Chain sets

[Psyclist]

If they go for too much, my friend on Pinkbike is selling a Super Maxy crankset. NOt sure if it's any good to you, but take a look.

Click here

 

[HovR]

Ok, so I'm looking at this from CRC. A few questions before I commit to buying.

It states 9 speed. I'll be putting this on a 5 speed Dawes (In my display pic - Don't want to respace the rear stays!) will this work okay? Sheldon seems to think so, I just wanted to make sure.

The description recommends 2 different BB model numbers (one 103mm, one 108) neither of which I can find anywhere! Will any 108mm or 103mm BB do? Seems like quite a change from my current 122mm BB.

Oh, and just to confuse me more, it also says it will fit JIS square taper BB's, and "power driver BB" which appears to be some sort of splined affair - How does this work for both?

Thanks!

 

[RecordAceFromNew]

Ok, so I'm looking at this from CRC. A few questions before I commit to buying.

It states 9 speed. I'll be putting this on a 5 speed Dawes (In my display pic - Don't want to respace the rear stays!) will this work okay? Sheldon seems to think so, I just wanted to make sure.

The description recommends 2 different BB model numbers (one 103mm, one 108) neither of which I can find anywhere! Will any 108mm or 103mm BB do? Seems like quite a change from my current 122mm BB.

Oh, and just to confuse me more, it also says it will fit JIS square taper BB's, and "power driver BB" which appears to be some sort of splined affair - How does this work for both?

Thanks!

I have only just come across this thread, a couple of comments/questions:

You said you might have exhausted your rear mech capacity. Unless I am mistaken you are running 52/42 front and 14/22 back. That is only 18T. While anything is possible for vintage equipment, my 30 year old Campag racing mechs have way more capacity than that. I read your chain double back observation on small small, but does the chain in large large look like the pic below? If not your rear mech might well have more capacity.

Regarding BB spindle, as I understand it you have traditional cup and cone, while again for vintage equipment anything is possible, chance is though for 122mm it is like you have the 3S or 3T but they are not the same. It is possible to get new alternative spindles (e.g. from ebay), but the first step, if I were changing chainset and don't want to switch front mech, is to check the chainline. Do you know what it was/is?

Modern JIS square tapered BB (e.g. the Shimano UN series) spindle lengths are not directly comparable with those traditional spindles mentioned above (e.g. while the asymmetry of the 121mm ZL is similar to the 3S, the 122.5mm NL is nowhere near the 3T). If you need to check cross-compatibility come back.

Also if you are planning to change from a 52T large ring to e.g. 46T you will have to move the front mech down the seat tube by at least 12mm, which usually is not an issue but worth checking. Also you should be aware that using a front mech designed for a 52T large ring on a 46T will not improve the front shift, since the mech tail will be somewhat further behind the chainset, making it harder to derail the chain.

 

[HovR]

I have only just come across this thread, a couple of comments/questions:

You said you might have exhausted your rear mech capacity. Unless I am mistaken you are running 52/42 front and 14/22 back. That is only 18T. While anything is possible for vintage equipment, my 30 year old Campag racing mechs have way more capacity than that. I read your chain double back observation on small small, but does the chain in large large look like the pic below? If not your rear mech might well have more capacity.

No, my rear mech isn't quite that stretched out, so it may be able to take a compact - However I'm not a big fan of compacts, and would much prefer a double or triple. I assume that changing to triple would be more of a pain? Although the gears are friction shift. I'd be open to this idea if it would be easier than changing to a lower geared double.

Regarding BB spindle, as I understand it you have traditional cup and cone, while again for vintage equipment anything is possible, chance is though for 122mm it is like you have the 3S or 3T but they are not the same. It is possible to get new alternative spindles (e.g. from ebay), but the first step, if I were changing chainset and don't want to switch front mech, is to check the chainline. Do you know what it was/is?

I don't have the most accurate measuring equipment, but I measured it as best I could, and along with consulting Sheldon's chainline page, I've come to the conclusion that it is 43.5mm - Like a standard road double chain set. As far as the BB is concerned, I figured I'd take the opportunity to upgrade to a modern sealed unit rather than replace only the spindle. I assume that a modern chainset would be better paired with a modern BB.

Modern JIS square tapered BB (e.g. the Shimano UN series) spindle lengths are not directly comparable with those traditional spindles mentioned above (e.g. while the asymmetry of the 121mm ZL is similar to the 3S, the 122.5mm NL is nowhere near the 3T). If you need to check cross-compatibility come back.

Also if you are planning to change from a 52T large ring to e.g. 46T you will have to move the front mech down the seat tube by at least 12mm, which usually is not an issue but worth checking. Also you should be aware that using a front mech designed for a 52T large ring on a 46T will not improve the front shift, since the mech tail will be somewhat further behind the chainset, making it harder to derail the chain.

