trials tire folding help

i can’t seem to stop folding my tire on my new 20" trials uni. enough of a side hop to take stairs two at a time makes it fold. i’ve tried pressures from 20 psi up to 45 psi. i’m running an alex dx rim, luna trials tire, and a standard bmx 20 X 1.75 or so tube. i remember hearing that a bigger/thicker tube would help a lot, but i can’t seem to track one down. any advice/help/suggestions/what do you do?

ps i’m 6’4 180lbs or so, not sure if that would make much of a difference, but i figure better mention it.


folding = the tire squishes too far on a sidehop, which like throws you off so you’re kind of on the edge of the rim, which could be bad at times.

Yeah, I heard that a thicker trials like tube helps the folding, but a thinner tube has a better prehop…

soundz like you need even more air pressure or find a Moped tube.


go to a shop and look at the tubes 1.75 is skinny, at least get a 2.215

More air pressure fo sho, or dont land at so much of a parallel angle to the ground when you sidehop.

it’s not landing. it’s on take off. i lean a little to one side, push down and go. the push makes the tire fold, and really messes with my hop. i’m running at close to the max pressure and it still does it. my LBS has no fatter tubes. i guess i’ll have to find a trials website or a moped tube or something. thanks though.

Darren Bedford has a 20x3.0 intertube for sale. I’ve never tried it but that sounds ideal. I am using a 20x2.125 tube which works ok, I have to inflate it to around 30 PSI to eleminate fold over for side hop (static lean and jump, no prehop = 62" long jump) I would think it’s your tube. Have you checked walmart for a kids bicycle tube (20x1.95-2.125)?

Oh yeah, I had that the other day when I was hopping around on this little play structure at park. I was hopping with crappy style. Then pumped up my tire and was hopping with… Cool style… sells a 20 inch by 2.15 tube, that works for most people, you cant use bedfords 20 by 3 inch because a trials is only 2.5 inchs wide. Go to genaric tubes and select that size

Have you checked Darren and been told the 20x3.0 would not fit? A non-inflated tube is way smaller then the listed size, from what I can tell, a “3.0” tube should fit a trials uni; I was planning to try out that beefer tube when I have to change my tire.

Also, lists a 20x2.125" tube, was that what you were refering to? Like I said before, that might be the easiest tube to buy; either online or at walmart or some other superstore that sells children’s mountain b*kes.

Does anyone know the stated diameter of a moped tube; I’d assume its larger then 3.0”?

well, there’s a conti modep tube that’s 20x2.5 and a maxxis trials tire, also 20x2.5. i haven’t checked wal-mart, mostly because i keep forgetting…anyway, thanks for the help and i’ll let you know how it comes out once i find a better tube.

The moped tube should solve your problems, I’ve personally ridden one.

u could just pump up the tube or if its too small then do what everyone else is sayin and get a fatter tube


Haha, what he said…perfect and to the point!

um, i did part 1, and i’m asking if part 2 is actually my problem, and it seems that it is, so now i gotta find a bigger tube. i just got back from wal-mart and they sell a 20x4.25 tube. that’s waaay too fat. loks like moped tube it is.

im sorry, UNIquelyCanadian, yes i was refering to the 2.125 inch tube, my mistake, I was off by less then a millimeter