Cycling UK Forum

Brucey wrote:you can do, but many riders absolutely hate it, and it is an obvious safety issue. You rarely if ever see much slack on chains these days whenever big track events are on. Needless to say if the chain is at all slack and the frameset is a floppy plastic one, it might be possible for it to come off in use; not good, not good at all...

Not sure I agree, sorry. A lot of riders run track chains with as much slack as they can get away with, as it will minimise friction losses. As long as you can't lift the chain off the side with your fingers, or as long as the chain doesn't fall off when you spin the pedals and hold the bike up sideways, then it's unlikely to unship during use. The term 'slack' is relative though. At the very least, it needs to be slack enough so that it doesn't bind anywhere during the crank's rotation.

Mario Vaz is the name you are looking for.

If all else fails, I can recommend Argos Cycles in Bristol..

Steel frame presumably?

Brucey wrote:the eccentricity concern applies just as well if you are only buying a chainring for a fixed gear setup.

Most derailleur setups with notionally round chainrings actually have slight eccentricity to them; those chainsets/chainrings would never pass muster for a 'just so' fixed gear transmission.

cheers

Eccentric chainrings - that is to say chainrings which are not quite round, as opposed to actual 'oval' rings - don't really matter on a derailleur setup, as the rear mech cage will compensate for variations in tension.

For track use, you can run a chain with much more slack than you might want to on the road, so 'imperfect' chain rings are far less of an issue.

Brucey - he's already got 144.

Agree about the chain slack/chain ring roundness - especially in a road application, where there is more likelihood of chain drop. But if the chain line is good, then this might be less of an issue.

mig wrote:for winter fixed / 1/8th chain / good chain line.

Nothing particularly special about Gebhartd, but nothing wrong with them either. I'd go with whatever you can get for the least amount of spend. Miche, Stronglight, TA, whatever. Assuming you don't want to pay Dura Ace or Sugino Zen prices

mig wrote:so would a rider be able to flex a chainring of 86bcd more than say a 150 bcd? or t'other way around? or is flex more perceived than real? more to do with cutouts? or number of bolts? BB setup?

It's not so much about the 'absolute' BCD, it's more the BCD in relation to the chainring size/tooth count.

mig wrote:sub topic. looking to buy a 144 ring and 'gebhardt' keep coming up. yay or nay? hard or cheese?

For what application?

The utility cyclist wrote:

thatsnotmyname wrote:

roubaixtuesday wrote:
Seems we agree

Seems you've mis-read the diagram, more like. You seem to think the 'green route' is a great idea - despite crossing onto the opposite carriageway on a potentially blind hairpin. If you can explain that one away, I'll be waiting..

Wouldn't coming DOWN hill mean that the blind aspect as you describe it, is in fact not blind at all in many instances because you're able to see what is around the bend due to the height differential? And if you can't see, then very few persons are going to risk taking that line into the opposite carriageway as per the diagram.

Absolutely. Which further underlines my point that a simplistic suggestion for ‘using all the road’ is a bad idea.

It pretty much is the move towards smaller rings that has driven the development of smaller BCDs. I think Shimano were the originators of the 130 standard and 144 is still in use on the track, partly as a way of keeping flex down, and partly because 'that's the way it's always been' ...

roubaixtuesday wrote:

thatsnotmyname wrote:

roubaixtuesday wrote:
Seems we agree

Seems you've mis-read the diagram, more like. You seem to think the 'green route' is a great idea - despite crossing onto the opposite carriageway on a potentially blind hairpin. If you can explain that one away, I'll be waiting..

Read what I wrote.

I've read it. Still waiting.

roubaixtuesday wrote:

thatsnotmyname wrote:

roubaixtuesday wrote:Obviously, this only applies, in the uk, to left hand corners.

Ironically, the accompanying diagram showed a right-hander. Which kind of illustrates the point I was making.

Seems we agree

Seems you've mis-read the diagram, more like. You seem to think the 'green route' is a great idea - despite crossing onto the opposite carriageway on a potentially blind hairpin. If you can explain that one away, I'll be waiting..

roubaixtuesday wrote:Obviously, this only applies, in the uk, to left hand corners.

Ironically, the accompanying diagram showed a right-hander. Which kind of illustrates the point I was making.

roubaixtuesday wrote:

thatsnotmyname wrote:

Marcus Aurelius wrote: Use all of the road.

....and get hit by a truck coming the other way. Great idea.

Using all of the road makes it less likely you'll get hit by a truck. It is, genuinely, a great idea.

You'll need to be clearer then. If you use 'all of the road', presumably that means using the 'entire width of the road', including the opposite carriageway? The 'opposite carriageway' that might have vehicles travelling in the opposite direction? I don't see how that's a great idea.

Marcus Aurelius wrote: Use all of the road.

....and get hit by a truck coming the other way. Great idea.