Moving the mech down is no issue - But I hadn't even considered that tooth count would affect front mech - I've seen selling pages stating a max number of teeth, but never a number of teeth that the mech was specifically designed for. Would this be a major concern?

My response in blue. Thanks for your help!

 

[RecordAceFromNew]

No, my rear mech isn't quite that stretched out, so it may be able to take a compact - However I'm not a big fan of compacts, and would much prefer a double or triple. I assume that changing to triple would be more of a pain? Although the gears are friction shift. I'd be open to this idea if it would be easier than changing to a lower geared double.

Moving the mech down is no issue - But I hadn't even considered that tooth count would affect front mech - I've seen selling pages stating a max number of teeth, but never a number of teeth that the mech was specifically designed for. Would this be a major concern?

The reason I mentioned rear mech capacity is not just in relation to options for the front, but also for the cluster at the back. As you probably are aware you can get much lower geared 5 speed freewheels than 14/22. If you want lower gears, and if you don't mind sticking with 52/42 up front (which was pretty much standard equipment for everybody in those days), you might well be able to use say a 14-28 freewheel, which are readily available. A 42x28 is actually lower than the 34x22 that a compact chainset gives you!

The difference in chain stretch between a 28 and 22 is 3 links (1.5 pairs). You can therefore try pulling the chain at the bottom back by 4 links while holding the pedal still and see if it would still give your chain a slight S like in the pic I attached earlier. If it can, your rear mech definitely has adequate additional wrap capacity to handle it.

The other thing to check if your rear mech can take a 28T is whether there is at least 12mm clearance between the rear mech's top jockey wheel and the 22T when you are on the 22T at the back. If not whether there is a B screw on the rear mech, and if so adjusting it will likely help.

Regarding the front options, for clean, easy shifts (actually I don't think there is ever a great front mechanical shift, since inevitably one is forever trying to derail a chain in significant tension, unlike the rear, where the chain is always only under the rear mech's puny spring tension) it is desirable, though not essential in your case with friction shift levers, to have a mech that matches the large ring size. As usual, the late great Sheldon has covered it.

It is good that you know the chainline you have/had. If and when you are shopping for a chainset / BB combo you should try to duplicate it, if you don't wish to change the front mech that is.

 

[TheDoctor]

Erm, if you don't need the 52 (which is how I read this) then why have a double at all? Spa do a 40/42/44/46T chainset at £20. Get a 14-28 freewheel at £10, and a chain, and you're sorted. A gear as high as you need (27mph is fast enough, surely) and a bottom gear lower than you have now.

 

[HovR]

The reason I mentioned rear mech capacity is not just in relation to options for the front, but also for the cluster at the back. As you probably are aware you can get much lower geared 5 speed freewheels than 14/22. If you want lower gears, and if you don't mind sticking with 52/42 up front (which was pretty much standard equipment for everybody in those days), you might well be able to use say a 14-28 freewheel, which are readily available. A 42x28 is actually lower than the 34x22 that a compact chainset gives you!

Regarding the front options, for clean, easy shifts (actually I don't think there is ever a great front mechanical shift, since inevitably one is forever trying to derail a chain in significant tension, unlike the rear, where the chain is always only under the rear mech's puny spring tension) it is desirable, though not essential in your case with friction shift levers, to have a mech that matches the large ring size. As usual, the late great Sheldon has covered it.

It is good that you know the chainline you have/had. If and when you are shopping for a chainset / BB combo you should try to duplicate it, if you don't wish to change the front mech that is.

I've seen those 14x28 freewheels, and was actually planning on getting one, along with a new chain and new chainset (and possibly jockey wheels), to provide a completely new drive chain. However now after looking further into it, almost every double chainset I've seen with the ratios I want something like a 103/107 BB to keep the 43.5 chainline.

Currently the cranks come fairly close to the chain stays upon rotation, and I'd be concerned about them striking the chainstays if I removed that much width from the bottom bracket.

Take for example the singlespeed chainset "TheDoctor" linked - It requires a 119mm BB, which seems much more reasonable, unlike the doubles I've been looking at.

Half of me says take it to the LBS, as they'll get it right.. The other half of me says they'll charge an arm and a leg for what is really a very simple fitting routine.

 

[HovR]

Erm, if you don't need the 52 (which is how I read this) then why have a double at all? Spa do a 40/42/44/46T chainset at £20. Get a 14-28 freewheel at £10, and a chain, and you're sorted. A gear as high as you need (27mph is fast enough, surely) and a bottom gear lower than you have now.

I'd considered a single chain ring up front, however the only real advantage is aesthetics, with the disadvantage of loosing top speed on down hills.

On the other hand if I were to change to a lower toothed double up front, then I'd have the huge advantage of easier climbing which would easily outweigh the disadvantage of loosing my downhill gear.

