The motor verses belt argument is interesting. I’ll have to look I to that more. I ha e had issue with alignment but I stay at it u til it’s right, 100% right. I’m all for being ballsy but running a board with alignment t issues is asking g for street face.
Lol, street face is right!! Yea, elasticity is one of the primary benefits of a belt drive versus chain. That and maintenance.
So, to summarize this entire thread: the trade-off between tension and tooth skipping, can come at the cost of either broken belts or wiped motor bearings, or both.
1 Like
If designed properly, idler wheels can:
- Prolong belt life
- Increase torque transfer ability without skipping
- Reduce required frequency of belt tensioning
- Increase motor bearing life
- Reduce drag in belt system, increasing the efficiency and thus range of the board.
So there are lots of benefits! Of course you have to design it properly for it to work well, as with any other component on your board.
Edit: I should explain why I think idlers can improve belt life:
You can run them with way less tension, in my case without tension works perfectly. This reduces strain and thus improves belt life. Not skipping teeth also greatly prolongs life of the actual teeth on the belt (and motor pulley too if its aluminum or plastic)
1 Like
In my case the idler reduced drastically the belt life, so i’m against them, my theory it that it increases the fatigue of the fiber strands inside the belt by bending them more than necessary
What diameter was your idler wheel? Did you reduce the tension in the belts after installing the idler?
yes, i used idler for a very long time before coming to this conclusion, 19mm if i’m not mistaken
when i jumped to a quality made steel pulley all my skipping problems were gone, running 12/36
So 19mm is a rather small diameter, skate bearings like most of use as idlers are 22mm and that is already a bit small for 5M belts. This may have cause a lot of extra strain in the belt (bending + tension).
Either way, if you get no teeth skipping without an idler and without a lot of tension on your belt then you dont really need one.
Also, the best way to avoid teeth skipping is wider belts, so if you can fit it onto your truck (i couldnt), get 15mm, you wont regret it.
I will have to trim the bushing a bit as well as the extra length of the bolt but I believe this will work.
1 Like
I agree, according to gates design manual the minimum for the 5M profile should be 30mm, but that’s too bulky to our usage, i think the main problem most people encounter is low quality pulleys, the aluminium ones with a few hundred kilometers on them already start to wear down, leading to skipping that accelerates this process
I’m already running 15mm, the accelerated wear i experienced is due to several factors, first a 12T pulley bends the belt too much, with a single drive the strain gets even bigger, join that with road debris and ocasional ridding on wet roads and as result the belt is severely punished
For my next built i gone bigger with 15/34, reducing bending fatigue, and dual drive with smaller motors, when it start to rain again i plan to test a spray that help to increase friction and also protects from water, that will take a while since it has been more than 3 months without a single drop of water from the sky
Judging by the head that’s a pretty small diameter bolt. Any issues with bending?
Nope. It’s an m6. By using a countersink bolt it can sit behind the wheel, with the right spacing. This is how I was able to run the 107’s without an issue.
2 Likes
@Pedrodemio : Seems like a lot of variables to be considered for the belt failures you have experienced. Your input is appreciated, but I posted this thread specifically to provide ideas for those who are frustrated with the problems I too, was having. Forgive me if that sounded rude, I mean no disrespect.
2 Likes
Whaaaat’s an idler? 
2 Likes
Might I ask why your idler and pulley is so far out from the mount? I’m sure there’s a good reason, but I can’t figure it out.
I like the idea of 2+ skate bearings for price point alone, looking for dedicated idler some time ago led me to this and it’s belt diameter ‘B’ is pretty much the same as a 50c bearing
I have to agree with @Stef my belt tension seems to be perfect,iv towed my mate up a very steep hill on his trike loaded up with fire wood for a beach bbq. Over 35 stone/490lb but I don’t get much if any slippage,the only reason I can see for iddlers is if you can’t find the sweet spot and wear down your pulleys constantly then it’s a good fix! but for me it’s if it ain’t broke dont fix it!
1 Like
Good question. I ended up mounting the motors a little too far inward so the idlers had to be longer. Shorter idlers would definitely be better, but no issues, so far.
3 Likes
Ok so I made my idlers and have them installed. Now for the belt length. I am attaching a picture of a belt that I cut so itvwiukd he flat gorbgaugung where to put my pulleys. When I wrap the belt around the pulleys as it will run I can line it up on the large pulley and count now many additional teeth I will need. The belt had 72 teeth and I need a remaining 16 teeth that it doesn’t cover. Would I be correct in assuming I need a 440 belt? My motors are close to the end of the mounts so I will slide them in about 1/8" so I was thinking I could get by with a pair of 420 belts? Opinions?
1 Like
What length was the old setup? 360mm (72×5)?