Carrera Subway Zero Chainline woes...

Can anyone offer any advice to this little problem I'm currently playing with.

I've been "gifted" (some might call it dumped on!) a 2nd Hand Carrera Subway Zero. Its a purpose built SS/FG Halfords-esque cash in on the SS/FG market as far as I can see but at heart its too good to send to the knackers yard just yet and I could do with a back up to my trusty 34 y/o Dawes conversion.

Its been used as a 4 mile-a-day station to work to station bike by a work colleague. Maintenance is a bad word in his book and has pretty much been non-existent, my book differs but there y'go! Anyway, underneath the grime and neglect is a purpose built 'modern' (ish) bike I want to use so I started fettling it during lunchtimes and after-work. The Brakes didn't, but after fettling and block replacement do now. The bottom bracket was creaking, so I replaced with a same 113.5mm replacement. Chain is totally beyond it, no biggie to replace.

The Rear wheel however is where things start hotting up. The original got damaged, so the owner replaced it not really knowing anything about O.L.D or chainline. Frame spacing is 126mm but the owner bought a 120mm O.L.D replacement. He only realised this when he went to fit, being in a workshop nearby he asked me to have a look and I ended up using washer's as spacers to make up the 6mm or so and he was stoked he could ride it again and has done for about 3 years. He doesn't need it anymore so he remembered me and donated it.

I've measured the chainline at the rear wheel and its 42mm... however at the BB it's closer to 51/52mm! s far as I know 42mm is usual for FG/SS flip flop hubs yes? So... did Carrera use wider hubs originally to get the chainline out to 52mm or so at the rear or summat? Or is it that I'm missing something really obvious here.

I've replaced the original clapped out BB with the same 113.5mm width, its a standard 68mm housing, English thread, nothing trickster that I can see. The frame doesn't look bent or nowt as far as I can see.

Help! (Please).

Dave.

I'm going to guess that the "original clapped out bb" is the "2nd clapped out bb" and it was replaced by a random at halfords who was thinking carerras all take 113.5(I think the geared ones do) when it probably took a 107mm or something.

107mm +/-3mm OLD = 9.5mm out?

Good guess Mr Clockwise but I don't think thats the case, but I'll check with the previous owner for sure tomorrow.

Another reason I don't think thats the case is that the gap between the crank and the BB shell looks OK. A 107mm BB would bring it in even closer to the shell wouldn't it? Close.... very close, here's a piccie to illustrate...

1 Attachment

Looks like it could go a couple mm inwards but I see your point. The difference would only be 3.75mm on either side anyway. Maybe take into account the ISO/JIS difference that can change spacing by a couple of mm if you mismatch crankset and BB...

Just for good measure: the bb shell is 68mm right? Standard BSA width? Surely no one would design a bb that lets the cranks touch the shell.

If the bb shell is wider than 68mm then that's a problem no spindle length will solve I'm afraid. You could try converting a road hub for easy chainline matching.

Edit: it says in your post that it's 68mm :/ in that case there must be something about the original hub. Is it also 'clapped out' or can you still fit it to check?

There's one final thing that seems a little weird in the above picture. The cranks are close to the shell but the chainring is nowhere near as close to the stays as it could be. Is it fitted okay? Maybe you have a spare crankset you could try?

Aye, deffo 68mm Mr Smolders, I check with a Vernier gauge face to face, 67.88mm actually.

The original BB was a 'Chin Haur CH52-68 113.5L', the replacement is one of these -> http://www.ebay.co.uk/itm/SHIMANO-TYPE-SEALED-CARTRIDGE-BOTTOM-BRACKET-SEALED-BEARINGS-110mm-to-127-5mm-/261272331430
in 113.5 sizing, seems identical. I do still have the old BB but damaged one of the 173110-2RS bearings. I was attempting to replace the actual bearings (I repair centrifuges and Lab equipment for a living so have access to a Bearing Press and pullers (which is handy!)) but then looked up the price for a complete BB and for £8.95 gave up!!! :-)

Yeah, I know what you mean re the Chainring to stays distance. To me it makes sense to utilise this big spacing and get the chainring inboard a bit. I think my only recourse to get the chainline back to match the 42mm at the rear hub is to use chainring spacers to offset the chainring.

I took the chainring off the crank spider to clean everything and reassembled it the same way it came apart. I don't think it had ever been cleaned (or seen oil either in the last year). There were no spacers so I dont think I've put anything back together wrong. See why I'm puzzling so much!? The Chainring is mounted on the inside of the spider already so I can't see how I can get it any nearer at the moment unless there's someway of mounting the chainguard inside too and then mounting the Chainring on top of that?

