Current HG50 7spd Cassettes

[cce]

Re: Re:

please tell me more.

Easy. Cyclocross due to the difficulty of the terrain where it's used offers more compact gearing (usually 46/36T or similar). Also, the low range of the road components usually also have compact gearing and practical solutions like chainguards. I guess Shimano thinks (probably correctly) that Dura-Ace is for the Freds and Sora, Claris, etc. is for the normal people that actually use the bike outside sunny Sundays.

If you check online for those groups, you can find chainrings like FC-2450 or FC-3550 in 46T version, and also chainguards to match. One example:

http://www.sjscycles.co.uk/shimano-clar ... prod36340/
http://www.sjscycles.co.uk/shimano-clar ... prod38676/

Those chainguards are extremely effective, despite their simplicity. I have one on my touring bike (FC-M430 crankset) and my working suit has not been caught up with the chainrings ever.

And another advantage of going with the Shimano low range. At least on the Claris, Alivio and Acera groupsets, the chainrings are steel. They last waaaay longer than the fancy aluminium ones on the higher range, while being cheaper. Win-win.

a suggested item at the bottom of the page landed pretty much exactly what i'm after which is this, so thanks

http://www.sjscycles.co.uk/thorn-high-q ... prod11144/

should cover the 34/110 on my pub bike nicely. Shame it costs nearly as much as the bike owes me!