Bigbandito

I'm a 6'6" 370 pound newbie riding a '12 Fuji Cross (and lovin' it, btw). The bike has a 36-46T up front and a 11-25T ten speed cassette in back. I posted my purchase of his bike here back in April, and while getting a lot of enouragement, one poster had this to say:

After riding a few months, I think this poster may be right. I would characterize my favorite route as rollers with a few mild hills - nothing major. I find myself riding most of the time on the smaller chainring (even on the flats) and in the lowest gear on most of the hills.

The current set up gives me 39.1 gear inches at 46/25. A 28T on the back would give me 34.9 and a 30T would give me 32.6. As a newbie I'm wondering if that's enough. What's your opinion? What's your lowest available gearing? What's the lowest you need? Do you think 32.6 would be enough for me? Are there any issues I need to consider in swapping out the cassette?

Thanks for your input.

goldfinch

Roughly, 31.9 is my lowest and I want lower. I have an 11-28 cassette, compact double 50/34 on the front, and 165 cranks.

The issue with going to a cassette on the rear that has more teeth than your 25 is whether your deraileur can handle it. I have a short cage derailleur on my bike and it isn't rated to handle a cassette with more teeth than what I have.

B8888S

I am not sure how to calculate gear inches, but my lowest gear on my road bike is 34 in the front and a 32 in the rear. I have a 50/34 in the front while the rear is a 10 speed SRAM Apex cassette with 11-32. I typically only ride on the big ring when on the flats. When climbing some steeper hills, I have been forced down into my lowest gear a couple of times and was very grateful to have it.

I just googled a calculator and it looks like my lowest possible is 28.03 inches. Not sure if this is correct or even what it means. I do know that I have never really need a lower gear than what I currently have.

Bigbandito

Mike Sherman's gear inch calculator says I need a RD capacity of 28. I have a 10 speed Tiagra RD, but can only find info on the older 9 speed. The 9 speed has a capacity of 31 on the short throw and 37 on the long, so I think I'd be OK.

Another way to get lower gearing would be to replace the 36 up font with something lower or go to a triple, I guess.

chrism32205

I have a cross bike that has the Shimano Deore LX M581 long cage derailleur. The crankset on the bike came with 36/50 chain rings, if since changed them to 34/46 chain rings and I run a 11/32 cassette. I could run a 11/34 or 12/34 cassette for even lower gearing. I run 25mm tires.

My lowest gear is 28.0 inches when using the 34/32. If I run a larger cassette I could get to 26.4 inches.

bikemig 

@B8888S: 34 running on a 32 is pretty darn low.

As far as the OP is concerned, there are trade offs. When you go with a larger cassette in the rear, you tend to lose some useful in between gears. That was a real problem when bikes had 5, 6, or 7 on the rear. With modern 9, 10, or 11 cassettes not so much. The fuji cross is a sweet bike as it the cross crank with 36-46 up front. I'd go as big as my rear derailleur could handle on the rear (talk to your LBS). You could also pick up on the new long cage shimano rear derailleurs that are rated to 30-32 teeth and go big in the rear: https://www.modernbike.com/itemgroup.asp?IGPK=2126204960

MRT2

My bike has a 26 tooth small chainring. The middle chainring is a 36 tooth. I have a 9 speed 12 - 25 cassette in the back. I need that small chainring for steeper or longer climbs. I toyed with the idea of switching to a compact double and a cassette with a 32 tooth gear, but I like the close ratios on my current cassette, not to mention I would need new shifters, and a new RD to make such a change.

Bigbandito

My RD looks like the Tiagra 4600 or 4601 (they both look the same). The 4600 is rated to 30T and the 4601 to 32.

Medic Zero

Same here. I'll have to look up the gear inches later, but I use a 48-32-22 triple with an 11-34 cassette and use the 22 tooth with the lower rear gears a lot on hills. Most days I don't actually get all the way down into the 34 tooth on the rear (but I get close!), but when I'm tired or a take steeper hills than my usual commute, I spend some time grinding along in that lowest gear and am thankful for it. I'm 6'2" and 280 pounds.

EDIT: looks like that gets me all the way down to 16.8 gear inches in 22-34!

