Road camber effects on EUC

[rcgldr]

The private streets in my neighborhood are blacktop, cambered high on the outside, low in the middle, about 2 or 3 degrees, with a cement drainage path in the middle. There are some sloped intersections where the camber is high on one side, low on the other. The camber doesn't seem to affect riding straight noticeably on my V8F (I weigh 190 lbs, and tire pressure is 35 psi), but tilt steering against the camber (if camber is high on left, low on right, then steering left), results in a smaller radius turn, due to the tilt relative to the pavement. 

Edited September 27, 2021 by rcgldr

[Tawpie]

Camber is a strange thing that you have to get used to. Single track MTB trails often develop a "channel" down the center with fairly steep sides. Man'o'man does the wheel want to be in the center. When you're on either side, the wheel DEMANDS to turn downhill toward the center and you really have to compensate to ride the sloped side. It's very tricky. I'm not sure of the physics at work but they absolutely rule.

[Flying W]

Single track mnt bike trails are a pain sometimes! 

The stock cat 1488 on my RS loves to follow any camber. You get used to it, but I'm looking forward to trying a different tire. 

I want one with more knobs but close spacing so it still works well on pavement. I was looking at either the Kenda on the Sherman, or the duro hf307. I'm leaning towards the duro if I can find one I stock just to be able to out my thoughts on the forum for a tire that is not used as much. 

I have about 500 more miles to find one, but without commuting on the wheel and having a baby at home I'm only riding about 100 miles a month so there's a lot of time 😂

[Planemo]

6 minutes ago, Flying W said:

The stock cat 1488 on my RS loves to follow any camber.

Try a Z10 and you will know what following camber on mtb tracks is really about!

My MSX in comparison felt totally unfazed when riding on the exact same trail.

[.....]

my mten with playdoh tire tells me where to go usually...

I hold a selfie in my left hand most times, to offset street camber on longer rides. My 18XL tire is visibly worn more just left of its centerline as well.

Edited September 27, 2021 by ShanesPlanet

[Paul A]

Maybe try a veledrome one day, that is really steep camber.

Couldn't ride it at all.

Don't know how cyclists do it.  

Maybe need to ride them at high speeds, like NASCAR's on banked tracks.

 

[rcgldr]

3 hours ago, Paul A said:

Maybe try a veledrome one day, that is really steep camber. Don't know how cyclists do it.  

Bicycles, motorcycles, ... are not affected by camber. Camber effect from the front tire would require skidding the rear tire sideways and vice versa. Instead bicycles, motorcyles, ... , steer by tracking, the front wheel is turned inwards relative to rear wheel. For a bicycle with constant lean angle, constant speed, constant turning radius, if you virtually extend the axis of the front and rear wheel, they will cross at some point below the pavement. The point on the pavement directly above where they cross would be the center of the circle that the bicycle would be turning about. For motorcycles with significant lateral force, the tires flex outwards (flex sideways and twist). The difference between the actual path the direction a tire is pointed is called slip angle, even though it is just flexing and not slipping. In this case, the point above where the virtual axis cross will move in a small circle, rather than being a single point.

[.....]

4 hours ago, Paul A said:

Maybe try a veledrome one day, that is really steep camber.

Couldn't ride it at all.

Don't know how cyclists do it.  

Maybe need to ride them at high speeds, like NASCAR's on banked tracks.

 

I rode my 18XL on a steep banked round track once. It was pretty fun and you could really keep that lean without much effort (I've walked Bristol Motor Speedway a dozen times, talk about steep!) However, the transitions on the old track were pretty rough and I didnt get past about 25mph. It was a small paved track once used for midget cart racing or something. Asheville, NC, the track was red and in a nice park. I dont recall the name. Was once very popular, long ago.

I'm sure I'm asking for trouble, but I disagree @rcgldr. ROAD camber effects 2 wheel and single wheel vehicles. Typically you dont see camber issues on bicycles and eucs, as the axle is centered on a straight rim and hub that stays inline with the frame and rider position. However, I have ridden a bicycle with off camber (screwed axles) and it definitely made a difference in how you had to ride it so it would track straight. Perhaps its not called road camber. Slip angle is an entirely different thing, and I dont think it applies to single wheeled vehicles.

Edited September 29, 2021 by ShanesPlanet

[rcgldr]

6 hours ago, ShanesPlanet said:

ROAD camber effects 2 wheel and single wheel vehicles. Typically you don't see camber issues on bicycles and eucs, as the axle is centered on a straight rim and hub that stays inline with the frame and rider position. However, I have ridden a bicycle with off camber (screwed axles) and it definitely made a difference in how you had to ride it so it would track straight. Perhaps its not called road camber. Slip angle is an entirely different thing, and I dont think it applies to single wheeled vehicles.

I meant camber effect. A tilted unicycle steers because it approximates a truncated cone. The tire profile is round, and when tilted, the outside of the contact patch has a larger radius (from the axle) than the inside of the contact patch, which creates a steering torque while rolling. Camber effect is reduced by lateral loads | slip angle. You can see this in EUC races where the pedals are nearly scraping, but the EUC's are taking high speed, large radius turns due to slip angle. A low speeds, if the pedals are nearly scraping, the turning radius is small. 

For 2 wheel vehicles, there is no camber effect, so road camber doesn't interfere with control, other than a banked surface increases the maximum possible inwards lean angle while reducing the maximum outwards lean angle. For 1 wheel vehicles, road camber can interfere with steering inputs. Back to 2 wheel vehicles, when braking on a cambered road, the braking force on the cambered side of the front tire can cause it to steer into the camber. The same thing happens when braking while leaned over on a motorcycle. This isn't much of an issue for a rider that uses counter-steering to control lean angle, as the rider just applies more counter-steering torque to compensate for braking related steering effects.

[supercurio]

I found the CST-C6004 tire to be the least affected by road camber of all the 14" rim size tires I've tried  (with maybe the Kenda K262 and CST C186 being second, depending on tire pressure)

It's one of the reasons I like it a lot.

IMO, a tire which is not affected by road camber is:

• safer: direction stability improves safety
• reduces fatigue: no compensation or real-time correction necessary, it becomes unnecessary to micro-manage the tire and wheel
• higher performance: allows to ride faster on surfaces with camber/lines/cracks/rocks
• better for off-road and skate park tricks: as the wheel keeps its direction and roll angle regardless of the surface.

 

Edited September 29, 2021 by supercurio

[RagingGrandpa]

On 9/27/2021 at 5:44 PM, rcgldr said:

The private streets in my neighborhood are blacktop, cambered high on the outside, low in the middle, about 2 or 3 degrees, with a cement drainage path in the middle. There are some sloped intersections where the camber is high on one side, low on the other. The camber doesn't seem to affect riding straight noticeably on my V8F (I weigh 190 lbs, and tire pressure is 35 psi), but tilt steering against the camber (if camber is high on left, low on right, then steering left), results in a smaller radius turn, due to the tilt relative to the pavement. 

I see you shared an observation.

What is your objective for this topic?

Would it fit within the steering theory discussion already in-progress below?
https://forum.electricunicycle.org/topic/24483-electric-unicycle-and-bicycle-dynamics-gyro-effects-on-steering/

[rcgldr]

54 minutes ago, RagingGrandpa said:

I see you shared an observation. What is your objective for this topic? ... steering theory ...

To see how other EUCs are affected by road camber.  As for steering theory, road camber, and camber effects, it could do into the steering theory, but since it seems to depend on the EUC, tire, tire profile, ... , until there is enough feedback in this thread, I'm not sure how a generic post could be added to the steering theory thread.