Dunno. I more puzzled than a Monkey Puzzle tree doing a tricky Jigsaw in the dark.

I've used one of these as a polo bike in the past, it had 120mm rear spacing.

Bb axle is way too long.

You needn't be able to see the axle 'tween crank arm and cup.

That said, a modern frame with 126mm spacing? I don't think so.

OOOoooo, summat weird going on with this bike maybe then?

Looking at these pics of this one on the eBay -> http://www.ebay.co.uk/itm/Carrera-Subway-Zero-Singlespeed-Fixie-ROAD-RACING-BIKE-/111492455022?pt=UK_Bikes_GL&hash=item19f577da6e
it looks like there's chain adjusters on it. The gifted one doesn't have these. Could that be the missing the 6mm betwixt what I measure and what n3il had on his?

Hmmm, I could see that putting chaintugs inside the frame instead of outside could make up the difference between a 120mm OLN wheel and a 126mm frame but still, a 126mm spaced frame these days?

I know/think Surly (and probably a few others) do frames with kind of 'in between' spacing so you have the choice of singlespeed or geared set up but a) steel not alu and b) Surly not Carrera.

Aha, I've found a vid on You Tube which shows what it should look like even better, roughly halfway through. http://www.youtube.com/watch?v=hIVZD5wkGUQ

I still don't know what to do mind.

enters thoughtful pondering mode and strokes hairy chin

You're not one for the easy life! :)

As mentioned already 126mm OLD is odd for a purpose built SS bike: that's the standard for 5-7 speed bikes.

However, having recently had my hands on a friend's Halfords POS, that's much more recent and he's had from new, nothing would surprise me: a random selection of dangerously mismatched parts.

Entirely likely that when they jumped on the bandwagon, they just bought what was cheap, ie outdated 126mm frames, and cobbled the lot together with no regard to proper function.

That or they just adapted leftover MTB: look at the bus-sized gap twixt tyre and fork of the bike on eBay!

What is the gap between the back of the crank and the chainstay like? Should only be a couple of mm or so.

If the chainring is on the inside of the spider, then it isn't a SS crankset but a double (or even a triple, any "spare" holes below those used to mount the existing ring).

In order to mount a bashguard (and hide their bodgery), the ring has been mounted on the inside.

In order for the ring (which is larger than what would normally be mounted in that position) to clear the chainstays (which are flared to accommodate the gears you don't have), a longer BB has been used (113.5mm is typical of a triple set-up).

"Chainline? What's that?"

You could ditch the bashguard and mount the chainring on the outside of the spider (so it clears the chainstays) and use a shorter BB to bring everything inboard, but my guess is that the cranks will bottom out on the BB shell before you get the desired chainline.

In fact, having written all the above, here's what I think happened:

• Halfords bought a load of old 3x7 speed MTB (hence the huge gaps above the tyres, V-brakes and 126mm OLD);
  
• they removed the two smallest chainrings, moved the large ring inboard and slapped on a bashguard;
  
• ditched the 7 speed freewheel and slapped a SS one on.
  
  

Result: a POS that will never work as intended and cash in the bank from unsuspecting punters.

If I'm right, then I'm afraid it really is more trouble than it's worth to get this running a SS set-up. Either turn it back into a geared MTB or write it off to experience.

You're not one for the easy life! :)

Aaahhh! You must've read about my previous project/triumph!!! :-) http://www.lfgss.com/conversations/231778/

Yeah, I learned a lot from that project and looks like this one is going the same way doesn't it.

I'll delve deeper at lunchtime and have a look at the Crank spider and frame spacing again but yeah, I agree the frame looks huge for an off-the-peg SS/FG bike but thats what it was sold as according to the original owner, no de-gearing or conversions, he's not 'that type'.... whereas I am. In the flesh it does look like a 'Mountain Bike' but with the addition of Track Ends in place of vertical dropouts. My 27 y/o Daughter has a geared version of this bike if it comes to it I'll get her to do a few measurements for me, I'd do it myself but she lives with her fella down in Surrey.

I like a challenge :-) I build Valve based Hifi Amplifiers for a hobby too, usually in Single Ended topology. pushes glasses up bridge of nose and blinks awkwardly

Yes, I've been following your adventures with interest.

I'm quite sure it is in the original spec: bodged at source.

Good point about the track ends: forgot about them. But I can quite imagine Halfords saying "Can we have another 1,000 of those MTB, but with trackends?".

You know, it does bear a distinct resemblance to my pal's bike: I'll have a closer look when I get the chance..

