Subcompact options-bottom brackets

[marciero]

Considering MarkMcm's SRAM Force 22 road subcompact set up discussed in the thread below. Would likely use with Engin spider with TA rings. Frame is a used-to-be standard BSA/English threaded 68mm bb. The SRAM site lists Force 22 as available in both 24 and 30 spindle, while CC simply lists "GXP" as spindle. Other vendors also dont seem to list options for spindle size either for the cranks or for the GXP bottom brackets. What are my options for bottom brackets? Probably buried somewhere on PL but could not find this below. Thanks in advance.

https://forums.thepaceline.net/showthread.php?t=232810

[AngryScientist]

marciero,

i know i'm not answering your question directly, but before you go too far down the rabbit hole...

that thread was started before there became available a slew of new, off the shelf subcompact options, and you may be better served by buying something in stock-ish configuration.

easton has a subcompact setup in both their carbon and alloy cranks now

same for rotor

GRX shimano has subcompact available

WI in both ST and outboard BB configuration

finally, absolute black makes subcompact rings for standard ultegra cranks.


point being, unless you want to modify a sram crank, there are new options available that may be easier.

sorry for the non-answer!

[R3awak3n]

as far as I understand, sram has 2 systems...

BB30 which is a 30mm spindle and GXP which is a 24mm spindle. On a BSA system you can use either. GXP you will need a GXP bb, the BB30 you will need a bsa 30mm bb like a rotor or something like that, there are a few (don't think sram has any that would work, this is kind of a hack but works fine).

So you can pick either crank, the GXP is a bit heavier but might not matter to you. I like the BB30 one better because will work with more frames, more future proof.

[NHAero]

I did Mark's hack with a Wheels Mfg. product for GXP.

Threaded Road ABEC-3 BB for 24/22mm Cranks (SRAM) - Gray

[marciero]

Thanks all. So it seems the SRam route would be straightforward.

Regarding Angry's remarks-

Am vaguely aware of some of the newer options. I actually have the Shimano GRX on my gravel/camping bike-cheap and awesome. On the other hand, I did not know WI had an outboard bearing version of the VBC. For this bike I have stronger preferences for the low Q, and also the 44/30 ring sizes. It appears the WI has 156 Q which is about like the GRX. Even the ST VBC is 150 Q.

The MarkMcm/SRAM/Engin route had 146 Q but also had the option of TA 5-arm rings, which to me is an advantage. On the other hand, would rather have alloy than carbon...

The Sugino OX 901 would really be what I am after, but aside from the expense, they only seem to be available from Japan and would take like a month to get here. (I broke a spindle on my OX 601 version of these which gives me pause but I think there may have circumstances leading to failure). There are also some crankarm-only versions of the 601 that seem to be available.

I suppose the simplest thing would be to just get another GRX. would not even need to change the BB on the bike.

Edit: Now looking at the Easton... low-ish Q at 149...

[ColonelJLloyd]

I've been using the the Q156 GXP version SRAM XX 42/28 and XX FD and RD for nearly three years now and have been extremely happy. BSA shell. Shifters are Red 22 hydraulic and everything works beautifully together.

https://live.staticflickr.com/65535/48175377986_c2a5265d55_z.jpg

https://live.staticflickr.com/4443/36805610563_660abb397c_z.jpg

My buddy just converted his Force22 crank to 42/28 using an XO GXP spider and rings. He had to grind down the chain peg to the right length, but was otherwise plug and play from what I understand. Finding the right spider took a little time. His bike also has a BSA shell. His drivetrain is otherwise Force22 hydraulic.

https://live.staticflickr.com/65535/49573704123_12051e2ec9_z.jpg

[unterhausen]

SRAM changed the spider on the better road cranks, because why not? I went to the lbs to see what arms I could get for the older style spider, and it was only low-end stuff, so I bought used.

I think I would have purchased a GRX if I had to do it all again and didn't find what I wanted used. I'm a lot happier with Shimano BB, the SRAM GXP bb are expensive and my experience with their longevity has been poor

[jtbadge]

If you have rim brakes/130mm rear spacing, the Shimano GRX crank will push your chainline outward and cause extra chainwear when using the larger cogs. I went Praxis 48/32 on my rim brake all-roader.


