Chainring selection

[slayer1962]

I have watched videos, read google searches. After only putting 60 miles or so on my e bike I want to gear it lower.
First gear is crazy fast with full throttle on sand trails. I have a 1000 watt mid drive Bolton e bike 26" fat tire bike.
I noticed the bike seems to go fastest on the road in like 3rd gear ( it has 7)
My thinking is changing the front chain ring to a smaller one can only help?
Gearing it down i might have to use the higher gears on the street but it would pull real nice on sand and hills.
When i checked with Bolton they said the chain ring has little offset since it was designed as an e bike??
I do not need to go 35 mph on an e bike even on the road.
Any suggestions where to get a proper chain ring? should i go to an e bike shop? ( i was a truck mechanic so handy but worried about getting the correct gear)
is there any drawback to gearing it lower

 

[indianajo]

Modifying your bike will void your warrenty.
Biggest US internet supplies I've found are modernbike.com and thebikeshopstore.com. Davidbrown in UK is highly competent but stuff might get stolen in customs like my recent Newark order.
Competitioncycling is competent but carries only high end racing gear. I bought my helmet there since only racers prevent breaking their chin with a chin guard.
No US supplier provides any dimensions on anything they sell. The tooth count might be right. Whether the mount holes will line up is totally up to chance, and your estimation of the picture. Shimano & sun websites are worthless on dimensions, pretty good on sales blather. I bought 4 rear sprockets and none of them fit.
A LBS might be able to send things back and get an actual support person on the phone. You'll pay a decent markup. Both my LBS have sold me garbage for accessories, and one dumped me on the street with improper assembly of a MBT, so I don't buy anything there but tires anymore. If you're not buying a top end racing cycle or getting it maintained don't expect much competence at a small city (2 million) LBS.
Count your teeth and estimate how much slower you want to go. You'll also need a chain splitter and master link to shorten the chain. Chains come in different widths, count the number of sprockets on the back axle to get the right one. The schwinn chain splitter doesn't work. The dodge small industrial splitter only works on single speed or 5 sprocket chain. Industrial 1/2" master links fit single speed & 5 sprocket (15 speed) chain.

 

[TForan]

Looks like it has a 46T. Maybe change it to around a 42 ? Finding one that will fit won't be hard.

 

[Browneye]

If Bolton can't help you and the bike has a standard bottomset with square-press arms, this would probly do it: https://www.amazon.com/gp/product/B007BWOPTC/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

I got one for our Roll conversion and it's great. $42.

 

[MikeDD]

Changing the front chain ring is pretty common on the Specialized Turbo Levo. With this bike, most riders are trying to get more speed.

 

[tomjasz]

If it’s their 1000w it’s maybe a BBSHD? Best to slow down the recommendations until we confirm the actual motor and setup.

If the BBSHD, Then it is a square taper bottom bracket. You do not need a crank arm and chainring assembly. It’s very common to change the chainring. Stock is 46T. Changing to a 42T should not affect a warranty. It will actually be easier on the drive. 42T is as small as you can go and still maintain the chainring offset and chainline with a simple chainwheel change. We sell scores of Lekkie BBSHD chainrings. A hugely popular accessory. You CAN go to a Lekkie 40T KIT, but that’ll double the price.

Lekkie – Premium Components

lekkie.bike

Looks like it has a 46T. Maybe change it to around a 42 ? Finding one that will fit won't be hard.

Must have the offset if a BBSHD. Typical 130BCD chainrings will change the chainline.


BTW you could go a wider range cassette. 12-32t the spec is 12-28t. I think 12-34t are out there too.

 

[Browneye]

Oh, it's a mid-drive??
And bolton said they don't have a chain ring???

 

[tomjasz]

Oh, it's a mid-drive??
And bolton said they don't have a chain ring???

The OP wrote,
”I have a 1000 watt mid drive Bolton”
and...
“When i checked with Bolton they said the chain ring has little offset since it was designed as an e bike??”
Sounds like some confusion all around.
FWIW 1000W mid drive would only be a Bafang.

 

[Browneye]

Yeah, I missed that. Oops, my apologies.
The Lekke alloy 40 would be a nice upgrade - where would he get one of those?
Based on the configuration a 42 might still be too high.

Then the cassette if that's not enough.
What about chain length?

 

[slayer1962]

yes befang 1000 watt mid drive. Bolton has not answered me yet. They would not change it before shipping the bike.

 

[Browneye]

BTW, was browsing aliexpress just now and found these: https://www.aliexpress.com/item/32878672340.html?spm=2114.12010612.8148356.18.998951aaOQCZ9O
42T Bafang chain ring - $35.99 free ship.

It also appears there is a 'spider' adapter ring to run even smaller chain rings: https://www.aliexpress.com/item/329...5.0&pvid=bc9451c9-f7cd-4a07-b9fe-3e6b864e9107

I'd likely try a 36 or 38 on there.

 

[tomjasz]

Browneye, please, I'm not trying to be rude here but the Aliexpress chainring was one that Luna first sold. It's a bomb, crap, cheap junk. And what for what you get, not worth $20!!!

