Cycling UK Forum

Hi All,

Hope that everyone is good.

I have a 2014 Genesis Day One which has a Shimano Alfine 8 speed internal gear hub (model SG-S501 ) and the bike is used primarily for commuting but also general everyday use (e.g. getting to the shops etc.). It's the bike in this Genesis catalogue:-

https://www.genesisbikes.co.uk/media/ca ... alogue.pdf

In it's time since getting it in 2014 it's had several new chains but it's got the original chinring and rear sprocket that the bike came with. However the chainring is now very worn and so my local bike shop has advised that it needs replacing and at the same time the rear sprocket and chain.

However it doesn't appear (at least from their parts suppliers) that a like-for-like chainring can be sourced. They're not saying they don't exist but just that they can't get one. The bike came with the following:-

Chainset: Driveline TK-13 w/ 40T
Chainring Sprocket: Shimano Alfine 20T

So essentialy they tried to find a suitbale like-for-like replacement which was made for a single speed front 40T chainring but couldn't find one. They've found a 40T chainring but it's a middle ring from a multi speed chainset and so they've said that it can be used but it just won't be as hard wearing as a designated designed for single speed ring.

The other option which is quite a lot more expensive than just replacing a chain ring is to go for the SHIMANO ALFINE Road Crankset with Chain Guard FC-S501. However If I do this I just wondered if firstly people know if this will be compatible with my current IGH being the Shimano Alfine 8 SG-S501? The bike shop said they think if I go for this they'd probably need to change the bottom bracket as well.

Secondly I've no idea what size chainring to go for becuase there isn't a 40T version of the Shimano Aline Road crankset.

I've only ever ridden bikes just as they come when I've bought them as complete bikes (I've never built up a bike from scratch) and when parts have worn out I've just replaced with like for like. Therefore changing a chainring size is new to me and I'll admit to knowing absolutely nothing at all about gear ratios.

What I can say is that the bike is generally used on a roughtly 15 mile each way commute and I live in East Anglia and so the commute is generally flat. (Though despite a flat'ish route I'd still rather keep the IGH as opposed to converting to a single speed because on days when the wind is blowing at the end of a long day at work I still appreatiate having the gears). I'm in my 40s and I'd say my average speeds on the commute vary between roughly say 14-16mph. I'm not racing anyone at all and just getting to and from work.

Also I have no idea whether or not this helps a bit or not in relation to gear ratios with my set up but off the top of my head I'd say that I roughly spend most of my time probably in gear number 6. I d use all of the gears at one time or another but probably 6 most of the time on the flat then say 7 or 8 with a tail wind or on the downhill and then say 5 (or pretty rarely 4) if going into a headwind or a bit up hill and then I can use 3, 2 or 1 if going up hill because there's just a couple of short sharp bits up hills on my commute.

So the original bike came with a 40T chainring and 20T sprocket.

The Shimano Aline Road crankset (link below) comes in either a 39T, 42T or 45T versions.

https://bike.shimano.com/en-EU/product/ ... -S501.html

I'll rule the 45T out straight away but I wasn't sure of whether to go for a 39T or 42T version or what to pair either of those up with in terms of sprocket size. You can get Shimano Alfine sprockets in either 18T or 20T:-

https://bike.shimano.com/en-EU/product/ ... -S500.html

I'm just a bit baffled as to which combination of chainring size and sprocket size to go for and if anybody has any advice that'll be much appreciated.

Thanks!

John

A Google search of 'Driveline TK-13' brings up your previous thread - viewtopic.php?t=102012. From that I see it's 130mm BCD, and Brucey gave good advice as ever.

SJS's range of 5 arm 130mm BCD 'single' (no shifting pins, cutaway teeth or ramps etc.) chainrings:

https://www.sjscycles.co.uk/130-bcd-5-arm-single/

You have a 2:1 chainring:sprocket ratio, and in your shoes I would aim to stick with that, but you might be happy to go higher.

