Thanks for all the responses they are appreciated.
There seems to be two divided schools of thought but no defintive answer (as there should be).
Being a dinosaur will probably take the easy option and stick with what is already fitted.
Thanks again.
Ray
Advice re changing chain set required
"Being a dinosaur will probably take the easy option and stick with what is already fitted. "
Unless you're unhappy with the rigidity (or lack of it?) of the existing BB, probably best to stick with it and get a 50/34 in just about anything square taper, preferably shimano if that's what the BB is - I've used lots of different makes with each other with no problems, the only exception being old stronglight (49D and 105bis) on campag BBs - too loose a fit so the crank went all the way up to the end of the taper so there was no wedging, consequently no amount off tightening bolts kept it on there for long, it would always work loose eventually.
On the other hand... buying a chainset minus BB is so little cost saving over buying a complete set, that I'm not sure whether it's worth even the tiny risk that you'll have unforseen compatibility problems. £10's worth of BB is so good these days - thanks to advances in technology that most of us were suspicious of when they first came out, e.g. sealed bearings then one-piece BBs - that you can almost regard it as a perishable item even though it lasts longer than ball-bearing BBs used to last even with the tenderest most loving caressing care.
I've got a pair of Stronglight 170mm 86PCD cranks if you want them for free. not sure what became of the rings - but even there, you might find that buying a pair of rings and a set of bolts costs so close to the price of an entire new chainset and BB that it's not worth messing about.
Unless you're unhappy with the rigidity (or lack of it?) of the existing BB, probably best to stick with it and get a 50/34 in just about anything square taper, preferably shimano if that's what the BB is - I've used lots of different makes with each other with no problems, the only exception being old stronglight (49D and 105bis) on campag BBs - too loose a fit so the crank went all the way up to the end of the taper so there was no wedging, consequently no amount off tightening bolts kept it on there for long, it would always work loose eventually.
On the other hand... buying a chainset minus BB is so little cost saving over buying a complete set, that I'm not sure whether it's worth even the tiny risk that you'll have unforseen compatibility problems. £10's worth of BB is so good these days - thanks to advances in technology that most of us were suspicious of when they first came out, e.g. sealed bearings then one-piece BBs - that you can almost regard it as a perishable item even though it lasts longer than ball-bearing BBs used to last even with the tenderest most loving caressing care.
I've got a pair of Stronglight 170mm 86PCD cranks if you want them for free. not sure what became of the rings - but even there, you might find that buying a pair of rings and a set of bolts costs so close to the price of an entire new chainset and BB that it's not worth messing about.
"Engineering aside, I have to say I reckon a lot of the newer ones are actually pig ugly"
Same here - but then I thought that at first of almost every innovation in bike design. My first decent chainset was a campag record in about 1980ish - it looked really weird to me then but now I occasionally come across those same cranks put away in a box of old bits and think what classic beauty... I remember the first dual-pivot brakes - YUK!!! It seemed so normal at the time to have to keep centering brakes and having to keep the springs perfectly greased to avoid having to centre them just about every time you braked - not to mention the fact that it was normal for brakes to be only just able to stop you if you were loaded down and going down a steep hill... and this was even with £100 campags - the objection to dual-pivots was purely cos they looked weird. Nowdays I associate that look with brakes that work and need no attention till the blocks wear out.
Same here - but then I thought that at first of almost every innovation in bike design. My first decent chainset was a campag record in about 1980ish - it looked really weird to me then but now I occasionally come across those same cranks put away in a box of old bits and think what classic beauty... I remember the first dual-pivot brakes - YUK!!! It seemed so normal at the time to have to keep centering brakes and having to keep the springs perfectly greased to avoid having to centre them just about every time you braked - not to mention the fact that it was normal for brakes to be only just able to stop you if you were loaded down and going down a steep hill... and this was even with £100 campags - the objection to dual-pivots was purely cos they looked weird. Nowdays I associate that look with brakes that work and need no attention till the blocks wear out.
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Warsash Blue
- Posts: 18
- Joined: 12 Jul 2007, 12:29pm
advice re changing chainset
Thanks Raph for the latest advice and offer of the cranks but will take your advice I think, and get complete chainset with the B/B as well. Will shop around and see what the price difference is between Stronglight and Shimano as they seem to be the most suggested.
Ray
Ray
Also consider FSA - I'm sure there are lots of others that are probably good too but the afore-mentioned "gossamer" I got with an ISIS BB is excellent - really rigid, no chain rub whatsoever, and cost about £80 with BB and 50/34 rings.
PS have a quick look at an ISIS BB - http://www.dotbike.com/ProductsP954.aspx?TRACK%3dDFR - the one I got was cheaper than this one but same principle. it's a lot more serious than the square taper we've all coped with for years, which has been ok though the flexing and resulting chain rub has always been considered something to put up with. And if you look at the forces on a square taper, they're anything but square - the most direct force between axle and crank surfaces is 45deg - the splines on the ISIS lock in far more solidly. Again, this is a bit of a cure for a problem that didn't exist anyway, but a couple of times when I've had square taper cranks come loose there's been a lot of damage, whereas I reckon the ISIS drive is a lot less likely to loosen in the first place, or suffer damage if it does.
PS have a quick look at an ISIS BB - http://www.dotbike.com/ProductsP954.aspx?TRACK%3dDFR - the one I got was cheaper than this one but same principle. it's a lot more serious than the square taper we've all coped with for years, which has been ok though the flexing and resulting chain rub has always been considered something to put up with. And if you look at the forces on a square taper, they're anything but square - the most direct force between axle and crank surfaces is 45deg - the splines on the ISIS lock in far more solidly. Again, this is a bit of a cure for a problem that didn't exist anyway, but a couple of times when I've had square taper cranks come loose there's been a lot of damage, whereas I reckon the ISIS drive is a lot less likely to loosen in the first place, or suffer damage if it does.