Bicycle Mechanics - Bottom Bracket U/S.. GIANT Bike

Hello Again, Been away a long time Illness, Computer problems etc. Question/s, I bought a Giant Expression, a DX? model I think. I paid a lot for it £10 approx $16:) I love the riding Position and the frame seems to fit me like no other. The Bottom Bracket is loose and pedals can be moved a good 1/4in in and out ,The chain constantly jumps off the larger drive chain wheel ,outwards rather than in to smaller chain wheel. If I put chain on smaller Wheel it stays there but creaks and Protests. Is the bike worth saving?. The Frame and Wheels are like new, The front Mudguard is missing and the problem/s with BB is all I can find fault with, HELP. I don't mind spending a few "Quid" on it :). Thanks for reading This. I should point out ,I have emailed GIANT twice and 'phoned once(They promised to Call back) No response or replies whatsoever, Are the always like this. Ged.

.. I bought a Giant Expression, a DX? model .. The Bottom Bracket is loose and pedals can be moved a good 1/4in in and out ...

Your description leave some doubt about what's actually happening, whether it's the crank arms that are loose, whether it's the pedals that are busted or if it actually is the BB. Crank arms that are loose on an otherwise OK BB quickly end up destroying the fit beween axle and arm. Some people have reported success in fixing this one way or another, but usually replacement is the sensible option. Luckily enough for you, finding a replacement part of equal quality won't cost much.
The bike matching your specifics that Google can find has a cartridge BB. To tighten/replace that you need to pull the crankarms off and then a special splined tool bit. If you haven't a crank arm puller and the BB tool, go visit your LBS.
Paedals(particularly cheap plastic flatties) can wear out to the point where they can slide back/forth on their spindle. Yet another case where matching quality replacent parts is the sensible way to go.

.. The chain constantly jumps off the larger drive chain wheel ,outwards rather than in to smaller chain wheel. . When you're shifting or during riding?. If it does so while shifting it sounds like the screws that set the end stops aren't done up right. If it does this while JRA it's the gears them selves that aren't adjusted right. Plenty of www-walk throughs for that on the web.



.. ..If I put chain on smaller Wheel it stays there but creaks and Protests. . Are you crosss-chaining perhaps?


...,I have emailed GIANT twice and 'phoned once(They promised to Call back) No response or replies whatsoever, Are the always like this. Ged.

Big ol'Giant, answering questions from a single customers - don't think that'll ever happen. If you'd been the first customer you might have gotten some support from where you'd bought it, but now it's the LBS, books or websites.

As dabac summarized there are two likely problems here. I'll discount the pedals since they wouldn't cause shifting problems.

1. The bottom bracket bearings are indeed shot and the cartridge must be replaced. A new Shimano cartridge shouldn't cost more than about $30 US and installation a bit more if the LBS does it. I assume if you really can't diagnose this, you don't have the tools or expertise to do the work yourself.

2. Your crank arms are loose on the bb spindle. If that's the case they are likely damaged beyond reuse and replacement is the only good option. Again, you will probably be at the mercy of the bike shop.

Thanks for reply, Crank arms are not loose at all and the Pedals are like new. It seems as though the spindle through the BB has lost it's Ball- Bearings there's so much play. The eccentric Motion when the Power is on the opposing sides seems to me the cause of the Chain protests. The "NUTS" that appear to hold Crank arms on are round and domed with a TRIANGLE key way in the centre of the NUT. I suppose thats to keep the DIY people out. I hope it's just a New Part thats needed. Why don't they make them like they used to. I never have problems with BBs on my Old Raleigh Bikes., I thought Giant would have been more helpful,Good aftersales service/spares availability is a major selling point. Ged.

