Broken Bike Help

SupraMel

My other half and I have started riding some fairly bumpy muddy trails. The first time we went out my other halfs crank came loose and by the time he realised, it was damaged as was the bottom bracket. We went for another ride last night just nipping up the crank every now and then (probably a bad idea but a bad day at work meant we were going regardless) and towards the end of the trail the deraillur snapped off .

It's a Dimondback bike (£260 in the sale at JE James 2 years ago) with a pretty nice, sturdy frame it just seems everything attached to it is rubbish. We don't have money to buy a new bike nevermind one more expensive. Would it be best to buy upgraded drive parts and just replace it all or would the money be better put towards a new bike and we just wait?

Also would buying second hand parts be a good idea? I've noticed there are lots of parts for sale on here.

Any advice would be much appreciated, thanks.

supersonic

Which parts do you need, and what sort of standard ie what is the cranks and bottom bracket? How many gears?

SupraMel

I can tell you 24 gears, but without looking at the bike that's it lol I will have a look tonight cause they're all cleaned off and need oiling anyway, so I'll post back again later.
Will need at least a bottom bracket, cranks, derailiur and chain, unless the front 3 gears are not transferable it will need those too!

supersonic

Probably worth changing the cassette too, so everything works together.

What is your max budget?

styxd

I'd probably buy a cheap 2nd hand rear mech for about 10 quid and then just run the lot into the ground and buy a new bike when its knackered. Try threadlocking your crank bolt on to stop it coming loose.

SupraMel

Budget is difficult really maybe £50 if I'm dreaming at that then we will just have to wait a bit longer as were paying for a trip to Lemans and taxing the car on friday so it's just happened at the wrong time! I have no idea what it's likely to cost really

I'll take some pics as the rear derailliur came off at the frame so I wonder if it's just the hangar that has had it.

We did already try threadlock on the crank bolt but it didn't work.

supersonic

If the bottom bracket axle is not worn, a new chainset will suffice. Do you know what standard it is ie square taper, octalink etc? Very likely it is the hanger that is bent.

SupraMel

It is a Square Taper, I had a look at the crank when the OH took it off so I know that's had it but I didn't look at the BB but surely if one is worn so will the other? or are the axels tougher? I will look again later on to confirm.

styxd

The BB axle will be steel so theres a good chance its ok.

You could always try the old coke can shim trick?

SupraMel

Wrapping a bit of coke can round the axel? lol I think I would still rather replace it even if it means spending a little bit of money. It's just not funny if it comes off mid ride

I'm getting hopeful this may not be as bad as it looks

SupraMel

Well it was too damn rainy to go and oil the bikes so I ended up not getting the info you asked for! But he has decided he wants to wait and buy up graded parts for the bike to replace the dead bits anyway.

Just a little question theough he want's to go from 3 cogs on the front to two can you just change this without changing the gear shifters? and do you have to have derailiurs to suit? I imagine he will change it all but we're both a bit new to this so don't know which bits have to be compatible and which are universal!

Thanks for all the help so far

The Rookie

If it's square taper the BB will be fine, just needs cranks.
You can go from 3 to 2 with the current shifter, set it up correctly and it will not allow the 'third' gear to be selected.

I have some Suntour Duro square taper crank arms for sale, currently with 3 rings, PM me if your interested, they are bolt on rings so can be changed to 2 (with a bash or shorter bolts) easily.

SupraMel

That sounds tempting, can you send me some pics? Also how much do you want for them?

green room

SupraMel wrote:

towards the end of the trail the deraillur snapped off

Any advice would be much appreciated, thanks.

Hey I hope I'm not talking down to you but are you sure it was the derailleur that snapped off? Most frames have a failsafe part called the rear gear hanger. It is made of inexpensive softer aluminium and it's whole purpose is to break before the more expensive gear mech or frame breaks, say for example you crash or hit a rock. They are normally between £8 -20 to buy a new one, and most people ride with a spare. If this part failed it would certainly look to an inexperienced person like the gear mechanism had snapped off. If this part has gone it's quite likely that the gear mechanism itself is fine.

Regarding your cranks, you can buy cheapo left hand cranks at halfords (£10) and any decent bike shop can order a right hand one from the likes of shimano which may just work out cheaper if it's the right hand one, however you might be better off buying a cheapo one second hand. Note that cranks come in several lengths stamped on the back and yours are probably 170 or 175mm long (measured from the centre of the axle hole to the centre of the pedal hole). If the bike hasn't seen much use I very much doubt you will need a new chain and cassette. If it's worn then you might but 8 speed is a bit more robust.

SupraMel

Hi thanks for the info, I think it is the hanger that is snapped as it broke at the frame and actually looked like the frame had snapped (thought this unlikely). I think he needs to go for something more robust as he is an aggressive rider and has already bent a link in the chain about a year back, repaired it but it's not quite been the same since!

Can you reccommend what sort of crank is best to go for? (I fear a cheap one will just get broken again) would he perhaps be better off saving up and replacing the bottom bracket for something with splines? I've seen on Chain reaction cycles they seem to have full chain sets at quite reasonable prices.

The Rookie

SupraMel wrote:

That sounds tempting, can you send me some pics? Also how much do you want for them?

Mel, Send me a PM and we can talk, don't like to do it in open forum - bad form.