2wheelsgood@no

Hi,
I have a Marin Four Corners with the Shimano Sora 3x9 speed groups set. I'm generally happy with it but I use the bike for some long distance touring and, as me legs ain't getting any younger, I would like to get a bigger granny gear on the bike. As it stands the lowest gear ratio is 30/32 (0.92) and ideally I'd like to get this down to at least 0.75. This would involve putting on a cassette with a largest cog of at least 40 on the back - the only cassette I can find this size is the new Shimano Cues LG400 Cassette LinkGlide, 9-speed 11-41T, which is described as being only compatible with the LINKGLIDE system, whatever that is.
An alternative is to reduce the front cogs, but I cannot find any cogs that are compatible with the Sora crankset.
Short of completely replacing everything, has anyone got any suggestions what I can do to reduce my gear ratios?

Iride01 

A entire new crank with smaller rings will probably be the best bet. I'm assuming you must have a 34/50 set of rings on the front. Your top end might suffer a tad with a smaller big ring, but not much. And likely only if you power down the backside of hills. If you go with a cassette that has a bigger bail out gear, you might exceed the capacity of the rear derailer or be outside it's limit for the max rear tooth. But we'd have to know the model numbers of it to be sure. If you don't size down the big ring too, then it might take a little more time for front shifts to complete or just generally they might be lousy shifts. And a possibility of the big ring interfering with the chain when you are in or near the small/small combo, if that is something you do.

Shimano puts the part number of the RD on the backside of the parallelogram, the backside of the FD and around the hole for the pedal on the inside of the crank arm. Knowing those will let us know what series Sora you have.

Welcome to BF.

Andrew R Stewart 

I suspect your bike has the stock 52-39-30 crankset. Swapping out the 30 granny for a 24t would help lower (not "increase") your easiest gear by the amount you seek.

I might suggest that you also swap out the road bike rear der for a mountain bike one, like a Deore for the greater chain wrap spec that wider range gearing has. You might also consider a 12-36t cassette when your current one wears out.

I've run 46 (or 44)- 36 (or 34)- 24 on most of my bikes for many years and am changing to that 36t cassette as each bike gets worn cogs renewed. Andy

dedhed

Trouble is he has a 74 BCD 4 bolt crank. Doesn't seem to be a lot of options for chain rings. 5 bolt available all day long.

dedhed

Says 3 x 9 Sora so 50/39/30 stock. A smaller granny isn't an option as it's a 4 bolt crank, not 5

icemilkcoffee 

I do know the Shimano RSX crank comes in a 110/74 BCD version, which has 26T/36T/46T

79pmooney

I wholeheartedly second getting a 110-74 BCD 5 spider crankset. If it were me, being 110-74 would be a lot more important than being Shimano. (Yes shifting might suffer without the proprietary chainrings, etc. but still, having that access to so many chairing options is a real blessing. And there's no danger the supplier (like Shimano) is going away or choosing to stop making the chainrings.

TC1

I make this offer from time to time when this comes up, but I make my own custom chainrings -- usually when the configuration I want isn't available for purchase, but occasionally for fun. So if OP is stuck, and the necessary part is not available, they can contact me privately and we can discuss a custom project, if they feel like it.

Crankycrank

Check out SPA cycles in the UK. They have a few triple options and from what I have seen their own SPA brand are very good quality and priced very reasonably. I believe they are basically licensed copies of Sugino cranks. They also have custom chainring options for you to select the size of each chainring and also pre-selected combos using the same crankarms. Price seems to determine the quality of the chainrings used, (i.e., more durable) and they use standard Stronglight and TA rings which should be readily available for years to come. You will alao need to purchase a square taper BB for these. Drivetrain | Chainsets | Spa Cycles

Andrew R Stewart 

Sorry to think that the OP might have an old enough version that was a 5 bolt 110/74 crankset. The issue with doing what I first suggested (which was the answer to the question, not the complete story though) is that the OP would end up with s 24 to 39t shift (granny to middle) which is pretty big and would only increase the effort to achieve this shift as well as retaining the 39t ring places a lot of gears still fairly high up in their ratios. This is why I run a 36 or a 34t as my middle rings, I end up with more ratios in the 8-12mph range that I need when loaded down.

I second the suggestion to get a 5 bolt 110/74 crankset. But make sure it's a road version to better match the ft der and lever road spec that is Sora. Andy

Iride01 

Yeah, I forgot about the 3x part by the time I got to the end of the OP's post.

