Power Kite Forum

Peter Lynn Axle Jam Nut Mod

rtz - 20-7-2016 at 05:34 PM

I have a lock nut on the front axle so I can tighten it tight enough so the bearing spacer doesn't rattle and not have to rely on the fastener being tight to stay tight. Front tire has always spun nicely.

The setup on the back has never been ideal from the start. If the bearing spacer was exact in length that would be half of it. How exact are the plastic wheels? The situation is when the axle bolt is tightened down; it side loads the ball bearings and makes them not spin nicely.

Finally got around to tracking down the proper jam nuts. These are for 20mm axles:

https://www.fastenal.com/products/details/0141496?term=01414...

Here's how much thread is available with the stock setup:




And now with the jam nut:



And the difference in how the wheel spins:



I rode someone else's buggy and theirs sure rolled nicely and I noticed it most in real light wind going slow. Mine has never been able to coast or roll. It would roll to a stop and always had resistance.

bigkid - 20-7-2016 at 05:44 PM

Biggest problem with the jam nut is it is thinner than most wrenches which make it hard to tighten. If it works it's a good deal.:thumbup:

ssayre - 20-7-2016 at 07:10 PM

Maybe I don't have long enough sessions to lose a wheel but I had the same issue and I just loosened my bolts. They have only been finger tight ever since I've owned the buggy. They loosen a little more when riding but usually not more than a full turn. I always finger tighten them before each session. I used to worry that they would come off but has never been close. I must not be going fast enough.

indigo_wolf - 21-7-2016 at 04:09 AM

Quote: Originally posted by bigkid  
Biggest problem with the jam nut is it is thinner than most wrenches which make it hard to tighten. If it works it's a good deal.:thumbup:


Thin wrench?



Expect to drop some coin, though.

ATB,
Sam

dangerdan - 21-7-2016 at 04:36 AM

What about buying a cheap wrench and grinding it thinner or buy a longer socket that will fit over the threads.

hiaguy - 21-7-2016 at 05:26 AM

Call me crazy :crazy: , but why not just use a spacer that's sized properly to take the load from tightening the bolt? (Or, maybe I'm missing something.) I have an XR+ and the only time I touch the wheel bolts is when I change the wheels for my semi-annual beach trip. Other than that, the bolts stay tight, and the wheels spin freely.

Your 2014 thread about bearings had some thoughts about spacers: http://www.powerkiteforum.com/viewthread.php?tid=28380#pid27...
Here's another more recent thread: http://www.extremekites.com.au/topic/12001-buggy-transport/?... (thanks Chook)

There's another thread around here somewhere (maybe it was XK?) that mentioned cutting spacers using a pipe cutter. I'd look at trying a couple of different lengths to see if a slightly longer spacer would allow the tightening you're looking for without binding the bearings.

bigkid - 21-7-2016 at 05:27 AM

Way to go Sam.:thumbup: now just don't loose it or forget it at home. Or if you do have it to with the buggy chances it will be awkward as heck to use if you're running Bigfoot's or at the worst you won't build a do it because there's no offset on the handle.

As for grinding on the tool to make it thinner, DONT DO THAT! All tools that are produced are made from materials that are not conducive to human health if they are ground on with a grinder, or altered with a torch.
If you do create a enough heat with what you're doing to alter the tool it will lose its strength, much like a knife would lose its strengths and cutting edge if you heated it up.

bigkid - 21-7-2016 at 05:40 AM

Here is a little info on the bearing and the very top picture in this post. When the bolt is tightened against the axle the problem is the buggy axle is rubbing on the outer race of the weight wheelbearings, that's a no-no. That's why the jam nut works because it doesn't stretch out to the outer race and only applies pressure to the inner race of the bearing. If you apply pressure to the outer race and the inner race at the same time the bearing is not able to spin freely if anything I would add a small piece of pipe between the buried and the axle and use a Little bit of Loctite and call it good. I understand why you were only running these wheels and bolts finger tight is because they were rubbing on the axle itself.

If this was my set up, I would buy a longer bolt and use a regular nut for the jam. I use this scenario on all my buggies along with one extra bit of information. I don't use a wrench on the jam not. I insert the bolt through the wheel, apply the nut by hand until it is finger tight then I screw the bolt on to the axle then use a socket wrench to tighten the bolt. I have never had an issue with a wheel coming off or not being able to come off when needed.

hiaguy - 21-7-2016 at 06:01 AM

So, wouldn't a washer between the bearing and "axel" (hey, it's a folder) solve the rubbing problem?

bigkid - 21-7-2016 at 06:31 AM

My guess is it originally had a small spacer between the bearing and the axle.
Even a washer would work if it doesn't reach out to the outer race of the bearing.

bigkid - 21-7-2016 at 07:14 AM

I measured the top pictures to see if the axle was rubbing on the outer race, looks like it doesn't. If the wheel doesn't spin freely while being bolted to the axle as it should, might be an issue with the bearing. Is there a spacer between the bearings in the wheel? Is it the correct spacing between bearings as to not pinch the bearings to allow free movement? Is the bearings old and dry?

Just to clarify the name and the definition of bearing, not all bearings are created equal. Some bearings are use for industrial use which do not spin freely. They are used for high-speed or low-speed, for long duration of time, days, weeks, years. Other bearings such as ones that are used in skateboards, rollerblades, etc. use lighter oil and are more high precision for quieter use and reduced drag for easier use. My point is there are thousands of bearings and types and cost. Which ones do you buy or have in your wheels?
The cheapest bearing in the marketplace for the wheels are not always the best ones to purchase. If I was going to race, I would end up spending about $20 per bearing for one that would do a better job at what I need as opposed to cheep industrial bearing I could buy for .99 each on eBay.

rtz - 21-7-2016 at 09:20 AM

The bearing spacers are the ones that came with the wheels. Next time I have the bearings out I'm going to do some measuring of the spacers and the wheels. These are just some eBay bearings; somewhat new and still spin nice.