What I did with that was to set it up SS, by removing the derailleurs but leaving the freewheel on: happily that gave us a reasonable gear/chainline.

Hey! A man needs a hobby right?

News from the front! Witness cutting-edge measurements being taken post-sarnie....

OK, never assume all the information you're given is correct. This includes me!

After a chat with the original owner things are beginning to unravel a bit. It turns out there WERE chaintugs/adjusters but he found them 'fiddly' so just binned them (!) when the original wheel broke....as a result when he replaced the rear wheel he found the wheel would slide forward when peddling hard. It was then that he asked me to have a look a few years ago which resulted in me fitting a series of washers to keep the stays parallel. aha!

Look what the frame spacing is when the rear wheel has been removed...

So, lets go back and measure the OLD of the rear wheel the original owner used as a replacement...

Aaaah! Thats where the missing 5mm went which resulted in me suppling washers to make up the gap.

Original owner also confirmed this bike never had gears ever, and the BB is original, he bought it from Halfords new and its never been in a bike shop so its as was supplied excepting the rear wheel.

The Chainring and guard are located correctly (or at least as it came from Halfords) so I'm beginning to think that either Carrera did use a wider hub to get the chainline closer to to the 49-50mm or so I read at the BB... OR maybe..... they just didn't bother as Mr Suffolk suggests.

I've got a hefty clearance betwixt chainring and stay... observe...

and even more betwixt pedal crank and stay...

So, if a I purchase a new 120mm O.L.D. Flip Flop wheel and chain tugs at least it'll give me a 42mm chainline to aim for at the front by using stackbolt spacers (I think thats their correct name yeah?) to get the chainring in closer to the frame which it can take.

Sound like a plan?

If there's nothing wrong with the rear wheel other than the OLN measurement then you could insert a washer or two between the cone and locknut on either side to bring spacing up to 120mm.

Personally, I'd bring the front chainline into...er...line by replacing the bb with a shorter one. I'm confident you'd be able to get the cranks to sit in the right place without them binding on the bb shell. This would, in my opinion, be highly preferable to spacing the ring away from the crank arm.

Thanks for the input M_V, I appreciate it. I would keep the wrong OLD rear wheel but unfortunately its pretty much pooped. It was the cheapest the original owner could find by his own admission and boy oh boy does it look it! Single wall and buckled enough to make setting up the brakes 'interesting' I've found, the rim is also damaged where he's ridden it with low tyre pressure and it's contacted the road in places by the looks of it plus its dished, it was designed for a geared freewheel I believe and its threaded on one side only. The front is fine, its a modern double walled deep rim and its still true but the rear is bleeeuuugh! I've got one of these on my other bike -> http://singlespeedcomponents.co.uk/wheels/700c-flipflop-black-549.html and it done really well so I'm tempted to buy a 120mm OLD variant and be done with it.

Tomorrow I'll see how close I could get the crank to the BB without a mash of either. IIRC there's only about 4mm or so gap at the moment but I see your point re:- gettting the chainline in the right ball park by reducing the BB axle width further rather than relying purely on Stackbolt spacers at the chainwheel/Spider interface.

Thanks again for your guidance M_V (and everyone else), its much appreciated and is helping me a lot.

EDIT. A further question, are modern cartridge type BB's symmetrical? Is there usually the same amount of axle sticking out of each side when its fitted into a 68mm shell?

... plus its dished, it was designed for a geared freewheel I believe and its threaded on one side only.

...

Tomorrow I'll see how close I could get the crank to the BB without a mash of either. IIRC there's only about 4mm or so gap at the moment but I see your point re:- gettting the chainline in the right ball park by reducing the BB axle width further rather than relying purely on Stackbolt spacers at the chainwheel/Spider interface.

Thanks again for your guidance M_V (and everyone else), its much appreciated and is helping me a lot.

EDIT. A further question, are modern cartridge type BB's symmetrical? Is there usually the same amount of axle sticking out of each side when its fitted into a 68mm shell?

If the wheel was originally designed for a geared freewheel then it would almost certainly have been 126mm or wider originally. Sounds like someone whipped some washers out of it to make it ss/track frame friendly but went too far. Best be rid of it sounds. Wheel you linked to looks ok, I think Raleigh probably do a cheaper one but it might not be sealed bearing.

The reason I say using a shorter bb axle would be much better than spacing the chainring is that the crank arm supports the chainring and keeps it centred. Add spacers and I think you'll lose the support and not have the centring effect.