I am not up on Alfine compatible sprockets, but hopefully other posters are, and will be able to advise. SJS's guide is below. It looks like the dedicated Alfine sprockets may only be available in 18t and 20t, which would rule out for example a 45t chairing and keeping to 2:1 ratio, but I suspect others will know better and may be able to confirm what other sprockets will work.

https://www.sjscycles.co.uk/hub-gear-sprockets-guide/

https://www.sjscycles.co.uk/sprockets-hub-gear/

https://www.sjscycles.co.uk/sprockets/1 ... ain-guide/

Hi slowster,

Thanks for your message!

Finding a link to that previous thread has made me chuckle! I can barely remember what I did yesterday these days and so I'd compleetly forgotten that a few years ago I coonsidered changing the bike to a single speed. Anyway I never did change it I think perhaps deciding in the end that it was maybe a bit too much work to do in order to change a bike that was in reasonable working order. To be honest I'm glad I stuck with the IGH because my joints aren't getting any younger and on days when you have a head wind on the commute home after a tiring day it's nice to have the gears! And despite a few annoyances with the IGH over the years with it slipping out of gear and not quite selecting the gear quite right because it's always been a bit of a pain getting the gears lines up and getting them to stay like that I've by and large been farily happy with the Alfine 8 IGH.

Re: your message that's a good point about the current ratio being 2:1 with the 40T chainring and 20T sprocket

If I was buying a new Shimano Alfine crackset and Alfine sprocket and trying to keep as close as possible to 2:1 using the Shimano Alfine options that would probably rule out the combination of the 39T chainring and the 18T sprocket. So the closest things would be the 39T chainring and the 20T sprocket albeit it I'd lose a bit on the hardest gear 8 but make gear 1 a bit esier. Or I go for the 42T chainring and the 20T sprocket making both gears 1 and 8 a bit harder to pedal.

Or of course I try to find a suitable 40T chainring to just bolt on as a direct replacement for my current one if I can find one that will work.

Thanks again for your message.

Cheers,

John

Yep don't use a middle ring. Not that its not hard wearing but it will try and throw the chain off without a FD or other type of chainguide . .

Looks like your Chainset (as slowster says) is 130BCD 5 Arm, . I would confirm on this on the bike , a quick google search will tell you how.

If correct then your looking for a 130BCD 5arm 40t Single speed or (narrow-wide) chainring - narrow -wide you just need to line the wider chainlinks with the wider teeth to help retain the chain. There is loads out there 42t or 44t is more common, but it not hard to fine a 40t one.

A 20t Shimano Sprocket won't cost much but if you want to save £5 put there are other options which will fit. Some of the sprocket come with (an utterly pointless) rubber sort of chain guide on them. I'd avoid these personally, as you can't use a single speed chain on them.

I changed the sprocket, chainring and chain on this set up recently cost me £15 all in for the parts. and you don't need more than an alum key, a chain tool, and a 15mm spanner.

If you have been happy with your crankset for 9 years. i wouldn't swap the crnankset out at all, and certainly not for the Afline Chainset. I've gone though two of them.

They are actually surprisingly heavy.
They are very expensive for what they are. £100+ and you will need £20 on a new (probably inferior) BB.
The non-drive side crank arm is notorious for getting stuck, and the bolts are made of cheese. so you need to change these bolts anyway.
Replacement left crank arms are hard to find and expensive.

They are not terrible, but as they are priced at £100+ there is far better options out there. But probably not even needed.

From the SJSC link in Slowster's post, I can recommend the Thorn reversible rings. A bit dearer than some others, offset by being reversible, I consider mine to have been good value.

Thanks to all for the additional replies!


Hi Jupestar,

Thanks for your message! Changing the sprocket, chainring and chain on this setup for £15 is impressive work! I'd be very pleased if I could do that. I've never fitted a new chain before or changed either the sprocket or chainring but maybe I'll have to serach online for videos to show me how.

When you've mentioned a Shimano sprocket I guess that you mean one of these?

https://www.sjscycles.co.uk/sprockets/1 ... ain-guide/

I think that this is the same sprocket that is currently on my bike and so I could get one of these again if changing like-for-like but thanks for letting me know that there will be alternatives out there.