PhotoJoe 

My bike showed up with 11-25. As the first C/A GMR ride approached, I realized I would never make it in my current condition. I swapped it out so I had 50/34 with 12-28. There are still times I wish I had lower, but I've sucked it up and survived. It's never stopped me, but do wish I could spin more on some hills.

brianogilvie 

There's also the question of the largest cog that a derailleur can handle, as well as the capacity. I got the new (2012) Shimano 105 RD for my latest bike because it can handle a 32t cog (spec; it might go to 34 in reality).

As for your original question, here are my low gears:

20.4" on my Bike Friday New World Tourist: 40-406 tires, 54/44/30 triple, 11-28 8-speed cassette
23.5" on my Surly Long Haul Trucker: 35-622 tires, 48/36/26 triple, 13-30 9-speed cassette (Harris Century Special)
24.3" on my Boulder All Road: 42-584 tires, 44/28 double, 13-30 9-speed cassette (also the Century Special)
27.7" on my Breezer Uptown 8 commuter: 40-559 tires, 38t ring, 18t cog, Nexus 8-speed hub

I did a ride yesterday on the All Road with some substantial climbs on dirt road, and I was happy to have the 24" low gear. On some British roads that go straight up the side of hills, I appreciated the 20" low gear of the NWT, particularly while carrying a load. I prefer to sit and spin on hills, especially since on some of the dirt roads I ride, if you stand to climb, your rear wheel slips!

Now that I have the All Road, I'll probably go back to a 34t small cog on the LHT, which had been my day ride bike; the 34 will give it a low gear for loaded touring.

blackvans1234

I feel your pain. I have the same thing, compact front 50/34, 11-28 cassette.
It's fine for most rollers, but I just attempted my first climb yesterday and I was in lactic acid hell.

Bill Kapaun

Slight correction-
It's not max cog size. Both short & medium cage DER's handle the same max SIZE cog.
It's chain wrap capacity.
(Largest ring - smallest ring) + (largest cog - smallest cog)

jsigone

currently running compacts (34s) with Sram 11-26 cassette. Has a nice range for my local roads.

700x 25ctire, 34x26 = 34.5"

awfulwaffle 

I've got a 21.6 inch lowest gear on my mtb (28 tooth small chainring and a 13-34 tooth cassette). On my road bike (recent purchase), my lowest is 26.3 gear inches (30 tooth small chainring, 12-30 tooth cassette).

That said, I've never had to go into the small chain ring on my road bike yet (and I've fought a few steep hills on it already), and I only need to on my mtb when I'm fighting a pretty darn steep grade we have on one of the mtb trails around here. Though I am also a clyde, you are a tad heavier than I, so if you feel like you're running out of gear range a few drivetrain changes couldn't hurt. I'm not sure what crankset you have on your bike, but perhaps it's possible to change your 36T chainring to something a little bit smaller? IDK how small they make chainrings in the 110 BCD I'm pretty sure your compact crankset uses, but it might help avoid having to replace the rear derailleur while going to a larger cassette.

goldfinch

Thanks.

SlowAndSlower

For touring and event rides I use my Soma Stanyan which is a 9 speed tripe 48-36-24 with a 11-34 cassete. I use an LX rear derailleur. https://indianbendsolutions.com/stanyan/
So I have a low of 19 inches.

BTW this is my calculator https://indianbendsolutions.com/plugi...le-gears-tool/

Null66

18.8

22,32,44 11-32 rear running 700x38's

https://sheldonbrown.com/gears/

Tel0004

28. 34x32 on 700x25 tires.

volosong

Depending on which RD you have, Ultegra and Tiagra come in a 12-30. I put this on my bikes. One has a Dura-Ace RD-7900-SS, which only comes in one cage length. The shop that did my BG Fit took out two links, so I can't go big-big anymore. Before he took out those links I could, (not that I want to, but some times I forget what gear I'm in and accidentally shift into big-big). Next time I remove my chain to clean it, I'm putting those two links back in. The other bike has an Ultegra RD-6700-SS (mid-cage length). No problems at all with that bike. Both bikes are 50/34 in front. (Another bike has a RD-6700-GS, (long cage), which is the triple dérailleur, so wouldn't expect it not to work on a compact.)

