32 tooth chainring with Shimano SM-CDE80 Chainguide?

[DrChris]

I'm about to swap over to a new drivetrain and wanted to go from a 34t to 32t front chainring, and go back to 11sp 11-42t cassette from a 12 speed set-up.

I just realised that the Shimano chainguide has 2 fixed positions only for 34t and 38t rings.

Anyone running with a 32t ring with the Shimano chainguide - does it still work OK ie. hold the chain on?

Thanks!
Dr Chris

 

[urastus]

I'm about to swap over to a new drivetrain and wanted to go from a 34t to 32t front chainring, and go back to 11sp 11-42t cassette from a 12 speed set-up.

I just realised that the Shimano chainguide has 2 fixed positions only for 34t and 38t rings.

Anyone running with a 32t ring with the Shimano chainguide - does it still work OK ie. hold the chain on?

Thanks!
Dr Chris

Hello Dr Chris

Have you done this? What did you find? I'm about to do the same thing.

 

[sdcoffeeroaster]

Hello Dr Chris

Have you done this? What did you find? I'm about to do the same thing.

Which chainring are you going to use? I find the 34 x 46 low gear lacking if you like to run in eco mode a lot. I usually end up using trail or boost to make up for the lack of a really low 1st gear. I ran the battery out on my Focus Jam2 the other day and had to slowly make my way home on a very steep street with what is a somewhat tall 1st gear. 30t or 32t sure would help. My former bike, Giant Anthem 2 was 30x46 and it was perfect for some of the very steep hills I encounter here is SoCal. Thanks

 

[R120]

I would just go the whole hog and change the chain guide, aside from being but ugly the OEM is not a great piece of kit - I have the Funn one on my bike.

 

[urastus]

Which chainring are you going to use? I find the 34 x 46 low gear lacking if you like to run in eco mode a lot. I usually end up using trail or boost to make up for the lack of a really low 1st gear. I ran the battery out on my Focus Jam2 the other day and had to slowly make my way home on a very steep street with what is a somewhat tall 1st gear. 30t or 32t sure would help. My former bike, Giant Anthem 2 was 30x46 and it was perfect for some of the very steep hills I encounter here is SoCal. Thanks

I ride in steep country. I have 51 on the rear, and 34 on the front. I have ordered a 32 front. The other reason. A lower gear isn't essential for me - I would use it, but I don't think I'd get up anything more than I am now - my limitation is skill and fitness. A 32 would also open up the other end a bit - I mostly use just 8 gears, the lowest 8. If I'm going over 25km/h, I'm usually going down steep rocky stuff and not pedalling. I was wondering how the standard chain guide went with the 32 chainring?

 

[sdcoffeeroaster]

I ride in steep country. I have 51 on the rear, and 34 on the front. I have ordered a 32 front. The other reason. A lower gear isn't essential for me - I would use it, but I don't think I'd get up anything more than I am now - my limitation is skill and fitness. A 32 would also open up the other end a bit - I mostly use just 8 gears, the lowest 8. If I'm going over 25km/h, I'm usually going down steep rocky stuff and not pedalling. I was wondering how the standard chain guide went with the 32 chainring?

Seems like you are going in the wrong direction if the bike is geared too low (slow) for you, or did I misunderstand you? You want a taller gear ratio for 1st which would be a 38 up front. My low gear is 46/34 and I need or want 46/32 or 46/30 so I don't have to resort to trail or boost up steeper climbs. When I ran out of battery and had to do one climb on the way home the other day, I really noticed how tall my 1st gear felt without any assist.

 

[urastus]

No, it's geared too high. I'm using from 1st to 8th (the 8 lowest gears). At the other end of the range they don't get used. I could still use lower, it isn't essential though. I'm hoping it will make 9 gears in regular use. Then, with the 32km limit fix, I might use 10 or 11? Where I ride now isn't much of an issue - if I'm going over 25km/h, I'm not pedalling (very steep here). 32 front and 51 rear will really be ideal for low gear.

 

[R120]

Also you dont really need the chain guide if you are not riding super aggressively. The clutch and the N/W chainring do a good job of retaining the chain in most conditions.

 

[urastus]

Also you dont really need the chain guide if you are not riding super aggressively. The clutch and the N/W chainring do a good job of retaining the chain in most conditions.

No, I'm not a hard rider; but the country I ride bucks me and the bike like we're in a rodeo . I had to play with the guide this afternoon actually, track side. I can see it will easily adjust to 32 teeth.

