Advise me how to replace my bottom bracket! - NOW FIXED! :)

[jimster99]

Hello Lovely Forumites,

The bottom bracket on my daily rider junker bike (a vintage i.e. decrepit Carrera Vulcan) has started making alarming grinding noises so I took it off today (in the cold) with various grunting noises required. To my further alarm, ball bearings flew everywhere. I was expecting a cartridge but no! Just loose ball bearings and a cage (one of which looks perished). So my quandries:

- Do I just replace the cages and ball bearings? And if so what sizes should I measure? Halfords has these: https://www.halfords.com/cycling/bike-p ... =undefined

- Should I install a cartridge bottom bracket? 120mm wide crank arms seem to be an uncommon size however! Although it is a Carrera Vulcan from probably the 90s so surely they'd use some fairly common standard?

- Do I clean out the bottom bracket space in the bike with some brake cleaner? It's really gunky in there. Or will that damage something?

The crank arm seems to be exactly 120mm wide. The ball bearings seem to be 1/4" (according to my calipers). Pics attached below! Help much appreciated Thanks!

[jimster99]

[jimster99]

[cycle tramp]

Wow, that's exciting.. what's the view from the other side of the bottom bracket like?

[jimster99]

Wow, that's exciting.. what's the view from the other side of the bottom bracket like?

You sound like a cheery fellow!

[gbnz]

Given that cartridge BB's are both universal and cheap, I'd simply try one. Personally, when simply doing 2-3k a year on a spare bike a few years back, can recall using a bit of epoxy resin to ensure the fit wasn't a problem, Can't recall a problem

[rjb]

Wow, that's exciting.. what's the view from the other side of the bottom bracket like?

You sound like a cheery fellow!

That's a genuine query to see if its a standard old cup or one that requires a dedicated removal tool. The damaged cage suggests your unit is knackered. I would just replace with a sealed unit as close to 120mm as you can find. You will need a dedicated tool to fit it. :wink
Ps measure the bottom bracket width to ensure your replacement is the right size. 68 or 73 mm

[cycle tramp]

Wow, that's exciting.. what's the view from the other side of the bottom bracket like?

You sound like a cheery fellow!

Too cheery?!

Sorry, as previously noted its a genuine enquiry, as I believe what you had* was a usual cup and cone bottom bracket, rather than a cartridge bottom bracket... a photo from the other side of the frame will confirm this... if I'm right your next question isn't 'what cartridge should I install?' but rather 'how do I get this bottom bracket cup off my bike frame because its sized solid to the frame and won't budge an inch?'

Now that's alot less cheery. Sorry, no one likes all their bad news at once... I thought 'cheery' might be the way to go.. on the plus side if that's an alloy bike frame, then removing it is probably going to be easier than if it was a steel frame.

(* past tense, what you had was a bottom bracket, what you now have, is some scrap metal)

[rjb]

Recent traditional bottom brackets often have a right cup which resembles a sealed unit and requires the same fitting tool to remove it. The giveaway is the left cup which has a lockring.

[jimster99]

Wow, that's exciting.. what's the view from the other side of the bottom bracket like?

You sound like a cheery fellow!

Too cheery?!

Sorry, as previously noted its a genuine enquiry, as I believe what you had* was a usual cup and cone bottom bracket, rather than a cartridge bottom bracket... a photo from the other side of the frame will confirm this... if I'm right your next question isn't 'what cartridge should I install?' but rather 'how do I get this bottom bracket cup off my bike frame because its sized solid to the frame and won't budge an inch?'

Now that's alot less cheery. Sorry, no one likes all their bad news at once... I thought 'cheery' might be the way to go.. on the plus side if that's an alloy bike frame, then removing it is probably going to be easier than if it was a steel frame.

(* past tense, what you had was a bottom bracket, what you now have, is some scrap metal)

Sorry. My bad!!! I read your response as suggesting my post was NOT exciting and had too many photos. Sincere apologies for my wild presumptiveness

The other side seems to have the same type of cover (I didn't take it off because it was a bit stuck, but I didn't try overly hard after a previous bad experience of brute-forcing off a crank arm, only to discover that I had forgotten to take out the inside bolt and the hard won "progress" that I felt I was making was in fact the threads of the extractor tool slowly tearing through the threads of the crank arm, with rather undesired results) ;D

Anyway photo below! I do think it's a cup-and-cone style. And it's an aluminium frame.

Next steps: I'll (i) measure the width of the bottom bracket and (ii) remove the cover that's still on (if I can).

[jimster99]

Other Side Of Bottom Bracket In Day Time

And (for good measure)...at night

PS it's not rust in the photo, just mud! Frame needs a good clean...

[peetee]

You may find that BB cup difficult to remove from the frame. The solution to this is not brute force (well, not to start with, anyway).
Hours before you wield the spanner it worth giving both ends of the cup a good spray of release oil. IME the best off-the-shelf is Plusgas but WD 40 might work if that is already on your shelf marked ‘Useful Items’.
The correct removal tool needs to be clamped into the splines of the cup. You can do this by passing long bolt through the tool and cup and securing it with a washer either side and a nut. Once tight on the tool cannot reduce the splines to metal shavings which is what usually happens when a newbie, willing, bike owner in the real world is assured by a shop “this tool is all you need”!
IMPORTANT (non-frivolous note): hold the frame secure by applying a willing helper and don’t forget the cup has an opposite thread so comes out by turning it clockwise, or forward and down, if you like.

[alexnharvey]

Fitting a new cartridge BB has been my most used approach to BB issues over the years, especially if I will be keeping the bike for a while and using it regularly. When you say crank arm width is 120mm, do you mean the axle is 120mm long? If so you may find that something within a few millimetres will work ok, say 118mm or 122. You should also inspect the axle to check if the axle is symmetric or asymmetric, ie one side projects more than the other

On the other hand, if neither the cups or the axle bearing surfaces are damaged you could replace the ball bearings and regrease it and be back on the road at low cost. I cannot see what your micrometer reading says about the ball diameter. I'd expect that BB to take 1/4" balls. The 5/16 balls that you link to are used in American style BMX bottom brackets which have a larger shell. I order my bearings from ebay or bearing suppliers as you will get better quality at lower cost than in Halfords. https://www.ebay.co.uk/itm/17430244841 as an example, not a specific recommendation.

Look for Chrome steel balls, grade 100 or better. I generally avoid weldtite balls as i think they are not very good quality. You do not need to use cages and this will allow you to fit a few more balls in each side. Use grease to stick the balls in place as you assemble. There's a bit of a knack to getting the assembly adjusted just right, so there's no play but not so tight that the bearings feel rough due to binding.

Use lots of grease when you reassemble and whichever you of BB you fit, use antiseize grease to make sure the cups don't seize to the shell.

[peetee]

Once you have a replacement BB (incidentally, a 122 or 123 would be my choice) you can double-check its suitability by pushing the cranks on to each axle in turn as a pair by hand, parallel (not opposed, like normal) and measuring between the outside faces of the cranks and comparing old to new. Hopefully they should be very similar measurements. If not then as long as you are careful with the new BB you have the option of returning it for exchange in erm, ‘unused’ condition.
It’s quite possible that even if those measurements are spot on that the drive side crank won’t be in exactly the same position and some adjustment of the front mech stops will be necessary.
We can advise on that too, if needed.
We’re good like that.

[colin54]

Spa Cycles stock a 120mm First Components DX30 cartridge BB for 68mm BB shell width which they show stock of, £16 plus P&P, the only one in that exact width from their selection of makes that I can see, other makes get close as peetee mentions above.
https://www.spacycles.co.uk/m16b0s110p3 ... om-Bracket