you gonna share some pictures of a stretched 200x50 on the wides tomrorrow?
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After I get off work. 10pm eastern time you should have photos!
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Highly relevant to my interests gentlemen. Carry on!
FWIW: I just got 2 different brands/sources of 200x75 slicks in. Total of 12 tires. Iāll snap some photos tomorrow to show the difference- thereās a clear winner between the two sources I ordered from. Same Kenda markings on each though. Guessing an A/B stock thing. 8 of them look great though, but now stretching my favorite Kenda k909s is super enticing.
@Soflo which tubes did Steve āThe Mountainā Honeycutt use when he stretched those Kendas?
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He said he used the 200x50 tubes in the k909s but was going to attempt the 200x75 and report back @DerelictRobot
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fucken sweet thats with the 75 tubes or the 50s?
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200x50 tube. Iām sure you could use the 200x75 youād just have to wrestle it more than you already do
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Just wanted to share that you can put the 200x75 on a rockstar2 rim. They fit and the pulley clears the tire
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Careful with how much of that bead is showing. I know you know what youāre doing but test them slow, youāre a good dude 
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I have to call bullshit on this, as your suggestion is dangerous. Yes, you can fit 2 rim halves into the tire, but only with a 3/4in gap between them. **** You can see said 3/4in gap in your photo! With much longer screws you might be able to compress the sandwich together, but at that point youād have stressed the rim and fasteners to near the breaking point. Thatās before you even air em up.
I tried Fivestars, Rockstar IIs, Evolve AT and Torqueboards AT with the qind 200x75 and I wouldnāt run it on any of them. I spun a captive nut just trying to compress em.
Iād sooner ride with a sketchy 3D printed spacer between halves than try to gorilla the halves together.
Id anyone is foolhardy enough to force any of these plastic hubs together with one of these 200x75s, at least use grade 12.9 hardened alloy screws and nuts, (not taffy-soft A2 Stainless.)
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I never said I would ride those rims like that, just that they do fit. I think the Qind 200x75 tires are trash and I wouldnāt recommend anyone ride those tires on any rim. Also that pic was just for show. The halfs do bolt together no problem, with stock screws. I can post photos of those if youād like.
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So glad youāre not riding on that Rockstar II / Qind 200x75 comboā¦ Totally unsafe.
I do see in the original photo that the halves are closed, was just the pulley showing through the spokes that looked like the back half of the hub. I was skeptical since I started to spin a nut long before the halves were closed when I tried the same comboā¦ I didnāt think it was even possible to close the halves.
I also realize that everyone (in this discussion at least) is done with these. Iād still like to try 'em, as theyāre sitting here, without blowing $400 on hubs that apparently donāt make them any safer.
Also, after receiving a bag of 5 200x50 tubes, clearly marked as such, sold as 200x75, I was about to give up. But, I did some math, determined that the 2.80/2.50-4 tubes should be perfect. The cross-sectional circumference of the lumen of a 200x50 tire is 50Pi = 157mm. The circumference of the oval cross-section of the 200x75 has the same 25mm radius ends, with a 25mm added between, so the circumference would be the same 157 + 50 = 207mm. So, 207/Pi should be the cross-sectional diameter of the tube = 65.9mm. Thatās roughly the same as a 225x65 ā9inā MBS T2, which works great with a 2.80/2.50-4 tube. Iād test fit with this tube before, looked a bit stuffed in there, was worried Iād pinch it between hub halves, gave up. After this calc, gave it another try last night.
Last night I used a long 5/16 bolt to compress the halves, on both Rockstar IIās and Fivestars. The Rockstar combo looks as spooky as yoursā¦ Maybe half the area between the bead and first circumferential rib are constrained, and the whole thing looks about ready to explode, even at a measly 20psi. Despite the bead seating on the inner, more closely-spaced 94mm rings, it worked great on the Fivestar, and Iād be fine riding that at 35mph.
I ordered another set of Fivestars, will pick up tubes at Harbor Freight ($4 and perfect for these), will give it a go on the Nazare and my āModel Treeā mountainboard first chance I get.
PIcs of the two combos:
On Fivestar at 20psi. Notice seam on sidewall is hidden.
On Rockstar II at 20psi. Run away!!! Notice the seam is showing and then some, the sidewalls look like they are about to pop.
Comparison of fit. Notice where that seam sits in relation to the bead on the unmounted tire, where it shows on the 2 hubs. No way Iād try the Rockstar II, I will absolutely ride the Fivestar. As good a fit as the 9in MBS T2 I removed.
I did a quick test spin, they definitely need to be balanced, but are no worse in the roundness / uniformity / quality department than any other tire Iāve tried. Iāve found that even if the tire and tread isnāt totally round / true, if at least static balanced, still rides like butter.
Yes, these are heavy tires. Yes, there are better choices that are lighter, better quality, and probably anything else would be more efficient, but for a wide contact patch for hard carving and hooning, Iām finally convinced this is a safe combo.
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I used a clamp to squeeze the halfs of the rims together. It was a lot easier to get the hardware in.
I agree, I wouldnāt ride the Rockstar2 with these tires. Glad you came up with a solution that youāre happy with! Good luck.
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I had mine on for a while now and I think the bead looks well seated. These were printed using carbon fiber filament with 100% infill. Am I going to die?
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One day in a blaze of glory.
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I think not. I was advocating exactly what you did, using a 3D printed spacer instead of forcing the hub halves together without adding anything to the sandwich. Iād be fine with ABS or Nylon for the spacer.
BTW, I tried again with both a Rockstar II and Fivestar, using a 5/16 bolt to close the sandwich (instead of the puny 4mm screws.) I used the same 2.80/2.50-4 tubes Ibuse in thr 9in 225x65 MBS T2s. (A round 50mm tire has a 50 x Pi = 157mm cross sectional circumference. The 200x75 has the same radius on the sides, with a 25mm flat section between, or 50 x Pi + 50 = 207mm. 207/Pi = 65.9mm. Bingo.)
No go on the Rockstar II, great on the Fivestar. Look where the seam is on the unmounted tire, howniys still visible and then some on the RSII, hidden on the Fivestar.
Iām happy enough with this combo to skate it.
I feel like if you print the part with 100% infill or even down to 80% infill with 6 outlines or something like that, it will be strong enough to take the loads. The direction of the forces in this application attributes well to a 3D printed part imo
More material more better?
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Agreed. Delamination and sag from heat have plagued some of my functional parts, but in this case the stack of layers is constrained by the hub halves, there isnāt any heat. Inward pressure from the tube is substantial, but shared by the hub halves and thru bolts.
Again, I wasnāt throwing ANY shade on 3D printed spacers for between hub halves, but rather vasting a nay vote on the Rockstar II for these tires.
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Yeah it was a good point I was just saying that I think in this application they are a better idea than stretching things past their limit haha