Also thanks for your message about the official Shimano Alfine chainset. In my head I'd of hoped that if I was spending quite a bit more money to get one of these then I'd of wanted it to be of better quality and and upgrade on what I have. Though based on what you've said the quality is perhaps not what should be hoped for so that's made me think twice about spending more money for something that doesn't actually sound like much of an upgrade.


Hi PH,

Thanks for your message. When you've mentioned the Thorn reversable rings do you mean these?

https://www.sjscycles.co.uk/chainrings/ ... ing-black/

I'm also wondering if this Shimano Alfine FC-S501 30mm BCD 5 Arm Single Chainring (Silver 42T) would work?

https://www.sjscycles.co.uk/chainrings/ ... ilver-42t/

The current set up is silver and so keeping a silver chainring would be my preference if I can get one that will work.


Many thanks to all.

John

John_S wrote: ↑10 Aug 2023, 3:20pm Hi PH,

Thanks for your message. When you've mentioned the Thorn reversable rings do you mean these?

https://www.sjscycles.co.uk/chainrings/ ... ing-black/

I'm also wondering if this Shimano Alfine FC-S501 30mm BCD 5 Arm Single Chainring (Silver 42T) would work?

https://www.sjscycles.co.uk/chainrings/ ... ilver-42t/

The current set up is silver and so keeping a silver chainring would be my preference if I can get one that will work.


Many thanks to all.

John

No, this one:
https://www.sjscycles.co.uk/chainrings/ ... ing-black/
It's reversible, that is when you've worn one side you can flip it and use the other. The one you linked too is lighter and non reversible, though the weight saving isn't my priority on such a bike.

The Shimano you linked looks like it'd be fine, though it isn't one I've used. Another alternative if you want silver, is the Surly stainless steel, I had one for a while, bought it secondhand from someone who considered it noisy, though that wasn't my experience. Again it's something with a higher price, that might still be better long term value. I only stopped using it when I changed ratios. Steel and reversible! If you get the ratio right it may well last a lifetime!!
https://www.sjscycles.co.uk/chainrings/ ... ng-silver/

Hi PH,

Many thanks for those links which are much appreciated and it looks like I've actually got quite a few options after all which is good!

Both the Thorn and Surly options sound good on the basis that they sound like they might have a fair bit of duability and longevity which is a good thing.

Thank you,

John

John_S wrote: ↑10 Aug 2023, 3:20pm
Changing the sprocket, chainring and chain on this setup for £15 is impressive work! I'd be very pleased if I could do that. I've never fitted a new chain before or changed either the sprocket or chainring but maybe I'll have to serach online for videos to show me how.

I have various sprockets for various sizes and hubs - mostly the 3 flange ones fit, although i think there can be an issue with dishing sometimes so best ot stick to shimano ones if you can. I didn't apply a cost to this.
Single speed chains could be brought for £3 or £4 - i always have a few spare, as i go through them every few months. and a cheap chainring can be had for £10-£12. Again you need to time it for the sales, and 42t is easier to get on a bargian. Again i have a couple in stock.

Cost of living may have increased this, its been a 3 years since i stocked up but i'm getting low,

One of the big advantages of this set up is the cheap cost of changing the transmission.

It relatively easy to do. especially if doing like for like,

Chainring is likey to be 5 bolts take them out,take ring off, put the new ring on. Bolt them up.
Sprocket - release gear cable, take wheel off, remove junction and junction lock. Remove the circlip (this can be a PITA). Take sprocket off, put Circlip back on (this can be a PITA). Put junction and lock back, wheel on. and connect gear. Line up the yellows.
remove old chain - with chain tool - shortern new chain to same length (if same set up). wrap chain around transmisson/chain stay, Connect chain with the joining pin or quick link. Intsall chain on sprocket and Chain ring.
Check tension of chain. Test ride with care.

John_S wrote: ↑10 Aug 2023, 3:20pm
When you've mentioned a Shimano sprocket I guess that you mean one of these?

https://www.sjscycles.co.uk/sprockets/1 ... ain-guide/

Yes but note if you get one with the chain guide (as per you link, which is the black disc) - I believe you need a 8s chain, and anything wider will not fit. Personally i think the chain guide is pointless and just attracts more dirt to the chain.

