Chainline woes!

Manc33

Guys I fixed it.

Manc33

Guys I fixed it.

dj58

Don't leaves us in suspense, tell us how.

imposter2.0

Best not to ask these things, where Manc33 is involved....

Manc33

DJ58 wrote:

Don't leaves us in suspense, tell us how.

It was 2 full pages of text lol.

How I fixed it:

I always had the right chainline (45mm) but needed to put on a flat bar triple shifter, long story.

At some point I will get a R770 left shifter as an upgrade to the R440 I am going to start using.

Using the FD-R443 this allows a road chainset to be used with a trigger shifter but it has to be flat bar specific, where a MTB left trigger shifter (or STi lever even) won't work with that flat bar FD.

What did I fix? All sorts. Slack cable when on the granny ring and swapping to separates means I can properly use my lovely "new" DA calipers with "flat bar" road levers - as opposed to my MTB brake levers that have only 50% of the leverage of a road lever. I thought my brakes were crap.

Not even put any of this stuff on my bike yet so don't know if it is really fixed, its all theoretical. :P

Manc33

Guys, my front mech inner limit screw is unscrewed the most and yet, I still have to have slack on the cable on the granny ring for the shifter to shift to chainrings normally. If I tighten that slack off (barrel adjuster), shifting causes way too much chainrub on middle > biggest.

In theory, the chainrings need to come in a bit to get the middle chainring nearer the biggest sprocket, but I had a narrower BB axle on before (a 115mm) and it wouldn't change from middle > large chainrings then. Since then I have put even bigger chainrings on but now have it working on a 122.5mm BB axle and about 45mm chainline like the Shimano PDF document says.

Should the chainline go bigger still? :x I think it might just have to have a little bit of slack there or something, its stupid that there'd be any "play" in a shifter! There's no excuses for it.

Creating a bigger chainline with say a 127mm axle... will make the chainrub issue bad (or would the mech accommodate?), but would mean the cable slack was taken up on granny - because the front mech expects the chainrings to be further out (obviously if the inner limit screw has to be right out / the mech tucked all the way in to change to granny). :roll:

I hate how I have to have it setup so the mech doesn't start moving as soon as I move the shifter.

All I haven't tried is a bigger BB axle, I just want to know if putting the chainrings out more (from the biggest sprocket) will create unfixable chain rub or will the FD then actually be working at the right angle and it could even help fix chain rub I currently have?

Does it all make sense?

darkhairedlord

the bb axle length is related to the make and model of chainset. Some require long axles some require short. My old Vero chainset had a 102mm axle. Without knowing the chainset and BB used there is little more than guess work involved. Just but a second hand spesh globe or something..

Ben6899

Can we start from the top? Tell us your setup, please. Because I no longer have any idea what your bike looks like... sometimes the problem jumps from the screen if everything is laid out in black and white. So...

Frame:
Shifters:
Front mech:
Rear mech:
Bottom bracket shell width and type:
Bottom bracket type and spindle length:
Chainset:
Rear wheel/Freehub:
Cassette no. speeds:

keef66

Ben6899 wrote:

Can we start from the top? Tell us your setup, please. Because I no longer have any idea what your bike looks like... sometimes the problems jumps from the screen if everything is laid out in black and white. So...

Frame:
Shifters:
Front mech:
Rear mech:
Bottom bracket shell width and type:
Bottom bracket type and spindle length:
Chainset:
Rear wheel/Freehub:
Cassette no. speeds:

Alternatively it might look like a listing for a bike jumble sale!

Ben6899

keef66 wrote:

Alternatively it might look like a listing for a bike jumble sale!

Admittedly, yes.

Manc33

Frame: Triban 3 Red 57cm
Shifters: Left: SL-R440 / Right: SL-M748
Front mech: FD-R443 (8-speed)
Rear mech: Deore XT M772 (9-Speed)
Bottom bracket shell width and type: 68mm English
Bottom bracket type and spindle length: square taper/ 122.5mm (had 115mm on already)
Chainset: FC-B124 (old Biopace triple, with Spa chainrings 24-38-52)
Rear wheel/Freehub: Stock Triban 3
Cassette no. speeds: 8

Here's what I'll do:
Put chain on middle>big by changing from granny to middle with one sweep (so it includes that "trim")
Make sure its down shifted on the trim
Adjust so the chain is lightly rubbing in middle>large
Screw inner limit out more (if possible)

That might take up some slack.

It is using a "flat bar" front shifter and "flat bar" front mech, in fact it is the exact parts that go together this time.

