BluesDawg

You're still missing something, or misinterpreting something. Praxis clearly states that the Alba crankset is compatible with BSA (English threaded) BB shells. Also the blog post states this, "Praxis made an intelligent decision to create a system that, while unique in some dimensions, allows for compatibility with five of the most common bottom bracket shell designs – BSA (English threaded), BB86 (common on Scott, Giant, Lapierre, and others), BB30, PF30, and Specialized’s proprietary OSBB."

The standard inside diameter of a BSA shell is 33.6-33.9 mm.

If this is the crank you really want to use, your search is over.

Cyclist0108

Long time, no hear. Great to see you.

For this bike, replacing the Di2 would be quite expensive. If I were starting all over, XT(R) with Di2 might have been the way to go. But the 32T cassette maxes out the RD capacity. The only limit on the front is the tooth difference must be 16T or fewer, so 46/30T is a reasonable option. (Also, I just put on a new chain and new cassettes on both wheel sets.)




That looks great. Although it certainly is expensive, the WI crank would be even a bit more, and with this I might be able to get away with keeping the same Shimano BB. It also offers the (alleged) advantage of keeping the hollowtech II type crankshaft.

Alternatively as someone else pointed out you could check out eBay; there are Japanese online vendors you can buy this from as well which will be could save you some coin.

https://alexscycle.com/products/sugi...act-plus-crank

https://alexscycle.com/products/sugi...601d-with-bb-1[/QUOTE]

Thanks so much for the links. I had given up on finding it.

Cyclist0108

I like the crank. Their own website doesn't seem to allow you to specify a 48/32T in the order, and the only 32T chainring I have found on their website is in the mountain crank section, and made of steel (which I would actually prefer to aluminum). The price seems right, too. I'd rather have 46/30T, since the 32T isn't going to differ than much from my 34T, but if it is steel, it might be worth it for longevity.

What's missing is my understanding of bottom brackets and their spindles, which is next to non-existent. I've read some basic descriptions, like this:

Bottom Bracket Standards | Park Tool
Complete guide to bottom brackets - BikeRadar USA

I really want to be wrong about this. The only thing I am confident of is that the word "standard" isn't accurate.

My current bottom-bracket is a Shimano Ultegra "BC 1.37 x 24 Road" and am 99.9% sure it is English threaded, corresponding to the first row in the bottom bracket table in the Wikipedia article you linked.

(I have a custom steel bike with a conventional bb shell that resembles that on my 1987 Bianchi (except for the threading). My frame bb shell can accommodate a 24mm Hollowtech II spindle, or a square taper bb.)

I guess the safest thing to do is ask my frame builder, who offered to install the thing for a few bucks (which might save me from making a costly mistake).

Added in edit:

It looks like WI (for example) makes a BSA bottom-bracket for 30mm https://www.whiteind.com/bsa . I had falsely assumed that this wouldn't work. That opens up a whole bunch of possibilities, including the rumored WI 30mm crankset.

BluesDawg

Yes, your Shimano BB fits a BSA threaded shell. It uses a 24mm diameter spindle, which fits easily within the 34mm hole in the shell, as will a 30mm spindle. It just has to have a shell interface that will fit and work with both.

BluesDawg

Not sure when (or if) it will actually be available, but FSA is supposed to be coming out with some cranks with versatile BB adaptability and chainring sizing.
FSA SL-k light Adventure Modular BB386EVO - FULL SPEED AHEAD
TPE16: FSA gets Modular with new cranks for MTB, Gravel, and Road, plus steel Comet 1x chainrings - Bikerumor

Cyclist0108

Thanks, again

cccorlew

I got all excited about the FSA 46-30 but couldn't find it anywhere.
I wrote FSA, who replied:

Hello Curtis,
That version of the Omega will be available later this year as a 2017 model year product.
Sincerely,
brysfleming

deepakvrao

Have a VElo Orange 30/46 waiting to be put on my wife's new Titanium touring bike. I think it will be a nice gearing for touring.

BluesDawg

Thanks for the info. Looks like they plan to release similar cranks at several price points. Seems the rise of gravel/adventure/any-road/mixed-surface/whatever-the-@*$*-you-want-t-call-it bikes is starting to produce benefits for a variety of riders.

bikemig 

+ 1. The 46/30 combo makes a lot of sense.

Wheever

The only crank on FSA's website I could find with a 46/30 is the OMEGA MEGAEXO, which says it's 110 BCD. I thought the smallest ring you could get on 110 BCD was a 33? How they do that?

JohnDThompson 

I run a 46/30 TA crank here:

clasher

Sugino OX601D seems available from this UK seller, so minus the taxes it should be under 300USD.

Cyclist0108

$224 at today's exchange rate.

rydabent

I use a triple on my trike. The bottom bracket has a 30-40-50 set up. Against all "real cyclist" rules, I use them basically up hill, level, and down hill..