Not sure I understand the smaller granny part as not being an option, unless you are just saying there is nothing they can do for changing rings on the current crank and are also suggesting the entire crankset needs to be replaced.

dedhed

Apparently the market isn't big enough for making 74 bcd 4 bolt granny rings. They just don't seem to make them. Changing to a 5 arm would open up lots of choices. As Andy mentioned it would likely want a different middle ring to lessen the jumps and have better shifting.

2wheelsgood@no

Hi, thanks for your reply.

Yeah, that sort of seems to be my conclusion too, replacing the whole crankset. I'm happy to downsize the big ring.
As far as I can read the numbers they are FD R3030 and RD R3000 (actually the numbers are clear, but the letter - I thinks it's an "R" - is harder to read. On the crank arm it has 175 FC-R3000/3030. If I understand correctly, the bottom bracket is Sora Hollowtech II, and I'm not sure what cranksets are compatible with that. And will the Sora shifters still work with a different crankset?

Calsun

Many 11-42t cassettes available with 9 cogs. Check on Amazon for the ones available. Be sure you really want a 42t cog. I had a 11-42t cassette on my road bike and swapped it out for a 11-34t that provided tighter spacing and with the 11-42t cassette I never used the largest cogs.

2wheelsgood@no

Indeed, options for the 4 bolt crank seem to be impossible to find. Annoying.

Not quite sure why I wrote "increasing" there!!

2wheelsgood@no

I'm using my bike for loaded touring - a front 30t / rear 42t give me a gear ratio of 0.71 - yeah, I'd use that. My old bike had a lowest gear ratio of 0.61.

I just wonder though how one can know if the spacing on the cogs is actually going to work with the Sora shifters? But thanks for the suggestion, I'lll browse the options and maybe give one a go.

Iride01 

These might work. But you might have to change out the BB. BB are inexpensive. So see if the BB is specific to the width of your BB shell or whether the supplied spacers make it work with a 68mm shell as opposed to a 72mm shell.

Or some other here might know how that works and will take time to check the compatibility to be certain.

https://cambriabike.com/products/shi...crankset-black

https://cambriabike.com/products/shi...crankset-black

I ordered a RaceFace crank from this place a dozen years ago and they shipped quick and I had no issues. Their prices on cranks are frequently pretty good. But go up and down with supply and demand.

dedhed

You want to stay away from riveted (not bolted) chainrings like this has. Screwed if you have a chainring issue on tour

​​​​​​https://cambriabike.com/products/shi...crankset-black

dedhed

Your existing crank is set up for a 45mm chainline so watch for that spec on cranks or your FD may not reach the outer chainring
https://bike.shimano.com/en-US/produ.../FC-R3030.html

2wheelsgood@no

Thanks for all the suggestions, much appreciated.

For now I think I'm going to try a RATUXTR 9 Speed Cassette for Mountain Bike, 11-42, with a hanger extension, and see how that works. It's quick and simple and not expensive. In time I'll look into shifting to a 5 bolt 110/74 crankset.

Bill Kapaun

42-11=31
52-30=22
31+22= 53 links of chain wrap required.
How are you going to manage that?
Extended hangars allow larger cogs, but they do nothing to take up the additional chain.

Andrew R Stewart 

Which is why I suggested a MtB rear der. Andy

Bill Kapaun

Don't "Mountain" RDER's max out at about 45T? I'm not up on the latest....

I needed to lower the gearing on my bikes, so I went from the 28-38-48 (-2 ea for the Rockhopper) and installed a 22-32-44.
Trouble is, the OP has a "Road" crank/shifter. I'm not sure how much of a mismatch it would be to try one. I've simply never dealt with "road stuff".

kommisar

With extreme wide range 3x setups, I just size the chain for the large chain ring, large cog and then only use the small chain ring with the largest 3-4 cogs. If you go small / small you get a loose chain.

2wheelsgood@no

An update for those who are interested: after all that, it turns out the Surly Long haul trucker uses the Shimano Alivio 48x36x26t crankset and the Shimano Alivio, 11-34t, 9 speed Cassette with Sora 3x9 shifters. Why it was impossible to find that information about their compaitbility from the Shimano website I don't know (well, i do know why, but that's another story), so that's what I'm going with now.

cheers, and thanks for the tips