The Mike Sherman Gear Calculator shows a 34-28 as being 32.3 gear inches and the 34-30 being 30.2 gear inches. That's a an extra 7%! Most useful for us heavier, out-of-shape folk when the grades ramp up steeper.

Some time later this year, I'm switching one of the bikes to that new Ultegra 6800 group, which is available with a 11-32 cassette. Using the 50/34, that would give me a lowest gear of 28.3 inches. Not quite as low as a triple with a 12-30, but low enough that the Baldy ski lifts are possible. There are large gaps, but I can live with them.

donalson

on my disc trucker I have 17.5" thats a 22t granny and a 34t out back... but thats all just MTB 29er stuff on a touring bike... in reality the lowest I ever use around here is the 32/34 which is 25.4" and that is if i'm feeling almost dead I can climb it at 33.8" without issue as long as I push myself a bit.



on my road bike I've got the same gearing as you... i'm tossing a 34t up front (techincally it's out of range on the front Der but by all accounts it works just fine... out back i'll prob go with the tiagra 12-30t cassette... so my bottom end will be a 30.3"


you can do both fairly inexpensively if you're der can handle it... i've read of a number of people running shimmy short cage der with the 12-30t cassette...

2 wheeler

My low gear is 30.5, which is 30t chainwheel/25t cassette. This is on a triple with 30/42/53 chainwheels and a 12x25 9 speed cassette with 700x23 tires.

Thanks to Null66 for the link to Sheldon Brown's gear calculator.

This is the lowest gear I've ever had on a road bike and I'm really glad that my bike has this setup. I live on the eastern slopes of the Cascade Mountains in Washington. There are some remarkable mountains here and lots of them to climb. I'm over 60 and weigh about 232, so the low gearing makes riding in this area possible. Some say triples are no longer in vogue. That's ok, I don't care about fashion, but I do know that I need some very low gears to ride here.

brawlo

Going back to your original post, are you struggling in your easiest gear, or are you getting by? Next question is are you intending on riding even steeper terrain than you already do?

My lowest gear is 39/28 or 36.6GI on 700Cx23.

For the terrain around where I live, that is pretty much fine for me. I was on a 172.5mm crankset last year and wanted that extra gear on the odd occasion. Back around Sept last year, I upgraded the crankset to 180mm (I'm 6'5"). I still had it in my head that I wanted another few teeth on the back, so when I upgraded the bike in Dec, I went with a 28/11 on the rear. Since doing so I can literally count on one hand the number of times I have used the 28. Going to the 180mm cranks pretty much filled the gap that I needed and wanting the 28 was really a thought in my head rather than what my body wanted. The few times I've used the 28, I really could have just slugged it out on the 25. What I have found is that I am wanting some closer ratios in the middle of the cassette in preference to the easier gear. NOW to the point of that whole rant, you say you've been using what you have for a few months now. As you ride more, you will get to be a stronger rider, which then leads into my second question from above. Do you see yourself riding steeper, harder terrain? If so, then you may search for better gearing. BUT, because you are 6'6", my suggestion would be to look at doing something about your cranks. Not a cheap option, but should be the better option for you in the longer term. However, if you're still not sure about this riding thing for the long term, then a larger sprocket on the rear could be the option you need right now.

Check out BigFred's posts on his journey into the longer crankset world.
https://www.bikeforums.net/showthread...k-Ghetto-Build

rdtompki

27" (52-39-30 and 12-30), but I'm going a bit lower. I'm barely over 200 lbs, but sneaking up on 68 y/o and we got some pretty good climbs hereabouts (3000' in 10 miles for example). I need the lower gearing when I'm doing a longer ride that incorporates one of these climbs.

Bill Kapaun

I have a 22-32-36 with a 12-23 9 speed on my hybrid. (Same on my grocery getter, except 38T largest ring, but it has 26x1.25" tires or about 10% smaller)

My lowest gear" is 23.8, which I don't use in my flatland riding.
I have gone as low as low as 31ish in stiff headwinds though. When they are BAD, I go to the smallest ring and have a lot of closely spaced gears in THAT range. I'm not concerned about cross chaining. If I need a gear, I use it.
I do make a couple trips/year to my old home town in Idaho which is hilly. I put on a 13-25 cassette for those trips. (until I round up a spare 27/28T 9 speed cog)