I'm looking to replace a worn front and rear dérailleur before cross season and need some advice. If I upgrade from Shimano 105s to Ultegra - would I lose durability?

The 105s have lasted 3 seasons with very little issues - shifted through mud and grass about 95% of the time with no problem and have withstood numerous power washings.

Would the Ultegras be just as durable or should I stick with the 105s?

If it were me I'd stick to 105. If it's still working then you can put money elsewhere or just save it for when other things break. I don't think Ultegra is less durable than 105 and in fact may well be the opposite. I like 105 on my bike because it works great and won't hurt the wallet as much.

You want Just one season out of it? .. crash much?

Do you keep the bike clean while racing?

The only Tiagra or better component I've been able to wear out other than obvious expendables like chains were the jockey wheels on an Ultegra rear derailleur. Cheap things didn't even last 10,000 miles.

On the other hand, I did do this to an Ultegra rear derailleur in a cross race:



I use 105 on my race bike now. It shifts just as well and doesn't cost quite as much to replace.

That's a sad Ben Franklin you have there wrapped around your cassette...

I'm on my second season of racing cross on a 6700 drivetrain and have had no issues with it. I just replaced the cables on my bike and everything is shifting like it was when new.

If you do have a tendency to crash more then I would say stick with 105 because it is cheaper to replace, but on the downside it is heavier.

I would stick with 105 and put that extra money towards better or more tires/wheels.

Really no reason to buy new either. A cross bike is a great place for old parts to live out the rest of their days.

The difference is about about 75 grams total for shifters and both derailleurs. The big weight savings between the groups comes with the cassette and crank, which generally don't break so Ultegra may be the way to go there if you've got the cash (though lighter alternatives are available for more moneym as always). The source I looked at for 105 weights actually has the 105 chain a little lighter than Shimano's claim for the Ultegra chain.

Heck, Ultegra is only $25 more for the rear. Most people here spend that on coffee every week.

IMHO save the money and spend a little extra and upgrade the brifters rather than the derailleurs when the time comes.

I daresay that Ultegra shifters on a 105 derailleur would perform better than 105 shifters on an Ultegra derailleur. Derailleurs are dumb while the shifters are the brains of the operation. Plus the derailleur is probably going to more of a consumable item on a CX race bike anyhow and be more like to break/wreck and need to be replaced again anyhow.

But if your derailleur is toast already that's not the option. Personally I don't think that spending more past the 105 level is worth it for derailleurs in the bang/buck equation. It's not going to give you much except a few ounces of weight-savings. The performance difference is nearly unmeasurable.

Cannondale, for one, thinks it'll be fine.

is that why many road/cross bikes come stock with 105 brifters but Ultegra R/Ds, but none come with Ultegra brifters and 105 R/Ds?

People BUY em.

PT Barnum was a genius.

"Upgrading" the rear der is a cheap way for a bike company to make a bike seem snazzier to the consumer.

I've got two sets of Ultegra brifters and 1.5 sets of 105's (picked up a spare right shifter at a swap meet). I've also got two Ultegra rear derailleurs and a 105 rear derailleur. When they're properly tuned I feel absolutely zero difference in the shifting response between 105 and Ultegra. I race with 105. I've got one set of Ultegras on my road bike and the other set on the shelf waiting to be needed.

Glad someone said it. Maintenance is everything. In typical cross condition everything gets gross.

its upgrading, not "upgrading". just like Tiagra would be downgrading

So you mean it will work exactly the same but have a nicer finish and weigh a few grams less?

My opinion is race the most awesome stuff you can afford to replace.

You can usually go cheaper on replacements and source them quickly if needed unless you make weird choices (I'm looking at you 130 spaced 11 speed Campy disc guy).

maybe we should all ride Tiagra, it works and its only a little heavier. its only a "downgrade" not a downgrade

Pretty much.