Also intriguing is this 46/30 set (seen on eBay from "bikinGreen") that mounts to standard 110bcd 5 bolt crank arms.

https://www.instagram.com/p/B85VM4llWz_/

https://scontent-lax3-1.cdninstagram.com/v/t51.2885-15/sh0.08/e35/s640x640/85206521_131069258426593_7157031866056755417_n.jpg ?_nc_ht=scontent-lax3-1.cdninstagram.com&_nc_cat=101&_nc_ohc=J7K5niielJoAX8LoCZZ&oh=a63206126a85071cdd57e492bef3f2fa&oe=5E83DFFC

[NHAero]

Mine is on my Litespeed drop bar conversion, and I'm running XO GXP 42-28. spider and rings off eBay. Crank came with the 110 BCD spider. The set-up is such that the 135 rear hub with a Shimano 11-40 11s cassette and Ultegra RD8000 on a Wolftooth puts the 42T ring roughly in the center of the cassette in terms of chainline, which is optimum because I use all 11 cogs with the big ring.

[robt57]

My buddy just converted his Force22 crank to 42/28 using an XO GXP spider and rings. He had to grind down the chain peg to the right length, but was otherwise plug and play from what I understand. Finding the right spider took a little time.

I can attest to this setup. I got the 28/42 rings on the spider, so mounting that to the CX1/Force arms was simple, pin shortening required as mentioned. I am using a FD-R8000 [rear R8000GS] and bar cons [indexed carbon microShift] for gravel bike. Almost never use the 28 really. But 11-40 rear without additional hanger drop device needed. I have an 11-42, but not tried it as the 40 is already very low, and not actually use the lowest gear out on the bike yet. other than to test range off bike stand etc.

I also have on another pair/bikes both 5800 and 6800 with 30/46 after market 7075 rings similar to absolute blacks.

The CX1_28/42 was totally plug and play and shifts better by a lot. But you kinda sit in the big ring and only drop for serious climbs. So not than big a deal, but I prefer the SRAM setup. It is not a post engineered add hoc, and it shows in shifting performance.

The 30/46 setup chain line had to be diddled, the SRAM totally plug/play. Wound up with a wavy washer drive side on the 30/46 setups to get the chainline usable.

Re: GXP BB on BSA, not big fan due to what I consider porky. But have a CX1 on two Trek BB90s where your just use the Non drive bearing with a 22mm ID, that without the GXP BB is quite the nice solution for the anti-pork crowd [me].

FYI: the Force carbon arms are nice low Q-factor, there-fore I have had situations where a generous chainstay width frame was either too close to use comfortably, or even hit.

And 30/46 rings referenced: eBay: bikinGreen CNC Road Chainring 46/30T BCD For 4 Arms Shimano 9-11 Speed

CX1 28/42 pic

http://coupekiss.host-ed.me//images/pics/SRAM%20CX1_28-42.jpg

[ColonelJLloyd]

I'm a lot happier with Shimano BB, the SRAM GXP bb are expensive and my experience with their longevity has been poor

Hmm. They're at most $30.

[unterhausen]

Okay, I'm cheap and they wear out every year for me.

[rccardr]

Anyone here have experience with the IRD Lobo subcompact system? External bearing, 24mm, 110/74, five bolt, come in both silver and black. Recently picked one up online for around $190 shipped, intend to run it as a 50/30 with an 11-28 cassette. Will give me a climbing range close to 34/34, but without the gigantor big cog, which I find less pleasing to the eye.

[ColonelJLloyd]

Anyone here have experience with the IRD Lobo subcompact system? External bearing, 24mm, 110/74, five bolt, come in both silver and black. Recently picked one up online for around $190 shipachped, intend to run it as a 50/30 with an 11-28 cassette. Will give me a climbing range close to 34/34, but without the gigantor big cog, which I find less pleasing to the eye.

I would not be interested in a 20t jump. Pretty sure that would throw off my "one shift with each lever" solution to dealing with rollers.

[marciero]

Anyone here have experience with the IRD Lobo subcompact system? External bearing, 24mm, 110/74, five bolt, come in both silver and black. Recently picked one up online for around $190 shipped, intend to run it as a 50/30 with an 11-28 cassette. Will give me a climbing range close to 34/34, but without the gigantor big cog, which I find less pleasing to the eye.

That was mentioned in a 2017 thread that I almost linked to in my OP. If you search "subcompact" in titles only it will come up. But I think it was only mentioned. I wound up ordering the Easton AC90-thanks Nick for calling that one out-and 46/30 direct-mount rings and Race Face BB for a complete proprietary matchy-match.

[robt57]

FWIW, the Force is highly configurable. I bought 3 sets NIB old stock for 99.00 each with 110 spiders no rings. Sram spider pulls and even new on eBay with and without rings abound on the cheap.

#2 is setup with Oval Rotar 36/53 rings for road, and #3 Red 34/50 rings for road.

As I said above, the GXP version used in BB90 frame with no GPX BB is a great light setup.

