29" crown issues

On my big apple pressure doesn’t change anything, and on my duro 3" it s the opposite hapening, the higher is pressure, the more sensitive to camber it is.

There’s necessary a relation between elements, I can find / calculate the relation, but I need kind of database to work on.

I’ve insisted for a long time that it would be a lot simpler to designate tire sizes by the rim diameter, as we do for cars, trucks, motorcycles, lawn tractors, wheelbarrows, etc. The 700c/28"/29" rim is simply a 24.5" rim on that basis. (24.5" x 25.4 mm/inch = 622.3 mm. It was an English size before it was a metric size.) What we call it depends on whether we assume the tire section to be 39 mm, 1.75", or 2.25" tall. Of course it’s rarely close to any of those and then only by coincidence.

“Building a true, 700c road uni”

Thanks for the link.

I agree that there should be a common thread between those tires affected and not affected by road camber. Here is my current best guess:

Maybe others could say if their experience agrees with this idea.

Jim

We can make sort of database with :

_ Tire model and sizes
_ Pressure
_ rim size (particulary width)
_ unicyclist weight

Kenda nevegal 26x2.7: my first and worst experience in term of road camber.
Was it because I Was a newbee ? Possible.

Big Apple 29x2". Best experience ever in term of camber sensitivity.

I don’t think such a list will ever be suitable for everyone.
It’s partially a subjective matter with so many parametter: pressure, rider’s style, weigth and technique, w/ handlebar, size of the wheel, and so on.

Which rim was it with your big apple tire ?

There’s necessary a relation, only need to find which one, that’s only basic physics :slight_smile:

The problem is that it is not basic physics. There is a major human factor involved. In your very first post you wrote, “I’ve read several topics about, but it doesn t solve my problem, I saw everywhere that round tires and high pressure would help, and big apple 2.0 tire wasn t sensitive, but with me it s the opposite.” Yet at the very same time others have reported that they had no problem with a Big Apple.

Some solve the problem with air pressure adjustments and some make slight adjustments in riding style. Some report that the very same tire will preform differently depending on the amount of tread wear on the tire. Some report based on their personal experience that the shape of the tire or the stiffness of the tire casing is the main issue for them.

Figure out some way to eliminate the riders feelings, impression, experience or any other human factor and that would be a step toward sound science or basic physics.

Jim

Nimbus dominator 2.

A Nimbus Dominator2 rim with a Big Apple 29 x 2.0 tire has not caused me any problems with road camber, as I mentioned before, but somewhere on this forum I read that the Big Apple 29 x 2.35 is a different story. This finding was confirmed by a unicyclist who gave me one of these 2.35" tires even though it was almost new because he didn’t want it anymore!

Once my 29 x 2.0 gets too worn out to ride anymore, I will try the 2.35 that he gave me and see for myself, but for now my understanding is that, if you ride on a 29-inch Big Apple tire, only the 2.35 causes problems with road camber. I guess that’s not the case for everybody, though!

Schwalbe Marathon Supreme 29x2" on a Dominator 2 rim is an absolute dream, and doesn’t seem affected by road camber at all. I dump about 40-50psi into it.

My Vee Trax Fatty 29x3 on the same rim, however, chucks me off just from riding a slightly wonky pavement. It’s amazing on dirt, but on road it’s ridiculous. No idea what pressure I put into this, I put 30 into it just to get it to mount correctly (The bead is very fiddly) and just deflate it until comfortable.

Halo Twin Rail 29x2.2" isn’t as good as the Marathon, but it’s miles better than the Vee. I’ve done shedloads of miles with this tyre on-road and never had any complaints! This was on a Qu-Ax rim though, not the Dominator, so not sure how much that’d affect it.

Qu-Ax TA 36" tyre doesn’t seem to be affected by camber, but I do pump it up a lot harder than its recommended (About 40-45). I’ve used both the regular and light version and they both feel pretty much the same (except the weight obviously). This is on a Qu-Ax Marathon rim.

I have no idea how much I weigh, so… yeah :smiley:

To big apple users, which grip was on the tire ? I saw different ones on that tire.

How long have you been riding the 29er? When I first got my 29er, which had a Dominator Rim and 2" Big Apple tire, I had tons of trouble with road camber. It took several months for me to stop feeling twisted. Previously I had no camber issues with my 24" wheel.

I’ve ridden thousands of miles on Big Apple tires and currently ride on a Marathon Supreme. The Big Apple and Marathon are very similar except the Marathon is lighter because it’s a foldable tire.

If your are new to riding a 29er then perhaps your body (or strength) hasn’t adjusted to it yet. Also have you checked whether your wheel is true? I did have mine slightly adjusted and it seemed to help.

Looking back, I believe I didn’t have enough body strength in my torso to handle the 29er. The problem went away after becoming a stronger rider.

My tire is at about 40 PSI. 60 is too much.

I think in general the longer you ride the more you learn to tackle road camber. When i first learned to ride i had a lot of difficulty with the road crown. My 29" I ride with 35psi. That is also a nice pressure when riding over bumps and through pits in the road. High pressure makes the tire bounce too much. Personally when the road declines to the right, i can better handle it then when it declines to the left. As for which way to direct the wheel, i reckon you should adjust to what feels more natural to you. Also on cycle paths i try to ride on the topmost side - either the middle or left side (we ride on the righthand side here)

Some hundread miles only, I had to stop cause of knee pain due to camber excessives corrections.

How do you check the wheel is true ?

[QUOTE=Blaznee;1695114

How do you check the wheel is true ?[/QUOTE]

If you have a brake on it, spin the wheel an if it touches the brake on one side it should be trued.

Ok, thanks. I don’t have a brake, but I see what you mean, I’ll do with a pencil.

The other thing to check is to see if the seat is in line with the wheel/frame. Also of you are riding on cambered roads consistently some have reported turning the saddle a little out of line with the wheel to compensate for the camber.

Another non-tire changing option is to shift your weight to the up hill side of the camber. Some have good luck by shifting sideways a little on the saddle and others have shifted to one side by changing their arm postilion. Just by holding the seat handle with one hand and holding the other arm out to the side away from the body a little will change the center off gravity a little.

I know some ways to correct camber on my other unicycles, but on my 29 it’s just impossible, don’t know why.
Can’t move saddle to help, camber is maybe 20% on a side, then 10 meters later it’s opposite, then 200m on left, then on right again, and it’s like that all time long. Roads (if we can call that roads) are evil here :smiley:

Knee strengthening exercises along with a little less of the 29" vs. evil roads.
BUT… of course keep them up because learning how to deal with shitty conditions makes everything else easy.

Something you might try is to reset your seating.

As you ride along and start to encounter undesirable unicycle control because of camber, then stand up on your pedals and push down with your hand(s) to gain control of the unicycle.
After 2-5 revolutions then sit down again.
If the problem is still there then stand up again and repeat.

Another small trick I find that works is to use handlebars and apply a little rotational force to them to counteract the camber. I rotate clockwise for right camber and counterclockwise for left camber.
Little camber=small force / Large camber=larger force

Maybe?

Oh ya… get handlebars if you don’t have them yet.