Yet another tire/rim related question. I am looking at the specs for weight loads on the discontinued 4WD1 kit. It states it supports up to five pounds, although I think the PROLINE 1071-00 tire with it’s standard foam insert is going to flatten with that much weight. I had the tires professionally mounted to avoid issues with my ten thumbs. The hubs are not vented and I’m certain they are not leaking air at any point. They are quite squishy and it doesn’t take much to deform/flatten them. But as I stated, they are not vented and I’m certain they are not leaking air. Is this the way these tires are supposed to be/perform? Your help and comments are appreciated. Thank you very much for your time.
The tires do squish down with the full 5lbs payload. It’s not easy to define the payload of a product like this…
Do we add enough weight that the base can barely move and call that the payload? Hey it moved… Do we try to measure the amount of tire squish and say the weight that results in 50% total squish is the limit? 40%? 25%? How do you accurately measure tire squish? What about the floor surface and turning ability? do we define the max payload when the robot takes 50% more current to turn? 25%? 10%? But should this be on tile floors, or carpet, or concrete, asphalt maybe? You can see how complicated a relatively simple spec can get…
The testing we did in house is to put a 6 pack of soda (~5lbs) onto the robot and make sure it could drive and turn under it’s own power, without too much difficulty, on low pile (office) carpet. This was with stock tires and rims that were not glued at all. I would think that tires that have no leaks and no vent holes should not compress though. Hope this helps…
if you look them up on the proline website they list the 1071-00 as being suitable for a couple 1/10 and 1/8 scale nitro buggys, the largest of which is about 3.6kg (over 8lbs) so 5lbs should certainly be in the design ballpark for them. remember at 5lbs there is only 1.25lbs on each wheel…
Thanks for the replies, I appreciate it. I’m just worried about the robot bottoming out on something like thick pile carpet, or hanging on a ledge or such. The tires just seem too squishy. I’ve seen firmer foam compound inserts at the hobby store, but they are designed for really wide tires. I’m not really that great with cutting the foam and trying to fit it into another set of tires so I’m kind of stuck using what I have. The tires do re-bound after being compressed by hand, so it leaves me wondering if they may have a leak somewhere. Or, is it just that the foam that comes with the standard 1071-00 PROLINE just too flimsy. Or, then again, am I expecting too much
You do know you can invert the motors to get more ground clearance right?
Dunno, the tires are what they are. Sometimes it’s best to just build something and let it’s performance determine if changes need to be made as the project progresses.
I’ve looked at all the video and pictures of the 4WD1 tires. Even with the arm attached to the 4WD1 in the video the tires don’t even look like they are bearing any deformation due to weight. My poor tires are deforming terribly under just the weight of the 7.2VDC 3000mAH battery. My tires were professionally mounted and not vented, but yet they act as if they were. I have manually given my tires a squeeze and I don’t hear any air rushing out, yet they don’t seem quite right. Can you provide me with a few close up pictures of the 4WD1 tires with and without weight bearing loads? I know I’m asking alot but I’m trying to get a comparison between my tires, and the tires you have used on your 4WD1’s. I really appreciate your assistance!!
The kit is discontinued and I no longer have one to photograph. Why don’t you post some images here and I will tell you if it looks normal or not. Did the guy actually install the foam inserts? I’m at a loss as to what to tell you.
I’ll post a picture as soon as possible. Yes, the foam inserts were installed. I’m at a loss of why they deflate the way they do. I even asked the hobby shop owner who assembled the tires if he vented the rubber, as many RC car owners do. He told me that no venting was done with the rim or the tire. I’m betting a gap exists within the rim and wheel on each of these tires. My belief is that if I squeeze the tire in my hand the entire tire should become bloated, due to the air trapped within. But mine just go semi-flat, then recover. Makes me wonder what the devil is going on.
Spread a thin layer of flour on a table (maybe on top of some wax paper so it’s easy to clean up) and put the tire down on its side and push down on it. look for a pattern in the flour where air is venting from the tire. if you don’t see it on the first side flip the tire over and try the other side.
You could also sink it in water and look for bubbles but if you relax the squeeze at all it will pull water back into the foam and that could get messy long term.
it is also kind of wierd, if it is just a leak, that all 4 tires are doing the same thing…
My question to you is, is this compression a problem? So it compresses when you squeeze the tire. We already know the wheels are going to have roughly 1.25lbs on them in operation. Your hand can provide much more pressure than this without you realizing it. I took the mounted but unglued tire and rim to the UPS scale and press down till the scale says 1.2lbs and the tires compresses about 100 thousandths! Are we stressing over nothing here?
Another note, the process of gluing the tires requires going around the rim and adding glue several times as you cover the entire circumference of the rim. I doubt very seriously anyone could make it air tight even if it was the goal from the beginning. The purpose of gluing the tire to the rim is to prevent it from coming off in use, not to make it pneumatic. Hope this helps…
Thanks for the many replies, this is one of the finest forums around!
Jim - Yes I have the correct rims, as pictured.
The compression ratio is much higher than the ratio you quote. My tires will almost flatten out to meet the inside of the plastic rim. They are that bad. I notice that the rubber compound these tires are made of isn’t very sturdy, and rather flimsy. Is it possible that these tires are defective? Perhaps a manufactoring mishap? I noticed that the release compound they used to produce the tires was still on my tires when I opened the kits. It was sort of a brownish powdery residue that would only come off once I washed the tires in plain water. (Maybe I should have mentioned this sooner in the posts). I wonder if that could have chemically altered the rubber in some way. Hmmm,
The tires and wheels I have on W.A.L.T.E.R. now are exactly like those in the picture. I don’t know exactly how much he weighs, but he’s carrying two battery packs, a front pan/tilt turret, 6 sensors, an SSC-32, and an ABB with Basic Atom, plus the weight of the two or three decks (which are very light). I’m sure he must weigh at least 3 pounds.
This is all being carried by a pair of those tires and wheels attached to a pair of GHM-04 motors. I do not see any compression at all when W.A.L.T.E.R. is down on his wheels. He’s only running at about 1/3 of his maximum speed.
Email me your address and I will send you a set of 4 tires and rims. They are slightly used, mostly just for pictures. I no longer carry them, so I can’t send NIB.