[Mark McM]

Anyone here have experience with the IRD Lobo subcompact system? External bearing, 24mm, 110/74, five bolt, come in both silver and black. Recently picked one up online for around $190 shipped, intend to run it as a 50/30 with an 11-28 cassette. Will give me a climbing range close to 34/34, but without the gigantor big cog, which I find less pleasing to the eye.

From what I can see, the IRD Lobo system is very similar to the Sugino OX_01 subcompact cranks, except that the Lobo system has a wider chainline & Q factor. This means that the OX_01 system is more optimized for road bikes, while the Lobo is more aimed at gravel and fat tire bikes.

The Sugino OX_01 and IRD Lobo chainrings appear to be interchangeable.

[Mark McM]

marciero,

i know i'm not answering your question directly, but before you go too far down the rabbit hole...

that thread was started before there became available a slew of new, off the shelf subcompact options, and you may be better served by buying something in stock-ish configuration.

easton has a subcompact setup in both their carbon and alloy cranks now

same for rotor

GRX shimano has subcompact available

WI in both ST and outboard BB configuration

finally, absolute black makes subcompact rings for standard ultegra cranks.


point being, unless you want to modify a sram crank, there are new options available that may be easier.

sorry for the non-answer!

As you say, there are now multiple options for subcompact cranks. However, most of these new options offer only slightly smaller chainrings - typically down to only 32 or 30 teeth (as compared to a minimum of 33 teeth for 'traditional' 110mm compact). Engin spider allows chainrings down to 24 teeth, and the XO spiders allows chainrings down to 26 (120/80) or 22 (104/64). Another advantage of the Engin spider is that they use very common BCDs (110/74) for which there are a wide variety of chainring sizes from a large number of manufacturers.

[rccardr]

From what I can see, the IRD Lobo system is very similar to the Sugino OX_01 subcompact cranks, except that the Lobo system has a wider chainline & Q factor. This means that the OX_01 system is more optimized for road bikes, while the Lobo is more aimed at gravel and fat tire bikes.

The Sugino OX_01 and IRD Lobo chainrings appear to be interchangeable.

Yep, noted the slightly wider Q but am less sensitive to Q width (and crank arm length) than some other riders, perhaps because my collection has such a wide diversity of cranksets. Intend to mount this on an italian threaded BB on a road bike with 30mm Vittoria Graphenes; it will be interesting to see where the final chainline falls. Generally a big fan of running the inside ring as close to the chain stay as possible and working from there. Since the crank shaft os wide enouh to mount on either a 68 or 73mm bottom bracket (68mm uses a supplied spacer), my assumption is that I can use various thinner spacers on each side to get it where I want it. We shall see.

The reason for a subcompact when planning this buildwas to wind up with a bike that had a wider range of gearing that was applicable to the kinds of roads actually ridden. Around here, with a 50 tooth (or a 48) big ring, I can ride pretty much anywhere without using the inside ring. A 30 inside ring makes it easier on some of the rides with more elevation like Southern Wisconsin, Skyline or Thunder Ridge while using a 28 big cog out back. Swapping to a 34 big cog makes it a double with gear inches low enough for Cino or Eroica.

At least...that's the plan.

[kingpin75s]

Even the ST VBC is 150 Q.


150mm Q for a chain line of 47.5 on a 113mm SqT BB. A fine chain line in my experience with running a lot of these but not strictly standard for a road double.

If you are looking for lower Q and this is for a 130mm rear spacing road bike, you could drop to a 108mm BB for a 45mm chain line and a 145mm Q. Want to get you chain line even closer to a road 2x at 43.5mm then drop down to a 104mm BB for a 43mm chain line and offset if 0.5mm if you choose.

All assumes you can clear the rings at your chain stay. Referenced standard length Phil JIS BBs available in my examples.

[marciero]

150mm Q for a chain line of 47.5 on a 113mm SqT BB. A fine chain line in my experience with running a lot of these but not strictly standard for a road double.

If you are looking for lower Q and this is for a 130mm rear spacing road bike, you could drop to a 108mm BB for a 45mm chain line and a 145mm Q. Want to get you chain line even closer to a road 2x at 43.5mm then drop down to a 104mm BB for a 43mm chain line and offset if 0.5mm if you choose.

All assumes you can clear the rings at your chain stay. Referenced standard length Phil JIS BBs available in my examples.

These are good points, and one forgets the role of the bb spindle in the world of outboard bearings and two-piece cranks. I went ahead and got the EA 90 crank as a quick and dirty, moderately priced, plug and play-along with the Race Face
Cinch bb bearing. Going to install, I notice the bb is 68/73, with spacers for 68. Something about using spacers when you dont need them and the point is low Q does not make sense. I may be sending these back and going square taper after all. Or, the Sugino which has over a month delivery time on ebay and seemingly unavailable elsewhere.