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Discussion in 'The Garage' started by Flynn_, May 21, 2016.
So have you done this on a 21" DR650se front wheel?
On a narrow 21" front rim with no safety bead (can't answer if your DR has one or not but I'mI'm guess it doesn't) the real concern is unseating the bead from losing air pressure and still running it or hitting a hard ledge. I figure this is probably not much more dangerous than a tube collapsing on the road/trail from a puncture or hard impact. Which is to say both really suck. Running low pressure on the trails would increase the likelihood of this happening.
Roadside repair would also be a pain compared to a tube since the bead would most certainly be unseated if the tire went down since there's no lip to retain it. Getting it to seat back on the bead seems like it might be a real pain unless your in the habit of traveling with a ratchet strap and big air compressor/cartridge (I doubt a little 12v can supply the volume needed quick enough to get it back on the bead before the air leaks past).
Hopefully someone whose experienced this will chime in shortly to confirm or dispute. But here's a guys report and testing of this type of thing for you to mull over and consider. He compared the different options out there and tried the DIY one using Marine 5200. He had an issue with the front and notes somethings that I found insightful and relevant for those with 21" wheels.
A lot depends on the tire. I've been running a 21" taped rim up front for two years now. Sun WM2 rim from Buchanan's. No retention bead.
Had a couple of loss of air episodes. Tires stay seated fine. I'm sure that the stiff side wall-type tires I run helped. 21" tires are a whole lot more flexible than a big, wide 17" rear. But getting the tire blown back onto the rim is still a concern, especially if it happens off-road where dirt and sand may get between the bead and the rim. I carry a MotoPumps Air-Shot, a small bottle of Ru-Glyde, a little 1" paint brush and just ordered these (68 gram size) for my 11,000 mile trip this summer, just in case.
About tires, I rode 70+ miles on a front flat (tube-type on my other rim) and didn't really notice it much. Didn't come off the rim at freeway speeds. Mitas E-07 Dakar. I've been waiting a year for them to start shipping the tubeless version. Been running the 140/80-17 Dakar tubeless (taped rim) in the rear for a few thousand miles with no issues.
One last item: always carry a few extra valve cores with you.
I had seen that article last night deepbarney
It was the basis of my questions
I was wanting to run shinko 244 (tube type) tires but that might not work out so well
I might try it either way though just to know for myself
Thanks for the feedback. And yes, tire selection is a big part of it I'm sure. Stiffer being better. Though compared to even a 19" wheel the 21" wheel be more subject to unseating the bead due to the small section width to height ratio.
But like you say you can ride on a flat tire, just got to know it's flat and ride accordingly. I have on multiple occasions myself. Handling will suck and rim damage may occur depending on the riding conditions and the bike/wheel in question. I don't factor the tire coming off the wheel as a big concern, just unseating the front bead after a nice pothole or root strike.
You need to run tubeless tires. The beads are different. Many tube-type tires have rubber obstacles on the seating surface that will prevent an airtight seal. Tubeless tires have a smooth seating area and a slightly different angle.
I've run those Shinkos. Personally I would not run them tubeless because of their comparatively soft/pliable sidewalls (again I worry more for the front than the rear, but if you're going to run one tube might as well run both in my opinion). But it depends on how you're using the bike. Commuter and hitting the dirt roads on occasion your risk would be less than if it was more for exploring back roads and trails.
The I found the Kenda K270 (almost the same tread pattern and price) was much more stiff a tire and would likely better suited to your weight of bike, but I would use a different front as I never really liked the front K270's profile or performance.
Ok I’ll have to check some tires I have laying around
Thanks for that info
Oddly enough, I was the cause of one of my front flats. I had just checked the tire pressure the night before and had evidently pushed some dirt/sand down into the valve. Found out after 70 high speed miles of it feeling wrong. Pulled the valve core, swabbed it with a Q-tip, reinserted and reinflated fine.
50/50 tires like the E-07 Dakar, K60 and I'm now trying out the MotoZ Tractionator Adventure all have very thick, stiff sidewalls. I particularly like the way the E-07 Dakar sidewall fits over the edge of the rim. Wish they'd get the tubeless 21 out.
Had just about forgotten about that. Some Shinko (and plenty of other manufacturers) dual sport tire sizes are tubeless design, but not all so you have to watch for that. The Shinko 705's on my spoked Bonneville are labeled tubeless but I've been running them with tubes.
NAPA stores sell a motorcycle wheel valve which fits a standard tube-size valve hole for $3.59. NAPA part number NTH 90246. And it looks like this
I've used these successfully. I run two tape wraps all the around the rim, cut a hole through the tape with a piece of metal tuning and insert the valve. I don't clear the tape away from the stem as I want the gooey sh!t to help seal it all up. And I toss the silly washer thing. So far, it has been working well.
Wonder if they have an angled one too.
I just compared the bead are of a tube type shinko 244 to some tubeless take offs a heidcow k60
A kenda big block and a shinko big block
The bead on the tires themselves are identical to my sight and touch
Am I missing something?
Not really. Supposedly the seating angle is different by a couple of degrees, but probably not enough to notice. But many tube-type tires do have different rim contact surfaces. The two new tube-type K60s I have downstairs have little rubber ridges running radially all around the contact surface. Some older Continentals I used to run had a knurled contact area. I think they do those things to keep tires from slipping on the rim. But any non-smoothness would prevent an airtight seal.
I'm considering using the 4412N tape in a single layer with the overlap at the stem as I've read here. Then I was thinking of putting a layer of Proxicast Pro-Grade self fusing silicon tape over that. Not only to protect the 3M stuff and to keep it in place (will squeeze the crap outta the 3M) but also for it's high tensile strength and tear resistance. Anyone see any issue with that...?
I just use Gorilla tape, but can't see any issues with the self-fusing tape. I'm sure it is rated about 200F. The outer tape is only there to protect the 3M tape during tire mounting/dismounting.
It is important to squeeze all the bubbles out and force the 3M tape into the valley as you apply it. You don't get a second chance. I use a suitably sized hard rubber ball, like a superball, pushing the tape into the valley as I apply. I go a full two wraps, just in case I need to tighten spokes and
break the inner layer somehow.
Ah good point about the double layer, I was thinking those who used the 4411N tape did that to build thickness.
Oh, and don't ever try to remove the 3M tape. My first try came out crappy so I thought I'd start over.
I had nothing on hand that would dissolve it. Scraped it off with a razor blade and used Goof which turned it into little sticky balls. Rolled up the little balls with my fingers.
You just want to be sure that it doesn't end up in too thick a layer in the center of the rim. The thicker the tape layers are the harder it becomes to mount a tire.
Try this NAPA part number NTH 90426 Cheers!