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Discussion Starter #1
I sent some questions to STI about the DOT approved Black Diamond and received a reply.



Here's what I'm talking about:







Here's my email:



There is an ongoing discussion on DOT approved tires on our Yamaha TW200 forum. As you might know, the TW200 sports larger tires than most dirt bikes, straight from the factory. Owners are running Maxxis Bighorns, Duro Power Grips, etc so we know that 8s and 9s (depending on the tire) do fit inside our swingarms. We would like to get an aggressive tread ATV tire that is DOT approved and yours looks like a maybe.



Not looking for an approval of the mounting but I've read comments that the tire is slightly narrower and shorter than expected when mounted - good things for us. Our stock tires are 180/80/14 but we stick lots of 26x8/9x14s on. Can you tell us what the inflated width and tire height would be on our rims? Thanks.





And here's their reply:



"Hello Thomas,



All of our Black Diamond tires are DOT Approved. The rear Black Diamond tires do run a little narrow, but the front size are closer to their claimed width. Both the front and rear tires are very close to the claimed tire height (OD).



We won’t be able to provide specs for you application, but I have attached our tire spec sheet that give all of the factory specs on the tires: section width, OD, load ratings, speed ratings and weights. Please keep in mind that all of these specs are based on a 7-inch wide wheel and the tires being inflated to 7 psi. Typically we adjust the recommended air pressure depending on the application; for example we recommend a minimum of 12 psi for a side by side (UTV) vehicle.



Hopefully this information helps.



Thanks,



Jamie Chisholm

STI Tire & Wheel"



This is the spreadsheet STI sent:



 

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Sounds promising. That 27.2 diameter could be an issue. Better order the right 9-incher. Who's gunne be first?
 

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I meant as opposed to the last item listed, which is 27x9.



Minor point, but it's happened in the past with other tires and would be a really expensive error.
 

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I'm up for something beefy with little to no modification needed. How many miles are people getting out of the stock rear? I have been looking for a decent atv tire that is rated for speeds up to 80mph. I also ran across a viper tire that may work for our TW's. I'll look up the specs for it when I get home.
 

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I've looked into it. The last outfit (Stockton Wheel) that was capable and even remotely interested in the project and willing to punch spoke holes into a bare automotive rim for me went out of buisiness awhile back. Buchanan's and the like wanted nothing to do with it, and even if they did it's doubtful anyone would be willing to pay for it. Aluminum automotim rim blanks exist, but they tend to start at 5" widths. The Stockton guys were doing the homework for us when they went under. I couldn't interesr anyone else in even discussing it, but it would be the easiest approach.



The mod you pictured was accomplished by spinning an entire new hub section out of billet, with bearing cups, sprocket, brake flanges and wheel offset on a lathe. It's really nice work but unless you're capable of doing such work yourself I'm guessing you'd have to be pretty committed to your TW. I haven't looked into actual costs. Maybe I'm wrong.



Something like an old school Centerline would really lighten things up a bit from a steel trailer wheel.
 

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Discussion Starter #8
I meant as opposed to the last item listed, which is 27x9.



Minor point, but it's happened in the past with other tires and would be a really expensive error.


Indeed it would be.
 

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Discussion Starter #9
Has anyone else done this mod with a regular rim? It would end the entire getting the bead to seat problem.. Plus make the tire tubeless. I forgot which user here did it.



The ADV thread I pulled the pictures from http://advrider.com/...=422523&page=44
If you don't have time to look, here's what "Dyno" said about his mod:



"After watching a Duro 14" tire rupture the bead before seating on a stock rim, I changed course. The 12" rim with a 5 bolt pattern is readily available nearly everywhere. I bored the center out slightly, built a rear axle for it and mounted it up. Tubeless and worth all the grief. The whole shebang weighs about 10 lbs more than a stock rear setup. The tire alone is 5 lbs heavier, and I suppose with a bit of work you could design a few pounds out of the axle assembly. But then again, it isn't a motocross bike. The tire is a Duro 25 x 8 x 12. You could find a 12" ATV tire a lot easier than a 14" if you were travelling, and in a real pinch, you could probably get home on a trailer tire.



Spent the afternoon playing in the snow. This thing is fun!"



Here's a picture of the wheel's left side showing the axle mounted to the trailer tire:





The really cool part of this is that it's a 25x8x12 which gives some very nice dimensions for mounting on the T-Dub.



 

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Discussion Starter #10
If you don't have time to look, here's what "Dyno" said about his mod:



" But then again, it isn't a motocross bike. The tire is a Duro 25 x 8 x 12. You could find a 12" ATV tire a lot easier than a 14" if you were travelling, and in a real pinch, you could probably get home on a trailer tire."


I've got three trailer wagon style wheels like that one sitting in my ranch yard right now - my pop-up is hard on tires.
 

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Discussion Starter #13
It would be neat if you could get the black rims that are shown on the above(STI) tire(s) for the TW.
They are cool - unfortunately, being ATV wheels, they look different on the "inside" than out and so would look unfinished on the sprocket side. Bummer. Also, being aluminum alloy they would be a bear to modify to fit out bikes. Bummer 2. I could see doing the modified trailer rims up in black powdercoat.
 

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WHO'S GONNA BE THE GUINEA PIG!!! And does anyone know the tread depth on these black diamonds?
 

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So as to no longer encroach on this sti thread I have removed my post and started a new thread.
 

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Discussion Starter #17
BTW the tires you posted a pic of are the EFX moto grip tires.
Right you are. That was what was posted at the retail site I started at. Here is the photo from the STI Site of the REAL Black Diamond - much better looking, actually. Thanks, and I've also corrected the original entry to resolve confusion
.



 
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