Hi there
As I have said in a previous thread, I recently received a cyclocross bike for my birthday, and being 15 I already want to upgrade it
So my question is , currently it is specked with Sora shifters and derailleurs, would I be able to buy a mixture of 105 and ultegra derailleurs for it and for them to just replace the current ones. Or would I have to change the whole system?

Thanks in advance
Ben

105/Ultegra likely to be 10spd, don't think that's trickled down to Sora?

Personally I'd just get out and ride it. When you wear it out or break it on an epic ride THEN replace it.

/pot calling kettle black

Modern 105/Ultegra has a different cable pull for the brakes than Sora.

Thanks for the replays, im gonna be try to be a bit more specific about the parts I'm looking at, so, could I fit this to my sora gears as a strait swap?
http://www.chainreactioncycles.com/Mode ... ouble+5501

http://www.merlincycles.com/bike-shop/r ... +Rear+Road


Thanks again
Ben

The rear derailleur should be fine, i run the short cage version with Sora shifters. It took a little while to get it set up (setting the upper and lower limits) but it has been great since and works perfectly fine.

The Sora one you have will do just the same job, the only reason i swapped was i bent the original derailleur coming off my bike.

You won't feel any difference from this upgrade. There is no need for Ultegra or 105, especially on cyclocross - because 10sp gears don't have clearance for mud. I'd suggest upgrading to new 9sp Sora with normal gear levers that are reachable from drops (http://www.bikeradar.com/news/article/s ... ook-33204/) best value for money.