Wheel hubs and air vents/good idea?

Thomas Jaszewski

Well-Known Member
We were all clueless....congratulations on jumping in and searching and learning. This tends to be a somewhat critical forum, but also one of the most respectful, and genuinely helpful. More and more it’s the kinder gentler forum, with good information and genuinely helpful posters.
 

Nelson37

Member
If those numbers are accurate then you have zero problem. Your earlier 33 mph number must have involved a downhill or extreme pedaling situation, which means it was not useful info and in fact, caused incorrect analysis and therefore should not have been posted without full explanation.

A temperature sensor must be mounted INSIDE the motor, in the coils, where the heat is. An external sensor is nearly worthless.

Voilamart is a company that puts a sticker on a bicycle, they are not a motor manufacturer. Still have no idea whether this is DD or geared, but, 18mph unassisted and 15 mph on the hill, combined with the battery voltage and wheel size, that says no overheating in 3 minutes, or several times that. No need for any modifications of any kind, and as these are somewhat dependent on the still unknown type of motor you have, I would strongly recommend against it.

Do you have regenerative braking, or any motor-assisted braking? That is almost exclusively the province of the DD motor.
 

Amish David

Active Member
If those numbers are accurate then you have zero problem. Your earlier 33 mph number must have involved a downhill or extreme pedaling situation, which means it was not useful info and in fact, caused incorrect analysis and therefore should not have been posted without full explanation.

A temperature sensor must be mounted INSIDE the motor, in the coils, where the heat is. An external sensor is nearly worthless.

Voilamart is a company that puts a sticker on a bicycle, they are not a motor manufacturer. Still have no idea whether this is DD or geared, but, 18mph unassisted and 15 mph on the hill, combined with the battery voltage and wheel size, that says no overheating in 3 minutes, or several times that. No need for any modifications of any kind, and as these are somewhat dependent on the still unknown type of motor you have, I would strongly recommend against it.

Do you have regenerative braking, or any motor-assisted braking? That is almost exclusively the province of the DD motor.
No the 33.2mph is a flat area in town., also disc breaks, motor has no breaking for down hill, also I said it will do 18mph easily up hill without PAS that is not the top speed going up. I just don't go fast☺that's all.
 

Nelson37

Member
I just spent 30 seconds doing the research you should have done and verified that at least several, and most likely all, of those motors are Direct Drive, and therefore are good candidates for either screened vent holes with varnished coils, Statorade and Hubsinks, or partial light oil or ATF with, again heatsinks of some sort. Putting the motor into a smaller wheel would negate the need for any modifications and run much better, but you definitely bought the wrong motor for your needs.

Also regarding the 18 mph statement - NO, that is most certainly NOT what you said before, go back and read it again.

The motor is capable of regen braking but most likely your controller does not support it.

There are several issues involved with putting fluids inside the motor, particularly on an inexpensive kit, I do suggest you spend some time looking into what needs done or you may have some real problems to deal with.
 

Amish David

Active Member
I just spent 30 seconds doing the research you should have done and verified that at least several, and most likely all, of those motors are Direct Drive, and therefore are good candidates for either screened vent holes with varnished coils, Statorade and Hubsinks, or partial light oil or ATF with, again heatsinks of some sort. Putting the motor into a smaller wheel would negate the need for any modifications and run much better, but you definitely bought the wrong motor for your needs.

Also regarding the 18 mph statement - NO, that is most certainly NOT what you said before, go back and read it again.

The motor is capable of regen braking but most likely your controller does not support it.

There are several issues involved with putting fluids inside the motor, particularly on an inexpensive kit, I do suggest you spend some time looking into what needs done or you may have some real problems to deal with.
Thank you, but don't assume I know how to use a computer phone, I have never owned one until 8 months ago, I am Amish living among the English for. Now. We live a. Lot different then you. Thanks. Again for the help.
 

Nelson37

Member
I am fairly familiar with how the Amish live. I've not known one who would back away from a job that needed doing. If a man can walk 5 miles north, then he can walk 5 miles south, east, or west. You got here.

You bought a quarter horse when you needed a plow horse. You are right on the edge of overworking the beast. You don't want to have to put it down.

Without an internal temp sensor, only rough rule of thumb is available.

Of the available solutions, holes with screens have been in use for the longest time, apparently successfully. Fluids leak, internal wires need to be more securely bedded down to resist the forces applied to them. Hot air expands and will blow out seals meant to keep the fluids in, so a vent is needed. Fluids and Statorade just move heat to the outer shell, between the spoke flanges, where the magnets live. Magnets are permanently weakened by high temps, cheaper magnets this happens at lower temperatures. Hence the need for heatsinks. Statorade appears to evaporate over time and loose effectiveness, requiring re-application of fairly pricey material.

You need a three-arm puller to get the cover off, and also to take some care putting it back on as you could loose some fingertips, the magnet force is considerable.

Just getting off the throttle a bit when on the hills might be the best answer, but this gets back to not knowing the internal temperature. The axle itself is a bit closer to internal temps than the side cover.

My best guess is that you are close to overheating, but not quite over the line, however, I just do not have enough data to make a confident statement on that. 18 mph on the hill should be sufficient, 15 mph not.
 

Amish David

Active Member
Thank you again, my nabor found Hubsink we ordered them, and i will speed up to 18mph on the hills Then go from there.
 

Vagos

New Member
Sorry for hijacking the thread, but anyone used those hubsinks? I live in Greece and we get pretty hot summer days, so I'm a little worried for my 250w front geared motor and i'm thinking on use them just to be sure...
 

Nelson37

Member
I live in Florida with a similar motor and they are just not necessary. Without combining them with Statorade or oil their effect is minimal. These are best for Direct Drive motors, and not for geared motors, as a general rule.

If cooling is necessary during normal operation then you have purchased the wrong motor for the task at hand, and/or you are pursuing maximum performance, or hot-rodding. I have absolutely nothing against such practice, but this is to emphasize that for the vast majority of folks, additional cooling is just not a high priority, unless you really bought the wrong motor for the job, and then the difference cooling can make is marginal.

It's kinda like putting a supercharger on your grocery-getter.

Painting the outside and inside of the motor shell a with a flat black thermally transmissive paint is both reasonably effective, cheap, and simple.

The absolutely most common problem is too fast of a motor in too large a wheel under too much load.

What you really need is an internal temp sensor, first, so you can determine if there actually is a problem and if so, how big it is. Sensor MUST be internal, embedded in the windings, I think. This is out of my comfort zone, but you can do a search at the Sphere and there are numerous installation threads.

You must also watch the KLANG! video before motor shell re-installation. Assuming you want to keep your fingertips.
 
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