I said before the chainrings could come out a bit to get rid of the cable slack but that would make it worse, the chainrings would need to come in... but with the inner limit screw already out on the FD its going to start getting to the point where it won't change down to the granny because its too far in. I think it already was getting like that on the 115mm BB axle.

When I first got this bike, the inner chainring was nearly touching the chainstay. That was with a different FD though.

I was thinking last night, do Shimano compensate for bigger seat post clamps on their derailleurs by adjusting the thickness of metal so the FD is always at the same point across different bikes with different seat tubes? No, they tell you to "use a 45mm chainline". Its so hard measuring that... but I don't know how far away from 45mm you can be before it goes totally wrong. It seems worse bringing the chainrings in than out.

darkhairedlord

My guess:
Frame: Holdsworth carbon from PX
Chainset: alivio or chinese copy of a carbon FSA triple MTB
BB shell: 68BSA
BB: 73 x 125
Rear Mech: Deore 9speed SLX
Cassette: C90 TDK mix tape off a mate that once worked in club circa '92 but still bangin.

I'll get me coat

darkhairedlord

you should have a 127.5 BB.
http://velobase.com/ViewComponent.aspx? ... 5&AbsPos=0

You do make life hard for yourself!

Manc33

It says on Velobase it needs a 127mm BB axle! :shock:

http://velobase.com/ViewComponent.aspx? ... 5&AbsPos=0

"For use with a D3-SS 121.5 mm bottom bracket with 5 mm drive side offset axle, or the more readily available symmetrical UN54 127.5 mm cartridge bottom bracket."

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGH!!!!

I know the old steel frame this came from had a BB axle that was 121 or 122mm, but that had a 28.6mm seat tube and my bike now with that crank on has a 31.8mm seat tube.

So you might need a 45mm chainline IF your seat tube is the "standard" size, but what if it isn't? Like I said, does Shimano accommodate for this? It doesn't say 45mm chainline on a standard width seat tube, it just says 45mm chainline, thats it. Pushing the mech out like that changes the angle. :roll:

Ben6899

See what I mean?

If you explain things clearly, then we can help. Turns out it looks like an easy fix.

Can I recommend you go for exactly what you need (127.5mm BB length); not something else with a bodge?

darkhairedlord

has the CS been on and off a lot of times? the hole may be slightly bigger than originaly so you might need a longer one .
You could bodge it though by buying a the italian taper

Manc33

The bike this came from has a 121mm BB axle and 28.6mm seat tube.

So how come it didn't have a 127mm spindle on THAT bike? I guess I did that wrong too - when it was set up by a bike shop 24 years ago? It would seem they didn't know what they were doing just as much as I don't know what I am doing, can you believe that? Well they sold hundreds of bikes to hundreds of people and they all worked.

That is approximately what I have on it now - 122.5mm axle - but on a bike with a 31.8mm seat tube.

darkhairedlord

seat tube is irrelevant.

The chain line needs to be correct or the chain wont be in line and the shifting wont play nicely.
see why its called "chain line"?

If it's too confusing sell all the parts back on ebay and buy the flat barred road bike like you always wanted, all set-up ready to go. Or a proper touring bike with high set drops from spa cycles or other beardy type shop.

Manc33

The chainline already is 45mm.



Source:
SI-5E70A-000-00-ENG_v1_m56577569830684418.pdf

I reckon if the axle is made more narrow or wider it will make it worse.

It will just have to "work" having a little cable slack on the granny ring and needing a big shove to change to middle.

rolf_f

Manc33 wrote:

Guys I fixed it.

Manc33 wrote:

Not even put any of this stuff on my bike yet so don't know if it is really fixed, its all theoretical. :P

Truly a forum legend.

darkhairedlord wrote:

Or a proper touring bike with high set drops from spa cycles or other beardy type shop.

I'd pay good money to watch Manc33 trying to buy a bike from Spa Cycles.......

darkhairedlord

Rolf F wrote:

Manc33 wrote:

Guys I fixed it.

Manc33 wrote:

Not even put any of this stuff on my bike yet so don't know if it is really fixed, its all theoretical. :P

Truly a forum legend.

darkhairedlord wrote:

Or a proper touring bike with high set drops from spa cycles or other beardy type shop.

I'd pay good money to watch Manc33 trying to buy a bike from Spa Cycles.......

Webcast.

darkhairedlord

Manc33 wrote:

The chainline already is 45mm.



Source:
SI-5E70A-000-00-ENG_v1_m56577569830684418.pdf

I reckon if the axle is made more narrow or wider it will make it worse.

It will just have to "work" having a little cable slack on the granny ring and needing a big shove to change to middle.

You trulY are out there aren't you?

