Ok, I bent the new rim... Looking for a stronger rim.

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PedalPedal   10 mW

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Ok, I bent the new rim... Looking for a stronger rim.

Post by PedalPedal » Oct 04 2018 12:26pm

Bought a BMX rim. The LBS cut some spokes for the motor. I built the wheel. Rode for months.

Last night I hit the 1.5 inch high threshold between a road and a driveway at a small angle and bent the rim. :oops: I really hate those thresholds because I've had several pinch flats from them-hence the steep angle. (Good news is that I was only a loooong walk - one mile from work.)

Since frame is too narrow (Rotovelo) for a fat rim/tire I'm looking for a stronger rim. The kit weighs about 260 lbs. including me.

The motor is a MAC 10. The wheel is 20 inch.

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Re: Ok, I bent the new rim... Looking for a stronger rim.

Post by Voltron » Oct 04 2018 1:23pm

Check out better BMX rims for burly 20's... they make triple wall ones that are effectively indestructible.
s1600_primo_rim_hula.jpg
s1600_primo_rim_hula.jpg (13.79 KiB) Viewed 870 times

ions82   100 W

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Re: Ok, I bent the new rim... Looking for a stronger rim.

Post by ions82 » Oct 06 2018 12:01am

What kind of bend did it suffer? Sidewall dented? Or, was the entire rim bent? If it's just the sidewall, I'd bend it back, true the wheel, and keep running it. What type of tire/tube are you running? Can you fit a little bigger tire in there? I'd run a Maxxis Hookworm with a thorn-resistant tube and pump it up to max pressure. It won't be a smooth ride, but it will help prevent pinch-flats. Is it possible to avoid those thresholds or at least slow down for them?

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PedalPedal   10 mW

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Re: Ok, I bent the new rim... Looking for a stronger rim.

Post by PedalPedal » Jun 02 2019 9:29am

The rim was fixed. It wobbles a little but it is not noticeable when riding.
Thanks for the suggestions.
The thresholds are everywhere now. 45 degrees seems to be the best angle, that and low speed works OK for me.

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Re: Ok, I bent the new rim... Looking for a stronger rim.

Post by markz » Jun 02 2019 10:19pm

Alex DM series rims are great!
Abused it hard by riding on a flat for 5 miles, just sanded down the sharp edges. It is a stout rim!

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Re: Ok, I bent the new rim... Looking for a stronger rim.

Post by amberwolf » Jun 03 2019 12:37am

ions82 wrote:
Oct 06 2018 12:01am
If it's just the sidewall, I'd bend it back, true the wheel, and keep running it.
Eventually that will probably crack, and spread, like this, which started because i bent such an impact-bend back:

Image

Image

Image

Another identical rim with similar (worse) impact-bend I left alone, and it's still usable

Image

Image

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Drunkskunk   100 GW

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Re: Ok, I bent the new rim... Looking for a stronger rim.

Post by Drunkskunk » Jun 03 2019 12:41pm

Since it's a 20" rim, the easy fix is a 16" moped/motorcycle rim. they're the same size.

36 hole seem to be slightly rare, but here's the first cheap hit on ebay: https://www.ebay.com/i/273846945226?rt= ... 3846945226
Buy the ticket, take the ride.
Monster Bike:http://endless-sphere.com/forums/viewto ... =6&t=38667

markz   100 GW

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Re: Ok, I bent the new rim... Looking for a stronger rim.

Post by markz » Jun 03 2019 2:29pm

Another source for rims, tubes, tires..... anything scootercycle-like.

I was going to purchase, but shipping to Canada is expensive. So I just look on ebay, one motorcycle shop has an ebay store with thousands of parts I just keep an eye on. Kijiji is online classifieds but not as much selection locally. Motorcycle junk yards is another source, there is a guy local to me who has a farm/acreage a ways past city limits that had aisles of wheels. Could be something local to you. I find that local motorcycle dealerships want make, model and year for any parts you order, and if they order it in, which they'd have to, and its not the right part, then theres most likely no return policy.

I bought spare Alex DM rims, and spare spokes, like instead of 36 spokes, I bought 50 or 60. Because I have the same rim as a spare, and its highly unlikely the motor will change.

www.treatland.tv - https://www.treatland.tv/new-puch-peuge ... s-s/88.htm

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Re: Ok, I bent the new rim... Looking for a stronger rim.