You can get the crank really close to the bb shell without it rubbing by the way. The cranks on my mountainbike are so close that I cannot see between crank arm and bb shell/cup. In fact, I suspect the crank arm is probably sitting inside the bb shell and cup if you see what I mean. You can get things a lot closer together at the bb than you can between the end of the crank arm and the chainstay as there is relatively very little flex at the bb.

As for your last question, the majority are yes. There are a few asymetrical bottom brackets out there but a regular Shimano UN5X or similar will be symmetrical

Ta for the thoughts and info on BB's again.

Another lunchtime spent measuring and BB fettlin'.

OOOoooh, I see what you mean M_V, I can move the crank boss actually inside the BB shell housing due to the shape of the crank casting. By doing that I can get the chainline at least 7-8mm inwards which gets it down from 50mm ish to 42-43mm ish. Cookin'... I believe the correct phrase is.

A 103mm BB is the smallest I've found after a quick trawl through eBay. If it's symmetrical, that would 'buy' me 5.5mm per side closer. Well, its a start!

Sounds promising!

Shimano UN-55 is the forum fave BB: in the event of a nuclear holocaust, there will remain only cockroaches and the UN-55; available in practically every flavour known to man and can be had for less than a tenner!

I meant to update this build/thread a while back, sorry for the delay. My excuse? I've been enjoying and riding it at weekends lots! :-)

Just as M_V and Scilly advised I managed to get the chainline down to 42mm is by fitting the 103mm BB cartridge. Awethumne, look at it now, phwwwwoooooaaarrr!

That pulled everything in nicely see...

Right, so thats how I've been riding it since just before Christmas, I fitted 25C Gatorskins and have kept it minimal, light and speedy. Love it. Very different from the Dawes fixie commuter in the other thread.

Talking of which, that Campag wheelset my chum gifted to me, thanks Mr Suffolk for the advice. Today Mr Postman delivered this lot in time for Saturday fettling...

Oooo, my flares are flapping, is it right to be excited by this kind of thing?

Good work with the chainline!

Shiny things are shiny: what's not to like?

The op was a success, whahey!

Chainline alignment was soooooo easy with that VeloSolo spacer kit. I ended up just taking a straight edge off the Chainwheel and combining different spacer widths to get the 16Tcog in the right place. I then rotated the chain wheel just in case there was any twist or warp to it which'd throw the chainline out a smidge. Easy peasy. Wichita Lineman....

You asked about PCD on the Dawes thread Scilly, I've decided that the Campag SS wheelset are going on this Carrera project not the Dawes for now. The Crank is branded 'Truvativ'. So, after a quick read of the Sheldon link you pointed me to I measured about 73.3mm C-C of the stack bolts, its a 4 bolt chainring so multiplying by 1.414 gives me a PCD of 103.62mm, I guess thats 104mm really?

The bike looks like this now, a smidge more aesthetically more pleasing to the eye than the Dawes project and the Fashionista's here perhaps?! :-)

and...

My christmas pressie from my long suffering partner was this...

Took it out for a 10 mile local hilly loop, feels nice, speedy, light. Crazy wind out there today, I'll get a few miles done on it 1st and see how I get on with the 16T cog before I fettle any further.

Thanks again for the guidance Mr Suffolk, really appreciated the pointers and help.

Cheers fella.

Phew!

Always a bit nerve-wracking offering online advice as to how other people should spend their hard-earned...

Flipping the chainring to check for warp is very "pro": kudos!

Speaking of which, yes that'll be 104mm PCD: if you do decide another ring is in order, then SJS are your friend.

Worth bookmarking them anyway: whenever you find you need some odd part that you're not quite sure the name of, SJS will have it.

Aesthetically more pleasing? No. But that's the point: what I like about your approach, is that rather than obsessing about the form, you've got the function sorted and are actually riding it.

:)

Chuffed with "Pro level Kudos" badge! I'm putting it next to my Cycling Proficiency badge I got in 1973 aged 8 :)

Bookmarked SJS, blimey, so many lovely things to play with.

If you think the bike follows function over form, thats nuthin', you wanna see the rider!!!

Hoping to take it on the 40 mile round trip commute this week when the weather lets up. Will report back /Salutes, clicks heels and exits briskly!

Woooaaaarrrh, I like this bike! I took advantage of the long weekend to knowingly clap myself out on a long ride and managed a PB for distance, 74.3 miles, whahey! I've never ever ever ridden that far before, it was brrrrrrrrwillyant.

I did this...

Ended up not as knackered as thought I was going to be so arranged to meet up with a mate at the pub for Pint post ride, hence the gap in start and finish points.

Thanks for all the guidance everyone on this project.

Twit and Machine in perfect harmony...