Chainline Question

Another one of these threads sorry! First fixed gear build, know very little about bikes...

Could some of you look at the following pictures & tell me if my chainline is straight enough please? Doesn't seem to make any noise when I'm riding (took it for it's first ride today!!!!) but when I spin the pedals inside I can clearly hear the chain connecting with cogs. Is it worth moving the chainring to the inside of the crank?

Thank you in advance.

If you really want to lay your fears at rest, take it for a ride down Highgate Hill West.

1st pic looks miles out, swap the ring to the middle or get another bb.

use the transition database to work out what length bb you need

hello guys, i was trying to put a new bottom bracket on my bike but the shell was 66mm instead of 68.. And the only spacer i had was 3mm. Now the chainset is 2mm off from what it was supposed to be and the chain makes some noise.. Is that really bad? Do i need to find a proper spacer or is it fine to leave it as it is..?

Hi, a few things to start the post:

I promise I genuinely have searched the forum for an answer to my problem and there are very similar threads, however having read them all I am now more confused than before!

My first post was in the 'Newbie' section and explained the error of my ways concerning the (regrettable) purchase of a Create bike. It broke after one month, I don't want to talk about it! Let's just say it was an impulse buy and it was only intended to get to uni and back until I could afford something better. I am now in the possession of the below bike which I have only swapped over the wheels from the Create until I can afford something better.

I am no expert with all of this, so please go easy on me!

Rightyo, I apologise...this is going to be a long post!

I initially swapped over the chainset from the Create bike, this consisted of a 44t chainring and 165mm crank arms. The bottom bracket is now a cheap Shimano UN25 which is 110mm in length. I also have a Lasco chainset which I have tried (same spec as before) but have the same problem which I will explain.

The Create wheels have a flip-flop hub and the fixed cog is 17t.

The rear fork spacing is 130mm.

The chainline on the rear is 42mm. The front is 52.5mm.

This is how it looks with the above installed:

As you can all (hopefully) see, it is quite a way off.

The original chainset is a Sakae Roundtech 2. This fits perfectly and creates a perfect chainline (42mm on the front):

Am I right in thinking it's not possible to disconnect the chainrings and get shorter bolts due to how these are made?

So there is my problem. From what I can tell the Lasco chainset and Shimano bottom bracket cause a 10.5mm difference between the front and back. It looks as if I don't have enough space for a shorter bottom bracket. If I do, then would it be a 100mm bottom bracket and does it exist?

Alternatively I need a new chainset. This is quite hard to explain, but the spider on the Sakae sits in closer to the chainring compared to the Lasco causing a shorter distance between the middle of the tube and the middle of the tooth on the chainring. What would my options be for a new chainset?

Please bear in mind that I recently graduated from a very, very expensive Uni course (materials, printing etc.) and I am on a budget!

Again, please excuse the lack of technical knowledge and terminology, I am a beginner when it comes to all of this, but I am enjoying learning everything, slowly and painfully!

Any help and advice greatly appreciated.

Andrew

102mm BBs are available and should do the job for you, it doesnt have to be exact
Alternatively, you could place the chainring on the inside of the spider, if there's space.
What's the minimum BB width your Cranks can run?

Thank you Rosmal, I'll do a little Google searching for the bottom bracket.

Although, I just swapped the chainring to the inside of the spider and now have it down to 48mm. I checked the chain and still have tight and loose spots at different points of several revolutions of the pedals (forgot to mention this previously).

I'm not sure about the minimum bottom bracket width. These are the cranks in question:

http://www.velosolo.co.uk/lasco.html

Tight and loose spots on the chain are more likely due to the chainring not being entirely circular. This is normal for most chainrings, but you can make it less noticable by centering the chainring on the cranks through small adjustments.

See here: http://www.sheldonbrown.com/fixed.html and look at the part on chain tension.

Thank you, Frankie. I keep finding new information on the Sheldon Brown site, there just seems to be endless amounts! I'll give this a go to try and resolve the tight and loose spots.

104/5mm b/b

Is that taking into account the new measurement with the chainring swapped over to the inside or the original figure of 10.5mm difference between front and back?

If the Shimano is 110mm and I went for a 104mm would this equate to the chainring being closer by 3mm considering the total difference is 6mm (3mm for each side)?

ish

a 102mm BB should do it - You might also want 10mm worth of spacers for the rear hub. With these spacers, you can then put, say, 6mm on the non-drive side, and 4mm on the drive side, bringing the sprocket more in line with the desired chainline.

Or remove the chainring and chainring bolts from the Lasco chainset and mount it on the Sakae crank.

Brilliant, thanks Pifko. Had a quick browse and Token seem to do one for around £20, very limited supply everywhere though from what I can see. Any other suggestions?

Is there an online tutorial for spacing out the rear hub? I kept looking at it today thinking that was all I needed but the cog is right on the edge so I don't understand how it would work? Or am I overlooking something obvious and being a bit stupid?

Sorry, I realise the above photograph doesn't show what I mean very clearly but the camera has run out of battery and I can't find the charger!

The shortest shimano UN54 bottom bracket is 107 mm, so that would bring the chainline down to 45mm if you were running the chainring on the inside.

3mm isn't too bad.

Is there an online tutorial for spacing out the rear hub? I kept looking at it today thinking that was all I needed but the cog is right on the edge so I don't understand how it would work? Or am I overlooking something obvious and being a bit stupid?

As an example, if you removed the locknut from the right side and put it on the left you will have shifted the hub across by the width of the locknut. That may not be able to be done with the locknuts in this case but is just to demonstrate what it means. The wheel would then need to be dished slightly to keep the rim centred in the frame (tighten left hand spokes, loosen right)

I see you also use a freewheel so spacing may not be a good idea anyway as it would though the chainline out when flipping to the freewheel. So not sure why I bothered to write the first paragraph now :-)

I apologise for bumping this thread back up to the top, but I need some advice please!

Firstly though, thank you all for your help and advice.

Thank you Kerley. I don't plan on using the freewheel so will definitely look into spacing out the rear.

However, as a quick fix, I found two Token bottom brackets. I went to order one of them and then realised one is 103mm and the other 102mm. I then researched a bit further and found that one is 'JIS' and the other 'ISO'. I've looked on Sheldon Brown and read that it can cause 4.5mm difference in chainline.

This has now confused me further so I am hoping someone can tell me which one would be best:

The JIS one is on Evans, so I am going to pop down tomorrow and see if they have it in stock (if that is the right one to buy).

Sorry if it's a stupid question. I have a suspicion that it might be!

Ok, I have now found more information on VeloSolo. Am I right in thinking a late 80's Raleigh Nottingham frame with Lasco chainset will need a JIS bottom bracket?

I found more options so just have to decide on one of the following (assuming I do need JIS tapered):

Token JIS 103mm
Sugino JIS 103mm (slightly more expensive)
Tange JIS 103mm

Suggestions please?

Yep, JIS BB is required.

Brillaint, thank you Pifko. Hopefully I can finally get this sorted and get on to riding this pain in the arse bike!

I am planning on finally building a set of wheels and was wondering if hub spacing can affect the chain line, and does there need to be a certain amount of compatibility between crankset and hubs

Upper right hand corner. Searchbox. Enter the term "chainline." Happy reading.

Wouldn't it be easier to get a shorter bb axle?

currently trying to get a chainline issue resolved
viking severn valley frame
bottom bracket width 68mm
using SJS fixed fixed hubs
and shimano golden arrow double crank set

Any idea what the BB axle length is that I should be getting
If i need to provide more detail please let me know