MSC

In the hopes of making an informed decision about a possible compact crank upgrade, I've been searching through the many threads on Shimano compact cranks here, as well as browsing Shimano's website. Unfortunately, getting clear answer on the differences between these cranks (particularly the differences between the R600 and R700) appears to be less straightforward than anticipated. It seems the company has been quite intentionally vague here. For example, it's pretty clear now from reading previous posts here that the R600 and R700 work fine on 9-speed setups even though they are badged as 10-speed. Moreover, the only visible difference appears to be the chainrings and weight - the Hollowtech II design and crank arms appear to be identical on all three - but the available documentation is less than explicit about this point.

The three options:

https://www.universalcycles.com/shopp...5&category=526

https://www.universalcycles.com/shopp...4&category=526

https://www.universalcycles.com/shopp...4&category=526

I am thinking of replacing my Ultegra 9 53/39 with a Shimano compact, but the price differences between the 3 options here are quite substantial (~$200 for R700, ~125 for $600, ~80 for 4550). My bike is light (2004 Litespeed Firenze), but not to the point that a few ounces would make or break here. That said, my Ultegra group has served me extremely well, and I don't want to sacrifice quality/durability/stiffness simply to go compact. In short, I'd pay the difference for the R700 over the other two options, provided that there really is a difference. Can anyone with experience with these cranks shed some light on their relative merits and actual qualities in use?

Thanks,

MSC

ruppster

I had a R600 on my Cannondale R1000 (2006, it came on it) and I have a 4550 on a Trek. The 4550 seems to work as well as the R600 did. It does say "Tiagra" on the arms, so no bling points.

Mash Master

there is also the ultegra cranks which at PBK are around $150....

I too am stuck trying to decide on the same upgrade

BananaTugger

The R700's are equivalent to Ultegra.

The R600's are 105-ish.

I'd get the R600.

ShadowGray

A crank's pretty much a crank. Weight is more of an issue here; if you're not that worried about the extra weight, go for the cheaper crankset.

ruppster

I disagree. I replaced the R600 (Cannondale archive calls it Ultegra, so maybe R700?) compact with a Truvativ 53/39. The Shimano compact actually shifted better (quicker shifting, less noise). A few guys I've talked to that have switch from Shimano (then normally back) agree.

pagliaci

I have both the R600 and R700 and I can tell no difference. Neither shift as smoothly as a standard 52/39 Ultegra but that's what you get with all compacts. The finish and looks are very close, go with the cheaper.

The new Ultegra compact is overpriced, I got my R700 (new) for $80 on eBay.

ridethecliche

FWIW the R4550 is the Tiagra compact crank, so it's supposed to be for 9 speed setups.

grudgemonkey

OK, this is from my "internet" research:

Weight with BB, 175 mm:
105 948 g
R600 Unknown
R700 885 g
Ultegra 848 g
Ult-SL 808 g

They will shift the same except the R600 is the original compact crankset and is improved in the r700:

"The inner chainring has a tooth profile designed to prevent the chain from falling off during shifts down to the inner ring"

I assume the 105 and Ultegras were desinged after the introduction of the r700 in 2006 and have the benefit of this design development.

If you have any weight stats that differ, please let me know and post links.

AEO

I've got the Tiagra 4550 and R600. The NDS arms are the same, but the drive side isn't. Inner 34T ring is the same, outer 50T ring is not.

shifting performance is pretty much the same.
the finishing on the R600 is much better.

that's all I could figure out.

Mash Master

between the R700 and the ultegra SL crank is the bottom bracket the same?

pagliaci

The R600 weighs about 890 grams.

Gee3

Yes. But the SL has the bling ice grey color! There isn't an issue with interchanging the BB's until you get into Dura Ace territory, I believe.

I have the R600 and it's been great over the last year. I've dropped the chain once but that was because of "user error", imo. I feel confident with it because it's a Shimano product.

When I called Shimano about it they basically said the main difference was the weight between the differring models.

