Smaller chainring?

David Dobson

Member
Nov 9, 2019
32
12
Ireland
Hi guys, i saw on a clip where Danny McCaskill told Steve Jones that he was putting a 30t(i think) chainring on his SC Heckler, and he was working on theory that when the motor stops assisting at 25kmph then any more gears after that were really pointless. He said he would much rather have the extra gears where it mattered in the fun bits. Has anyone gone that low on the front and where if any are the issues? I have a "23 E-reign +0.
Thanks
 

jeanmarc

Well-known member
Mar 2, 2021
419
418
Canada
A 30t chainring seems excessive, if doable, the Reign E+ comes with 36t. That would change the riding characteristics of your bike quite a lot.
 

David Dobson

Member
Nov 9, 2019
32
12
Ireland
I broke one of the original carbon crank arms on a stump the 1st week i had it and the LBS said tough shit without even an attempt to talk to Giant about even a cost price/crash replacment! He offered to get me a pair of hope crank arms at full price which was decent of him so i got a pair of 155mm arms online instead. I find it a struggle on a very sharp climb to keep my cadence up so i figured a smaller chainring would help but i dont know how small id get away with. With the standard gearing it would do 40kmph on the flat if i had the legs. That isnt really a great help.
 

bcmtb

Member
Nov 1, 2021
35
21
WA
I was thinking of doing the same thing, replacing the 36 with a 30. I have a 2022 Reign E+0.

I happened to have this spreadsheet, not sure if it helps.

30323436
112.732.913.093.27
132.312.462.622.77
152.002.132.272.40
171.761.882.002.12
191.581.681.791.89
221.361.451.551.64
251.201.281.361.44
281.071.141.211.29
320.941.001.061.13
360.830.890.941.00
420.710.760.810.86
500.600.640.680.72
 

Jurassic

Active member
Subscriber
Jul 22, 2022
228
239
Helensburgh, Scotland.
I dropped down from the OEM 36t to a 34t soon after getting my bike (2022 E+1) to get more clearance. I ride a lot of tight techy trails with rooty and rocky drop offs that are too slow to pop off so have to be rolled and I was constantly decking the 36t chainring out. I imagine all the force from doing that would be transferred to the bearings in the motor so I was keen to get a smaller one asap. I got the 34 as it was a Praxxis steel ring (same as OEM but smaller) and it was heavily discounted. I don't miss the top end gears at all and I no longer get the decking out issues. When the time comes to renew my transmission I'll probably go 32t or 30t and maybe try a smaller cassette with closer ratios.
 

CraigR

Member
Aug 10, 2020
58
57
Livermore, Ca
I have had a Stance EMBT and now a Trance X Advanced and in both cases I went from 36t to 34t. Most EMTB companies put a 34t on their bikes. I don't know why Giant puts a 36t on their bikes. There was little noticeable difference in high end speed (How often are you peddling that fast on a MTB?). But it does help with climbing and clearance a bit.
 

David Dobson

Member
Nov 9, 2019
32
12
Ireland
I was thinking of doing the same thing, replacing the 36 with a 30. I have a 2022 Reign E+0.

I happened to have this spreadsheet, not sure if it helps.

30323436
112.732.913.093.27
132.312.462.622.77
152.002.132.272.40
171.761.882.002.12
191.581.681.791.89
221.361.451.551.64
251.201.281.361.44
281.071.141.211.29
320.941.001.061.13
360.830.890.941.00
420.710.760.810.86
500.600.640.680.72
I see a few advantages and few drawbacks by loosing top end gearing...
 

bcmtb

Member
Nov 1, 2021
35
21
WA
I see a few advantages and few drawbacks by loosing top end gearing...
In my experience I find I mostly use 19-32 in my daily riding, and occasionally as low as 15. Don't think I ever use 11 or 13. On steep climbs (PNW) I'll use the largest gears.

Actually looking at this again, I might go to 32T instead of 30. TBD.
 

Jurassic

Active member
Subscriber
Jul 22, 2022
228
239
Helensburgh, Scotland.
In my experience I find I mostly use 19-32 in my daily riding, and occasionally as low as 15. Don't think I ever use 11 or 13. On steep climbs (PNW) I'll use the largest gears.

Actually looking at this again, I might go to 32T instead of 30. TBD.
I suspect that 32t will be the sweet spot for me as well. I honestly can't see the point of big gears when the assistance cuts around 15mph, does anyone routinely ride above 15mph off-road other than downhill (when the motor cut is less significant)?
 

Digital

Member
May 2, 2022
13
6
Penticton, BC
Went from 34 OEM to 32 - best move ever. Better super-tight climbing, but moving only two teeth down doesn't throw off the sometimes unavoidable two-track rides.
 

Jamescoughlan

Active member
Subscriber
Jul 13, 2020
113
123
Aberporth
Can anyone recommend a steel 104bcd 32t thick/thin narrow/wide 12s chain ring?
I cannot find any steel 32t for 12 speed.
UK preferably!
Cheers
 

big_scot_nanny

Active member
Subscriber
Nov 23, 2022
88
115
Scotland
32 here, agree seems the sweet spot. Maybe if 29 rear would go 30t.