If I don't find a setup I am confident will work then I may end up buying a new 42t chainring (as this is the replaceable one on my chainset) and a 14x28 cassette. Not ideal, but still less worn and with lower gearing for the hills.

 

[RecordAceFromNew]

I've seen those 14x28 freewheels, and was actually planning on getting one, along with a new chain and new chainset (and possibly jockey wheels), to provide a completely new drive chain. However now after looking further into it, almost every double chainset I've seen with the ratios I want something like a 103/107 BB to keep the 43.5 chainline.

Currently the cranks come fairly close to the chain stays upon rotation, and I'd be concerned about them striking the chainstays if I removed that much width from the bottom bracket.

Take for example the singlespeed chainset "TheDoctor" linked - It requires a 119mm BB, which seems much more reasonable, unlike the doubles I've been looking at.

Half of me says take it to the LBS, as they'll get it right.. The other half of me says they'll charge an arm and a leg for what is really a very simple fitting routine.

Incidentally which chainset are you talking about that needs 103/107mm BB?

The fact that a chainset requiring a shorter BB spindle than your existing does not mean it will be that much closer, or indeed any closer, than your existing chainset to the chainstay. The reason is each chainset is designed with a BB spindle length in mind. In other words, chainset A with matching 110mm BB could give more chainstay clearance than chainset B with matching 122mm BB.

The link The Doc provided seems missing something, but I suspect he is talking about the Stronglight 55? I run one on my folder. A standard Shimano UN series 118mm JIS BB delivers 45mm chainline for me (and I believe both the 113mm and 115mm Shimano UN series BBs will deliver approximately 43mm of chainline - the 115mm is less asymmetric, longer on the non-drive side). Incidentally are you aware that an additional small ring can be bolted onto that chainset (see the bottom of the page)? The 55 is not the most robust chainset around, but it is very light.

Since a 28T at the back is a significantly lower gear than a 22T, assuming the rear mech checks I mentioned earlier pass you could always switch the freewheel and chain first, at very little cost, and see how you like it, and whether a new chainset arrangement is warranted.

 

[HovR]

Incidentally which chainset are you talking about that needs 103/107mm BB?

These were the two I've been looking at, (posted in this thread earlier by other members) with the BB widths I've been mentioning. 103 or 108 here, and 107 here.

The fact that a chainset requiring a shorter BB spindle than your existing does not mean it will be that much closer, or indeed any closer, than your existing chainset to the chainstay. The reason is each chainset is designed with a BB spindle length in mind. In other words, chainset A with matching 110mm BB could give more chainstay clearance than chainset B with matching 122mm BB.

I did wonder if this might be the case, and this is really want I wanted to hear - Thanks!

The link The Doc provided seems missing something, but I suspect he is talking about the Stronglight 55? I run one on my folder. A standard Shimano UN series 118mm JIS BB delivers 45mm chainline for me (and I believe both the 113mm and 115mm Shimano UN series BBs will deliver approximately 43mm of chainline - the 115mm is less asymmetric, longer on the non-drive side). Incidentally are you aware that an additional small ring can be bolted onto that chainset (see the bottom of the page)? The 55 is not the most robust chainset around, but it is very light.

Yes, I had noticed that - However if I'm going the double route, I'm trying to steer clear of chainsets with chainrings permanently attatched to the crank - Otherwise at some point in the future I'll be faced with this conundrum again when the fixed on chainring is worn out! Thanks for the tip though.

Since a 28T at the back is a significantly lower gear than a 22T, assuming the rear mech checks I mentioned earlier pass you could always switch the freewheel and chain first, at very little cost, and see how you like it, and whether a new chainset arrangement is warranted.

This seems like the most sensible route to go, and yes, the mech does pass those checks.

If I do still want the lower geared chainset, then I'll probably get the Stronglight Impact Double along with the recommended Stronglight JP400 BB (which I can actually find for sale, unlike the BB's recommended for the FSA chainset!)

Thanks again!

 

[HovR]

As you probably are aware you can get much lower geared 5 speed freewheels than 14/22. If you want lower gears, and if you don't mind sticking with 52/42 up front (which was pretty much standard equipment for everybody in those days), you might well be able to use say a 14-28 freewheel, which are readily available. A 42x28 is actually lower than the 34x22 that a compact chainset gives you!

Well I decided to try this out before splashing out a large sum of money on a new chainset. Ended up buying

14-28 "Eagle" freewheel (NOS): £5
Alivio RD: £20
Cabling: £10

Ordered a new RD even though the old one would have worked, as the old one was getting pretty worn and noisy anyway, and the Alivio derailleur looks nicer! All fitted today, and shifting is much nicer. Went on a 10 mile test run, and the new low gear kept me sitting and spinning on hills I was having to grind up previously, so initial impressions are good.

I'll hopefully get out on my 25 mile route some time this week, which has more hills including one fairly grueling climb to give the final verdict!