 

[sdcoffeeroaster]

No, it's geared too high. I'm using from 1st to 8th (the 8 lowest gears). At the other end of the range they don't get used. I could still use lower, it isn't essential though. I'm hoping it will make 9 gears in regular use. Then, with the 32km limit fix, I might use 10 or 11? Where I ride now isn't much of an issue - if I'm going over 25km/h, I'm not pedalling (very steep here). 32 front and 51 rear will really be ideal for low gear.

I think we are saying the same thing or maybe not, lol. Going from 34 to 32 makes all of the gears lower. There isn't a good way or inexpensive way for me to just lower 1st with my 11-46 cassette which is why I'm after 32 or 30 chainring and wondering where you found one. I do use the taller gears here in the states since we have the 20 mph limit riding in groups (pre-covid of course). I often use the 11th gear although 10th is probably adequate. I think you probably found that gear outside the US. I just don't see anyone here selling anything but 34 or 38t. thanks

 

[urastus]

I think we are saying the same thing or maybe not, lol. Going from 34 to 32 makes all of the gears lower. There isn't a good way or inexpensive way for me to just lower 1st with my 11-46 cassette which is why I'm after 32 or 30 chainring and wondering where you found one. I do use the taller gears here in the states since we have the 20 mph limit riding in groups (pre-covid of course). I often use the 11th gear although 10th is probably adequate. I think you probably found that gear outside the US. I just don't see anyone here selling anything but 34 or 38t. thanks

The only time I get into 12th is when I've finished riding and I store the bike in 12th to relax the rear mech spring.

This info is for shimano e8000 which has a 104bcd.

There are quite a few around. I was initially looking for a 30, but a 32 will give me the same low gear as I have on my ancient acoustic (taking in different crank lengths, wheel sizes etc) which is perfect. 30 is the smallest that will fit on a 104bcd. I have a 32 on order. The spider is a straight forward 104bcd, so you just need the ring. The main problem I found is not many for 12 x, and a lot of sellers don't say what system they are compatible with ie 12x, 11x etc. A 12 x will work with 11x etc but not the other way around. Also, some of the rings are threaded - I don't know what that is about. If you have 11x, you have a huge choice. A few members here are using deckas chain rings which are 11x compatible. If you're after 12x, let me know. I tried to find out if the deckas where 12x via research - answers are so random but it looks like they are 11x and might work with 12x (ie a tight fit), so I've avoided them.
Unfortunately for you, going from 34 to 32 only makes a small difference on your largest rear gear (the 46). If I understand correctly it is 1.2 gear inches. It will make a bigger difference at the other end where the difference is 5 gear inches lower. This means you'll get to use 11th more, but won't feel a huge difference in your first. That's if I've understood everything correctly.

 

[sdcoffeeroaster]

The only time I get into 12th is when I've finished riding and I store the bike in 12th to relax the rear mech spring.

This info is for shimano e8000 which has a 104bcd.

There are quite a few around. I was initially looking for a 30, but a 32 will give me the same low gear as I have on my ancient acoustic (taking in different crank lengths, wheel sizes etc) which is perfect. 30 is the smallest that will fit on a 104bcd. I have a 32 on order. The spider is a straight forward 104bcd, so you just need the ring. The main problem I found is not many for 12 x, and a lot of sellers don't say what system they are compatible with ie 12x, 11x etc. A 12 x will work with 11x etc but not the other way around. Also, some of the rings are threaded - I don't know what that is about. If you have 11x, you have a huge choice. A few members here are using deckas chain rings which are 11x compatible. If you're after 12x, let me know. I tried to find out if the deckas where 12x via research - answers are so random but it looks like they are 11x and might work with 12x (ie a tight fit), so I've avoided them.
Unfortunately for you, going from 34 to 32 only makes a small difference on your largest rear gear (the 46). If I understand correctly it is 1.2 gear inches. It will make a bigger difference at the other end where the difference is 5 gear inches lower. This means you'll get to use 11th more, but won't feel a huge difference in your first. That's if I've understood everything correctly.

After some research I've found a few 104bcd that say will work. Wolftooth also makes one for 12 speeds but I need their 11 speed version for my 2018. They also have 7075 aluminum and SS. But they say their 30t won't fit my bike. I'm not sure about the bolt issue with their 32t either since it says 6mm and we have 8mm. So in the end I decided to order a very inexpensive Chinese one I found on Amazon for $14. to "try out" the fit and see how the chain tensioner accommodates that. I need to look around some more for the 30t that will work.