Cyclist0108

My one remaining concern is the DI2 wire in the frame ...

Road Fan

Sorry for mansplaining (ALERT! ALERT!), I'm afraid there is room for misinterpretation, but not really BluesDawg's fault. The BB specs the OP read off define a British threaded (AKA "BSC") bottom bracket. All normal British-threaded BBs (Shimano, Campy, Tange, Phil, and pre-cartridge cup/ball/spindle models) are able to fit that frame, because of those specs and because the BB shell width is always 68 mm. The shell has to have a 1.37" inner diameter at the threads AND a 24 thread per inch threading. The spec has nothing to do with the diameter of the spindle. Any BB with those thread specs should screw right in, given the thread are clean and in good condition. It also says nothing about spindle length, the length of the left end, or the length of the right end. That is what the "standard" accomplishes and what it doesn't accomplish.

A lot of the difficulty is due to the existence of different standards. "Italian" is another one, and the Swiss seemed to mix and match. That's it for the traditional standards. Other variations exist, however, for example Octolink (look it up at Sheldon's) and the different square-taper spindle end designs.

In modern days we have a lot of new standards for BB shells and BBs. I can't say I dig them all yet, nor have any preferences.

The spindle is not visible on a Shimano BB, because it's sealed inside a metal cylinder. The metal cylinder diameter is (I guess) around 24 mm, but that dimension does not affect spindle breakage or longevity. If you had a BB in your hand with a shell diameter of 30 mm and threaded sections that meet your frame's British threading requirements, it should still screw in no problem.

Spindles themselves are around 12 to 15 mm (really, I'm just guessing here). For some special new standards like recent Campagnolo and SRAM, the spindle diameter is a lot larger, but in these cases there is no over-shell. I like both of these designs.

Not sure if this is really useful, but I hope it helps. Mainly, "24" is key because it's the threading spec, not because it's the shell or spindle diameter.

John E

I began cycling when 100 gear-inches (52/14 or 48/13) was a standard top gear, although one still saw an occasional 94 incher (49/14), and a few racing bikes had 108 (52/13). Having never found a real need for anything higher, I currently run top gears of 45/13 (UO-8 transportation beater), and 49/14, 50/14, 47/13 (three road bikes, 94 to 98 gear-inches). I run 104 gear-inches (48/13 on 26" wheels) on the mountain bike. Omitting the high gears that seem fashionable today allows one to have both desirably low bottom gears and reasonable gaps between the ratios. The proposed 46/12 should provide all the top gear you really need -- I would obviously go with 46/13 or 50/14 myself.

fietsbob

Shipped back a trans continental race guys bike with all premium gear. including that crankset..

rm -rf

Yeah, I agree. I ran a 13-29 10-speed Campagnolo cassette with 50/34. I would spin out the 50-13 around 32-34 mph, and by then I was coasting downhill anyway.

So I assumed that the 11-28 in 11-speed standard cassettes were "marketing".

But I do find two uses for the 50-11:
1. I can cross chain to the 34-12 (since it's not the final cog), and avoid a front chainring shift. That extends the 34 chainring's speeds up past 20 mph.
2. On really long downhills, it's nice to soft pedal in the 50-11, to keep my legs moving.

irwin7638

I use a 46/30 with a 12/36 nine speed on my Hillborne. I think it's great. I very rarely have to resort to the small chainring, but it's nice when I do. I have a Sugino triple crank, mounted the 46T in the center position and use the outer for a chain guard. Easy peasy!



Marc

dbg

Ditto on the triple to double conversion. I love it. Have converted several shimano ultegras to 46-30, 44-28, and 42-26. I put a CF chain guard on the outside spot. Even 42-11 gives me plenty of speed for light touring.

ct-vt-trekker

you can buy just the 46T chainring for your existing crankset. It's available because Shimano makes a 46/36 version of the Ultegra crankset for cyclocross bikes. This ring is expensive though! the best price I could find was over $100 for just the 46T ring. You can buy the entire 46/36 crankset for about $160.00 online. Biketiresdirect.com has the 46T ring in stock for $106.50

another option is to run a larger cassette using the roadlink.
https://www.wolftoothcomponents.com/products/roadlink

Cyclist0108

Yeah, but what I am after is the lower gearing with the 30T small chainring, not a smaller large chain-ring per se. (The 46T is just to keep the gap less than or equal to 16T.)

Mr IGH

That's just a recommendation, I expect it'll work fine on a 20T gap. In fact, this thread is pepping me up. The only way I can see dumping my 3x9 is a 2x11 with a 46/26 in front and 13-28 out back (I hate big steps and can't see ever using a 12-36 cassette on my road bike). And now I see how it's possible, thx! Now I gotta wear out my existing drivetrain....