I have a Rize RX bike which has the bafang ultra motor and I'm running out of gear at speed. Solution seems to be go up to a 48 tooth front chainring to replace the 44 which should give me one extra gear. The chainring on it now is a 130mm BCD with an outside guard. I can find a 48 tooth chainring that fits but I can't find a guard that also fits on the new ring. I'd actually prefer an inner AND outer guard but so far no luck. As is there is an outer guard on the chainring which will become useless with a larger chainring. Anyone know of any solutions?
Need help for new chainring
- Thread starter aileron
- Start date
wturber
1 MW
It took me less than a minute to find this. I'd assume you could find others maybe cheaper out of plastic if you do some online searching. Brave search found this.
I think I did see that one but I wonder how it can be effective if it's for 42-58 teeth. It must be really tall and if so I risk it hitting my chain stay. I guess w/ Amazon, easy enough to order and send it back if the fit is wrong. Still no luck finding an inner guard though. Thank-You
Pants usually catch on the outer chainring, if you wear pants while bicycling, that is. One could not wear pants
and never have that problem at all.
Last edited:
You know I ain't bullshittin'.Wise guy eh?
If you need a pants guard for your bike, you do, though. I understand.
Should be able to ride in a full tuxedo and have zero grease on your slacks.
We hab deh techmology.
Why not just select the size from the drop-down consistent with the chainring you’ll be using?
I didn't see the drop down!.. I'm an idiot. But then there's this from a review "Product is completely flat and when installed fits up against outer chainwheel. It contacts outer edge of chain and prevents shifting into the outer chainwheel. Returned."
You’d need to use shim washers and longer chainring bolts if that’s the case.
There’s always DIY. Five minutes with an angle grinder converts a chainring into a chainguard. You want four teeth more than the ring, so for your 48T you want to remove teeth from a 52 … which is luckily a very common size in 130BCD.
Of course I’m not suggesting buying a ring to hack, just a way to repurpose old rings.
There’s always DIY. Five minutes with an angle grinder converts a chainring into a chainguard. You want four teeth more than the ring, so for your 48T you want to remove teeth from a 52 … which is luckily a very common size in 130BCD.
Of course I’m not suggesting buying a ring to hack, just a way to repurpose old rings.
wturber
1 MW
As @glennb says, you could space it out. But you seem to miss the main point of my post - these aren't really rare. You could do a more careful and thorough search and probably find the outer guard. The inner guard may be harder to find.
If you have a 3D printer or a friend with one, you could probably find something on Thingiverse.com and print it out.
Actually, the one on amazon was the only one I found and I didn't follow up on it because of the poor ratings. My search has only started. In fact I've done a LOT of searching for the proper tools I need for freewheel, crank removal etc. etc. I was hoping someone with an ultra could say "hey this is what you need right here" with a link, someone who's done what I'm trying to do but instead I'll take the criticism and walk of shame for not searching hard enough on my own
lnanek
10 kW
- Joined
- Sep 26, 2022
- Messages
- 685
I like big chain wheels to help my pedaling keep up with my rear hub, and like guards to keep the chain grease off my calves. I think last time I needed one I just slapped an entire Brompton 50 tooth chain wheel plus guard set on, though:
Brompton Chainring 50T Silver with black chain guard - 130BCD | eBay
Brompton Chainring 50T Silver with black chain guard - 130BCD
www.ebay.com
wturber
1 MW
Well, if you get stuck, I have a 3D printer.
wturber
1 MW
Here's one.
also:
One of the problems with many chainguards - especially the plastic ones - is that they do not mount using the chainring bolts. Instead they used 4 or 5 small screws. So your chainring needs to have those holes so the guard can be mounted. If you can drill five holes with sufficient precision, this may be a solution for you. Keep in mind that an inner chain guard for a 48T chainring may run into your chainstay. If a 50T chainring threatens to do this, a 48T inner guard is likely to do so as well.
Bike Chainring Chainwheel 130 BCD 50T Alloy Guard Single Speed For Brompton | eBay
Fit For BYA 412 P8,P18 Fnhon Brompton Pikes and 3Sixty folding bike ,BMX single-speed crank set. Chainring size: 50T, 48T. #Aceoffix #Bike #Chainring #Chainwheel #130BCD #50T #Alloy #Guard #Brompton #3Sixty #Fnhon #Dahon #Folding.
www.ebay.com
also:
One of the problems with many chainguards - especially the plastic ones - is that they do not mount using the chainring bolts. Instead they used 4 or 5 small screws. So your chainring needs to have those holes so the guard can be mounted. If you can drill five holes with sufficient precision, this may be a solution for you. Keep in mind that an inner chain guard for a 48T chainring may run into your chainstay. If a 50T chainring threatens to do this, a 48T inner guard is likely to do so as well.
Last edited:
wturber
1 MW
Yep. With the mid-drive motor it is likely to wear out even faster. In the end, it may make more sense to try to figure out how to adapt something like this Bafang chainring to your 130 BCD crank/spider.
https://www.amazon.com/BAFANG-Chain-BBS02B-Middle-Conversion/dp/B0BRKKM4T2/ref=sr_1_10?sr=8-10&psc=1
Or if the chainring you already have is steel, drill holes in it so that you can mount one (or two) of the plastic chainguards.
wturber
1 MW
I didn't think so. That's why I said you'd have to figure out a way to adapt it. But as I dig deeper, it seems like your bike has a Bafang motor. Did they use an adapter to give the bike a 130 BCD spider? If so, then maybe it will bolt right on if you remove that spider adapter. Look closer at things and maybe you can tell us.
If not, and if you have patience and either a drill press or a steady hand with a hand drill, you can adapt all kinds of chainrings to different setups.
Also, there are pre-made adapters that might do the trick for you. This adapter was made so you could put a 130 BCD chainring on a BBS drive. But maybe it would work to put a BBS chainring onto a 130 BCD spider?
The freewheeling crank I used on my cargo bike was intended for use on gas powered bikes. I ended up doing a lot of poking around and fiddling with spacers to come up with a combo that worked for me. You can adapt just about any chainring to any system if you are willing to fiddle and maybe accept some chainline compromises. I had to wrestle with this kind of thing with my cargo bike since the only freewheeling crank I could find was made with gas assist bikes in mind. So I had to adapt adapters, add spacers (pennies) to get these two steel chainrings to work. This is a 50T and a 46T.
Yes, some creative thinking could be needed. With the popularity of the ultra, I'd have expected a direct bolt on solution for a 4 tooth larger chainring with guard would be available but it appears to be a little more complicated. I'll figure it out and thanks for your help, it's appreciated. When I DO figure it out, I'll return to this thread and post what worked (or what didn't work) for me. That might not happen until winter, right now I'm riding the last of the good weather here in Michigan, the bike comes apart when the snow flies and I'll also be taking the motor apart to regrease etc. I was warned that the ultra was loud and gets louder but I haven't found that the case with mine. I have 650mi. on it so far and it sounds the same as day one and that's pretty quiet. Oh I am unable to measure any chain wear with two different gauges so I'm very happy about that. I was expecting to be at least replacing chains every 1,000mi.
wturber
1 MW
Keep monitoring the chains. When they start to wear, they often begin to wear rather quickly.
Similar threads