46:34 is 1.353 and 46:32 is 1.438 or around a 6.3% improvement, not much but it's something. 49:34 is 1.441 just a bit better. 46:30 is 1.533 or 13.3% improvement (about the same as 49:32, 1.531) but that's a big jump for the chain tensioner to adjust to. I'll give the 32 a try and if it works I'll probably go for the Wolftooth SS version. Going big on the cassette involves Wolftooth again. They have a gear and cage kit for the 49t addition. 49:32 is1.531 or about the same as the 46:30. That kit is $125. So with the Wolftooth SS chainring I'm up to $225. That's getting closer to just buying a 12 speed, lol. You're 51:32 is 1.594 or almost 20% slower than my 46:34!

 

[urastus]

Well that deckas ring @ 32 teeth is working for members here and it is 11 x. I looked at wolf tooth before but was put off by the price. Do you realise that wolf tooth are talking about bolt length (6mm and 8mm)? 6mm sounds very small, considering most rings are 4mm thick. I wouldn't worry about bolts being too long - even if they really are there is enough space behind the ring for that. Unless they are talking about the pieces that the bolts screw into! That would make a difference if they were too long - you wouldn't be able to tighten the ring up.

 

[Gary]

@urastus I run a 36t 104bcd ring with the shimano steps chainguide.
Obviously I need to run the top guide in the 38T position to clear the 36T which means it's a little higher than ideal so I run a strip of 3M mastic 2228 tape along the underside of the guide plastic. - this serves 2 purposes. firstly it reduces the space above the chain to a similar spacing to what I'd have with a 38T ring and secondly it reduces noise.
Doing the same should work with a 32t ring with your guide in the 34t position

 

[Gary]

I wouldn't worry about bolts being too long - even if they really are there is enough space behind the ring for that. Unless they are talking about the pieces that the bolts screw into! That would make a difference if they were too long - you wouldn't be able to tighten the ring up.

I'm not sure if you fully understand how a chainring bolt should be fitted.
Ideally you want the (female) chainring nut to be the correct length to run through the back of the chainring spider's bolt hole and partially through the actual chainring. The bolts should ideally be long enough that they just reach the shoulder of the chainring nut when in place for maximum strength/security.
badly set up chairing bolts can allow movement between the ring and the spider and cause a weak/wear point. Too long a bolt can work but will not always go all the way through certain chainring nut designs. If it's all you have, I'd only use too long a bolt temporarily and source correct length bolts reasonably soon after.
I changed my OEM chainring bolts to 5mm allen key versions for better purchase to the hex key when torquing
a loose or lost chainring bolt is really not something you want to happen on an Ebike motor.

 

[Gary]

Oh... and an 11 speed ring will work fine with a 7,8,9,10,11or12 speed chain

 

[sdcoffeeroaster]

Well that deckas ring @ 32 teeth is working for members here and it is 11 x. I looked at wolf tooth before but was put off by the price. Do you realise that wolf tooth are talking about bolt length (6mm and 8mm)? 6mm sounds very small, considering most rings are 4mm thick. I wouldn't worry about bolts being too long - even if they really are there is enough space behind the ring for that. Unless they are talking about the pieces that the bolts screw into! That would make a difference if they were too long - you wouldn't be able to tighten the ring up.

Yes I realized yesterday that they are talking about bolt length. The chain is pretty close to the chain stay in the 11th gear now with 32t. I guess that's my only concern. Yes Wolftooth is very pricey on everything!

I ordered the JGBike ring before I found out it was 6061 so it will go right back free shipping. I have a 7075 32t coming made by Dymoece. I also see a 30t that FoMotor makes that I might order to try. 30t would be ideal but that's going to be really close to the chain stay pivot area. My dealer here is telling me to stay with the 34t but not sure why. If you creep up anything at 4 mph or less in 1st you better be using trail mode or boost.

 

[sdcoffeeroaster]

Yes I realized yesterday that they are talking about bolt length. The chain is pretty close to the chain stay in the 11th gear now with 32t. I guess that's my only concern. Yes Wolftooth is very pricey on everything!

I ordered the JGBike ring before I found out it was 6061 so it will go right back free shipping. I have a 7075 32t coming made by Dymoece. I also see a 30t that FoMotor makes that I might order to try. 30t would be ideal but that's going to be really close to the chain stay pivot area. My dealer here is telling me to stay with the 34t but not sure why. If you creep up anything at 4 mph or less in 1st you better be using trail mode or boost.

Well I tried both of these this morning. The Dymoece one fit but I could not get the bike to shift into low gear and in fact the derailleur seems to just lock up. I'm thinking it's a chainline issue but I did not want to screw around with it for 6% improvement. The gear is thicker than stock but the std chainring bolts fit with about 5 thread engagement.

The JGbike chainring will NOT fit without some filing. Both 32t chainrings left the guide in a non-optimal position and the chain really very close to the rubber strip on the stay. Just not worth it for me. I'll just continue to deal with the tall gearing by using trail or boost as needed.