The only reason I'd want the compact SL is to match the rest of my SL gruppo. But I can't justify the extra $$ on one just yet. So I'm sticking with the R600.

Mash Master

pulled the trigger on the r700, got it for $162 from pbk

whrl1

The main issue I have run into with the compact cranks and 9 speed is the spacing between rings. I switched from a DA 39/53 to an FSA SLK compact and generally liked the range, but the tighter spacing means you will have chain rub on the 2 biggest gears in the small ring. When a manufacturer says "works with 9 or 10 speed" it usually just means "the chain will fit onto the rings" but they don't mention the chainline issues. All non-Shimano made "9-speed" compacts I have seen are just Campy 10 set-ups, i.e. the chain will fit nicely on the rings but the ring spacing is for 10sp.

I have now switched to a 4550, which has 9-speed ring spacings, and can get the entire range without rubbing ( on the repair stand, haven't yet ridden it, the 11t might rub under load which, of course, was normal with my previous DA 39/53).

This might not seem all that important at first, but I run into several situations on moderate grades of around 4-6% where one has to constantly switch between chainrings or let the chain rub. For a casual fitness rider this probably isn't worth fussing about, but it's a problem when racing and trying to respond to attacks and speed changes on a climb. The crossover of the gears is smaller on a compact to begin with, so if you can't get the biggest 2 gears this becomes even more of an issue.

All this fuss over the "dreaded double-shift" really puzzles me. Having a 39/53 doesn't mean you dont have to double shift, it usually just means 1 or 2 RD shifts instead of 2 or 3 on a compact. Never bothered me a bit when I switched.

I live in a hilly area and I use a Powertap, so having the extra range of the compact is nice for recovery rides since I use the same wheel for all rides ( having extra Powertap wheels is rather pricey.... ).

The weight of the 4550 (w/ a 7800 BB, probably not much difference in weights of the cups) is 955g on my digital scale for anyone interested. I had no luck finding the weight for a 4550 posted anywhere on the web. My FSA SLK weighs 790g.

If anyone knows of any other compacts that have 9-speed ring spacing, I'd be interested to know. I'm not really a weight-weenie, but would like something lighter than the 4550 if I can.

I recently bought a low-end CX bike that had a Truvativ Touro compact crank on it that has the wider spacing, however it has steel rings and uses a standard tapered BB. This would be a lower-cost option (roughly $50 retail) than the 4550 for anyone interested, but it doesn't seem to be widely available and seems more an OEM part. ( Having now removed the Truvativ, weight is 845 for the crank alone, 1150g w/the cheap BB installed, quite beefy! [No worries about floating in water] I'll probably e-bay it soon so if anyone's interested ... )

Ok, I'm finally done ranting.

weavers

i want to make the switch to compact as well, but i have an 8 speed. do the 9/10speed cranks work with an 8 speed sora drivetrain? i'd asume a 9 speed would but how well would it shift?

right now i have Truvativ ISOflow SRAM Weight: 940g and the BB is 340g, meaning it weights 1280grams, nearly 3 lbs of crank.it says it can handles 9 speed, but it falls off the small ring alot. chain fell off twice on a 25mile ride. also when i move my bike into or out of a car/truck the chain tends to fall as well. just a minor nusence.

i would like something lighter, since its an upgrade and a chain that won't fall off to much. the Shimano R4550 seems really good, dunno if need to buy bottom bracket cups or how much they are. but i found a really cheap one on ebay.

https://cgi.ebay.com/PZ-Racing-CR-3-3...742.m153.l1262

10speed, maybe i'll upgrade someday, 645 grams, and it uses the same bottom bracket as i have right now. or i could upgrade my bottom bracket for 30bucks and take off 100grams making the crankset only 890grams w/ BB. saving 13 oz on my bike isn't the biggest thing, but saving money and being able to spin up steep hills is.

should i go tigra or some no name and save 50bucks?