Thanks for reply, Crank arms are not loose at all and the Pedals are like new. It seems as though the spindle through the BB has lost it's Ball- Bearings there's so much play. The eccentric Motion when the Power is on the opposing sides seems to me the cause of the Chain protests. The "NUTS" that appear to hold Crank arms on are round and domed with a TRIANGLE key way in the centre of the NUT. I suppose thats to keep the DIY people out. I hope it's just a New Part thats needed. Why don't they make them like they used to. I never have problems with BBs on my Old Raleigh Bikes., I thought Giant would have been more helpful,Good aftersales service/spares availability is a major selling point. Ged.
I just looked up Giant's web site listing for that model and the crank and bottom bracket seem to be the lowest of the low no-name items. I recommend you take it to a shop and have both replaced with entry level Shimano parts. The cost shouldn't be much and the upgrade will be well worth it.

I just looked up Giant's web site listing for that model and the crank and bottom bracket seem to be the lowest of the low no-name items. I recommend you take it to a shop and have both replaced with entry level Shimano parts. The cost shouldn't be much and the upgrade will be well worth it.

Hello Again, I don't know what you mean by Both, I thought BB Cartridge or Cassette needed replacing, Do you mean Front Chain Wheel as well?. I have a "Mobile Bicycle Mechanic" coming tomorrow morning to look at Bike and give a price to do JOB. Will keep you informed. Ged.

..Crank arms are not loose at all and the Pedals are like new...
Cartridge bottom brackets usually don't fail that spectactularly, but with that description there's not much else it can be. As hillrider said, they're not that expensive to replace.


.. The "NUTS" that appear to hold Crank arms on are round and domed with a TRIANGLE key way in the centre of the NUT. I suppose thats to keep the DIY people out. ....
Odds are, what you're seeing aren't the actual "nuts", but rather the equivalent of a hubcap on a car, a decorative piece covering the structural element - which probably is a screw/bolt rather than a nut. Pick whatever you've got around that's a decent fit for the opening and they should come off.


.... Why don't they make them like they used to. I never have problems with BBs on my Old Raleigh Bikes...
Well, you tend to get what you pay for. The bike you're referring to in this post is really close to the bottom of the barrel. It's a fair bet that the old raleighs you mention were far more expensive when new, if you'd recalculate their price into current terms.


...I thought Giant would have been more helpful....

But you're trying to shortcut the chain of distribution, which also is the chain of customer care. You don't try to call Ford main office if your car don't run right, do you?

Thanks for Reply, I take your point about contacting Giant and lack of response, but reading their Website they claim to be and lead one to believe they are the most caring and Best Cycle Co in the World.They don't say as long as your'e in the Trade. According to Giant's Ad's, List price of Expression was/is Around £400, Hardly the bottom of the Barrel surely. ASDA/WALMART and several other Large outlets are selling Bikes at less than £200, They must be made of Pot Metal if that's the case.:). Ged.

you could have had something like this happen. the retainer that hold the bearings are so cheap. i remove the retainers on my and install 2 more bearings on each side and i no longer have this problem and i am hard on bikes. if the retainer is destroyed you will have to replace the bearings.
http://www.sammich.org/hurr/img/bearings.jpg

..According to Giant's Ad's, List price of Expression was/is Around £400, Hardly the bottom of the Barrel surely. ASDA/WALMART and several other Large outlets are selling Bikes at less than £200, They must be made of Pot Metal if that's the case.:). Ged.