Next, I already explained the smallest, with OFFSET TO MAINTAIN CHAINLINE is a 40T Lekkie HD kit. $175. Otherwise 42T is the smallest. $90. Please do not recommend chainrings that will pose problems for the fellow. The spider adapter will run the chainring out to far to maintain chainline.

The Lekke alloy 40 would be a nice upgrade - where would he get one of those?

40t Package-Lekkie Bling Ring BBSHD - California Ebike

In the past the smallest ring that offered the perfect chain line was the Lekkie 42T, but that is no longer the case. The Lekkie blingring 40T is now the smallest tooth count ring available on the market that maintains the correct offset and chain line. Lekkie made this possible by also...

california-ebike.com

Expensive and really not needed! A taller cassette would be a better value.

Based on the configuration a 42 might still be too high.

Based on what about the config? Look 42T is the most commonly used size with this motor. It's small enough with a taller cassette and big enough for most to feel they've not given up top end. I've frustrated you before and I have to say I find this very frustrating. I try to not interject when I'm not familiar with a setup. I know you try to be helpful, but you're just not grasping this setup. Every suggestion other than the cheap chainring will completely ruin his chainline.

I'd likely try a 36 or 38 on there.

And you'd lose half of gear range and possibly create a chainline so bad that the chain wouldn't properly move on the cassette in the gears left, wear faster than normal and create undo wear on the cassette! WTF?

 

[tomjasz]

My thinking is changing the front chain ring to a smaller one can only help?

Smallest is 40T with offset and $175. Most common is 42T designed for the BBSHD like the Lekkie Bling Ing or the Luna Eclipse. A taller cassette, 14T-34T(aka Mega Range) with a 42T chainring would be the least expensive. $175 for a 40T smaller by 2T change is kinda spendy for most.

The very thing you dislike about the HD is the major selling point. Heavy Duty higher power.

There are other things you can do. Reprogramming and dropping amperage is fairly common. One vendor, who doesn't sell ANY 52V batteries drops the amps by at least 5A in the programming. He thinks, and I tend to agree, there's a small loss but a big gain in reliability. Bafang has NEVER liked 52V batteries. The caps are 60V and a 52V is 58.6V. They even changed the firmware early this year to shut down BBSHD motors with a 52V battery. A real vendor nightmare...

 

[Browneye]

We’re glad you’re here!

 

[Ken M]

If it’s their 1000w it’s maybe a BBSHD? Best to slow down the recommendations until we confirm the actual motor and setup.

If the BBSHD, Then it is a square taper bottom bracket. You do not need a crank arm and chainring assembly. It’s very common to change the chainring. Stock is 46T. Changing to a 42T should not affect a warranty. It will actually be easier on the drive. 42T is as small as you can go and still maintain the chainring offset and chainline with a simple chainwheel change. We sell scores of Lekkie BBSHD chainrings. A hugely popular accessory. You CAN go to a Lekkie 40T KIT, but that’ll double the price.

Lekkie – Premium Components

lekkie.bike

Must have the offset if a BBSHD. Typical 130BCD chainrings will change the chainline.


BTW you could go a wider range cassette. 12-32t the spec is 12-28t. I think 12-34t are out there too.

That would not result in more speed. The larger lower gear chainrings will improve climbing / low speed performance for the riders efforts.

 

[tomjasz]

That would not result in more speed. The larger lower gear chainrings will improve climbing / low speed performance for the riders efforts.

Yes, I get that. His OEM is 46T. 42T is the most popular. Not much speed loss for those worried about not getting near 30mph. Reducing 4T will give a bit on the grunt range he wants. 14Tx43T cassette will help. Most BBSHD kit buyers want that power. 32-34T with a front 42T will provide lots of power in sand , snow , and climbing. Reducing programmed amps can calm things down a bit.

 

[slayer1962]

I think i am going to try a local bike shop so i do not have to worry about selecting the right offset.

 

[TForan]

if you keep the spider, how can the offset be wrong ?

 

[tomjasz]

I think i am going to try a local bike shop so i do not have to worry about selecting the right offset.

Good luck! But a typical bike shop will not have offset chainrings. Lekkie and Luna are pretty much it except for the OEM Bafang rings. I gave you the answers.

if you keep the spider, how can the offset be wrong ?

The OEM BBSHD needs a chainring that dishes in around the body of the motor. Again, anything smaller than a 42T can't dish in enough to preserve the chainline like the 46T OEM. And adding a spider/adapter pushes the ring out.

 

[TForan]

Good luck! But a typical bike shop will not have offset chainrings. Lekkie and Luna are pretty much it except for the OEM Bafang rings. I gave you the answers.


The OEM BBSHD needs a chainring that dishes in around the body of the motor. Again, anything smaller than a 42T can't dish in enough to preserve the chainline like the 46T OEM. And adding a spider/adapter pushes the ring out.

But , if you only change the sprocket and not the spider, how can that change the chainline ? What am I missing ?