2007, 01:55 PM   #21
Senior Member
 
Brian B-P's Avatar
 
Name: Brian
Trailer: Boler (B1700RGH) 1979
Alberta
Posts: 5,000
Quote:
The previous owner/s already modified this rig by installing a 3" Dexter 5200# axle...
I didn't realize that the axle was already changed out to a higher capacity than stock. One consequence of that is that it has a larger tube size, so the curve of the spring seat (pad) must be larger - good catch, Steve.

Another consequence of the larger tube (and probably thicker seat), is that a spring-over conversion will add more height than it would with the smaller components... at least 5" sounds about right to me. Conversion to a straight axle would still provide a rise equal to the drop which is eliminated.

Quote:
...It has been fitted with a shackle and a 4 leaf spring stack...
If the D52 axle (up to 5200 lb capacity) uses the same size springs as the D35 (up to 3500 lb capacity), then the stock is likely at least 4 leaves, since any less would not have sufficient capacity - these might be the stock springs.

Since every leaf spring setup (except slipper types) has shackles, I'm a little confused. Tom, do you mean longer shackles? That would be one way to gain a bit of height, may help explain why the big tires fit, and would be a good item to eliminate while the working on the axle. Long shackles are an ineffective and undesirable way to raise a suspension.
__________________
1979 Boler B1700RGH, pulled by 2004 Toyota Sienna LE 2WD
Information is good. Lack of information is not so good, but misinformation is much worse. Check facts, and apply common sense liberally.
STATUS: No longer active in forum.
Brian B-P is offline   Reply With Quote
Old 06-17-2007, 02:05 PM   #22
Senior Member
 
Brian B-P's Avatar
 
Name: Brian
Trailer: Boler (B1700RGH) 1979
Alberta
Posts: 5,000
Quote:
I'm surprised the 15" tires fit inside the fender skirts at all. I wonder if the axle is narrower than original, or if negative offset rims were used as there isn't a whole lot of clearance even with the original 14" tires...
If the clearance problem is on the outside shoulders of the tires, then it would be helped by wheels that are centred further inboard than the hub faces - although it never seemed right to me, that seems to be called positive offset (I think the term refers to the mounting face relative to the wheel centre). Stock trailer wheels are commonly 1/2" or zero offset, but modern cars and trucks all have positive offset, and front-wheel-drive cars are routinely up to 50 mm (two inches) offset.

If too much offset (positive or negative) is used, the loads are not properly located relative to the bearings, and axle capacity is reduced.

So, I think Steve has a good point, although I think the terminology is reversed.

Tom, if you later decide that the springover was a good test of height but you want to go with a straight axle, I think you'll want to put some thought into the width (hub face to hub face) selection for the new axle beam.
__________________
1979 Boler B1700RGH, pulled by 2004 Toyota Sienna LE 2WD
Information is good. Lack of information is not so good, but misinformation is much worse. Check facts, and apply common sense liberally.
STATUS: No longer active in forum.
Brian B-P is offline   Reply With Quote
Old 06-17-2007, 04:18 PM   #23
Junior Member
 
Trailer: 29 ft Arctic Fox and 17 ft Bigfoot
Posts: 20
Thanx Steve, I will keep that in mind. As for now I will try the springover configuration and look into adding shock absorbers. My wife is but a wee person and hopefully the 1st step will not be too high for her. May have to build her a small platform. Or stretch her. Guess I better figure on a platform tho'.
__________________
Tom Myers is offline   Reply With Quote
Old 06-17-2007, 05:08 PM   #24
Member
 
Trailer: 2000 Bigfoot 17 ft (15B17CB)
Posts: 75
Quote:
If the clearance problem is on the outside shoulders of the tires, then it would be helped by wheels that are centred further inboard than the hub faces - although it never seemed right to me, that seems to be called positive offset (I think the term refers to the mounting face relative to the wheel centre). Stock trailer wheels are commonly 1/2" or zero offset, but modern cars and trucks all have positive offset, and front-wheel-drive cars are routinely up to 50 mm (two inches) offset.

If too much offset (positive or negative) is used, the loads are not properly located relative to the bearings, and axle capacity is reduced.

So, I think Steve has a good point, although I think the terminology is reversed
Brian,

You are correct, I wasn't thinking - I should have said positive offset. I will edit my original post to reflect the proper information.

