Tires for Scamp

[Karl K]

I have a couple questions relating to Scamp Travel Trailers and the tires that fit them.

1) Does anyone have any experience with using a Carlisle ST175/80D13 SPORT TRAIL (radial) tire on a 1989 Scamp 16. Recently I purchased a couple of the above listed radial tires at a Tractor Supply Company (used to be Farm & Fleet) store, and have found them to be 7 3/8" wide (inflated) while the original tires on my Scamp 16 are Carlisle ST175/80D13 USA TRAIL bias ply tires that measure 6 3/4" wide(inflated). I am wondering if there will be sufficient wheel well room from a width standpoint? And yes you read it right, both tires (radial and bias ply) have the same size nomenclature. I think height of the tire will not be an issue? I spoke to the Scamp "parts" guy, but he didn't seem to know what tires they currently use, nor was he familiar with the Carlisle tires that I bought. The folks at Scamp have gone to radial tires on all their trailers, and they report that many trailering issues have gone away with the use of radial stye tires. Those familiar with these trailers will know that there is little wheel well room, even when the axle is fairly new. Also in the event of a tire blow out, has anyone experienced damage to the fiberglass hull of the trailer?

2) Does anyone have any experience with using 12 inch tires (say 5.30 X 12) on a Scamp 13? My reasoning for considering this is that my 13 ft trailer rides pretty low, and I was hoping to get a little more wheel well clearance on it from a height standpoint. Obviously, the 5.30 X 12 tire will easily (they are fairly narrow) fit in the wheel well from a width standpoint. I was just sort of hoping that I could put off purchasing a new axle for the 13 ft. trailer, by using 12 inch tires. Both trailers have 4 lug bolt patterns, and now I'm wondering if there are standard 12 inch rims out there that will match the Scamp 4 lug bolt pattern.

Any info on either question above will be greatly appreciated.

Karl K

Scamp 13 & 16

[Roger H]

Karl, I don't have much info on the Carlisle tires nor their size, but switching size tires to compensate for a sagging axle isn't probably a good idea. A bad axle doesn't have suspension, and will pound the frame and body apart. A new axle for a Scamp 13 is only about $300, so it doesn't make a lot of sense financially to invest in new wheels and tires without swapping the axle out.

Good luck!

Roger

[Brian B-P]

...Carlisle ST175/80D13 [b]SPORT TRAIL (radial) tire on a 1989 Scamp 16. Recently I purchased a couple of the above listed radial tires at a Tractor Supply Company (used to be Farm & Fleet) store, and have found them to be 7 3/8" wide (inflated) while the original tires on my Scamp 16 are Carlisle ST175/80D13 [b]USA TRAIL bias ply tires that measure 6 3/4" wide(inflated)...

The Sport Trails would be ST175/80[b]R13 (not "D"), if they are radials... and the Carlisle catalog I recently downloaded shows the Sport Trail only as a bias (diagonal=D) ply tire. Are the Sport Trail tires really radials, Karl?

Carlisle does make [b]radial trailer tires; the models in the 2007 catalog are Ultra Sport (low profile, not Karl's tires), Radial Trail, and Radial ST. I suppose it's possible that the "Sport Trail" name could be moulded into the sidewall of a Radial Trail tire, but I would hope that the construction letter in the size spec ("R" or "D") and other informational text on the tire sidwall would be correct, regardless of the marketing text.

The [b]section width of a tire depends significantly on the wheel width, which is why the tire specifications list a "measuring rim width" (the width of wheel used for the reference tire width measurement, as well as a range of acceptable rim widths. Were the Sport Trail and USA Trail tires measured on the same rims? In both cases, the "measuring rim width" is 4.50", and the allowable range is 4-1/2" to 5-1/2".

Tires also bulge at the bottom where they are "squashed" by load. My guess is that the widths were not measured down there, but if they were, the measured width would be changed due to the amount of load on the tires, as well as their construction.

According to the [b]specifications in the 2007 Carlisle catalog, the section width of an ST175/80D13 Sport Trail is 6.6" (for load range B ) or 6.8" (for load range C ): that shows that there is a significant variation within the same nominal size, and that the measured width of 7.375" is too wide (so they must be on a wide wheel, or something else is strange). The same catalog shows the same size of USA Trail to be 6.65" wide (LR B ) or 6.67" wide (LR C )... essentially the same as the spec for the Sport Trail, and about the same as measured by Karl (6.75").

The Carlisle Radial Trail ST175/80R13 (load range C ) tire shows a section width of 6.97" on a 5.00" measuring rim (with the same allowed rim width range); my guess is that the difference (from the bias ply models) is almost entirely due to the wider rim.

[Brian B-P]

...using 12 inch tires (say 5.30 X 12) on a Scamp 13?

I heartily second Roger's comments on this one. I, too, vote for fixing the problem rather than masking it with a smaller tire.

Also, I personally feel that these stock trailer tire sizes are too small for modern driving conditions to start with, and going even smaller is not the right direction. No modern automobile with a similar axle load would use a tire which is so small.

[Pete Dumbleton]

Using a smaller tire might put you into a Catch-22 situation, where you need more tire pressure to handle the load, but also need less tire pressure to soften the jolts to the trailer frame, body and components.

[Karl K]

Brian,

Thanks ever so much for your insight. The tread pattern on the "Sport Trail" tires looks like an "All Season" type, and since the store also sells "USA Trail" version I ASSumed that the "Sport Trail" was/ is a Radial. We all know about assumptions. The USA TRAIL version has a tread pattern that is like what I am familiar with on bias ply trailer tires. Additionally there is a note moulded into the rubber of the "Sport Trail" that says not to mix Radial and Bias ply tires. Perhaps for people like me who think the way the tread looks may tell you what type of tire it is??

At any rate I fired off the question to "Carlisle" just to be more certain.

Again, thanks so much for your very informative answer.

Karl

[Garret Walther]

I thought I could jump in and add my thoughts. I have a 2002 13 ft. Scamp, purchased new. Decided to go with wider and bigger wheels. They came close to the outside surface, so I simply removed some of the rivets holding the rubber trim, then cut about 1 in. out of the wheel wells. Then put the trim back, with new rivets. Works great.

I agree about staying away from smaller wheels.

[Frederick L. Simson]

I agree about staying away from smaller wheels.

Unless you have more of them...



I run 4 each 5.30 x 12 on the Fiber Stream. The stock tires were 4.80 x 12.

[Darwin Maring]

I was in Tractor Supply yesterday (10jan08) and they had a new supply of 6ply trailer tires mounted on white rims for the price of $89.99 to $99.99 each. 14s and 15s. Load raiting at 1,800+lbs each. just can't remember the over number.

[Alf S.]

Hi: Changing tires is a great time to switch to radials...spare included...but the equivalent size radial will take up a bit more room in the wheel wells...width wise and when the wheels are off is the perfect time to re pack the bearings!!! I changed to Goodyear Marathon radials @48 psi and notice slightly more bounce from the trailer while towing
Alf S. North shore of Lake Erie

[Karl K]

Hi: Changing tires is a great time to switch to radials...spare included...but the equivalent size radial will take up a bit more room in the wheel wells...width wise and when the wheels are off is the perfect time to re pack the bearings!!! I changed to Goodyear Marathon radials @48 psi and notice slightly more bounce from the trailer while towing
Alf S. North shore of Lake Erie

Is more "bounce" a desirable thing from your trailer? Also, are radials (in general) superior for these egg types of trailers?

Karl K