Post by spinningmagnets » Jun 03 2019 5:51pm

20-inch bicycle rim is the same diameter as a 16-inch moped rim...maybe an option.

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Re: Ok, I bent the new rim... Looking for a stronger rim.

Post by markz » Jun 03 2019 8:28pm

Nice article btw Spinning Magnets
https://www.electricbike.com/moped-rims ... hubmotors/

Bicycle - Motorcycle
20" - 16" or 17"
24" - 19"
26" - 20" <I was on the hunt for one, but they are old rims, popular way back when. If its for sale, its probably expensive. However this article is stating that their is a resurgence. https://motocrossactionmag.com/the-20-i ... evolution/
Rarity - https://thumpertalk.com/forums/topic/97 ... ill-exist/
The 20" died because essentially, the tires were wider then the 21" tires not allowing the 20" tires to sink into the 21" ruts making cornering problematic.
spinningmagnets wrote:
Jun 03 2019 5:51pm
20-inch bicycle rim is the same diameter as a 16-inch moped rim...maybe an option.

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Re: Ok, I bent the new rim... Looking for a stronger rim.

Post by Voltron » Jun 05 2019 10:26am

Just be ready for the effect the extra wheel weight will have on the handling.... Those steel rims are heavy, and wheels are just about the worst place to add unnecessary weight with the way the spinning magnifies the weight difference.

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Re: Ok, I bent the new rim... Looking for a stronger rim.

Post by AF7JA » Aug 18 2019 11:05am

I am looking at this thread because I am trying to find a suitable rim for my rotovelo 20" 406.

I want to build a wheel using the NuVinci 380 (125mm flange diameter). It will be used with a BBS02 in the front. Any rim recomendations would be welcome.

markz   100 GW

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Re: Ok, I bent the new rim... Looking for a stronger rim.

Post by markz » Aug 18 2019 12:42pm

Alex DM24 in 20" 32mm wide so might be too wide for you.
https://www.ebikes.ca/shop/electric-bic ... -dm24.html

Crystalyte 20" 31mm wide
https://www.ebikes.ca/shop/electric-bic ... 20j31.html

Over those 2, I'd pick Alex DM24

More options here, with quick fast shipping
https://www.chainreactioncycles.com/rim ... t=pricelow
I'd go with Sun Ringle Envy BMX 20" 36h 28.5mm wide rim

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neptronix   100 GW

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Re: Ok, I bent the new rim... Looking for a stronger rim.

Post by neptronix » Aug 18 2019 1:03pm

The best preventer of pinch flats and rim damage is as large of tires as you can stick on the bike, plus as high PSI as you can get.
Suspension will help do the job as well. But a large diameter of compressed air inside a tire is your best defense.
Efficiency is everything :bolt:

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Re: Ok, I bent the new rim... Looking for a stronger rim.

Post by MadRhino » Aug 18 2019 6:46pm

The best prevention for pinch flats and rim damage is riding tubeless with Cush Core inserts and half a cup of slime. That is because the insert won’t let the rim pinch the tire or touch the ground. It won’t let the tire off the rim, even riding on a flat. The slime will plug most of the flats, and those that aren’t can be fixed quickly with a tubeless plug.
Make it fool-proof, and I will make a better fool.
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Re: Ok, I bent the new rim... Looking for a stronger rim.

Post by amberwolf » Aug 18 2019 11:34pm

AF7JA wrote:
Aug 18 2019 11:05am
I am looking at this thread because I am trying to find a suitable rim for my rotovelo 20" 406.

I want to build a wheel using the NuVinci 380 (125mm flange diameter). It will be used with a BBS02 in the front. Any rim recomendations would be welcome.
Grin has these
https://www.ebikes.ca/shop/electric-bic ... om_size=62

If you can fit it in there, I'd go with
https://www.ebikes.ca/shop/electric-bic ... 0-fat.html
and the widest tire you can use on it. If you want good flat protection, and don't mind weight, you can use the Shinko SR714 moped tire, in 2.5" (maybe even 3", if they'll fit in teh frame/fork). They have other kinds with different treads and featurs, but these work well on my SB Cruiser in city conditions.

Otherwise there's a bunch of good tire recommendations around the forum if you need something different than what you have.

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