Chainring issue

[spanos]

So I have a sram x5 crankset (2 chainring) hooked up to my alfine 8 on rear. Front hub motor

The biggest chainring is 39 tooth and I need higher gear, so 42 I gues

I'm clueless here. I don't want to spend lots, hoping to buy a mid drive in New year

Chainring says 120 bcd . Can I buy any 4 hole 120 bcd 42 tooth ring ? Any pointers appreciated

 

[brightonebikes]

A 4 point mount 120 bcd ring should indeed fit, but what are you using to take up the chain length difference with the Alfine at the rear? Just a singulator?
Also, is chain line difference not an issue?


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[tommie]

So I have a sram x5 crankset (2 chainring) hooked up to my alfine 8 on rear. Front hub motor

The biggest chainring is 39 tooth and I need higher gear, so 42 I gues

I'm clueless here. I don't want to spend lots, hoping to buy a mid drive in New year

Chainring says 120 bcd . Can I buy any 4 hole 120 bcd 42 tooth ring ? Any pointers appreciated

If you have a front hub motor is there any point in an Alfine 8 hub?
Anyway, just put on a 16T sprocket on the Alfine, that will give you a similar result.
They`re cheap, around a fiver.

 

[spanos]

If you have a front hub motor is there any point in an Alfine 8 hub?
Anyway, just put on a 16T sprocket on the Alfine, that will give you a similar result.
They`re cheap, around a fiver.

Well , firstly- thanks ! I didn't even think that was an option. It's perfect

As for the point , well , horses for courses but on my commuting machines I prefer bullet proof, no maintenance, keep it simple approach

So hub motor , hub gears work for me

Also I actually really like the 2wd sense you get from the setup. Especially in throttle only mode as one cann play with the ratio of power between wheels very instantly and finely

 

[spanos]

If you have a front hub motor is there any point in an Alfine 8 hub?
Anyway, just put on a 16T sprocket on the Alfine, that will give you a similar result.
They`re cheap, around a fiver.

I'm struggling to find a 16t for alfine , I think it's same as nexus but the internet is unclear on this

Have you actually fit one at all please Tommie ?

 

[tommie]

Yes, same as Nexus..

http://www.ebay.ie/itm/Shimano-Alfine-Nexus-Single-Cog-Rear-Sprocket-for-Internal-Hub-Gears-16Th-/282639344171?hash=item41ce9e222b:g:ZqsAAOSwa-dWlun6

also Evans..
https://www.evanscycles.com/shimano-nexus-sprocket-EV174104?esvt=54372-GOUKE2186868&esvq=&esvadt=999999-0-1212948-1&esvcrea=183731865742&esvplace=&esvd=c&esvtg=pla-298165464860&esvo=EV174104-16-NA&esvaid=50080&gclid=EAIaIQobChMIkJWpoezU1gIVrbvtCh0NZAKNEAYYASABEgLyG_D_BwE

there`s a Youtube video somewhere on changing one out, simple enough except for that steel spring circlip which can be a pain

 

[brightonebikes]

I don't think Alfine go down as small as 16T, not sure though?..but the nexus fit fine.
I replaced one (Robin's) the other day, about £9 from Rayments. I invert on his on one for better chain line so you'll have to see which way best suits your chain line. Piece easy you fit.
Got an 18T here if you think it may do?

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[tommie]

I don't think Alfine go down as small as 16T, not sure though?..but the nexus fit fine.

I read on my Alfine 8 IGH leaflet that Alfine don`t recommend anything smaller than 18T, however the 16T Nexus i got does the job ok.

BTW spanos, what are you using to take up the slack when changing over to that small chainring up front?

 

[spanos]

I don't think Alfine go down as small as 16T, not sure though?..but the nexus fit fine.
I replaced one (Robin's) the other day, about £9 from Rayments. I invert on his on one for better chain line so you'll have to see which way best suits your chain line. Piece easy you fit.
Got an 18T here if you think it may do?

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Thanks but I've got 18 at the moment !

 

[spanos]

I read on my Alfine 8 IGH leaflet that Alfine don`t recommend anything smaller than 18T, however the 16T Nexus i got does the job ok.

BTW spanos, what are you using to take up the slack when changing over to that small chainring up front?

Ahh , I don't. I just use an alfine tensioner and the largest chainring

The bike is a bit of a frankenbike made of leftovers from other bikes - other than the frame, forks and alfine.

Plan is to go mid drive on this within 6 months. It's doing commuter service in the interim

 

[brightonebikes]

Thanks but I've got 18 at the moment !

Wondered....
42T / 16T is what's on Robin's.

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[anotherkiwi]

https://www.bike24.com/1.php?content=8;product=138135;menu=1000,4,27

The recommendation is to keep torque within the range the hub can handle. It won't really matter because you are pedaling not driving the hub with the motor.

 

[spanos]

Wondered....
42T / 16T is what's on Robin's.

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Ahh cool, I think 39t / 16t will work perfectly for me then

 

[anotherkiwi]

The recommended ratio is 1.9:1 you get to do the math

 

[spanos]

https://www.bike24.com/1.php?content=8;product=138135;menu=1000,4,27

The recommendation is to keep torque within the range the hub can handle. It won't really matter because you are pedaling not driving the hub with the motor.

Thanks

 

[spanos]

I don't think Alfine go down as small as 16T, not sure though?..but the nexus fit fine.
I replaced one (Robin's) the other day, about £9 from Rayments. I invert on his on one for better chain line so you'll have to see which way best suits your chain line. Piece easy you fit.
Got an 18T here if you think it may do?

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Sprocket bought from rayments
Several you tube vids watched

Just need time to do the job now. Shall report back on success (or otherwise)

Looks a wee bit fiddly

 

[brightonebikes]

Sprocket bought from rayments
Several you tube vids watched

Just need time to do the job now. Shall report back on success (or otherwise)

Looks a wee bit fiddly

Good stuff.
Sure you'll be fine

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[spanos]

Update - sprocket now changed and no spinning out anymore. It's spot on for me

Cost was a tenner plus time , very happy with result and new skills learned

Thanks all

Only complication was the fiddly circlip and the fact my old 18t sprocket had a moulded on plastic chain retainer /guide. Wasn't an issue other than served to confuse when trying to copy various you tube vids

 

[brightonebikes]

Update - sprocket now changed and no spinning out anymore. It's spot on for me

Cost was a tenner plus time , very happy with result and new skills learned

Thanks all

Only complication was the fiddly circlip and the fact my old 18t sprocket had a moulded on plastic chain retainer /guide. Wasn't an issue other than served to confuse when trying to copy various you tube vids

Good work fella

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[anotherkiwi]

I am now dreaming of a Rohloff with a 13 tooth cog and 32-48 on the front. That gives a range from 17 to 140 gear inches Not very useful on a commuter but on a touring recumbent trike...