Chainline Question

(Hangs head in shame)

Never happened when I was younger... must be stress.

Thanks for the support.

i was just going to say with 36.3mm chainline you need to head over to the "clown bikes" thread.

It was late... I was tired...

36.3mm doesn't include the sprocket. Add 7mm for an EAI or Dura-Ace, which gives an actual chainline of 43.3mm.

please don't crucify me!

i don't know much about conversions, but i've bought a loPro that's 130mm in the rear because it was too hot to pass up!

i haven't bought much for it, but this is what i'm planning.

i've got a set of the SJSC high flange track hubs because the rear spaces to 130mm easily and i hear for the price they're worthwhile. apparently, they support a 42mm chainline.

i've got a hold of some RD2s (which apparently support 45mm with the ring where it's meant to be, no clue if it's flipped)

my bb length that i need is about 109/111 though, or somewhere around there as it would appear.

my issue is directing my concern. do i skip the 103mm sugino RD2 bb for the cranks and get a phil or something so i can adjust chainline to a ludacris degree and not worry about anything? should i just wham in whatever bb i can get in there, and space out the cog on the rear? i know chainline can be out a mm here or there, but to be honest i'd really rather it wasn't.

as you can probably tell, i'm not too up on conversions. track bikes aren't a problem for me, but i'm just concerned about chainline.

the bb casing is 68mm standard, and the bb that's in there (some square taper jobbie that came with the frame) looks to be a 109-111 as i mentioned before.

please help! i've been scouring sheldon brown on my phone regarding conversions and chainline but am seemingly getting nowhere fast.

cheers.

Have you read this Sheldon Brown piece;

http://www.sheldonbrown.com/chainline.html

It should tell you everything you need.

cheers andy, yes i have done, i'm just mostly wondering what the best solution to take for adjustments is. somehow, spacers and such just seems like an awful idea to me...

If the hubs you have give a 42mm chainline then why buy cranks that have a 45mm chainline?

Is it because with a 42mm chainline the chain ring would strike the chainstay?

it's really only the price of the cranks, just getting them from a mate on the cheap with a 42t chainring (as i hear clearing the chainstays can be an absolute bastard.

i'm sure this doesn't help at all but here's pictures of the frame.... i can take any measurement tonight when i'm back at home and report back if anything helps.

http://s590.photobucket.com/albums/ss344/samajap-pajamas/orbit/

Get cranks and BB that give a 42mm chainline (unless aforementioned chainstay strike scuppers you, which you might solve by downsizing both sprocket and chainring to keep the GI you want) and avoid spacers if at all possible.

Spacing the rear hub is fine, I'm running a conversion with 130 mm rear dropouts and Miche track hubs using spacers and it's been trouble free for a year or so. The spacers are actually slightly offset, so 2 mms more on one side, to allow me to get a decent chainline.

does that mean the wheel sits in a funny fashion offset? do you feel that when you're riding?

It's slightly off centre and I can't say I've ever noticed it when riding.

It's slightly off centre and I can't say I've ever noticed it when riding.

and technically you could even dish the wheel ever so slightly so the rim is still central.

On my conversion I have 126mm dropouts, I just chucked a couple of washers in each side.

Note that this is a temporary measure, but it works

so with all this in mind, i should probably go for the chainset minus the bb, get a phil to have ultimate control, and if spacers are necessary on the rear to pull off a good line i'm going to have to go for it - does that seem like a sensible solution?

i do kind of want this to be an elegant solution aswell though. i have a fuji that's quite nice, done alot to it, this was meant to be my cool-sunday-best-riding loPro covered in shiny things...

why dont you just find the recommended bb length for 45mm chainline and minus 3mm off it and get that bb length?

well i'm guessing it's meant to be 45mm with the 103mm bb they supply in the same RD2 line.... considering that won't be any good for me I guess it's going to be pushed all the way out by 6-8mm by the time i get a 109-11.... i'm confused and losing sleep over not getting this concept.

oh i see what you mean. why are you getting a 109-11?

seemingly that's the length required to clear the chainstays. it was the recommended length from the seller of the frame to me for purposes of running it as a conversion as it's a road frame. :/

should get the ends stamped off and forks welded on, i just don't want to do this because i really don't want to get it repainted!

oh i see. then i guess you could respace the hub to give correct chainline and redish wheel.

edit post morning coffee: like andyp and dammit sez, a few axle spacers are fine, and I have run bikes like this (even with a few mm rear wheel "offset") without any noticable problems before. I had sprocket and chainring spacers in my mind primarily, which are sometimes-okay and naff respectively.

Best bet to get the right crank/bb for a 42mm chainline, but if you've got a 45mm one handy already, and don't mind trying a setup to see how it works out, howsabout something like this: say you are going to need to space out the rear hub from 120mm to get 130mm OLN right? So, 10 x 1mm plain washer are in order, five on each side, to be located nice and secure behind the threaded spacer nuts. But, clever you puts 8 of them on the non-drive side and 2 on drive side. This gives you 130mm OLN and a theoretical 45mm chainline, with a rear tyre 3mm off centre (only you can decide whether this will keep you awake at night. Or re-dish).

Hopefully I'm not talking poopoo. Cost of spacers - pence. Cost of Phil - pints (and pints)

Worth a tinker on these long dark nights.

olly: cheers for that, i had thought that this would be possible, but am worried about the concept of being 3mm out. i just figure it'll look stupid, it's less that i would notice a pull or anything silly like that, because from UTFS'ing i've noticed quite a few people going on about it.

i reckon if i go with the phil (despite it's nearly 75gbp pricetag) it'll give me best look and most flexibility as far as modifying the chainline from the front - is that a correct assumption? i'm not TOO bothered about the cost, obviously i'd like it to be less, but if it comes down to it, i'd rather spend to get a good look then skimp and have it 3mm out and simply "working" as opposed to "butter"

I too hate fudges, but I hate even more spending money when theres a good alternative ;-)

I dunno about the Phil because I've never used one, but a quick google tells me that "Judicious setup allows you to move the 'line 2mm either way" so I guess it would help - but not quite 3mm that you need. Don't forget that different brands of sprocket have different shoulder to tooth dimensions which can be very usefull when your a mm or so out. Looks like a phil BB, cups and install tool is coming in at £120 from HubJub (good people, Will is helpful you might wanna call him).

A re-dish if you don't have a truing stand should be a tenner, a score max at a decent LBS. Thus with the axle spacers option you'd get working, butter and perhaps a hundred quid in your back pocket to buy some rad threads, pink deep Vs, campag giant corkscrew or some other essential goodies.