Take a look at the spec sheet:
Model - Expression DX
Sizes - M ( 19"), L (21"), XL (23")
Colours - Metallic Silver
Frame - AluxX aluminium = seems to be mostly another name for 6000 grade aluminium alloy
Fork - HiTensile steel = HiTen is low-end steel, pretty much the first one that's even given a "name". Cr-Mo would be better.
Shock - N/A
Handlebar - Aluminium = unspecified manufacturer, always an indication of low-end component
Stem - Aluminium quill = unspecified manufacturer, always an indication of low-end component
Seatpost - Aluminium = unspecified manufacturer, always an indication of low-end component
Saddle - Giant = most likely a rebranded item, also an indication of low-end component
Pedals - Resin anti slip = unspecified manufacturer, always an indication of low-end component
Shifters - Shimano EZ Fire 50 21 speed = it's been years and years since you found 7-speed rears on a bike with any hint of performance in it.
Front Derailleur - Shimano TX51 = Shimano Tourney - on their site listed under "other comfort components". You can draw your own assumptions from that
Rear Derailleur - Shimano TX31 = Shimano Tourney - on their site listed under "other comfort components". You can draw your own assumptions from that
Brakes - Linear pull = unspecified manufacturer, always an indication of low-end component
Brake Levers - Shimano EF50 = Shimano Tourney - on their site listed under "other comfort components".
Cassette - Shimano 14-28 freewheel = 7-speed was pretty much the death of multi-speed freewheel technology, as it leaves a lot of unsupported axle. Again, something that isn't used in a "performance" setting.
Chain - KMC Z51
Crankset - Prowheel 28/38/48 = looks like it's got riveted chainwheels/rings, also a low-end indicator.
Bottom Bracket - Semi cartridge = unspecified manufacturer, always an indication of low-end component
Rims - Giant CH18 SW aluminium = most likely a rebranded item, also an indication of low-end component
Hubs - Joy Tech
Spokes - Steel = unspecified manufacturer, always an indication of low-end component
Tyres - Kenda 700x40mm
Extras - Mudguards and rear carrier


... ASDA/WALMART and several other Large outlets are selling Bikes at less than £200, They must be made of Pot Metal if that's the case...

Indeed they are. They are regularly referred to as BLOs - Bike Looking Objects...

you could have had something like this happen.

Thing is, it's listed as having a cartridge BB. Servicing the bearings in one of those isn't that easy.

I would say that since you have virtually no real money in the bike,,,, just take it to a shop to be repaired, since you are not mechanically inclined enough to do the repairs. After the shop repairs it, you will probably still have a good bike for the total cost !

Thing is, it's listed as having a cartridge BB. Servicing the bearings in one of those isn't that easy.
The actual spec sheet says "semi - cartridge", what ever that means. It may indeed be a cup-and-cone with retainers.

To the OP: this is not a high quality bike and at £400 was overpriced for what it delivered.

Hello Again, Mobile Bike Mechanic came today and took Bike away, He is to fit a new BB and adjust for estimated £20 ($30). I will keep you informed. I accept what most of you say about Bike quality, but I find it is a good ride and I feel good on it, Looks the part too. Your'e also right I have very little money invested in it, so its a win win situation if Mechanic sorts it. Thanks for all your help and advice. Ged.

The actual spec sheet says "semi - cartridge", what ever that means. ..

Different sites say different things. This one http://www.cyclestore.co.uk/productDetails.asp?productID=15461, the first I found, says "BOTTOM BRACKET Cartridge" while http://www.giant-bicycles.com/en-gb/bikes/model/expression.dx/7094/43407/ says "semi-cartridge".
I'd be inclined to put more faith in the Giant site if I knew what they meant by semi-cartridge...

Hello Again , Mobile Mechanic took bike away and fitted new BB, He reported old BB was or seemed to be an experimental or prototype semi Cartridge but made by a Company that makes parts for Shimano. It was a total wreck. I have bike back and all is well ,I have been for a ride and changed up and down the gears. Total cost £22 I gave him a tip to buy a Pint. Thanks for all your help and advice. Ged.:)

Hello Again , Mobile Mechanic took bike away and fitted new BB, He reported old BB was or seemed to be an experimental or prototype semi Cartridge but made by a Company that makes parts for Shimano. It was a total wreck. I have bike back and all is well ,I have been for a ride and changed up and down the gears. Total cost £22 I gave him a tip to buy a Pint. Thanks for all your help and advice. Ged.:)

If I had a " Mobile Bike Mechanic " who only charged so little, I would never repair a bike again !!!
Sounds like you are fine, now. Looks like you have about $50 in the bike. CHEAP !
I am on a low fixed income & cannot afford the luxury of an expensive car,,,, much less an expensive bike. I ride a Giant bike, that cost a little over $400, when new, & I am well pleased. This is MY OPINION> Giant bikes are hard to beat for the price.
Enjoy your " new " ride !