Asked — Edited
Resolved Resolved by Zap Brannigan!

Roli Wheel Keeps Falling Off

The right front wheel of my Roli keeps falling off. I open up the wheel and the e-clip has fallen off the axle. I push it back on, but it is not very tight, and keeps falling off. It now doesn't stay on at all.

I think it would be better to replace with the metal collar and set screw like the outside of the wheel, but I don't know what to search for.

Does anyone know what that collar is called and what size, or at the least what size e-clips I need to try and find?

For now, I tried using a bit of Sugru wrapped around the axle. When it cures I'll know if it worked, but I suspect it is just a temporary fix at best.



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@Alan... Zap Brannigan had the same issue... You should "ping" him and ask him how he resolved the issue of the e-clips falling off...


Hi Alan,

I'm sorry to hear that your Roli Wheel is falling off, one thing you can do is use a set of needlenose pliers and squeeze the e-clip in a bit and then snap it into place on the shaft. You just have to be careful you don't slip cause e-clips are known to fly away and never come back! I believe Zap found another e-clip in his stash of parts and replaced his.



Already tried to tighten it without success. Do you have the size? I would like some spares before trying again and I don't own a pair of calipers to get an accurate measurement. Better still would be the name and size of the collar used on the outside of the wheel. Looks like more than enough room inside for that, and it looks like a more reliable option.



I had the exact same issue. I also suggested using the same collar and grub screw on the inside as used on the outside of the axle but I did not get any feedback or assistance with that. It seems to me that the e-clips that came on mine were either slightly too big are were stretched out/bent.

I just happened to have some e-clip spares from my supply of RC parts. e-clips are used a lot in oil shocks for RC cars. The ones I used are from a Tamiya shock set (CVA Mini Shock set). There are roughly the same size but a bit beefier. I have not had an issue with them popping off since I replaced them with better clips but I still think the collar would be a better solution.


Thanks Zap, they are also used to hold the propellers on my AR-Drone, but those ones are much much smaller.

I'll look up the Tamiya shock set and see if I can get a size from that if @Jeremie or someone else from EZ-Robots doesn't come back with the specific size needed.

I should probably get myself a set of calipers anyway. I am sure I will need them, and some other tools as I start making more robots and need to do precise measurements.



@thetechguru you can get digital calipers cheap from Harbor Freight if you use their coupons, probably around 9 bucks. The ones I use I got from there and usually each month they have them in their coupon catalog.


I will see if I can come up with a couple of more spares and measure the size. If I can find a couple I wouldn't even mind mailing them to you. I have a meeting this evening after work but I will check as soon as I get home.



Thanks for the tip. I actually have a local Harbor Freight store and it is in the same parking lot of the nearest hobby shop in the area, that is likely to have e-clips, so no waiting:) (as long as I take the wheel with me).

Zap, would appreciate it if you can check as well when you get a chance.

The Sugru temporary fix has cured, and I suspect it will work for a couple of days at least, so I don't need to get replacement parts until the weekend.



Just using a ruler, it looks like the axle is 4mm. Not sure if I need a 4mm e-clip, or 3.5 or 3 to fit the slot in the shaft. Since Zap said he used one from a Tamyia shock kit, I am guessing either 3 or 4, not 3.5 since they sell this replacement kit that has 2,3, and 4's in it, but no half sizes:

It was so cheap, I went ahead and ordered this set. I'll know next week if it includes the right ones.



To help you out the dimensions of the e-clip are: 6.3mm(OD) x 2.3mm(ID) x 0.6mm(thickness). I'll snail mail you some replacements as the Tamiya ones may not work.


Since Jeremie took care of this for you I did not look for anything last night. However, my offer still stands if what you get does not work. Just let me know.