medic75

I'm trying to get some better low end gearing for steep hills. I'm looking into my options. The bike is a stock Diamondback Haanjo Trail with the FSA Gossamer Pro 46/36 crank and a Ultegra R6800 with an 11-32 cassette on the rear. My original thought, due to the limitation of the Ultegra, was a to replace the inner chianring with a 30T. After some online shopping, this doesn't look possible. So, my next option, and the one suggested by my LBS, would be an 11-40 cassette with a derailleur hanger extension. I am now reading that the newer Ultegra R8000 can handle the 40T cog on the cassette. I have alot of faith in my LBS, but the idea of the extension concerns me a bit. Are there any issues created by using these extensions?

Marcus_Ti

Sub-34T is not physically possible on 110BCD cranks*, is what the problem is. It is a geometrical one, the wheel circumference is too small for any fewer teeth for 1/2" pitch chain. To get a 30T, you need a non Hollowtech crankset (AKA one with a smaller BCD...or direct-mount rings with no BCD at all). Such as FSA Modular Energy (same price thereabouts), or Sugino OX, or White Industries, or IRD, etc.

*Mr. Asterisk, my old friend, is here due to Praxis cranks managing a 32T with some very intricate machining....they're the one exception.

R8000 officially supports up to 34T cassette. People do push the limits. You could do a WolfTooth, which is what your LBS is thinking. You'd of course need a new chain...and would have far wider gear spacing than your 11-32.

HillRider

Some older Hollowtech II cranks support 30T and even smaller chainrings. 105 FC-5703 cranks have 130/74 bolt circles and the inner bolt circle allows down to a 24T chainring. Tiagra FC-4700 and Ultegra FC-6703 cranks have no inner bolt circle but the middle chainring has a auxiliary 92 mm bolt circle and takes a 30T chainring.

Canker

https://absoluteblack.cc/oval-road-c...-for-110-4bcd/
You can get a 30 on a 110BCD shimano crank but it isn't cheap

I know people have gotten away with running a 11-36 cassette with the Shimano Ultegra RX rd-rx800, the new one with a clutch, but even that one I think you would be pushing it to try a 11-40. If you don't want to run a road link and want a 11-40 cassette then you can switch to a shimano mtn RD and run a wolftooth tanpan
https://www.wolftoothcomponents.com/products/tanpan

Personally I'd just get one of the chinese $3 road links off ebay and try that first with your current RD and if it works great, if not you are out $3.

medic75

So I am getting the impression that the hanger extension will likely not create any shifting issues? I have no idea what brand my LBS would be using, but from what I can tell, even the brand name ones aren't overly expensive.

pennpaul

Sorry for the hijack, but I was about to ask the same question for my DB Haanjo Trail except I want to keep the double chainring and get an 11-40 or 11-42 cassette. Any suggestions for which cassette will replace the stock Shimano 105 CS-5800 cogset? To do this upgrade, I'd need the following (and tools, of course)?

--RoadLink
--longer chain
--11-40/11-42 cassette

Is that it?

Thanks,
Paul

Cyclist0108

I've gotten 11-36 working with a mid-cage Ultegra Di2 rear derailleur just by cranking in the B-screw.

I've put a 46/30T crank on the front.

I am told the wolf tooth adapter would allow for an even larger rear cassette, but I haven't tried it myself.

zze86

I have a wolftooth adaptor on one of my bikes with an Ultrgra 6500 rear derailleur shifting a 11-36 cog. No issues with the adaptor.

Stormsedge

A buddy of mine has the arrangement you are asking about with no issues (Ultegra).

Canker

Any 11-40 cassette will work from shimano, sram, or sunrace. I'm sure people have done it but Wolftooth says the roadlink tops out at 11-40. You also need a spacer because the mtn 11 speed cassettes are made to work on 10 speed and less hubs. Somebody just asked about that in another post.

https://www.bikeforums.net/bicycle-m...onversion.html

pennpaul

That was me that asked that question

Bought the Sunrace MX8 11-40 and Roadlink online. Now I need to buy (another) chainwhip and (another) cassette removal tool--those got packed into storage. Also need to buy spacers.

medic75

Quick update for the Haanjo Trail owners - my LBS called me. He found a 32T inner chainring for the FSA Gossamer ABS crank. While it isn't the 30T I had originally wanted, it seemed like a potentially viable option, giving me down to 1.00 gearing vs the 0.94 that I was trying to achieve and the 0.88 that I have on my hybrid. The stock low gear was 1.13. With 1.00 gearing and some good leg workouts over winter, I am hoping I will be all set. I see this as a win because it will not affect the gearing on the 46T ring which is what I use 90% of the time and 100% of the time on my daily commute.

This is a bit off of the original larger cassette topic, but a definite option for those of us with the crank in question and looking for a lower gear.

TX Tandem

I have a bike that came with 36/46 chain rings and found the same lack of options as you.. until I found Absolute Black oval rings in 32/48 that fit my 110 bcd shimano CX cranks. I wasn't looking for oval, but to be honest, I can't tell a difference now while riding them. And the gearing seems perfect. BTW, Absolute Black offered a 30/46 combo that also fits.

fietsbob

given its function is shoving the chain inward , all you do is move the whole thing downward
so it has a possibility of clearing a cassette cog the size of a front chainring.

A longer gap to the smaller cogs , may not be a super .. fast shift because the chains for faster shifting are laterally flexible..

and now the gap is bigger.. pulley to cog with a flexible chain ..





...

TimothyH

I'm running Absolute Black 46/30 chainrings on Ultegra cranks. Oval rings feel quite different to me and I'm not sure why others can't feel a difference. I love them.

The rear has an RX-805 GS derailleur and an 11-42 XT mountain bike cassette. A 1.85 mm spacer was used behind the cassette and the B screw was reversed.

Sizing the chain is easy as it uses all 116 links.

Low gear is 19.5 inches.

The photo below gives an idea of how it looks in the lowest gear as well as why it was done.




-Tim-

aggiegrads

Marcus_Ti

Oval rings+ 4-bolt mounting lets this work

Canker

https://absoluteblack.cc/oval-road-c...-for-110-4bcd/

Rather expensive but compared to buying a whole new crank and BB to get 46/30 it isn't too bad, well that is how I justified them anyway.

aggiegrads

Wheever

Canker

I can't tell any difference between oval and round, all feels the same to me. I really like having the 46 since it puts me in the tighter range of my cassette for normal cruising. Yeah I have to spin pretty fast at 40mph but I spend a little more time riding around at 15-22mph. The 30 comes in pretty handy too though. I don't think I'm getting up the super steep hills any faster with the 30 than my old 34, not any slower either, but when I get to the top my legs aren't as destroyed and I recover faster.