The chain line "should" be 45 according to your documentation. This assumes it is on the correct BB, which it isn't.

imposter2.0

The more this goes on, the more I think that Manc33 is actually the ghost of Sheldon Brown, on a massive wind-up...

Manc33

I got a thin metal ruler in from the outside (my large chainring is big enough to allow it).

This way I could put the ruler up against the seat tube. It came out to 26.5mm.

So a 31.8mm seat tube diameter ÷ 2 = 15.9mm

15.9mm + the gap of 26.5mm makes it 42.4mm chainline, which means the chainrings are 2.6mm too far in.

Going from a 122.5mm axle to a 127mm will add 2.25mm to the chainline.

I think I was probably putting the metal ruler in that little cutout part for the front mech. :oops: If so that means my chainline is going to be even more narrow than 42.4mm.

Either way it needs a 127mm spindle.

darkhairedlord wrote:

The chain line "should" be 45 according to your documentation. This assumes it is on the correct BB, which it isn't.

I would think that if you have a chainline of 45mm and its meant to be 45mm, whichever BB spindle you have on must be the right one. It goes off making the chainline the right distance, not choosing this size BB or that size BB.

I thought it was 45mm but that was "trying" to guess where the middle of the seat tube is. It seems to be about 42mm.

Its not exactly the weather anyway, I'd be fuming if it was sunny out.

You know what worries me now, you can't even get a UN-55 bottom bracket wider than 127mm. What the hell kind of bike needs that on it. :shock:

The BB on the old bike that crank came off is indeed a 121mm but it will be asymmetrical, where the equivalent symmetrical one would need to be a 127mm.

You even made me think what it would be like ordering a bike from Spa. :P I change my mind every day but I call it striving for perfection and adapting.

Ben6899

I thought we'd solved this [by identifying the correct BB you need]?

darkhairedlord

Ben6899 wrote:

I thought we'd solved this [by identifying the correct BB you need]?

he can't hear you under his tin foil hat!

Manc33

With a 122.5mm BB spindle it had a 44.0mm chainline.
With a 127mm BB spindle it has a 46.5mm chainline.

Both work - but the 127mm works better. Chainline is meant to be 45.0mm.

I got it working, that's it. Now what do I do. :twisted:

Everyone is moving to a 1x10 setup...

dj58

In view of your woe's with the triple, that might be the ideal solution for you Manc33, then all you have to do is decide what size front chain ring and which cassette ratio's and long cage RD. Simples.

Manc33

DJ58 wrote:

In view of your woe's with the triple, that might be the ideal solution for you Manc33, then all you have to do is decide what size front chain ring and which cassette ratio's and long cage RD. Simples.

I was joking, or were you joking too?

Its just taken months on end to get the triple setup right.

dj58

Manc33 wrote:

DJ58 wrote:

In view of your woe's with the triple, that might be the ideal solution for you Manc33, then all you have to do is decide what size front chain ring and which cassette ratio's and long cage RD. Simples.

I was joking, or were you joking too?

Its just taken months on end to get the triple setup right.

Yes, I was, though no doubt it will be one of your future projects. :?:

Manc33

There's no woes at all with it now, there's a bit of slack in the cable on the granny but only a normal amount. I hated having that trim on the trigger shifter but you can get used to it. Never thought a 28t difference would work when Shimano say max is 22t but there's no problems shifting at all.

The #1 thing to remember is that small-small will write off the rear mech. :!: So accidental shifts are a no-no.

I do want to upgrade the SL-R440 to a R770 and the SL-M748 8-speed to a M980 10-speed, but then it needs a cassette and chain and I can't justify doing it, but I miss that XTR shifting, its true, XTR rear shifter (M951) beats the XT one (M748). Definitely more accuracy on the XTR, it gives you more peace of mind, shifts are crisp and instant, with the XT one there's a millisecond of a stutter, shifter doesn't have the same quality feel to it either.

I'd give my left nut for a M950/M951 8-speed shifter pod, but they are too rare. Someone in Germany had a NOS pair but I don't need the left shifter and I ain't paying that. If anyone has got one I would pay up to £40 just for the right shifter, I'd rob a granny to pay for one. :twisted: The irony is I have a pair already but they have brake levers incorporated and I am on road calipers, its dangerous because of the cable pull running MTB brake levers with road calipers and with UK weather being how it is I decided best to be safe. Its got Ultegra flat bar brake levers on now. 8)

EDIT: Sold in the past...
http://www.ebay.com/itm/Shimano-XTR-sl- ... 1542812656

If one does come up its probably going to be abroad. Finding a pair is hard enough but finding someone just selling a right pod pfffffffffff. Its a stretch.