Hi everyone, I am a alumni mentor and my team is currently planning on using 5" colson wheels for their drivetrain (packaging concerns and still getting over the rendezvous bump). We were fortunate enough to get the andymark 17t #25 sprockets from first choice. I have seen people saying that these are fine for 4" wheels but not 6" wheels. would 5" still be a small enough wheel to not break chains? or should we be using larger sprockets or #35 chain?
Thank you for your time.
Where did you hear these aren’t fine for 6” wheels?
I know plenty of teams have run #25 on drivetrains without an issue… but personally, I’d always bump it up to #35. Call it overkill, but I like that assurance of knowing I’m no where near the limit on something as critical as a drive train.
If it’s the 17t sprockets you’re concerned about, I haven’t used those specifically. However last year we ran #25 chain on 17t sprockets with 8” wheels. Never had any issues.
I am concerned about breaking chains, the team is currently considering chain in tube and I don’t really want to recommend that route if breaking chains is a serious concern
We ran it with chain in tube
out of curiosity, do you know if you used 25 or 25h?
Flipped 2 NEO Gearbox Feedback this is one of the posts I saw recommending against using 17t with 6" wheels
I’m not sure, all I know is that it is prestretched/used #25 chain
We’ve run chain in tube for the last 5 years, and don’t have any issues running #25, 17T dual sprockets, and up to 6" wheels. The only time I’ve seen a chain break was related to either severe misalignment (bearing holes not milled square to the tube) in early years, or a foreign object getting in the tube (screw, rivet heads, etc).
Gotcha. We’ve ran 25H for the past couple years on 6” and never had an issue.
I know that different manufacturers have slightly different tolerances and materials, do you have a recommendation for where to get 25H chain?
They’re probably fine for 8” wheels tbh. I don’t understand the paranoia surrounding drive chain at all, except for maybe in 2016. People have ran #25 16t on 6” wheels and 6 CIMs (or equivalent) without issue for a few years now. Just make sure everything stays tensioned correctly (you shouldn’t be able to strum your drive chains), and reasonably inline.
We get it from VexPro and run it in tube with the 17t sprockets from AM.
I have always preferred 35 chain on drivetrians because it is less likely to slip because of the larger profile. Sure 25 chain is more than strong enough under most circumstances, but I just don’t like the idea of having it as a potential failure point on the system.
We ran #25 on 9" wheels in 2016. We’ve always run #25 chain, and I can recall only one chain break throughout it all.
The weight of #35 isn’t worth it, IMO. A properly aligned, properly tensioned #25 chain run is sufficient for FRC loads.
In 2017 we used chain in tube with 16t sprockets and 4" colsons, in 2018 the same setup but with 5" wheels, and in 2019 we used the double 17t sprockets with 6" wheels, all with regular 25 chain, and we never once broke a chain, even after dropping off of hab lvl 2 every match for 8 events.
Ditto, except ours were the 8” pneumatics from AndyMark and (because it was the first time we had done chain in tube, 25 chain on drive, or cantilevered wheels and we expected it to get the snot beat out of it on top of all that) we supported the other end of the axle.
In a less murderous game with smaller wheels and the right manufacturing aid, I would have zero qualms with doing this cantilevered and with 25 chain.
does anyone know what the max distance from the center of the tube the sprockets could be in .125 wall tube? just wondering on how much drop center is feasible with these sprockets
You can get at most .1" of drop with 1/8 wall tubing.