Anybody swap out their chainring for a smaller one for better climbing?

reed scott said:
Speaking of tools ...What is the tool for holding the 'inside' slotted nuts as you wrench the bolt side with Allen wrench? And have you any idea where to buy such a tool?
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Good question! One of the tools I don’t have! I did struggle a bit on that one. I see Park Tool has one.
 
Bike will actually go 25 mph with the 32 tooth chainring using throttle only. Cadence is too fast for pedaling though. It’s okay because like I said, I rarely want to go over 20mph. I now have a better range of gears f off road riding.
 
Beebad said:
Bike will actually go 25 mph with the 32 tooth chainring using throttle only. Cadence is too fast for pedaling though. It’s okay because like I said, I rarely want to go over 20mph. I now have a better range of gears f off road riding.
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That's not bad actually... i can only get my stunner X to about 28 with heavy assistance
 
I installed a 48T so I could keep up with the pedals in top gear on my commute , gears 2-4 are actually useful now.
 
Man Without Shadow said:
Can you give a name for the 48T or a link to purchase please?
Also any other parts or chain adjustments that were needed...

thank you!
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This was from my spares box, so no identifying it’s origin. Look for bcd 130 48T chainrings on Amazon or EBay . for safety I also replaced the outer chain ring bash guard with a larger 50T and changed the spacers from 3mm to 5mm thickness.
I may add a couple of links to the chain at some point, it works fine in 1st gear ( I have not used it) but could maybe use a bit more slack.
 
Depending on the bike changing out the rear cassette might be a good option. I replaced my 11-32t with an 11-46t in conjunction with a 42t bling ring and this is great for climbing hills while still capable of high cruising speeds.
 
John Thompson said:
That's exactly where I am too, Dave.
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Hi John
I just noticed this thread now, so might be out of date. But I changed my Vado SL chainring from 42T to a Raceface narrow wide 38T and it's made all the difference. I have a lot of tarmac lanes and gravel by roads/bridleways here with gradients over 20%. Now with the 38T my cadence is faster and the motor works much better. It likes a good fast cadence! Like Dave I haven't lost anything at the top end, it's very rare I'll spin out as it's not often I'll be on a straight or down hill straight where I don't need to brake due to sharp bends or tricky surfaces. But that's the bumpy terrain around here, either going up steeply or down steeply. Best change I made to the Vado SL in the 6 months since I got it.
 
Hey Ras, The front chainring is a must if you don't need top speed. Did the 38t fit without the cristini?
I found an 11-46 rear with a 40T front is a great compromise for great power and more speed than I need. My main reason for not putting the cristini on the Ultra FS is the chain hits my Surly Bud & Knard tires. Factory Bafang front spyder holds the chain out just far enough to clear the tire on the 46t rear cog.
 
daveybike said:
Hey Ras, The front chainring is a must if you don't need top speed. Did the 38t fit without the cristini?
I found an 11-46 rear with a 40T front is a great compromise for great power and more speed than I need. My main reason for not putting the cristini on the Ultra FS is the chain hits my Surly Bud & Knard tires. Factory Bafang front spyder holds the chain out just far enough to clear the tire on the 46t rear cog.
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Hi Davey what’s a cristini? (And no predictive text I do not mean Christina, bloody hell) is that the chain guard? I used a mountain biking RaceFace 38T it’s a narrow wide so I’ve had no chain drop issues thankfully.
 
Rás Cnoic said:
Hi Davey what’s a cristini? (And no predictive text I do not mean Christina, bloody hell) is that the chain guard? I used a mountain biking RaceFace 38T it’s a narrow wide so I’ve had no chain drop issues thankfully.
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Sorry, just realised this is in the Bixtrix forum, not general so my comments are probably not relevant, apart from the fact that I guess any e bike climbs better with a smaller chainring or bigger rear cogs. 🙂
 
Rás Cnoic said:
Sorry, just realised this is in the Bixtrix forum, not general so my comments are probably not relevant, apart from the fact that I guess any e bike climbs better with a smaller chainring or bigger rear cogs. 🙂
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Ha!, sorry I should not have assumed. see link: https://electricbike-blog.com/2019/...-the-torque-monster-on-your-trail-snow-ebike/
It lets you take a Bafang Ultra motor front chainring down as small as 30T or so. Usually 38t-40t is the smallest without the cristini adapter.
 
ExPatBrit said:
I have the opposite question.
What is the max chainring recommended size, I find with my Ultra (44T) At about 20 ish mph in 9th gear my legs can’t keep up with the cadence required ? I want to be able to use PAS up till about 25 mph.
I find that I only use gears 4-9, even on the trail with steep inclines.

Could I go to 48T or 50T , need to install larger guard as well. Any issues with that?
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My e bike is not a BikTrix but it is a BBS02 based hunting e bike with a 3 speed Stormy Archer rear. It was geared very low and slow for off road riding and pulling game out of the woods and my legs just couldn’t keep up with the pedal revolution at road speeds. So I upgraded the original 34t front sprocket to a 46t I got from BafangUSA.

That still wasn’t enough, so I went up to a 52t front sprocket and it’s almost there, but could still be tweaked a bit, so now I’m considering changing out the rear sprocket too since I’m not aware of a larger front sprocket.
 
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Lots of sizes available for the SA 3 spa I use to run a 36t in front and a 20t in the rear. I think it's Universal cycles or modern bike has a bunch of Stermy stuff. Good luck.
 
BrianK said:
My e bike is not a BikTrix but it is a BBS02 based hunting e bike with a 3 speed Stormy Archer rear. It was geared very low and slow for off road riding and pulling game out of the woods and my legs just couldn’t keep up with the pedal revolution at road speeds. So I upgraded the original 34t front sprocket to a 46t I got from BafangUSA.

That still wasn’t enough, so I went up to a 52t front sprocket and it’s almost there, but could still be tweaked a bit, so now I’m considering changing out the rear sprocket too since I’m not aware of a larger front sprocket.
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I’ve seen more fried BBS02 motors running 52T. You MUST be aware of the stresses of running a 52T. Very easy to fry a controller running 52t on BBS02 and BBS01 motors. Being throttle heavy and in the wrong gear can cook them.
 
tomjasz said:
I’ve seen more fried BBS02 motors running 52T. You MUST be aware of the stresses of running a 52T. Very easy to fry a controller running 52t on BBS02 and BBS01 motors. Being throttle heavy and in the wrong gear can cook them.
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Yes, thanks, I’m well aware of the risks, so I’m quite gentle with it. If I do fry it I’ll upgrade to a BBSHD. Luna sells a bare bones BBSHD for $499 and says it’s a direct easy swap that only takes a couple minutes. Regardless my plan is to eventually upgrade it anyway.
 
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