Thanks,
Steve.
__________________
Steve C. is offline   Reply With Quote
Old 06-28-2007, 04:15 PM   #25
Senior Member
 
Brian B-P's Avatar
 
Name: Brian
Trailer: Boler (B1700RGH) 1979
Alberta
Posts: 5,000
Here's Tom's Bigfoot, in the original (spring-under) and new (spring-over) configurations:

Click image for larger version

Name:	Bigfoot.jpg
Views:	33
Size:	59.1 KB
ID:	8500

The bottom edge of the body was just over the hub centre, now it's closer to the top of the wheel, visually suggesting about a 5" to 6" rise, which makes sense for a 3" axle, 0.6" pad thickness, and over an inch of spring pack.

The "original" picture is the same one from post #15 of this topic, shown again here for convenience.
Attached Images
 
__________________
1979 Boler B1700RGH, pulled by 2004 Toyota Sienna LE 2WD
Information is good. Lack of information is not so good, but misinformation is much worse. Check facts, and apply common sense liberally.
STATUS: No longer active in forum.
Brian B-P is offline   Reply With Quote
Old 07-03-2007, 07:38 AM   #26
Senior Member
 
BobB's Avatar
 
Trailer: 2004 Bigfoot 17 ft ('Beastie')
Posts: 564
Registry
I have been reading this thread with interest, as I bought a Bigfoot recently. It is a 2004 with a straight 3500# axle mounted above the springs. The story is the trailer was lowered about 2" by a previous owner. The question is how was that done? Did he just add the square piece as a spacer? Anyone familiar with the set-up as it came from the factory? Apparently the shocks were added at the same time. Thanks.
Attached Thumbnails
axle.jpg  
__________________
BobB is offline   Reply With Quote
Old 07-03-2007, 09:58 AM   #27
Senior Member
 
Herb P's Avatar
 
Trailer: Boler 1700SGH (Stage II twoftitis)
Posts: 284
Quote:
I have been reading this thread with interest, as I bought a Bigfoot recently. It is a 2004 with a straight 3500# axle mounted above the springs. The story is the trailer was lowered about 2" by a previous owner. The question is how was that done? Did he just add the square piece as a spacer? Anyone familiar with the set-up as it came from the factory? Apparently the shocks were added at the same time. Thanks.
Yikes. That looks like a disaster waiting to happen. I would undo that fairly quickly.. That 2" square tube is probably the extra bit there. Looks like you have very little suspension travel left before the axle hits the frame...
__________________
Herb P is offline   Reply With Quote
Old 07-03-2007, 10:16 AM   #28
Senior Member
 
Roger H's Avatar
 
Name: Roger
Trailer: Y2K6 Born Free 32RQ on the Kodiak chassis, 1995 Coachmen 19' B-van and 1996 Precision 21' Sailboat
Iowa
Posts: 5,000
Quote:
I have been reading this thread with interest, as I bought a Bigfoot recently. It is a 2004 with a straight 3500# axle mounted above the springs. The story is the trailer was lowered about 2" by a previous owner. The question is how was that done? Did he just add the square piece as a spacer? Anyone familiar with the set-up as it came from the factory? Apparently the shocks were added at the same time. Thanks.
Bob,

I believe that removing the spacer is all that's required, but of course, the shocks will have to go as well. I suspect that the U bolts are longer than the stock ones, so you could either replace them or cut them off as required.

Roger
__________________

__________________
Roger H is offline   Reply With Quote
Reply

Tags
bigfoot


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Raising one bench Dave Bese Problem Solving | Owners Helping Owners 1 05-27-2010 11:21 PM
Snow tire chains / Bigfoot 17CB wheel clearance breid19 Towing, Hitching, Axles and Running Gear 9 02-17-2010 11:18 AM
Raising 17' Boler sarah j Problem Solving | Owners Helping Owners 0 06-10-2009 04:17 PM
Raising a Bigfoot Peter DBK Modifications, Alterations and Updates 16 09-09-2008 06:06 PM
Raising a Casita SD16 Steve Rosenberg Modifications, Alterations and Updates 8 11-26-2005 11:54 AM

» Upcoming Events
No events scheduled in
the next 465 days.
» Virginia Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 10:54 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.