John_S wrote: ↑10 Aug 2023, 3:20pm I think that this is the same sprocket that is currently on my bike and so I could get one of these again if changing like-for-like but thanks for letting me know that there will be alternatives out there.

There are alternatives, but like i say its saving £5. There is also a slightly higher risk its non compatable.

https://www.sjscycles.co.uk/sprockets/s ... ared-hubs/

This one for example i'm pretty sure will fit. but worth double checking with sjs.

John_S wrote: ↑10 Aug 2023, 3:20pm Also thanks for your message about the official Shimano Alfine chainset. In my head I'd of hoped that if I was spending quite a bit more money to get one of these then I'd of wanted it to be of better quality and and upgrade on what I have.

Hard for me to compare - as i'm not familar with your Crankset - but i would say there is better options available for less than half the price. If you go down this route - which i'm really not sure you need to.

John_S wrote: ↑10 Aug 2023, 3:46pm a fair bit of duability and longevity which is a good thing.

Thank you,

John

I think my approach is to opposite of Jupestar's, I like to buy to last, for me that represents the best value. We don't all have to do the same of course, but I think the best choices are at those extremes, top quality or the cheapest, the middle ground seems to offer the least value.
On the subject of longevity - Larger sprockets and chainrings not only last longer but are also likely to increase chain life. Last time I was making changes I increased chainring and sprocket size for an almost identical ratio and that seems to have worked well (On a Rohloff so the actual ratios are not comparable)

Another option in silver/stainless is Bikepunx, which sells on ebay - https://www.ebay.co.uk/str/bikepunxuk?_sop=16.

If you do a search you will find them discussed in a number of previous threads, and at least one member has bought one of their chainrings.

NB If you buy one, make sure you order the correct one, i.e. 5 arm not 4 arm, 2mm thickness if using a 3/32" chain, 130mm BCD.

PH wrote: ↑10 Aug 2023, 4:14pm I think my approach is to opposite of Jupestar's.

I think you'd be surprised although I don't have a Rohloff.

My single speed which I ride about 19miles a day, is Surly 46t front, with WI 17t rear. Surly Chainring is on a very stiff FSA Gimondi Single Speed Crankset with a UN72 BB.

I ride on KMC single speed chains, which if you not fussy about the colours you can pick up for £3 if you get them at the right time.

I've rode that set up for 6 years now, purposely increasing the sprocket and chainring sizes to preserve the drive train. I change the chain about 4 times a year. Service the WI before and after winter normally.

I've not seen better longevity from more expensive chains. So the chain has become my only regularly disposable item on my commuter and I bin it as soon as it shows stretch.

I was merely making the point that it doesn't have to cost the earth or a relatively simple drivetrain change.

The £15 set up i did on a friend's Alfine bike, he doesn't know how to look after it, so it will get ridden into the ground, and then repeated. But it's doesn't matter cause it's so cheap! It's still an original Shimano sprocket (I think), cheap KMC chain and FSA steel chainring. So not shabby set up. I actually have the same on my Alfine set up, but I hardly ever use it. So can't comment on longevity.

In general I think a FSA £10 chainring or a £40 Surly will last approximately the same time if you don't look after the chain. Maybe the Surly will last 1000miles longer.

I did use an Alloy Chainring once when experimenting with ratios, I do grind the pedal up the hills, but after about 2 weeks the teeth were flattened.

Jupestar wrote: ↑10 Aug 2023, 9:24pm

PH wrote: ↑10 Aug 2023, 4:14pm I think my approach is to opposite of Jupestar's.

I think you'd be surprised although I don't have a Rohloff.

Fair enough, I wasn't intending to be competitive and was contrasting with you saying you'd changed the lot for £15.
If it's of interest, I still take a different approach to you.
Best KMC chain (EP-1?), I bought five for £100 when it was easier to buy from Germany
Reversible Thorn chainring 47T, £42
Rohloff splined sprocket, reversible £18

I let all three wear together, I don't measure, I do no more than wipe and oil. This bike is currently on 19,000km, I'll probably change it at the winter service. New chain, flip the chainring and sprocket, total cost £50.
I'm happy enough with that, it's twice the price of changing £3 chains four times a year, though without the measuring and maintenance.