SDI Trail Doctor 1.9" Tires
Written by Keith   
Tuesday, 28 August 2007

Take a look at SDI's new 1.9" tires, the Trail Doctor


I for one have been waiting a long time for a nice scale, capable, 1.9" tire. The usual array of offerings from Tamiya are nice, but sometimes they leave you asking for more, much more. Wink

Scale Designs International has answered the calling, and very nicely I might add, with their 1.9" Trail Doctor tires. Lets take a look...

My first impression upon opening the package was, "Wow, these things are perfect!" The look is spot-on, and the compound is great. I'd compare it to something on the level of HPI and Pro-Line in pliability, as well as stickiness. Heavier rigs may require the use of foams, which are not included, but would be dead-simple to make. The specs from SDI are as follows:

Fits all 1:10 touring car wheels , 26 and 24 mm width, also tamiya F-350 rims


- 95 mm outside diameter
- 33 mm width
- 48 mm inner diameter (1.9 inches)


I found those measuerements to be very accurate...

Compared to a stock Hummer tire, they are a little taller, and much more aggresive!

So, it's time to mount them up and try them out! For the test run, I mounted them on my Tamiya Hummer, which has locked diffs and a Permax600 motor. I chose not to use foams, and after running them I think I'll leave them this way. I was concerned that they may rub the body, but that has turned out to be unwarranted. They fit fine, and look spectacular!

It's immediately obvious how much better these tires work that the hard Tamiya tires. With the large lugs and wide spacing between them, they bite very well! I drove on dry dirt, with a few roots thrown in for good measure. Typical Louisiana terrain!  Smile

I love the way these tires will conform to the contours of whatever you're driving on. They worked better than anything else I've driven here, and I bet will really shine on the rocks!

There's a few steep dusty hills nearby which always prove a challenge to climb. Even my Land Rover with Geolandars struggles to make it up them. I was pleasantly surprised to see these Trail Doctors walk right up them, barely spinning a wheel!

One thing to note, if you do alot of off-camber stuff, you'll want to glue these to your rims, and use foams on anything heavier than a Hummer! They'll tend to roll right off the rim otherwise. I'm 100% confident that this won't be an issue once I get them properly mounted, and glued!

My final thoughts are good ones. I'd highly recommend these tires to anyone looking for something that not only looks great, but will perform just as well! My Hummer feels like a whole new truck with these, and will tackle terrain that it never has been able to with the stock tires.

If you're building a truck and would like to use these as well as a spare, there's no need to purchase 3 pairs and have an extra tire left over! SDI sells these individually. To learn more and purchase your own, be sure to visit Scale Designs International!

Try them, you won't be disappointed!

Scale Designs International