Borked bottom bracket

Kieran_Burns

Arsebiscuits.

While cleaning the chain, adjusting the brakes and sorting out the gear change last night I noticed this weird soft crunchy noise coming from the bike every time I turned the crank.

Hmmmm..... :?

Listening closely - well not that closely it was pretty obvious :roll: and then actually registering what it felt like, I realised the bottom bracket is knackered on my Tricross.

Now, having never needed to replace anything beyond the chain (my fault) on my trusty steed, I don't know which one to get.

Help?

What's a suitable BB for a Tricross Sport?

In other news: my rear wheel is seriously (ish) buckled - you'd have thought my mate (who spends the entire journey cycling in 'together' wheel sucking) would've mentioned that my rear wheel resembles a pringle in shape.

So that's off down to the LBS as well

rolf_f

Some cheapo boggo ordinary Shimano £15 jobbie will do it I'm sure. I've had a good 7000 miles out of the one in my Dawes so far - out in all weathers and no attention paid to it.

vorsprung

If the info on the Specialized website is correct for your particular bike, it lists the BB of the Tricross sport as being a "BB-7420"which seems to be a fairly ordinary square taper item. Just make sure you get the right width and thread

This sort of BB lasts a very long time usually, but maybe you've been unlucky
The price of the part is what Rolf said

To fit this type of BB you need a special splined spanner and maybe a crank extractor but it's not difficult

UndercoverElephant

If it's a square-taper BB, are you not able to just replace the bearings and re-grease?

Kieran_Burns

I've just confirmed it's the BB-7420 and yup it's a square taper BB

As to replacing the bearings - I can't even see how to get into the thing. Oh, and this is the original BB that's gone through 2 winters on my 2009 model Tricross so it's done pretty well.

I've got the spline tool and crank extractor, so there's no problem getting it out. I just need to know what to replace it with.

Kieran_Burns

spec says 68x103mm, would this http://www.wiggle.co.uk/token-tk867-iso ... m-bracket/ (68x102mm be okay?)


edit: http://www.bikeradar.com/forum/viewtopic.php?p=16171942

says

For future reference the BB on the 2009 specialized Tricross Triple is 68x118mm

Okay - now I am confused!!!!

redvee

I just looked at the Evan spec sheet, which is a CTRL+C, CTRL+V from the Specialsed webby and they quote 103mm which is the same size that I'm using in my SS Tricross, ignore it, 103mm will work but the chainset might rub Go with the 118 or ask in a Specialised dealer but get it elsewhere.

rjsterry

UndercoverElephant wrote:

If it's a square-taper BB, are you not able to just replace the bearings and re-grease?

Only on really old school BBs with loose ball bearings. The cheapo Shimano square taper ones are sealed units and therefore 'disoposable' but at £15 a throw for a few years use, why not?

craker

.. or take the cranks off and measure it. If you've got a vernier gauge that's easy.

I'm two months into a new extra cheap bottom bracket on my clunker

http://www.chainreactioncycles.com/Models.aspx?ModelID=22376

£5 and I've had 500 miles out of it so far.

Still if that's your best bike you might want something better than the cheapest thing available.

Kieran_Burns

Right after 3 trips ('cos Specialized don't even know the size of their own parts...) I can confirm it is a 6x118mm bottom bracket for the Tricross Sport


muttermuttermutter


However, after fitting bracket and glorying in my excellent fettling skills I noticed one of the spokes on the rear wheel has snapped.

Arse cheese.

UndercoverElephant

rjsterry wrote:

UndercoverElephant wrote:

If it's a square-taper BB, are you not able to just replace the bearings and re-grease?

Only on really old school BBs with loose ball bearings. The cheapo Shimano square taper ones are sealed units and therefore 'disoposable' but at £15 a throw for a few years use, why not?

Living in the past, me. I remember when all of this were just fields.

Kieran_Burns

God this is turning into a saga....

Remembered I had an old wheel with good spokes lying at the back of the garage. Spoke out, broken one removed and.... arse.

Rear wheel spoke gone so I need a cassette tool. I don't have one and can't get one 'til Monday.

All I want to do is ride my bike


Still - if the weather's good, this may be an excuse to get out on the Madone. Hmmmmmm.....