For steel, not sure, but avoid uberbike - I bought their steel one and it was not made correctly so chain never sat on it and made a terrible racket (yes, chain was oriented on it properly). Also they were a pain in the hoop to deal with re returns.
 

Jurassic

Active member
Subscriber
Jul 22, 2022
228
239
Helensburgh, Scotland.
I managed to find a Praxxis steel 34t when I was looking to gear down, it was heavily discounted though so maybe it was end of line/end of stock. It was identical to the OEM chainring fitted to my Reign E+1 other than being two teeth smaller.
 

Madonas

Member
Dec 21, 2020
19
6
Delta BC
i have a 2023 reign E+3 and have changed the 36 t chainring to 34t and then to 32t .
I can use the same chain ( I removed 3 chain links so that the 36,34 and 32 t chainrings work without changine chains.
I use praxxis wide narrow chainrings.
I remove the right side pedal to get the 32 tooh ring without removing the chainring lock nut.

Reason for doing this is that a higher cadence while climbing will save battery % wh and even on the flat will provide far more greater range.
first three power levels are mostly what I use
they are tuned as follows

TORQUE N-M support level % lauch level
eco 20 100 1
eco+ 30 125 1
active 40 150 3

the sport level and power level are set to 60 nm and 85 nm respectively.

with the 12 speed gearing and 32 tooth chainring this provides the best economical range for me and full power only when I need it .

you can see that the first three power levels are tuned down significantly .
I ride with a senior road bike crew every now and then and will put a 34 or 36 tooth on the bike for those road rides where the average speeds are near the cutout speed of 32km/h.
I have an 800 wh battery and did an 80 km ride with 675 meters of climb and used only 62% of battery capacity from a full charge .
by calculation I could have gone 129km and
and 1088 mm elevation climb , if the battery would drain in a linear fashion to 0% ( probably would not )

the link to where I purchase the 32 tooh chainring is here
Praxis eRing 104 BCD Steel Mountain Bike Chainring
 

David Dobson

Member
Nov 9, 2019
32
12
Ireland
i have a 2023 reign E+3 and have changed the 36 t chainring to 34t and then to 32t .
I can use the same chain ( I removed 3 chain links so that the 36,34 and 32 t chainrings work without changine chains.
I use praxxis wide narrow chainrings.
I remove the right side pedal to get the 32 tooh ring without removing the chainring lock nut.

Reason for doing this is that a higher cadence while climbing will save battery % wh and even on the flat will provide far more greater range.
first three power levels are mostly what I use
they are tuned as follows

TORQUE N-M support level % lauch level
eco 20 100 1
eco+ 30 125 1
active 40 150 3

the sport level and power level are set to 60 nm and 85 nm respectively.

with the 12 speed gearing and 32 tooth chainring this provides the best economical range for me and full power only when I need it .

you can see that the first three power levels are tuned down significantly .
I ride with a senior road bike crew every now and then and will put a 34 or 36 tooth on the bike for those road rides where the average speeds are near the cutout speed of 32km/h.
I have an 800 wh battery and did an 80 km ride with 675 meters of climb and used only 62% of battery capacity from a full charge .
by calculation I could have gone 129km and
and 1088 mm elevation climb , if the battery would drain in a linear fashion to 0% ( probably would not )

the link to where I purchase the 32 tooh chainring is here
Praxis eRing 104 BCD Steel Mountain Bike Chainring
Thank you very much Madonas. That is a really helpful email and the link to the chainring is a cool touch. My bike is limited to 25kmph and my road rides are mostly are only to get to the local woods about 15kms away so i definately wont need to go back to a 36t. The comment you made about the smaller ring keeping you in a higher cadence makes perfect sense and makes me question the manufacturers choice of a 36t in the first place.
Thanks again
David.
 

Rando_12345

Active member
Nov 16, 2022
227
307
France
I run 11speed 10-42 out back on my reign, so changed to a 32 tooth.

I almost never use the 10 tooth cog, the only scenario would be pedalling down a paved road.

I use 11speed to save 300g over 12speed and save several hundred euros on replacing parts.

I also think 32tooth is an advantage on the reign due to the stupidly low BB.
 

Jurassic

Active member
Subscriber
Jul 22, 2022
228
239
Helensburgh, Scotland.
IMG20240623155555.jpg


This is the plastic panel/bashplate from under my motor. I recently completely rebuilt my Reign so had the opportunity to have a good look at the various bits. You can see the obvious damage caused by decking out on logs, roots, rocks etc. there is a hole punched through it but it seems to largely have been doing it's job in protecting the bottom of the motor. There's a drain hole in the plate anyway so I'm not worried about the damage and structurally it seems okay. It does go to show how much these bikes deck out in certain riding conditions though and I think it justifies the reduction in chain ring size being discussed here as with the 36t ring fitted it will deck out before the bashplate.
 

Rando_12345

Active member
Nov 16, 2022
227
307
France
I'm on my third set of 150mm cranks since buying the bike ~18 months ago. I dont seem to have bashed the 32t chainring on the reign, but on one of my previous bikes, a mk1 jeffsy that was also dangerously low, I once snapped the chainring clean off from the spider, so those impacts can happen.

Sorry for my negative tone in this post and the last, but I am dealing with 3 months of concussion symptoms from my last crash which was due to a pedal strike, so pretty pissed off.
 

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